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: Fog implementation
sl@0: *
sl@0: */
sl@0: 
sl@0: 
sl@0: /*!
sl@0:  * \internal
sl@0:  * \file
sl@0:  * \brief Fog implementation
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_fog.h"
sl@0: #include "m3g_animationtrack.h"
sl@0: 
sl@0: /*----------------------------------------------------------------------
sl@0:  * Internal functions
sl@0:  *--------------------------------------------------------------------*/
sl@0: 
sl@0: /*!
sl@0:  * \internal
sl@0:  * \brief Destroys this Fog object.
sl@0:  *
sl@0:  * \param obj Fog object
sl@0:  */
sl@0: static void m3gDestroyFog(Object *obj)
sl@0: {
sl@0:     Fog *fog = (Fog *) obj;
sl@0:     M3G_VALIDATE_OBJECT(fog);
sl@0: 
sl@0:     m3gDestroyObject(&fog->object);
sl@0: }
sl@0: 
sl@0: /*!
sl@0:  * \internal
sl@0:  * \brief Overloaded Object3D method.
sl@0:  *
sl@0:  * \param property      animation property
sl@0:  * \retval M3G_TRUE     property supported
sl@0:  * \retval M3G_FALSE    property not supported
sl@0:  */
sl@0: static M3Gbool m3gFogIsCompatible(M3Gint property)
sl@0: {
sl@0:     switch (property) {
sl@0:     case M3G_ANIM_COLOR:
sl@0:     case M3G_ANIM_DENSITY:
sl@0:     case M3G_ANIM_FAR_DISTANCE:
sl@0:     case M3G_ANIM_NEAR_DISTANCE:
sl@0:         return M3G_TRUE;
sl@0:     default:
sl@0:         return m3gObjectIsCompatible(property);
sl@0:     }
sl@0: }
sl@0: 
sl@0: /*!
sl@0:  * \internal
sl@0:  * \brief Overloaded Object3D method.
sl@0:  *
sl@0:  * \param self          Fog object
sl@0:  * \param property      animation property
sl@0:  * \param valueSize     size of value array
sl@0:  * \param value         value array
sl@0:  */
sl@0: static void m3gFogUpdateProperty(Object *self,
sl@0:                                  M3Gint property,
sl@0:                                  M3Gint valueSize,
sl@0:                                  const M3Gfloat *value)
sl@0: {
sl@0:     Fog *fog = (Fog *)self;
sl@0:     M3G_VALIDATE_OBJECT(fog);
sl@0:     M3G_ASSERT_PTR(value);
sl@0: 
sl@0:     switch (property) {
sl@0:     case M3G_ANIM_COLOR:
sl@0:         M3G_ASSERT(valueSize >= 3);
sl@0:         fog->color = m3gColor3f(value[0], value[1], value[2]) & M3G_RGB_MASK;
sl@0:         break;
sl@0:     case M3G_ANIM_DENSITY:
sl@0:         M3G_ASSERT(valueSize >= 1);
sl@0:         fog->density = (value[0] < 0.f) ? 0.f : value[0];
sl@0:         break;
sl@0:     case M3G_ANIM_FAR_DISTANCE:
sl@0:         M3G_ASSERT(valueSize >= 1);
sl@0:         fog->end = value[0];
sl@0:         break;
sl@0:     case M3G_ANIM_NEAR_DISTANCE:
sl@0:         M3G_ASSERT(valueSize >= 1);
sl@0:         fog->start = value[0];
sl@0:         break;
sl@0:     default:
sl@0:         m3gObjectUpdateProperty(self, property, valueSize, value);
sl@0:     }
sl@0: }
sl@0: 
sl@0: /*!
sl@0:  * \internal
sl@0:  * \brief Overloaded Object3D method.
sl@0:  *
sl@0:  * \param originalObj original Fog object
sl@0:  * \param cloneObj pointer to cloned Fog object
sl@0:  * \param pairs array for all object-duplicate pairs
sl@0:  * \param numPairs number of pairs
sl@0:  */
sl@0: static M3Gbool m3gFogDuplicate(const Object *originalObj,
sl@0:                                Object **cloneObj,
sl@0:                                Object **pairs,
sl@0:                                M3Gint *numPairs)
sl@0: {
sl@0:     Fog *original = (Fog *)originalObj;
sl@0:     Fog *clone = (Fog *)m3gCreateFog(originalObj->interface);
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:         clone->color = original->color;
sl@0:         clone->density = original->density;
sl@0:         clone->start = original->start;
sl@0:         clone->end = original->end;
sl@0:         clone->mode = original->mode;
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:  * \brief Initializes a Fog object. See specification
sl@0:  * for default values.
sl@0:  *
sl@0:  * \param m3g           M3G interface
sl@0:  * \param fog           Fog object
sl@0:  */
sl@0: static void m3gInitFog(Interface *m3g, Fog *fog)
sl@0: {
sl@0: 	/* Fog is derived from object */
sl@0: 	m3gInitObject(&fog->object, m3g, M3G_CLASS_FOG);
sl@0: 
sl@0: 	fog->density = 1.0f;
sl@0: 	fog->start = 0.0f;
sl@0: 	fog->end = 1.0f;
sl@0: 	fog->mode = M3G_LINEAR_FOG;
sl@0: }
sl@0: 
sl@0: /*!
sl@0:  * \internal
sl@0:  * \brief Applies fog to OpenGL. This is used for
sl@0:  * all Mesh objects.
sl@0:  *
sl@0:  * \param self          Fog object
sl@0:  */
sl@0: static void m3gApplyFog(const Fog *self)
sl@0: {
sl@0: 	if (self != NULL) {
sl@0: 		GLfixed temp[4];
sl@0: 
sl@0:         m3gGLColor(self->color, temp);
sl@0: 
sl@0: 		switch (self->mode) {
sl@0: 		case M3G_LINEAR_FOG:
sl@0: 			glEnable(GL_FOG);
sl@0: 			glFogf(GL_FOG_MODE, GL_LINEAR);
sl@0: 			glFogf(GL_FOG_START, self->start);
sl@0: 			glFogf(GL_FOG_END, self->end);
sl@0: 			glFogxv(GL_FOG_COLOR, temp);
sl@0: 			break;
sl@0: 		case M3G_EXPONENTIAL_FOG:
sl@0: 			glEnable(GL_FOG);
sl@0: 			glFogf(GL_FOG_MODE, GL_EXP);
sl@0: 			glFogf(GL_FOG_DENSITY, self->density);
sl@0: 			glFogxv(GL_FOG_COLOR, temp);
sl@0: 			break;
sl@0: 		}
sl@0: 	}
sl@0: 	else {
sl@0: 		glDisable(GL_FOG);
sl@0: 	}
sl@0:     M3G_ASSERT_GL;
sl@0: }
sl@0: 
sl@0: #ifdef M3G_USE_NGL_API
sl@0: /*!
sl@0:  * \internal
sl@0:  * \brief Applies fog to NGL. This is used for
sl@0:  * Sprite3D objects only.
sl@0:  *
sl@0:  * \param self          Fog object
sl@0:  * \param eyeZ          Eye space Z (e.g. after modelview)
sl@0:  * \param finalZ        Final Z (e.g. after modelview and projection)
sl@0:  */
sl@0: static void m3gApplySpriteFog(const Fog *self, M3Gfloat eyeZ, M3Gfloat finalZ)
sl@0: {
sl@0:     if(self != NULL) {
sl@0: 		M3Gint temp[4];
sl@0:     	M3Gfloat fogValue = 1;
sl@0: 
sl@0:         /* Calculate fog value and use OpenGL linear fog
sl@0:          * to result in same value. Sprites are drawn with
sl@0:          * identity MV and P and therefore the fog has to
sl@0:          * be adjusted like this */
sl@0:         switch (self->mode) {
sl@0:     	case M3G_LINEAR_FOG:
sl@0:             fogValue = m3gDiv(m3gAdd(self->end, eyeZ), m3gSub(self->end, self->start));
sl@0:     		break;
sl@0:     	case M3G_EXPONENTIAL_FOG:
sl@0:             fogValue = m3gExp(m3gMul(self->density, eyeZ));
sl@0:     		break;
sl@0:         default:
sl@0:             M3G_ASSERT(M3G_FALSE);
sl@0:             break;
sl@0:     	}
sl@0: 
sl@0:         m3gGLColor(self->color, temp);
sl@0: 
sl@0: 		glEnable(GL_FOG);
sl@0: 		glFogf(GL_FOG_MODE, GL_LINEAR);
sl@0: 
sl@0:         /* NGL works differently in fog calculation */
sl@0: 		glFogf(GL_FOG_START, -m3gDiv(finalZ, fogValue));
sl@0: 		glFogf(GL_FOG_END, 0.f);
sl@0: 		glFogxv(GL_FOG_COLOR, temp);
sl@0:     }
sl@0:     else {
sl@0: 		glDisable(GL_FOG);
sl@0:     }
sl@0: }
sl@0: #endif
sl@0: /*----------------------------------------------------------------------
sl@0:  * Virtual function table
sl@0:  *--------------------------------------------------------------------*/
sl@0: 
sl@0: static const ObjectVFTable m3gvf_Fog = {
sl@0:     m3gObjectApplyAnimation,
sl@0:     m3gFogIsCompatible,
sl@0:     m3gFogUpdateProperty,
sl@0:     m3gObjectDoGetReferences,
sl@0:     m3gObjectFindID,
sl@0:     m3gFogDuplicate,
sl@0:     m3gDestroyFog
sl@0: };
sl@0: 
sl@0: 
sl@0: /*----------------------------------------------------------------------
sl@0:  * Public API functions
sl@0:  *--------------------------------------------------------------------*/
sl@0: 
sl@0: /*!
sl@0:  * \brief Creates a Fog object.
sl@0:  *
sl@0:  * \param interface     M3G interface
sl@0:  * \retval Fog new Fog object
sl@0:  * \retval NULL Fog creating failed
sl@0:  */
sl@0: M3G_API M3GFog m3gCreateFog(M3GInterface interface)
sl@0: {
sl@0:     Interface *m3g = (Interface *) interface;
sl@0:     M3G_VALIDATE_INTERFACE(m3g);
sl@0: 
sl@0: 	{
sl@0: 		Fog *fog =  m3gAllocZ(m3g, sizeof(Fog));
sl@0: 
sl@0:         if (fog != NULL) {
sl@0:     		m3gInitFog(m3g, fog);
sl@0:         }
sl@0: 
sl@0: 		return (M3GFog) fog;
sl@0: 	}
sl@0: }
sl@0: 
sl@0: /*!
sl@0:  * \brief Sets fog mode.
sl@0:  *
sl@0:  * \param handle        Fog object
sl@0:  * \param mode          fog mode
sl@0:  */
sl@0: M3G_API void m3gSetFogMode(M3GFog handle, M3Gint mode)
sl@0: {
sl@0: 	Fog *fog = (Fog *) handle;
sl@0: 	M3G_VALIDATE_OBJECT(fog);
sl@0: 
sl@0: 	/* Check for errors */
sl@0: 	if(mode < M3G_EXPONENTIAL_FOG || mode > M3G_LINEAR_FOG) {
sl@0: 		m3gRaiseError(M3G_INTERFACE(fog), M3G_INVALID_VALUE);
sl@0:         return;
sl@0: 	}
sl@0: 
sl@0: 	fog->mode = mode;
sl@0: }
sl@0: 
sl@0: /*!
sl@0:  * \brief Gets fog mode.
sl@0:  *
sl@0:  * \param handle        Fog object
sl@0:  * \return              fog mode
sl@0:  */
sl@0: M3G_API M3Gint m3gGetFogMode(M3GFog handle)
sl@0: {
sl@0: 	Fog *fog = (Fog *) handle;
sl@0: 	M3G_VALIDATE_OBJECT(fog);
sl@0: 
sl@0: 	return fog->mode;
sl@0: }
sl@0: 
sl@0: /*!
sl@0:  * \brief Sets linear fog parameters.
sl@0:  *
sl@0:  * \param handle        Fog object
sl@0:  * \param fogNear       near distance
sl@0:  * \param fogFar        far distance
sl@0:  */
sl@0: M3G_API void m3gSetFogLinear(M3GFog handle, M3Gfloat fogNear, M3Gfloat fogFar)
sl@0: {
sl@0: 	Fog *fog = (Fog *) handle;
sl@0: 	M3G_VALIDATE_OBJECT(fog);
sl@0: 
sl@0: 	fog->start = fogNear;
sl@0: 	fog->end = fogFar;
sl@0: }
sl@0: 
sl@0: /*!
sl@0:  * \brief Gets linear fog parameters.
sl@0:  *
sl@0:  * \param handle        Fog object
sl@0:  * \param which         which parameter to return
sl@0:  *                      \arg M3G_GET_NEAR
sl@0:  *                      \arg M3G_GET_FAR
sl@0:  * \return              near or far distance
sl@0:  */
sl@0: M3G_API M3Gfloat m3gGetFogDistance(M3GFog handle, M3Gint which)
sl@0: {
sl@0: 	Fog *fog = (Fog *) handle;
sl@0: 	M3G_VALIDATE_OBJECT(fog);
sl@0: 
sl@0: 	switch(which) {
sl@0: 	case M3G_GET_NEAR:
sl@0: 		return fog->start;
sl@0: 	case M3G_GET_FAR:
sl@0: 	default:
sl@0: 		return fog->end;
sl@0: 	}
sl@0: }
sl@0: 
sl@0: /*!
sl@0:  * \brief Sets exponential fog density.
sl@0:  *
sl@0:  * \param handle        Fog object
sl@0:  * \param density       fog density
sl@0:  */
sl@0: M3G_API void m3gSetFogDensity(M3GFog handle, M3Gfloat density)
sl@0: {
sl@0: 	Fog *fog = (Fog *) handle;
sl@0: 	M3G_VALIDATE_OBJECT(fog);
sl@0: 
sl@0: 	if(density < 0.f) {
sl@0: 		m3gRaiseError(M3G_INTERFACE(fog), M3G_INVALID_VALUE);
sl@0:         return;
sl@0: 	}
sl@0: 
sl@0: 	fog->density = density;
sl@0: }
sl@0: 
sl@0: /*!
sl@0:  * \brief Gets exponential fog density.
sl@0:  *
sl@0:  * \param handle        Fog object
sl@0:  * \return              fog density
sl@0:  */
sl@0: M3G_API M3Gfloat m3gGetFogDensity(M3GFog handle)
sl@0: {
sl@0: 	Fog *fog = (Fog *) handle;
sl@0: 	M3G_VALIDATE_OBJECT(fog);
sl@0: 
sl@0: 	return fog->density;
sl@0: }
sl@0: 
sl@0: /*!
sl@0:  * \brief Sets fog color as RGB.
sl@0:  *
sl@0:  * \param handle        Fog object
sl@0:  * \param rgb           fog color as RGB
sl@0:  */
sl@0: M3G_API void m3gSetFogColor(M3GFog handle, M3Guint rgb)
sl@0: {
sl@0: 	Fog *fog = (Fog *) handle;
sl@0: 	M3G_VALIDATE_OBJECT(fog);
sl@0: 
sl@0:     fog->color = rgb & M3G_RGB_MASK;
sl@0: }
sl@0: 
sl@0: /*!
sl@0:  * \brief Gets fog color as RGB.
sl@0:  *
sl@0:  * \param handle        Fog object
sl@0:  * \return              fog color as RGB
sl@0:  */
sl@0: M3G_API M3Guint m3gGetFogColor(M3GFog handle)
sl@0: {
sl@0: 	Fog *fog = (Fog *) handle;
sl@0: 	M3G_VALIDATE_OBJECT(fog);
sl@0: 
sl@0:     return fog->color;
sl@0: }
sl@0: