sl@0: /*
sl@0: * Copyright (c) 2003 Nokia Corporation and/or its subsidiary(-ies).
sl@0: * All rights reserved.
sl@0: * This component and the accompanying materials are made available
sl@0: * under the terms of the License "Eclipse Public License v1.0"
sl@0: * which accompanies this distribution, and is available
sl@0: * at the URL "http://www.eclipse.org/legal/epl-v10.html".
sl@0: *
sl@0: * Initial Contributors:
sl@0: * Nokia Corporation - initial contribution.
sl@0: *
sl@0: * Contributors:
sl@0: *
sl@0: * Description: Image implementation
sl@0: *
sl@0: */
sl@0: 
sl@0: 
sl@0: /*!
sl@0:  * \internal
sl@0:  * \file
sl@0:  * \brief Image implementation
sl@0:  *
sl@0:  */
sl@0: 
sl@0: #ifndef M3G_CORE_INCLUDE
sl@0: #   error included by m3g_core.c; do not compile separately.
sl@0: #endif
sl@0: 
sl@0: #include "m3g_image.h"
sl@0: #include "m3g_texture.h"
sl@0: 
sl@0: /* Declare prototypes for some of the helper functions called from the
sl@0:  * platform-dependent code included below */
sl@0: 
sl@0: static M3Gint  m3gBytesPerPixel(M3GPixelFormat format);
sl@0: static M3Gint  m3gGetNumMipmapLevels(M3Gint w, M3Gint h);
sl@0: static void m3gDownsample(M3GPixelFormat format, const M3Gubyte *srcPixels, M3Gint *pw, M3Gint *ph, M3Gubyte *dstPixels);
sl@0: static void m3gFreeImageData(Image *img);
sl@0: 
sl@0: /* Include platform-dependent functionality */
sl@0: #include "m3g_image.inl"
sl@0: 
sl@0: /* Size of the buffer used in pixel format conversions; this should be
sl@0:  * an even number */
sl@0: #define SPAN_BUFFER_SIZE 32
sl@0: 
sl@0: M3G_CT_ASSERT((SPAN_BUFFER_SIZE & 1) == 0);
sl@0: 
sl@0: /*----------------------------------------------------------------------
sl@0:  * Private functions
sl@0:  *--------------------------------------------------------------------*/
sl@0: 
sl@0: /*!
sl@0:  * \internal
sl@0:  * \brief Destroys this Image object.
sl@0:  *
sl@0:  * \param obj Image object
sl@0:  */
sl@0: static void m3gDestroyImage(Object *obj)
sl@0: {
sl@0:     Image *image = (Image*)obj;
sl@0:     Interface *m3g = M3G_INTERFACE(image);
sl@0:     M3G_VALIDATE_OBJECT(image);
sl@0: 
sl@0:     if (!image->copyOf) {
sl@0:         m3gFreeObject(m3g, image->data);
sl@0:         m3gFreeObject(m3g, image->mipData);
sl@0:     }
sl@0:     M3G_ASSIGN_REF(image->copyOf, NULL);
sl@0:     
sl@0:     if (image->powerOfTwo != image) {
sl@0:         M3G_ASSIGN_REF(image->powerOfTwo, NULL);
sl@0:     }
sl@0: 
sl@0: #   if !defined(M3G_NGL_TEXTURE_API)
sl@0:     if (image->texObject) {
sl@0:         m3gDeleteGLTextures(m3g, 1, &image->texObject);
sl@0:     }
sl@0:     if (image->large != NULL) {
sl@0:         m3gDestroyLargeImage(image);
sl@0:     }
sl@0: #   endif
sl@0: 
sl@0:     m3gDestroyObject(obj);
sl@0: }
sl@0: 
sl@0: /*--------------------------------------------------------------------*/
sl@0: 
sl@0: #define RED(argb)   (((argb) >> 16) & 0xFFu)
sl@0: #define GREEN(argb) (((argb) >>  8) & 0xFFu)
sl@0: #define BLUE(argb)  ( (argb)        & 0xFFu)
sl@0: #define ALPHA(argb) (((argb) >> 24) & 0xFFu)
sl@0: 
sl@0: #define RGBSUM(argb) (0x4CB2u * RED(argb) +     \
sl@0:                       0x9691u * GREEN(argb) +   \
sl@0:                       0x1D3Eu * BLUE(argb))
sl@0: 
sl@0: /*!
sl@0:  * \internal \brief ARGB -> A
sl@0:  */
sl@0: static void convertARGBToA8(const M3Guint *src, M3Gsizei count, M3Gubyte *dst)
sl@0: {
sl@0:     while (count--) {
sl@0:         *dst++ = (M3Gubyte) ALPHA(*src++);
sl@0:     }
sl@0: }
sl@0: 
sl@0: /*!
sl@0:  * \internal \brief ARGB -> L
sl@0:  */
sl@0: static void convertARGBToL8(const M3Guint *src, M3Gsizei count, M3Gubyte *dst)
sl@0: {
sl@0:     while (count--) {
sl@0:         M3Guint argb = *src++;
sl@0:         M3Guint sum = RGBSUM(argb);
sl@0:         *dst++ = (M3Gubyte)(sum >> 16);
sl@0:     }
sl@0: }
sl@0: 
sl@0: /*!
sl@0:  * \internal \brief ARGB -> LA */
sl@0: static void convertARGBToLA4(const M3Guint *src, M3Gsizei count, M3Gubyte *dst)
sl@0: {
sl@0:     while (count--) {
sl@0:         M3Guint argb = *src++;
sl@0:         M3Guint sum = RGBSUM(argb);
sl@0:         *dst++ = (M3Gubyte)(((sum >> 16) & 0xF0) | ((argb >> 28) & 0x0F));
sl@0:     }
sl@0: }
sl@0: 
sl@0: /*!
sl@0:  * \internal \brief ARGB -> LA8
sl@0:  */
sl@0: static void convertARGBToLA8(const M3Guint *src, M3Gsizei count, M3Gubyte *dst)
sl@0: {
sl@0:     while (count--) {
sl@0:         M3Guint argb = *src++;
sl@0:         M3Guint sum = RGBSUM(argb);
sl@0:         *dst++ = (M3Gubyte)(sum >> 16);       /* L */
sl@0:         *dst++ = (M3Gubyte) ALPHA(argb);
sl@0:     }
sl@0: }
sl@0: 
sl@0: /*!
sl@0:  * \internal \brief ARGB -> RGB
sl@0:  */
sl@0: static void convertARGBToRGB8(const M3Guint *src, M3Gsizei count, M3Gubyte *dst)
sl@0: {
sl@0:     while (count--) {
sl@0:         M3Guint argb = *src++;
sl@0:         *dst++ = (M3Gubyte) RED(argb);
sl@0:         *dst++ = (M3Gubyte) GREEN(argb);
sl@0:         *dst++ = (M3Gubyte) BLUE(argb);
sl@0:     }
sl@0: }
sl@0: 
sl@0: /*!
sl@0:  * \internal \brief ARGB -> RGB565
sl@0:  */
sl@0: static void convertARGBToRGB565(const M3Guint *src, M3Gsizei count, M3Gubyte *dst)
sl@0: {
sl@0:     while (count--) {
sl@0:         M3Guint argb = *src++;
sl@0:         *(M3Gushort*)dst = (M3Gushort)(((argb >> 8) & 0xF800u)|
sl@0:                                        ((argb >> 5) & 0x07E0u)|
sl@0:                                        ((argb >> 3) & 0x001Fu));
sl@0:         dst += 2;
sl@0:     }
sl@0: }
sl@0: 
sl@0: /*!
sl@0:  * \internal \brief ARGB -> RGBA
sl@0:  */
sl@0: static void convertARGBToRGBA8(const M3Guint *src, M3Gsizei count, M3Gubyte *dst)
sl@0: {
sl@0:     while (count--) {
sl@0:         M3Guint argb = *src++;
sl@0:         *dst++ = (M3Gubyte) RED(argb);
sl@0:         *dst++ = (M3Gubyte) GREEN(argb);
sl@0:         *dst++ = (M3Gubyte) BLUE(argb);
sl@0:         *dst++ = (M3Gubyte) ALPHA(argb);
sl@0:     }
sl@0: }
sl@0: 
sl@0: /*!
sl@0:  * \internal \brief ARGB -> BGRA
sl@0:  */
sl@0: static void convertARGBToBGRA8(const M3Guint *src, M3Gsizei count, M3Gubyte *dst)
sl@0: {
sl@0:     while (count--) {
sl@0:         M3Guint argb = *src++;
sl@0:         *dst++ = (M3Gubyte) BLUE(argb);
sl@0:         *dst++ = (M3Gubyte) GREEN(argb);
sl@0:         *dst++ = (M3Gubyte) RED(argb);
sl@0:         *dst++ = (M3Gubyte) ALPHA(argb);
sl@0:     }
sl@0: }
sl@0: 
sl@0: #undef RED
sl@0: #undef GREEN
sl@0: #undef BLUE
sl@0: #undef ALPHA
sl@0: 
sl@0: /*!
sl@0:  * \internal
sl@0:  * \brief Converts a span of ARGB pixels to another format
sl@0:  *
sl@0:  * \param src   source pixels
sl@0:  * \param count pixel count
sl@0:  * \param dstFormat destination format
sl@0:  * \param dst destination pixels
sl@0:  */
sl@0: static void convertFromARGB(const M3Guint *src,
sl@0:                             M3Gsizei count,
sl@0:                             M3GPixelFormat dstFormat,
sl@0:                             M3Gubyte *dst)
sl@0: {
sl@0:     switch (dstFormat) {
sl@0:     case M3G_L8:
sl@0:         convertARGBToL8(src, count, dst);
sl@0:         break;
sl@0:     case M3G_A8:
sl@0:         convertARGBToA8(src, count, dst);
sl@0:         break;
sl@0:     case M3G_LA4:
sl@0:         convertARGBToLA4(src, count, dst);
sl@0:         break;
sl@0:     case M3G_LA8:
sl@0:         convertARGBToLA8(src, count, dst);
sl@0:         break;
sl@0:     case M3G_RGB8:
sl@0:         convertARGBToRGB8(src, count, dst);
sl@0:         break;
sl@0:     case M3G_RGB565:
sl@0:         convertARGBToRGB565(src, count, dst);
sl@0:         break;
sl@0:     case M3G_RGBA8:
sl@0:     case M3G_RGB8_32:
sl@0:         convertARGBToRGBA8(src, count, dst);
sl@0:         break;
sl@0:     case M3G_BGRA8:
sl@0:     case M3G_BGR8_32:
sl@0:         convertARGBToBGRA8(src, count, dst);
sl@0:         break;
sl@0:     default:
sl@0:         M3G_ASSERT(M3G_FALSE);  /* conversion not supported */
sl@0:     }
sl@0: }
sl@0: 
sl@0: /*--------------------------------------------------------------------*/
sl@0: 
sl@0: /*!
sl@0:  * \internal \brief A8 -> ARGB
sl@0:  */
sl@0: static void convertA8ToARGB(const M3Gubyte *src, M3Gsizei count, M3Guint *dst)
sl@0: {
sl@0:     while (count--) {
sl@0:         M3Guint argb = M3G_RGB_MASK;
sl@0:         argb |= ((M3Guint) *src++) << 24;
sl@0:         *dst++ = argb;
sl@0:     }
sl@0: }
sl@0: 
sl@0: /*!
sl@0:  * \internal \brief L8 -> ARGB
sl@0:  */
sl@0: static void convertL8ToARGB(const M3Gubyte *src, M3Gsizei count, M3Guint *dst)
sl@0: {
sl@0:     while (count--) {
sl@0:         M3Guint argb = *src++;
sl@0:         argb |= (argb << 8) | (argb << 16);
sl@0:         argb |= M3G_ALPHA_MASK;
sl@0:         *dst++ = argb;
sl@0:     }
sl@0: }
sl@0: 
sl@0: /*!
sl@0:  * \internal \brief LA8 -> ARGB
sl@0:  */
sl@0: static void convertLA8ToARGB(const M3Gubyte *src, M3Gsizei count, M3Guint *dst)
sl@0: {
sl@0:     while (count--) {
sl@0:         M3Guint argb = *src++;
sl@0:         argb |= (argb << 8) | (argb << 16);
sl@0:         argb |= ((M3Guint) *src++) << 24;
sl@0:         *dst++ = argb;
sl@0:     }
sl@0: }
sl@0: 
sl@0: /*!
sl@0:  * \internal \brief RGB8 -> ARGB
sl@0:  */
sl@0: static void convertRGB8ToARGB(const M3Gubyte *src, M3Gsizei count, M3Guint *dst)
sl@0: {
sl@0:     while (count--) {
sl@0:         M3Guint argb = M3G_ALPHA_MASK;
sl@0:         argb |= ((M3Guint)(*src++)) << 16;
sl@0:         argb |= ((M3Guint)(*src++)) <<  8;
sl@0:         argb |=  (M3Guint)(*src++);
sl@0:         *dst++ = argb;
sl@0:     }
sl@0: }
sl@0: 
sl@0: /*!
sl@0:  * \internal \brief RGB565 -> ARGB
sl@0:  */
sl@0: static void convertRGB565ToARGB(const M3Gubyte *src, M3Gsizei count, M3Guint *dst)
sl@0: {
sl@0:     while (count--) {
sl@0:         M3Guint argb = M3G_ALPHA_MASK;
sl@0:         const M3Guint rgb565 = *(const M3Gushort*)src;
sl@0:         argb |= ((rgb565 & 0xF800u) << 8)|((rgb565 & 0xE000u) << 3);
sl@0:         argb |= ((rgb565 & 0x07E0u) << 5)|((rgb565 & 0x0600u) >> 1);
sl@0:         argb |= ((rgb565 & 0x001Fu) << 3)|((rgb565 & 0x001Cu) >> 2);
sl@0:         *dst++ = argb;
sl@0:         src += 2;
sl@0:     }
sl@0: }
sl@0: 
sl@0: /*!
sl@0:  * \internal \brief RGBA8 -> ARGB
sl@0:  */
sl@0: static void convertRGBA8ToARGB(const M3Gubyte *src, M3Gsizei count, M3Guint *dst)
sl@0: {
sl@0:     while (count--) {
sl@0:         M3Guint argb;
sl@0:         argb  = ((M3Guint)(*src++)) << 16;
sl@0:         argb |= ((M3Guint)(*src++)) <<  8;
sl@0:         argb |=  (M3Guint)(*src++);
sl@0:         argb |= ((M3Guint)(*src++)) << 24;
sl@0:         *dst++ = argb;
sl@0:     }
sl@0: }
sl@0: 
sl@0: /*!
sl@0:  * \internal \brief BGRA8 -> ARGB
sl@0:  */
sl@0: static void convertBGRA8ToARGB(const M3Gubyte *src, M3Gsizei count, M3Guint *dst)
sl@0: {
sl@0:     while (count--) {
sl@0:         M3Guint argb;
sl@0:         argb  =  (M3Guint)(*src++);
sl@0:         argb |= ((M3Guint)(*src++)) <<  8;
sl@0:         argb |= ((M3Guint)(*src++)) << 16;
sl@0:         argb |= ((M3Guint)(*src++)) << 24;
sl@0:         *dst++ = argb;
sl@0:     }
sl@0: }
sl@0: 
sl@0: /*!
sl@0:  * \internal
sl@0:  * \brief Converts a span of pixels to ARGB
sl@0:  *
sl@0:  * \param srcFormat source format
sl@0:  * \param src   source pixels
sl@0:  * \param count pixel count
sl@0:  * \param dst destination pixels
sl@0:  */
sl@0: static void convertToARGB(M3GPixelFormat srcFormat,
sl@0:                           const M3Gubyte *src,
sl@0:                           M3Gsizei count,
sl@0:                           M3Guint *dst)
sl@0: {
sl@0:     switch (srcFormat) {
sl@0:     case M3G_A8:
sl@0:         convertA8ToARGB(src, count, dst);
sl@0:         break;
sl@0:     case M3G_L8:
sl@0:         convertL8ToARGB(src, count, dst);
sl@0:         break;
sl@0:     case M3G_LA8:
sl@0:         convertLA8ToARGB(src, count, dst);
sl@0:         break;
sl@0:     case M3G_RGB8:
sl@0:         convertRGB8ToARGB(src, count, dst);
sl@0:         break;
sl@0:     case M3G_RGB565:
sl@0:         convertRGB565ToARGB(src, count, dst);
sl@0:         break;
sl@0:     case M3G_RGBA8:
sl@0:     case M3G_RGB8_32:
sl@0:         convertRGBA8ToARGB(src, count, dst);
sl@0:         break;
sl@0:     case M3G_BGRA8:
sl@0:     case M3G_BGR8_32:
sl@0:         convertBGRA8ToARGB(src, count, dst);
sl@0:         break;
sl@0:     default:
sl@0:         M3G_ASSERT(M3G_FALSE);  /* conversion not supported */
sl@0:     }
sl@0: }
sl@0: 
sl@0: /*!
sl@0:  * \internal
sl@0:  * \brief Fast path for BGRA-to-RGBA conversion
sl@0:  */
sl@0: #if defined (M3G_HW_ARMV6)
sl@0: __asm void fastConvertBGRAToRGBA(const M3Gubyte *src, M3Gsizei srcStride,
sl@0:                                  M3Gsizei width, M3Gsizei height,
sl@0:                                  M3Gubyte *dst)
sl@0: {
sl@0: // r0 = *src
sl@0: // r1 = srcStride
sl@0: // r2 = width
sl@0: // r3 = height
sl@0: // sp[0] = *dst
sl@0: 
sl@0: 		CODE32
sl@0: 
sl@0: 		CMP		r3, #0				// if height = 0, do nothing
sl@0: 		BXEQ	lr
sl@0: 
sl@0:   		STMFD	sp!, {r4-r12, lr} 
sl@0: 
sl@0: 		LDR		r12, [sp, #(10*4)]
sl@0: 		SUB		r1, r1, r2, LSL #2
sl@0: 		MOV		r14, r2
sl@0: 
sl@0: _fastConvertBGRAToRGBA_outerLoop
sl@0: 		MOVS	r2, r14, ASR #2			// amount of 4x32 bit writes
sl@0: 		BEQ		_fastConvertBGRAToRGBA_tail
sl@0: 
sl@0: _fastConvertBGRAToRGBA_innerLoop
sl@0: 
sl@0: 		LDMIA	r0!, {r4-r7}		// AARRGGBB
sl@0: 		SUBS	r2, #1
sl@0: 		REV		r4, r4				// BBGGRRAA
sl@0: 		REV		r5, r5
sl@0: 		REV		r6, r6				
sl@0: 		REV		r7, r7
sl@0: 		MOV		r8, r4, ROR #8		// AABBGGRR
sl@0: 		MOV		r9, r5, ROR #8
sl@0: 		MOV		r10, r6, ROR #8		
sl@0: 		MOV		r11, r7, ROR #8
sl@0: 		STMIA	r12!, {r8-r11}
sl@0: 		BNE		_fastConvertBGRAToRGBA_innerLoop
sl@0: 
sl@0: _fastConvertBGRAToRGBA_tail
sl@0: 		MOV 	r2, r14, ASR #2
sl@0: 		SUBS	r2, r14, r2, LSL #2		// number of remaining writes in the tail
sl@0: 
sl@0: _fastConvertBGRAToRGBA_tail_loop
sl@0: 
sl@0: 		LDRNE	r4, [r0], #4
sl@0: 		REVNE	r4, r4
sl@0: 		MOVNE	r8, r4, ROR #8
sl@0: 		STRNE	r8, [r12], #4
sl@0: 		SUBNES	r2, #1
sl@0: 		BNE		_fastConvertBGRAToRGBA_tail_loop
sl@0: 
sl@0: 		SUBS	r3, #1
sl@0: 		ADD		r0, r0, r1
sl@0: 		BNE		_fastConvertBGRAToRGBA_outerLoop
sl@0: 
sl@0: 		LDMFD	sp!, {r4-r12, lr}
sl@0: 		BX		lr
sl@0: 
sl@0: }
sl@0: #else /* #if defined (M3G_HW_ARMV6) */
sl@0: static void fastConvertBGRAToRGBA(const M3Gubyte *src, M3Gsizei srcStride,
sl@0:                                   M3Gsizei width, M3Gsizei height,
sl@0:                                   M3Gubyte *dst)
sl@0: {
sl@0:     unsigned int pixel, pixel2;
sl@0:     unsigned int temp;
sl@0:     unsigned int mask = 0x00ff00ff;
sl@0:     int spanwidth = (width >> 1) - 1;
sl@0:     int x, y;
sl@0:     unsigned int *d = (unsigned int *)dst;
sl@0: 
sl@0:     M3G_ASSERT(width > 2);
sl@0:     
sl@0:     for (y = 0; y < height; ++y) {
sl@0:         unsigned int *s = (unsigned int *)(src + y*srcStride);
sl@0: 
sl@0:         pixel = *s++;
sl@0: 
sl@0:         for (x = 0; x < spanwidth; ++x) {
sl@0:             pixel2 = *s++;
sl@0: 
sl@0:             temp   = pixel & mask;          /* 00RR00BB */
sl@0:             pixel  = pixel - temp;          /* AA00GG00 */
sl@0:             pixel  = pixel | (temp << 16);  /* AABBGG00 */
sl@0:             *d++   = pixel | (temp >> 16);  /* AABBGGRR */
sl@0: 
sl@0:             pixel = *s++;
sl@0: 
sl@0:             temp   = pixel2 & mask;          /* 00RR00BB */
sl@0:             pixel2 = pixel2 - temp;          /* AA00GG00 */
sl@0:             pixel2 = pixel2 | (temp << 16);  /* AABBGG00 */
sl@0:             *d++   = pixel2 | (temp >> 16);  /* AABBGGRR */
sl@0:         }
sl@0:         
sl@0:         pixel2 = *s++;
sl@0:         temp   = pixel & mask;          /* 00RR00BB */
sl@0:         pixel  = pixel - temp;          /* AA00GG00 */
sl@0:         pixel  = pixel | (temp << 16);  /* AABBGG00 */
sl@0:         *d++   = pixel | (temp >> 16);  /* AABBGGRR */
sl@0: 
sl@0:         temp   = pixel2 & mask;          /* 00RR00BB */
sl@0:         pixel2 = pixel2 - temp;          /* AA00GG00 */
sl@0:         pixel2 = pixel2 | (temp << 16);  /* AABBGG00 */
sl@0:         *d++   = pixel2 | (temp >> 16);  /* AABBGGRR */
sl@0:     }
sl@0: }
sl@0: #endif /* #if defined (M3G_HW_ARMV6) */
sl@0: 
sl@0: /*--------------------------------------------------------------------*/
sl@0: 
sl@0: /*!
sl@0:  * \internal
sl@0:  * \brief Maps a logical image format to an internal pixel format
sl@0:  *
sl@0:  * \param imgFormat logical image format
sl@0:  * \param paletted  paletted flag
sl@0:  * \return the internal image pixel format
sl@0:  */
sl@0: static M3GPixelFormat getInternalFormat(M3GImageFormat imgFormat,
sl@0:                                         M3Gbool paletted)
sl@0: {
sl@0:     if (paletted) {
sl@0:         switch (imgFormat) {
sl@0:         case M3G_RGB:
sl@0: #           if defined(M3G_NGL_TEXTURE_API)
sl@0:             return M3G_PALETTE8_RGB8_32;
sl@0: #           else
sl@0:             return M3G_PALETTE8_RGB8;
sl@0: #           endif
sl@0:         case M3G_RGBA:
sl@0:             return M3G_PALETTE8_RGBA8;
sl@0:         default:
sl@0:             M3G_ASSERT(M3G_FALSE);
sl@0:             return (M3GPixelFormat)0;
sl@0:         }
sl@0:     }
sl@0:     else {
sl@0:         M3GPixelFormat format = m3gPixelFormat(imgFormat);
sl@0:         
sl@0: #       if defined(M3G_NGL_TEXTURE_API)
sl@0:         if (format == M3G_RGB8) {
sl@0:             return (M3G_USE_16BIT_TEXTURES) ? M3G_RGB565 : M3G_RGB8_32;
sl@0:         }
sl@0:         if (format == M3G_LA8) {
sl@0:             return M3G_LA4;
sl@0:         }
sl@0: #       endif
sl@0:         
sl@0:         return format;
sl@0:     }
sl@0: }
sl@0: 
sl@0: /*!
sl@0:  * \internal
sl@0:  * \brief Gets the correct pixel format for setting data to an image
sl@0:  */
sl@0: static M3GPixelFormat m3gInputDataFormat(const Image *img)
sl@0: {
sl@0:     /* Any of the paletted formats will do for a paletted image, as
sl@0:      * they all have 8-bit indices; we pick PALETTE8_RGBA8 here */
sl@0:     
sl@0:     if (img->flags & M3G_PALETTED) {
sl@0:         return M3G_PALETTE8_RGBA8;
sl@0:     }
sl@0:     
sl@0:     return m3gPixelFormat(img->format);
sl@0: }
sl@0: 
sl@0: 
sl@0: /*!
sl@0:  * \internal
sl@0:  * \brief Returns log2(resolution)+1. Assumes that resolution is power of two.
sl@0:  *
sl@0:  * \param w width in pixels
sl@0:  * \param h height in pixels
sl@0:  * \return number of needed mipmap levels
sl@0:  */
sl@0: static M3Gint m3gGetNumMipmapLevels(M3Gint w, M3Gint h)
sl@0: {
sl@0:     M3Gint res = (w > h) ? w : h;
sl@0:     M3Gint levels = 0;
sl@0:     while (res > 0) {
sl@0:         ++levels;
sl@0:         res >>= 1;
sl@0:     };
sl@0:     return levels;
sl@0: }
sl@0: 
sl@0: /*!
sl@0:  * \internal
sl@0:  * \brief Downsamples an image to half the original size
sl@0:  *
sl@0:  *
sl@0:  * \param format    pixel format
sl@0:  * \param srcPixels source pixels
sl@0:  * \param pw        pointer to width
sl@0:  * \param ph        pointer to height
sl@0:  * \param dstPixels destination pixels
sl@0:  */
sl@0: static void m3gDownsample(M3GPixelFormat format,
sl@0:                           const M3Gubyte *srcPixels,
sl@0:                           M3Gint *pw, M3Gint *ph,
sl@0:                           M3Gubyte *dstPixels)
sl@0: {
sl@0:     M3Gint i, j, bpp, pixStride, lineStride;
sl@0:     M3Gint w = *pw, h = *ph;
sl@0:     M3Gubyte *dst;
sl@0:     M3Guint temp[2][SPAN_BUFFER_SIZE/2];
sl@0: 
sl@0:     M3G_ASSERT_PTR(srcPixels);
sl@0:     M3G_ASSERT(w >= 1 && h >= 1);
sl@0: 
sl@0:     bpp = m3gBytesPerPixel(format);
sl@0:     lineStride = (h > 1) ? w * bpp : 0;
sl@0:     pixStride = (w > 1) ? bpp : 0;
sl@0: 
sl@0:     dst = dstPixels;
sl@0: 
sl@0:     /* Iterate over buffer-sized blocks in the image */
sl@0:     
sl@0:     for (j = 0; j < h; j += 2) {
sl@0:         for (i = 0; i < w; i += SPAN_BUFFER_SIZE/2) {
sl@0:             
sl@0:             /* Fill the buffer from the source image */
sl@0:             
sl@0:             const M3Gubyte *src = srcPixels + (j*lineStride + i*pixStride);
sl@0:             M3Gint c = SPAN_BUFFER_SIZE/2;
sl@0:             if (w - i < c) {
sl@0:                 c = w - i;
sl@0:             }
sl@0:             convertToARGB(format, src, c, &temp[0][0]);
sl@0:             convertToARGB(format, src + lineStride, c, &temp[1][0]);
sl@0:             if (w == 1) {
sl@0:                 temp[0][1] = temp[0][0];
sl@0:                 temp[1][1] = temp[1][0];
sl@0:             }
sl@0:             
sl@0:             /* Average the pixels in the buffer */
sl@0:             {
sl@0: #               define AG_MASK 0xFF00FF00u
sl@0: #               define RB_MASK 0x00FF00FFu
sl@0:                 
sl@0:                 M3Gint k;
sl@0:                 for (k = 0; k < c; k += 2) {
sl@0:                     M3Guint ag, rb;
sl@0: 
sl@0:                     /* Add two components in parallel */
sl@0:                     
sl@0:                     ag =  ((temp[0][k] & AG_MASK) >> 8)
sl@0:                         + ((temp[1][k] & AG_MASK) >> 8)
sl@0:                         + ((temp[0][k+1] & AG_MASK) >> 8)
sl@0:                         + ((temp[1][k+1] & AG_MASK) >> 8);
sl@0:                         
sl@0:                     rb =  (temp[0][k] & RB_MASK)
sl@0:                         + (temp[1][k] & RB_MASK)
sl@0:                         + (temp[0][k+1] & RB_MASK)
sl@0:                         + (temp[1][k+1] & RB_MASK);
sl@0: 
sl@0:                     /* Shift to divide by 4, adding ½ for rounding */
sl@0:                     
sl@0:                     temp[0][k>>1] = ((((ag + 0x00020002u) << 6) & AG_MASK) |
sl@0:                                      (((rb + 0x00020002u) >> 2) & RB_MASK));
sl@0:                 }
sl@0:                 
sl@0: #               undef AG_MASK
sl@0: #               undef RB_MASK
sl@0:             }
sl@0: 
sl@0:             /* Write result to the output buffer */
sl@0: 
sl@0:             convertFromARGB(&temp[0][0], c>>1, format, dst);
sl@0:             dst += (c>>1) * bpp;
sl@0:         }
sl@0:     }
sl@0: 
sl@0:     /* Return output width and height */
sl@0:     
sl@0:     if (w > 1) {
sl@0:         *pw = (w >> 1);
sl@0:     }
sl@0:     if (h > 1) {
sl@0:         *ph = (h >> 1);
sl@0:     }
sl@0: }
sl@0: 
sl@0: /*!
sl@0:  * \internal
sl@0:  * \brief Returns the OpenGL minification filter corresponding to M3G
sl@0:  * filtering flags
sl@0:  */
sl@0: static GLenum m3gGetGLMinFilter(M3Genum levelFilter, M3Genum imageFilter) 
sl@0: {
sl@0:     static const GLenum minFilter[3][2] = {
sl@0:         GL_LINEAR, GL_NEAREST,
sl@0:         GL_LINEAR_MIPMAP_LINEAR, GL_NEAREST_MIPMAP_LINEAR,
sl@0:         GL_LINEAR_MIPMAP_NEAREST, GL_NEAREST_MIPMAP_NEAREST
sl@0:     };
sl@0: 
sl@0:     return minFilter[levelFilter - M3G_FILTER_BASE_LEVEL][imageFilter - M3G_FILTER_LINEAR];
sl@0: }
sl@0: 
sl@0: /*----------------------------------------------------------------------
sl@0:  * Internal functions
sl@0:  *--------------------------------------------------------------------*/
sl@0: 
sl@0: /*!
sl@0:  * \internal
sl@0:  * \brief Converts an internal ARGB color to four GLfixed components
sl@0:  */
sl@0: static void m3gGLColor(M3Guint argb, GLfixed *dst)
sl@0: {
sl@0:     GLfixed r, g, b, a;
sl@0:         
sl@0:     r = (GLfixed)((argb & 0x00FF0000u) >> 16);
sl@0:     g = (GLfixed)((argb & 0x0000FF00u) >>  8);
sl@0:     b = (GLfixed)( argb & 0x000000FFu       );
sl@0:     a = (GLfixed)((argb & 0xFF000000u) >> 24);
sl@0: 
sl@0:     dst[0] = ((r << 8) | r) + (r >> 7);
sl@0:     dst[1] = ((g << 8) | g) + (g >> 7);
sl@0:     dst[2] = ((b << 8) | b) + (b >> 7);
sl@0:     dst[3] = ((a << 8) | a) + (a >> 7);
sl@0: }
sl@0: 
sl@0: /*!
sl@0:  * \internal
sl@0:  * \brief Binds an image into the current texture unit and sets up
sl@0:  * texture filtering
sl@0:  */
sl@0: static void m3gBindTextureImage(Image *img, M3Genum levelFilter, M3Genum imageFilter)
sl@0: {
sl@0:     M3G_ASSERT_GL;
sl@0:     
sl@0:     /* We have no mipmap generation for paletted images, so disable
sl@0:      * mipmapping in that case */
sl@0:     
sl@0:     if (m3gIsInternallyPaletted(img)) {
sl@0:         levelFilter = M3G_FILTER_BASE_LEVEL;
sl@0:     }
sl@0: 
sl@0:     /* Bind the OpenGL texture object, generating mipmaps if
sl@0:      * required */
sl@0:     
sl@0:     m3gBindTextureObject(img, levelFilter != M3G_FILTER_BASE_LEVEL);
sl@0: 
sl@0:     /* Set up OpenGL texture filtering according to our flags */
sl@0: 
sl@0:     glTexParameterx(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER,
sl@0:                     (imageFilter == M3G_FILTER_LINEAR) ? GL_LINEAR : GL_NEAREST);
sl@0:     glTexParameterx(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER,
sl@0:                     m3gGetGLMinFilter(levelFilter, imageFilter));
sl@0:     
sl@0:     M3G_ASSERT_GL;
sl@0: }
sl@0: 
sl@0: /*!
sl@0:  * \internal
sl@0:  * \brief Maps a logical image format to the matching default pixel
sl@0:  * format
sl@0:  * 
sl@0:  * \param imgFormat logical image format
sl@0:  * \return a one-byte-per-pixel pixel format
sl@0:  */
sl@0: static M3GPixelFormat m3gPixelFormat(M3GImageFormat imgFormat)
sl@0: {
sl@0:     switch (imgFormat) {
sl@0:     case M3G_ALPHA:
sl@0:         return M3G_A8;
sl@0:     case M3G_LUMINANCE:
sl@0:         return M3G_L8;
sl@0:     case M3G_LUMINANCE_ALPHA:
sl@0:         return M3G_LA8;
sl@0:     case M3G_RGB:
sl@0:         return M3G_RGB8;
sl@0:     case M3G_RGBA:
sl@0:         return M3G_RGBA8;
sl@0:     default:
sl@0:         M3G_ASSERT(M3G_FALSE);
sl@0:         return M3G_NO_FORMAT;
sl@0:     }
sl@0: }
sl@0: 
sl@0: /*!
sl@0:  * \internal
sl@0:  * \brief Returns the number of bytes per pixel in a given pixel format
sl@0:  *
sl@0:  * \param format pixel format
sl@0:  * \return bytes per pixel
sl@0:  */
sl@0: static M3Gint m3gBytesPerPixel(M3GPixelFormat format)
sl@0: {
sl@0:     switch (format) {
sl@0:     case M3G_L8:
sl@0:     case M3G_A8:
sl@0:     case M3G_LA4:
sl@0:     case M3G_PALETTE8_RGB8:
sl@0:     case M3G_PALETTE8_RGB8_32:
sl@0:     case M3G_PALETTE8_RGBA8:
sl@0:         return 1;
sl@0:     case M3G_RGB4:
sl@0:     case M3G_RGB565:
sl@0:     case M3G_RGBA4:
sl@0:     case M3G_RGB5A1:
sl@0:     case M3G_LA8:
sl@0:         return 2;
sl@0:     case M3G_RGB8:
sl@0:         return 3;
sl@0:     case M3G_RGBA8:
sl@0:     case M3G_BGRA8:
sl@0:     case M3G_ARGB8:
sl@0:     case M3G_BGR8_32:
sl@0:     case M3G_RGB8_32:
sl@0:         return 4;
sl@0:     default:
sl@0:         M3G_ASSERT(M3G_FALSE);
sl@0:         return 0;
sl@0:     }
sl@0: }
sl@0: 
sl@0: /*!
sl@0:  * \internal
sl@0:  * \brief Converts pixels between formats
sl@0:  *
sl@0:  * \note Only a limited subset of source and destination formats may
sl@0:  * be supported; see the \c convert functions in m3g_image.c
sl@0:  *
sl@0:  * \param srcFormat source format
sl@0:  * \param src       source pixels
sl@0:  * \param dstFormat destination format
sl@0:  * \param dst       destination pixels
sl@0:  * \param count     pixel count
sl@0:  */
sl@0: static void m3gConvertPixels(M3GPixelFormat srcFormat, const M3Gubyte *src,
sl@0:                              M3GPixelFormat dstFormat, M3Gubyte *dst,
sl@0:                              M3Gsizei count)
sl@0: {
sl@0:     M3Guint temp[SPAN_BUFFER_SIZE];
sl@0:     const char endianTest[4] = { 1, 0, 0, 0 };
sl@0: 
sl@0:     M3Guint srcBpp = m3gBytesPerPixel(srcFormat);
sl@0:     M3Guint dstBpp = m3gBytesPerPixel(dstFormat);
sl@0:     M3G_ASSERT(srcBpp > 0 && dstBpp > 0);
sl@0: 
sl@0:     while (count > 0) {
sl@0:         M3Gsizei n = count;
sl@0: 
sl@0:         /* Check the source and destination formats to avoid 
sl@0:            the intermediate ARGB format conversion. */
sl@0:         if (((srcFormat == M3G_RGBA8 && (dstFormat == M3G_BGRA8 || dstFormat == M3G_BGR8_32))
sl@0:             || (dstFormat == M3G_RGBA8 && (srcFormat == M3G_BGRA8 || srcFormat == M3G_BGR8_32))) 
sl@0:             && (n > 2) && ((*(const int *)endianTest) == 1)) {
sl@0:             /* use fast path for RGBA<->BGRA conversion */
sl@0:             fastConvertBGRAToRGBA(src, n * srcBpp, n, 1, dst);
sl@0:         } else if (srcFormat == M3G_ARGB8 && dstFormat != M3G_ARGB8) {
sl@0:             convertFromARGB((M3Guint*)src, n, dstFormat, dst);
sl@0:         } else if (srcFormat != M3G_ARGB8 && dstFormat == M3G_ARGB8) {
sl@0:             convertToARGB(srcFormat, src, n, (M3Guint*)dst);
sl@0:         } else {
sl@0:             /* no luck, do the conversion via ARGB (source format -> ARGB -> destination format) */
sl@0:             n = (count < SPAN_BUFFER_SIZE) ? count : SPAN_BUFFER_SIZE;
sl@0:             convertToARGB(srcFormat, src, n, temp);
sl@0:             convertFromARGB(temp, n, dstFormat, dst);
sl@0:         }
sl@0:         count -= n;
sl@0:         src += n * srcBpp;
sl@0:         dst += n * dstBpp;
sl@0:     }
sl@0: }
sl@0: 
sl@0: /*!
sl@0:  * \internal
sl@0:  * \brief Copies image data. The source image is copied to
sl@0:  * the destination image.
sl@0:  *
sl@0:  * \param dst destination image
sl@0:  * \param src source image
sl@0:  */
sl@0: static void m3gCopyImagePixels(Image *dst,
sl@0:                                const Image *src)
sl@0: {
sl@0:     const M3Gubyte *pSrc;
sl@0:     M3Gubyte *pDst;
sl@0:     M3Gint bpp;
sl@0: 
sl@0:     /* Check inputs (debug only!) */
sl@0:     M3G_VALIDATE_OBJECT(dst);
sl@0:     M3G_VALIDATE_OBJECT(src);
sl@0: 
sl@0:     M3G_ASSERT(src->internalFormat == dst->internalFormat);
sl@0:     M3G_ASSERT(src->format == dst->format);
sl@0: 
sl@0:     M3G_ASSERT(src->paletteBytes == dst->paletteBytes);
sl@0:     
sl@0:     /* Compute source and destination pixel data pointers */
sl@0:     pSrc = (M3Gubyte *)m3gMapObject(M3G_INTERFACE(src), src->data);
sl@0:     pDst = (M3Gubyte *)m3gMapObject(M3G_INTERFACE(dst), dst->data);
sl@0: 
sl@0:     bpp = m3gBytesPerPixel(src->internalFormat);
sl@0: 
sl@0:     if (src->paletteBytes > 0) {
sl@0:         m3gCopy(pDst, pSrc, src->paletteBytes);
sl@0:         pDst += dst->paletteBytes;
sl@0:         pSrc += src->paletteBytes;
sl@0:     }
sl@0: 
sl@0:     /* Do a straight copy if the sizes match, or resample if not */
sl@0:     if (src->width == dst->width && src->height == dst->height ) {
sl@0:         m3gCopy(pDst, pSrc, src->width * src->height * bpp);
sl@0:     }
sl@0:     else {
sl@0:         /* Adder values as 8.8 fixed point */
sl@0:         M3Gint xAdd, yAdd;
sl@0:         M3Gint x, y;
sl@0: 
sl@0:         xAdd = (256 * src->width) / dst->width;
sl@0:         yAdd = (256 * src->height) / dst->height;
sl@0: 
sl@0:         for (y = 0; y < dst->height; y++) {
sl@0:             for (x = 0; x < dst->width; x++) {
sl@0:                 m3gCopy(pDst, pSrc + bpp * (((xAdd * x) >> 8) + ((yAdd * y) >> 8) * src->width), bpp);
sl@0:                 pDst += bpp;
sl@0:             }
sl@0:         }
sl@0:     }
sl@0: 
sl@0:     m3gUnmapObject(M3G_INTERFACE(dst), dst->data);
sl@0:     m3gUnmapObject(M3G_INTERFACE(src), src->data);
sl@0: 
sl@0:     m3gInvalidateImage(dst);
sl@0: }
sl@0: 
sl@0: /*!
sl@0:  * \internal
sl@0:  * \brief Invalidates any cached data for this image
sl@0:  *
sl@0:  * Used when rendering to the image.
sl@0:  *
sl@0:  * \param img Image object
sl@0:  */
sl@0: static void m3gInvalidateImage(Image *img)
sl@0: {
sl@0:     M3G_VALIDATE_OBJECT(img);
sl@0:     img->dirty = M3G_TRUE;
sl@0:     
sl@0: #   if !defined(M3G_NGL_TEXTURE_API)
sl@0:     if (img->large) {
sl@0:         img->large->dirty = M3G_TRUE;
sl@0:     }
sl@0: #   endif /*M3G_NGL_TEXTURE_API*/
sl@0: 
sl@0:     if (img->powerOfTwo != img) {
sl@0:         img->powerOfTwoDirty = M3G_TRUE;
sl@0:     }
sl@0: }
sl@0: 
sl@0: /*!
sl@0:  * \internal
sl@0:  * \brief Overloaded Object3D method.
sl@0:  *
sl@0:  * \param originalObj original Image object
sl@0:  * \param cloneObj pointer to cloned Image object
sl@0:  * \param pairs array for all object-duplicate pairs
sl@0:  * \param numPairs number of pairs
sl@0:  */
sl@0: static M3Gbool m3gImageDuplicate(const Object *originalObj,
sl@0:                                  Object **cloneObj,
sl@0:                                  Object **pairs,
sl@0:                                  M3Gint *numPairs)
sl@0: {
sl@0:     Image *original = (Image *)originalObj;
sl@0:     Image *clone;
sl@0: 
sl@0:     /* If the original image still has its pixel data, make a full
sl@0:      * copy -- this is wasteful for immutable images, but the shame's
sl@0:      * on the user in that case */
sl@0:     
sl@0:     if (original->data) {
sl@0:         clone = (Image*) m3gCreateImage(originalObj->interface,
sl@0:                                         original->format,
sl@0:                                         original->width,
sl@0:                                         original->height,
sl@0:                                         original->flags);
sl@0:     }
sl@0:     else {
sl@0: 
sl@0:         /* Otherwise, just point to the original and use its data
sl@0:          * buffers */
sl@0:         
sl@0:         clone = (Image*) m3gAlloc(M3G_INTERFACE(original), sizeof(*clone));
sl@0:         *clone = *original;
sl@0:         M3G_ASSIGN_REF(clone->copyOf, original);
sl@0:     }
sl@0:     
sl@0:     *cloneObj = (Object *)clone;
sl@0:     if (*cloneObj == NULL) {
sl@0:         return M3G_FALSE;
sl@0:     }
sl@0: 
sl@0:     if (m3gObjectDuplicate(originalObj, cloneObj, pairs, numPairs)) {
sl@0:         /* Copy image contents */
sl@0:         if (original->data) {
sl@0:             m3gCopyImagePixels(clone, original);
sl@0:         }
sl@0:         return M3G_TRUE;
sl@0:     }
sl@0:     else {
sl@0:         return M3G_FALSE;
sl@0:     }
sl@0: }
sl@0: 
sl@0: /*!
sl@0:  * \internal
sl@0:  *
sl@0:  * \brief Frees the pixel data associated with this image; used for
sl@0:  * optimizing memory usage after copying the data to a secondary
sl@0:  * location
sl@0:  */
sl@0: static void m3gFreeImageData(Image *img)
sl@0: {
sl@0:     M3G_ASSERT(img->format == M3G_RGB || img->format == M3G_LUMINANCE);
sl@0: #   if !defined(M3G_NGL_TEXTURE_API)
sl@0:     M3G_ASSERT(!img->mipmapsDirty);
sl@0: #   endif
sl@0:     M3G_ASSERT(!img->powerOfTwoDirty);
sl@0:     M3G_ASSERT(img->powerOfTwo != NULL);
sl@0:     M3G_ASSERT(!img->pinned);
sl@0:     
sl@0:     M3G_LOG1(M3G_LOG_IMAGES, "Freeing copy of image 0x%08X\n",
sl@0:              (unsigned) img);
sl@0: 
sl@0:     if (!img->copyOf) {
sl@0:         m3gFreeObject(M3G_INTERFACE(img), img->data);
sl@0:         img->data = 0;
sl@0:         m3gFreeObject(M3G_INTERFACE(img), img->mipData);
sl@0:         img->mipData = 0;
sl@0:     }
sl@0:     M3G_ASSIGN_REF(img->copyOf, NULL);
sl@0: }
sl@0: 
sl@0: /*!
sl@0:  * \internal
sl@0:  * \brief Returns a power-of-two variant of an image
sl@0:  *
sl@0:  * This is used for sprites and background images.
sl@0:  */
sl@0: static Image *m3gGetPowerOfTwoImage(Image *img)
sl@0: {
sl@0:     M3G_VALIDATE_OBJECT(img);
sl@0:     
sl@0:     /* Create a power-of-two variant of the image if one doesn't exist
sl@0:      * already */
sl@0:     
sl@0:     if (img->powerOfTwo == NULL) {
sl@0: 
sl@0:         M3Gint width, height;
sl@0:         M3Gbitmask flags;
sl@0:         Image *potImage;
sl@0:         
sl@0:         M3G_ASSERT(!m3gIsPowerOfTwo(img->width) ||
sl@0:                    !m3gIsPowerOfTwo(img->height));
sl@0:         
sl@0:         /* Choose new image size to allow a maximum shrinkage of 25%;
sl@0:          * this is to weed out pathological cases of quadruple memory
sl@0:          * usage because an image is one pixel too wide */
sl@0: 
sl@0:         width  = m3gNextPowerOfTwo((img->width * 3) >> 2);
sl@0:         height = m3gNextPowerOfTwo((img->height * 3) >> 2);
sl@0:         
sl@0:         width  = M3G_MIN(width, M3G_MAX_TEXTURE_DIMENSION);
sl@0:         height = M3G_MIN(height, M3G_MAX_TEXTURE_DIMENSION);
sl@0:         
sl@0:         flags = img->flags & (~M3G_RENDERING_TARGET);
sl@0:         
sl@0:         potImage = m3gCreateImage(M3G_INTERFACE(img),
sl@0:                                   img->format,
sl@0:                                   width, height,
sl@0:                                   flags);
sl@0:         if (!potImage) {
sl@0:             return NULL; /* automatic out-of-memory */
sl@0:         }
sl@0: 
sl@0:         M3G_ASSIGN_REF(img->powerOfTwo, potImage);
sl@0:         img->powerOfTwoDirty = M3G_TRUE;
sl@0:     }
sl@0: 
sl@0:     /* Update POT image data if necessary */
sl@0:     
sl@0:     if (img->powerOfTwoDirty) {
sl@0:         m3gCopyImagePixels(img->powerOfTwo, img);
sl@0:         img->powerOfTwoDirty = M3G_FALSE;
sl@0: 
sl@0:         /* Get rid of the original at this point if we can */
sl@0:         
sl@0:         if (!img->pinned) {
sl@0:             m3gFreeImageData(img);
sl@0:         }
sl@0:     }
sl@0: 
sl@0:     return img->powerOfTwo;
sl@0: }
sl@0: 
sl@0: /*!
sl@0:  * \internal
sl@0:  * \brief Gets image alpha at x, y.
sl@0:  *
sl@0:  * \param image Image object
sl@0:  * \param x x-coordinate
sl@0:  * \param y y-coordinate
sl@0:  * \return alpha value
sl@0:  *
sl@0:  */
sl@0: static M3Gint m3gGetAlpha(Image *image, M3Gint x, M3Gint y)
sl@0: {
sl@0:     M3Gint alpha = 255;
sl@0:     M3Gint bpp = m3gBytesPerPixel(image->internalFormat);
sl@0:     M3Guint data = 0;
sl@0:     M3Gubyte *pixels;
sl@0: 
sl@0:     /* Quick exit for non-alpha formats */
sl@0:     
sl@0:     if (image->format == M3G_RGB || image->format == M3G_LUMINANCE) {
sl@0:         return alpha;
sl@0:     }
sl@0: 
sl@0:     /* For other formats, we have to sample the image data */
sl@0: 
sl@0:     if (!image->data) {
sl@0:         Image *potImage = image->powerOfTwo;
sl@0:         M3G_ASSERT(potImage != image);
sl@0:         return m3gGetAlpha(potImage,
sl@0:                            (x * image->width) / potImage->width,
sl@0:                            (y * image->height) / potImage->height);
sl@0:     }
sl@0:     
sl@0:     pixels = ((M3Gubyte *)m3gMapObject(M3G_INTERFACE(image), image->data));
sl@0: 
sl@0:     if (image->paletteBytes == 0) {
sl@0:         if (bpp == 1) {
sl@0:             data = pixels[x + y * image->width];
sl@0:         }
sl@0:         else if (bpp == 2) {
sl@0:             data = ((M3Gushort *)pixels)[x + y * image->width];
sl@0:         }
sl@0:         else {
sl@0:             data = ((M3Guint *)pixels)[x + y * image->width];
sl@0:         }
sl@0:     }
sl@0:     else {
sl@0:         M3Guint *palette;
sl@0:         palette = (M3Guint *)pixels;
sl@0:         pixels += image->paletteBytes;
sl@0: 
sl@0:         data = palette[pixels[x + y * image->width]];
sl@0:     }
sl@0: 
sl@0:     m3gUnmapObject(M3G_INTERFACE(image), image->data);
sl@0: 
sl@0:     switch (image->internalFormat) {
sl@0: 
sl@0:     case M3G_A8:
sl@0:         alpha = data;
sl@0:         break;
sl@0:     case M3G_LA8:
sl@0:         alpha = data >> 8;
sl@0:         break;
sl@0:     case M3G_RGBA8:
sl@0:         alpha = data >> 24;
sl@0:         break;
sl@0:     default:
sl@0:         /* Should never be here!! */
sl@0:         M3G_ASSERT(M3G_FALSE);
sl@0:     }
sl@0: 
sl@0:     return alpha;
sl@0: }
sl@0: 
sl@0: /*!
sl@0:  * \internal
sl@0:  * \brief Computes the scanline stride of an image
sl@0:  */
sl@0: static M3Gsizei m3gGetImageStride(const Image *img)
sl@0: {
sl@0:     M3G_VALIDATE_OBJECT(img);
sl@0:     return img->width * m3gBytesPerPixel(img->internalFormat);
sl@0: }
sl@0: 
sl@0: /*----------------------------------------------------------------------
sl@0:  * Virtual function table
sl@0:  *--------------------------------------------------------------------*/
sl@0: 
sl@0: static const ObjectVFTable m3gvf_Image = {
sl@0:     m3gObjectApplyAnimation,
sl@0:     m3gObjectIsCompatible,
sl@0:     m3gObjectUpdateProperty,
sl@0:     m3gObjectDoGetReferences,
sl@0:     m3gObjectFindID,
sl@0:     m3gImageDuplicate,
sl@0:     m3gDestroyImage
sl@0: };
sl@0: 
sl@0: 
sl@0: /*----------------------------------------------------------------------
sl@0:  * Public API functions
sl@0:  *--------------------------------------------------------------------*/
sl@0: 
sl@0: /*!
sl@0:  * \brief Creates a new Image
sl@0:  *
sl@0:  * \param interface     M3G interface
sl@0:  * \param srcFormat     source format
sl@0:  * \param width         width in pixels
sl@0:  * \param height        height in pixels
sl@0:  * \param flags         creation flags; a combination of
sl@0:  *                      M3G_DYNAMIC, M3G_STATIC,
sl@0:  *                      M3G_RENDERING_TARGET, and M3G_PALETTED
sl@0:  * \retval Image new Image object
sl@0:  * \retval NULL Image creating failed
sl@0:  */
sl@0: M3G_API M3GImage m3gCreateImage(/*@dependent@*/ M3GInterface interface,
sl@0:                                 M3GImageFormat srcFormat,
sl@0:                                 M3Gint width, M3Gint height,
sl@0:                                 M3Gbitmask flags)
sl@0: {
sl@0:     Interface *m3g = (Interface *) interface;
sl@0:     M3G_VALIDATE_INTERFACE(m3g);
sl@0:     
sl@0:     /* Check errors */
sl@0:     
sl@0:     if (width <= 0 || height <= 0) {
sl@0:         m3gRaiseError(m3g, M3G_INVALID_VALUE);
sl@0:         return NULL;
sl@0:     }
sl@0: 
sl@0:     if (!m3gInRange(srcFormat, M3G_ALPHA, M3G_RGBA)) {
sl@0:         m3gRaiseError(m3g, M3G_INVALID_ENUM);
sl@0:         return NULL;
sl@0:     }
sl@0: 
sl@0:     /* Parameters OK; allocate and initialize the object */
sl@0: 
sl@0:     {
sl@0:         Image *img = m3gAllocZ(m3g, sizeof(Image));
sl@0:         if (img == NULL) {
sl@0:             return NULL;
sl@0:         }
sl@0: 
sl@0:         /* Clean up and set flags */
sl@0: 
sl@0:         M3G_LOG3(M3G_LOG_IMAGES, "Image 0x%08X is %d x %d",
sl@0:                  (unsigned) img, width, height);
sl@0:         
sl@0:         flags |= M3G_DYNAMIC;   /* the default */
sl@0:         
sl@0:         if (flags & M3G_STATIC) {
sl@0:             M3G_LOG(M3G_LOG_IMAGES, ", immutable");
sl@0:             flags &= ~M3G_DYNAMIC;
sl@0:         }
sl@0:         if (flags & M3G_RENDERING_TARGET) {
sl@0:             M3G_LOG(M3G_LOG_IMAGES, ", rendertarget");
sl@0:             flags |= M3G_DYNAMIC;
sl@0:         }
sl@0:         if (flags & M3G_PALETTED) {
sl@0:             M3G_LOG(M3G_LOG_IMAGES, ", paletted");
sl@0:         }
sl@0:         img->flags = flags;
sl@0: 
sl@0:         M3G_LOG(M3G_LOG_IMAGES, "\n");
sl@0:         
sl@0:         {
sl@0:             /* Allocate pixel & palette data; the palette is stored at
sl@0:              * the beginning of the pixel data chunk */
sl@0: 
sl@0:             M3Gbool paletted = ((img->flags & M3G_PALETTED) != 0)
sl@0:                 && m3gSupportedPaletteFormat(srcFormat);
sl@0:             M3GPixelFormat internalFormat = getInternalFormat(srcFormat,
sl@0:                                                               paletted);
sl@0:             M3Guint bpp = m3gBytesPerPixel(internalFormat);
sl@0:             M3Guint pixelBytes = width * height * bpp;
sl@0: 
sl@0:             if ((img->flags & M3G_PALETTED) != 0 && !paletted) {
sl@0:                 M3G_LOG(M3G_LOG_WARNINGS|M3G_LOG_IMAGES,
sl@0:                         "Warning: Unsupported paletted format\n");
sl@0:             }
sl@0:                 
sl@0:             /* The palette will always have 256 elements and one byte
sl@0:              * per color component (except padded 32-bit for NGL) */
sl@0:             
sl@0:             if (paletted) {
sl@0:                 img->paletteBytes =
sl@0: #                   if defined(M3G_NGL_TEXTURE_API)
sl@0:                     256 * 4;
sl@0: #                   else
sl@0:                     256 * m3gBytesPerPixel(m3gPixelFormat(srcFormat));
sl@0: #                   endif
sl@0:             }
sl@0: 
sl@0:             /* Set up the rest of the image parameters */
sl@0:             
sl@0:             img->width = width;
sl@0:             img->height = height;
sl@0:             img->format = srcFormat;
sl@0:             img->internalFormat = internalFormat;
sl@0:             img->glFormat = m3gGetGLFormat(internalFormat);
sl@0: 
sl@0:             M3G_LOG1(M3G_LOG_IMAGES, "Image data %d bytes\n",
sl@0:                      pixelBytes + img->paletteBytes);
sl@0:             
sl@0:             /* Allocate the image memory */
sl@0:             
sl@0:             img->data = m3gAllocObject(m3g, pixelBytes + img->paletteBytes);
sl@0:             if (img->data == 0) {
sl@0:                 m3gFree(m3g, img);
sl@0:                 return NULL;
sl@0:             }
sl@0: 
sl@0: #ifdef M3G_ENABLE_GLES_RESOURCE_HANDLING
sl@0:             /* If GLES resource freeing (see function m3gFreeGLESResources) 
sl@0:                is enabled, the GL texture might get deleted at any point, so
sl@0: 			   a copy of the texture data has to be always kept in memory. */
sl@0:             img->pinned = M3G_TRUE;
sl@0: #else           
sl@0:             /* Lock the image data in memory if the image is dynamic,
sl@0:              * or the format has alpha information; otherwise, we'll
sl@0:              * be able to get rid of an extra copy when generating a
sl@0:              * power-of-two version or uploading to OpenGL */
sl@0:             
sl@0:             if ((img->flags & M3G_DYNAMIC) != 0
sl@0:                 || (img->format != M3G_RGB &&
sl@0:                     img->format != M3G_LUMINANCE)) {
sl@0:                 img->pinned = M3G_TRUE;
sl@0:             }
sl@0: #endif
sl@0:             /* If the image can be used as a rendering target, clear
sl@0:              * to opaque white by default */
sl@0:             
sl@0:             if ((img->flags & M3G_RENDERING_TARGET) != 0) {
sl@0:                 M3Gubyte *pixels = ((M3Gubyte *)m3gMapObject(m3g, img->data))
sl@0:                     + img->paletteBytes;
sl@0:                 m3gFill(pixels, (size_t) pixelBytes, -1); 
sl@0:                 m3gUnmapObject(m3g, img->data);
sl@0:             }
sl@0: 
sl@0:             /* Check for "special" images that can't be used as
sl@0:              * textures without some extra trickery */
sl@0: 
sl@0:             if (!m3gIsPowerOfTwo((M3Guint) width) ||
sl@0:                 !m3gIsPowerOfTwo((M3Guint) height)) {
sl@0:                 img->special |= IMG_NPOT;
sl@0:             }
sl@0:             else {
sl@0:                 img->powerOfTwo = img;
sl@0:             }
sl@0:             
sl@0:             if (width > M3G_MAX_TEXTURE_DIMENSION ||
sl@0:                 height > M3G_MAX_TEXTURE_DIMENSION) {
sl@0:                 img->special |= IMG_LARGE;
sl@0:             }
sl@0:         }
sl@0: 
sl@0:         /* Call base class constructor (can not fail) and return */
sl@0:         m3gInitObject(&img->object, m3g, M3G_CLASS_IMAGE);
sl@0: 
sl@0:         M3G_VALIDATE_OBJECT(img);
sl@0:         return (M3GImage) img;
sl@0:     }
sl@0: }
sl@0: 
sl@0: /*!
sl@0:  * \brief Prevents further modifications to an image
sl@0:  *
sl@0:  * Essentially, this changes the default M3G_DYNAMIC flag to
sl@0:  * M3G_STATIC; this allows the implementation to make memory and
sl@0:  * performance optimizations not possible for dynamically modified
sl@0:  * images.
sl@0:  */
sl@0: M3G_API void m3gCommitImage(M3GImage hImage)
sl@0: {
sl@0:     Image *image = (Image *) hImage;
sl@0:     M3Gbitmask flags;
sl@0:     M3G_VALIDATE_OBJECT(image);
sl@0:     
sl@0:     flags = image->flags;
sl@0:     flags &= ~(M3G_DYNAMIC|M3G_RENDERING_TARGET);
sl@0:     flags |= M3G_STATIC;
sl@0:     
sl@0:     image->flags = flags;
sl@0: 
sl@0: #ifndef M3G_ENABLE_GLES_RESOURCE_HANDLING
sl@0:     /* If the image format has no alpha information, we can discard
sl@0:      * the image data under suitable conditions */
sl@0:     
sl@0:     if (image->format == M3G_RGB || image->format == M3G_LUMINANCE) {
sl@0:         image->pinned = M3G_FALSE;
sl@0:     }
sl@0: #endif    
sl@0:     M3G_LOG1(M3G_LOG_IMAGES, "Image 0x%08X made immutable\n",
sl@0:              (unsigned) image);
sl@0: }
sl@0: 
sl@0: /*!
sl@0:  * \brief Check if image is mutable.
sl@0:  * 
sl@0:  * \param hImage Image object
sl@0:  * \retval M3G_TRUE image is mutable
sl@0:  * \retval M3G_FALSE image is immutable
sl@0:  */
sl@0: M3G_API M3Gbool m3gIsMutable(M3GImage hImage)
sl@0: {
sl@0:     Image *image = (Image *) hImage;
sl@0:     M3G_VALIDATE_OBJECT(image);
sl@0:     return ((image->flags & M3G_DYNAMIC) != 0);
sl@0: }
sl@0: 
sl@0: /*!
sl@0:  * \brief Gets image format as JSR-184 constant
sl@0:  * 
sl@0:  * \param hImage Image object
sl@0:  * \return JSR-184 format
sl@0:  */
sl@0: M3G_API M3GImageFormat m3gGetFormat(M3GImage hImage)
sl@0: {
sl@0:     Image *image = (Image *) hImage;
sl@0:     M3G_VALIDATE_OBJECT(image);
sl@0:     return image->format;
sl@0: }
sl@0: 
sl@0: /*!
sl@0:  * \brief Gets image width
sl@0:  * 
sl@0:  * \param hImage Image object
sl@0:  * \return width in pixels
sl@0:  */
sl@0: M3G_API M3Gint m3gGetWidth(M3GImage hImage)
sl@0: {
sl@0:     Image *image = (Image *) hImage;
sl@0:     M3G_VALIDATE_OBJECT(image);
sl@0:     return image->width;
sl@0: }
sl@0: 
sl@0: /*!
sl@0:  * \brief Gets image height
sl@0:  * 
sl@0:  * \param hImage Image object
sl@0:  * \return height in pixels
sl@0:  */
sl@0: M3G_API M3Gint m3gGetHeight(M3GImage hImage)
sl@0: {
sl@0:     Image *image = (Image *) hImage;
sl@0:     M3G_VALIDATE_OBJECT(image);
sl@0:     return image->height;
sl@0: }
sl@0: 
sl@0: /*!
sl@0:  * \brief Converts a rectangle of pixels of src to dst as srcFormat to
sl@0:  * dstFormat conversion requires.
sl@0:  *
sl@0:  * \param srcFormat source format
sl@0:  * \param src       source pixels
sl@0:  * \param srcStride source stride
sl@0:  * \param width     width in pixels
sl@0:  * \param height    height in pixels
sl@0:  * \param dstFormat destination format
sl@0:  * \param dst       destination pixels
sl@0:  * \param dstStride destination stride
sl@0:  */
sl@0: static void m3gConvertPixelRect(
sl@0:     M3GPixelFormat srcFormat, const M3Gubyte *src, M3Gsizei srcStride,
sl@0:     M3Gsizei width, M3Gsizei height,
sl@0:     M3GPixelFormat dstFormat, M3Gubyte *dst, M3Gsizei dstStride)
sl@0: {
sl@0:     /* Detect any fast path cases */
sl@0:     
sl@0:     if ((srcFormat == M3G_BGRA8 || srcFormat == M3G_BGR8_32)
sl@0:         && dstFormat == M3G_RGBA8) {
sl@0:         if (width > 2 && dstStride == width*4) {
sl@0: 
sl@0:             const char endianTest[4] = { 1, 0, 0, 0 };
sl@0:             if ((*(const int *)endianTest) == 1) {
sl@0:                 fastConvertBGRAToRGBA(src, srcStride, width, height, dst);
sl@0:             }
sl@0:             return;
sl@0:         }
sl@0:     }
sl@0: 
sl@0:     /* No luck, do the generic conversion */
sl@0:         
sl@0:     while (height-- > 0) {
sl@0:         m3gConvertPixels(srcFormat, src, dstFormat, dst, width);
sl@0:         src += srcStride;
sl@0:         dst += dstStride;
sl@0:     }
sl@0: }
sl@0: 
sl@0: /*!
sl@0:  * \brief Sets the pixel data for an image
sl@0:  * 
sl@0:  * \param hImage Image object
sl@0:  * \param srcPixels source pixels
sl@0:  */
sl@0: M3G_API void m3gSetImage(M3GImage hImage, const void *srcPixels)
sl@0: {
sl@0:     Image *img = (Image *) hImage;
sl@0:     M3G_VALIDATE_OBJECT(img);
sl@0: 
sl@0:     {
sl@0:         M3Gsizei bpp = m3gBytesPerPixel(m3gInputDataFormat(img));
sl@0:         m3gSetSubImage(hImage,
sl@0:                        0, 0, img->width, img->height,
sl@0:                        img->width * img->height * bpp, srcPixels);
sl@0:     }
sl@0: }
sl@0: 
sl@0: /*!
sl@0:  * \brief Reads pixel data from an image
sl@0:  *
sl@0:  * \param hImage Image object
sl@0:  * \param pixels output buffer for pixels
sl@0:  */
sl@0: M3G_API void m3gGetImageARGB(M3GImage hImage, M3Guint *pixels)
sl@0: {
sl@0:     Interface *m3g;
sl@0:     const Image *img = (const Image *) hImage;
sl@0:     M3G_VALIDATE_OBJECT(img);
sl@0:     m3g = M3G_INTERFACE(img);
sl@0:     
sl@0:     if (!pixels) {
sl@0:         m3gRaiseError(m3g, M3G_NULL_POINTER);
sl@0:         return;
sl@0:     }
sl@0:     
sl@0:     if (img->data) {
sl@0:         const M3Gubyte *src = (const M3Gubyte*) m3gMapObject(m3g, img->data);
sl@0:         convertToARGB(img->internalFormat, src,
sl@0:                       img->width * img->height,
sl@0:                       pixels);
sl@0:         m3gUnmapObject(m3g, img->data);
sl@0:     }
sl@0: }
sl@0: 
sl@0: /*!
sl@0:  * \brief Sets the palette for an image
sl@0:  * 
sl@0:  * \param hImage Image object
sl@0:  * \param paletteLength length of the palette
sl@0:  * \param srcPalette palette data
sl@0:  */
sl@0: M3G_API void m3gSetImagePalette(M3GImage hImage,
sl@0:                                 M3Gint paletteLength,
sl@0:                                 const void *srcPalette)
sl@0: {
sl@0:     Interface *m3g;
sl@0:     Image *img = (Image *) hImage;
sl@0:     M3G_VALIDATE_OBJECT(img);
sl@0:     m3g = M3G_INTERFACE(img);
sl@0: 
sl@0:     /* Check for errors */
sl@0: 
sl@0:     if (img->data == 0 || (img->flags & M3G_STATIC) != 0
sl@0:             || (img->flags & M3G_PALETTED) == 0) {
sl@0:         M3G_ASSERT(!(img->flags & M3G_DYNAMIC));
sl@0:         m3gRaiseError(m3g, M3G_INVALID_OPERATION);
sl@0:         return;
sl@0:     }
sl@0:     if (srcPalette == NULL) {
sl@0:         m3gRaiseError(m3g, M3G_NULL_POINTER);
sl@0:         return;
sl@0:     }
sl@0:     if (!m3gInRange(paletteLength, 0, 256)) {
sl@0:         m3gRaiseError(m3g, M3G_INVALID_VALUE);
sl@0:         return;
sl@0:     }
sl@0: 
sl@0:     /*
sl@0:      * Copy the palette data into the allocated palette (for natively
sl@0:      * supported paletted formats), or remap the existing image data
sl@0:      * using the supplied palette entries (for non-native formats)
sl@0:      *
sl@0:      * NOTE the latter is a one-time operation!
sl@0:      */
sl@0:     if (img->paletteBytes > 0) {
sl@0:         M3Gubyte *palette = (M3Gubyte *)m3gMapObject(m3g, img->data);
sl@0: #       if defined(M3G_NGL_TEXTURE_API)
sl@0:         m3gConvertPixels(m3gPixelFormat(img->format), srcPalette,
sl@0:                          M3G_RGBA8, palette,
sl@0:                          paletteLength);
sl@0: #       else
sl@0:         M3Gsizei bpp = m3gBytesPerPixel(m3gPixelFormat(img->format));
sl@0:         m3gCopy(palette, srcPalette, (size_t) paletteLength * bpp);
sl@0: #       endif
sl@0:     }
sl@0:     else {
sl@0:         M3Gint count = img->width * img->height;
sl@0:         M3Gubyte *pixel = (M3Gubyte*)m3gMapObject(m3g, img->data);
sl@0:         const M3Gubyte *bytePalette = (const M3Gubyte *) srcPalette;
sl@0: 
sl@0:         /* We need to treat the input and internal formats as
sl@0:          * separate, as the internal storage may be padded to more
sl@0:          * bytes than there are color components */
sl@0: 
sl@0:         M3GPixelFormat paletteFormat = m3gPixelFormat(img->format);
sl@0:         const int numComponents = m3gBytesPerPixel(paletteFormat);
sl@0:         M3GPixelFormat imgFormat = img->internalFormat;
sl@0:         const int imgBpp = m3gBytesPerPixel(imgFormat);
sl@0: 
sl@0:         /* In most cases we can just copy the corresponding palette
sl@0:          * entry on top of each pixel based on the pixel intensity (R
sl@0:          * or L component), but special formats require a more
sl@0:          * complicated conversion.  We just use the (slow) general
sl@0:          * conversion routine, as it already incorporates support for
sl@0:          * all formats. */
sl@0:         
sl@0:         if (imgBpp >= numComponents) {
sl@0:             while (count--) {
sl@0:                 int offset = (*pixel) * numComponents;
sl@0:                 int c;
sl@0:                 for (c = 0; c < numComponents; ++c) {
sl@0:                     *pixel++ = bytePalette[offset + c];
sl@0:                 }
sl@0:                 while (c++ < imgBpp) { /* padding for e.g. 24-bit RGB */
sl@0:                     *pixel++ = 0xFF;
sl@0:                 }
sl@0:             }
sl@0:         }
sl@0:         else {
sl@0:             while (count--) {
sl@0:                 int offset = (*pixel) * numComponents;
sl@0:                 m3gConvertPixels(paletteFormat, &bytePalette[offset],
sl@0:                                  imgFormat, pixel,
sl@0:                                  1);
sl@0:                 pixel += imgBpp;
sl@0:             }
sl@0:         }
sl@0:     }
sl@0:     m3gUnmapObject(m3g, img->data);
sl@0:     m3gInvalidateImage(img);
sl@0: }
sl@0: 
sl@0: /*!
sl@0:  * \brief Sets a scanline of an image
sl@0:  * 
sl@0:  * \param hImage Image object
sl@0:  * \param line scanline
sl@0:  * \param trueAlpha M3G_TRUE if the source image has an alpha channel,
sl@0:  *                  M3G_FALSE if it should come from the RGB values;
sl@0:  *                  this only matters for alpha-only destination images
sl@0:  * \param pixels souce pixels
sl@0:  */
sl@0: M3G_API void m3gSetImageScanline(M3GImage hImage,
sl@0:                                  M3Gint line,
sl@0:                                  M3Gbool trueAlpha,
sl@0:                                  const M3Guint *pixels)
sl@0: {
sl@0:     Image *img = (Image *) hImage;
sl@0:     M3G_VALIDATE_OBJECT(img);
sl@0: 
sl@0:     if (img->data == 0 || (img->flags & M3G_STATIC) != 0
sl@0:             || img->paletteBytes != 0) {
sl@0:         m3gRaiseError(M3G_INTERFACE(img), M3G_INVALID_OPERATION);
sl@0:         return;
sl@0:     }
sl@0:     
sl@0:     {
sl@0:         Interface *m3g = M3G_INTERFACE(img);
sl@0:         M3Gint stride = img->width * m3gBytesPerPixel(img->internalFormat);
sl@0:         M3Gubyte *dst = ((M3Gubyte *) m3gMapObject(m3g, img->data))
sl@0:             + img->paletteBytes;
sl@0: 
sl@0: #ifdef M3G_NGL_TEXTURE_API
sl@0:         /* For RGB images without alpha channel, source alpha is
sl@0:          * forced to 0xff. */
sl@0: 
sl@0:         if (img->format == M3G_RGB) {
sl@0:             M3Gint i;
sl@0:             M3Guint argb, *dst;
sl@0: 
sl@0:             dst = (M3Guint *) pixels;
sl@0: 
sl@0:             for (i = 0; i < img->width; i++) {
sl@0:                 argb = *dst | 0xff000000;
sl@0:                 *dst++ = argb;
sl@0:             }
sl@0:         }
sl@0: #endif
sl@0: 
sl@0:         /* Note that an alpha-only destination format is faked for
sl@0:          * luminance if the source contained no true alpha data; alpha
sl@0:          * is then inferred from the RGB values instead */
sl@0:         
sl@0:         convertFromARGB(pixels,
sl@0:                         img->width,
sl@0:                         (img->internalFormat == M3G_A8 && !trueAlpha) ? M3G_L8 : img->internalFormat,
sl@0:                         dst + line * stride);
sl@0: 
sl@0:         m3gUnmapObject(m3g, img->data);
sl@0:         m3gInvalidateImage(img);
sl@0:     }
sl@0: }
sl@0: 
sl@0: /*!
sl@0:  * \brief Sets a rectangular subregion of an image
sl@0:  * 
sl@0:  * \param hImage Image object
sl@0:  * \param x x-coordinate in destination image
sl@0:  * \param y y-coordinate in destination image
sl@0:  * \param width width of source pixels
sl@0:  * \param height height of source pixels
sl@0:  * \param length length of source data, in bytes
sl@0:  * \param pixels source pixels
sl@0:  */
sl@0: M3G_API void m3gSetSubImage(M3GImage hImage,
sl@0:                             M3Gint x, M3Gint y,
sl@0:                             M3Gint width, M3Gint height,
sl@0:                             M3Gint length, const void *pixels)
sl@0: {
sl@0:     Interface *m3g;
sl@0:     Image *img = (Image *) hImage;
sl@0: 
sl@0:     M3GPixelFormat srcFormat;
sl@0:     M3Gsizei srcBpp;
sl@0: 
sl@0:     M3G_VALIDATE_OBJECT(img);
sl@0:     m3g = M3G_INTERFACE(img);
sl@0: 
sl@0:     /* Check for errors */
sl@0: 
sl@0:     if (img->data == 0 || (img->flags & M3G_STATIC) != 0) {
sl@0:         M3G_ASSERT(!(img->flags & M3G_DYNAMIC));
sl@0:         m3gRaiseError(m3g, M3G_INVALID_OPERATION);
sl@0:         return;
sl@0:     }
sl@0:     if (pixels == NULL) {
sl@0:         m3gRaiseError(m3g, M3G_INVALID_VALUE);
sl@0:         return;
sl@0:     }
sl@0:     if (x < 0 || y < 0 || width <= 0 || height <= 0
sl@0:             || x+width > img->width || y+height > img->height) {
sl@0:         m3gRaiseError(m3g, M3G_INVALID_VALUE);
sl@0:         return;
sl@0:     }
sl@0:     
sl@0:     srcFormat = m3gInputDataFormat(img);
sl@0:     srcBpp = m3gBytesPerPixel(srcFormat);
sl@0:     
sl@0:     if (length < width * height * srcBpp) {
sl@0:         m3gRaiseError(m3g, M3G_INVALID_VALUE);
sl@0:         return;
sl@0:     }    
sl@0: 
sl@0:     /* Copy the image data, doing a conversion if the input format
sl@0:      * does not match the internal storage format */
sl@0:     {
sl@0:         const M3Gubyte *srcPixels = (const M3Gubyte*) pixels;
sl@0:         M3Gsizei srcStride = width * srcBpp;
sl@0: 
sl@0:         M3GPixelFormat dstFormat = img->internalFormat;
sl@0:         M3Gsizei dstBpp = m3gBytesPerPixel(dstFormat);
sl@0:         M3Gsizei dstStride = img->width * dstBpp;
sl@0:         M3Gubyte *dstPixels =
sl@0:             ((M3Gubyte *)m3gMapObject(m3g, img->data))
sl@0:             + img->paletteBytes
sl@0:             + y * dstStride + x * dstBpp;
sl@0:         
sl@0:         M3Gint numLines = height, numPixels = width;
sl@0:         M3Gbool paletted = (img->flags & M3G_PALETTED) != 0;
sl@0:         
sl@0:         /* Optimize the copy for full image width */
sl@0:         
sl@0:         if (width == img->width) {
sl@0:             numLines = 1;
sl@0:             numPixels = width * height;
sl@0:         }
sl@0:         
sl@0:         /* Copy a scanline at a time, converting as necessary */
sl@0:         
sl@0:         while (numLines-- > 0) {
sl@0:             
sl@0:             /* Matching pixel formats are just copied without
sl@0:              * conversion, and all internally supported paletted
sl@0:              * formats match each other physically, so they can be
sl@0:              * copied as well */
sl@0:         
sl@0:             if (dstFormat == srcFormat || img->paletteBytes > 0) {
sl@0:                 m3gCopy(dstPixels, srcPixels, numPixels * dstBpp);
sl@0:             }
sl@0:             else {
sl@0:                 if (!paletted) {
sl@0: 
sl@0:                     /* Ordinary conversion into an internal format
sl@0:                      * that is encoded differently from the external
sl@0:                      * format; can not be a paletted image */
sl@0: 
sl@0:                     M3G_ASSERT((img->flags & M3G_PALETTED) == 0);
sl@0:                     m3gConvertPixels(srcFormat, srcPixels,
sl@0:                                      dstFormat, dstPixels,
sl@0:                                      numPixels);
sl@0:                 }
sl@0:                 else {
sl@0:                     M3G_ASSERT(!m3gSupportedPaletteFormat(img->format));
sl@0:                     
sl@0:                     /* Palette indices for one-byte-per-pixel formats
sl@0:                      * are just copied in and mapped to actual values
sl@0:                      * later; multibyte paletted formats require a
sl@0:                      * conversion into LA, RGB, or RGBA format
sl@0:                      * intensity levels temporarily before remapping
sl@0:                      * to actual colors in m3gSetImagePalette */
sl@0:                     
sl@0:                     if (dstBpp == 1) {
sl@0:                         m3gCopy(dstPixels, srcPixels, numPixels);
sl@0:                     }
sl@0:                     else {
sl@0:                         m3gConvertPixels(M3G_L8, srcPixels,
sl@0:                                          dstFormat, dstPixels,
sl@0:                                          numPixels);
sl@0:                     }
sl@0:                 }
sl@0:             }
sl@0:             
sl@0:             srcPixels += srcStride;
sl@0:             dstPixels += dstStride;
sl@0:         }
sl@0: 
sl@0:         /* Release the image data and invalidate mipmap levels */
sl@0:         
sl@0:         m3gUnmapObject(m3g, img->data);
sl@0:         m3gInvalidateImage(img);
sl@0:     }
sl@0:     M3G_VALIDATE_OBJECT(img);
sl@0: }
sl@0: 
sl@0: #undef SPAN_BUFFER_SIZE
sl@0: