OpenGL2: Use CPU vertex animation if too few vertex attributes

OpenGL ES has a minimum of 8 vertex attributes while desktop OpenGL has
a minimum of 16. Vertex animation uses attributes 10 to 12.

taken from ioq3: ioquake/ioq3#664

code/renderergl2/tr_glsl.c

@@ -864,6 +864,15 @@ void GLSL_InitGPUShaders(void) {
 
 	startTime = ri.Milliseconds();
 
+	// OpenGL ES may not have enough attributes to fit ones used for vertex animation
+	if (glRefConfig.maxVertexAttribs > ATTR_INDEX_NORMAL2) {
+		ri.Printf(PRINT_ALL, "Using GPU vertex animation\n");
+		glRefConfig.gpuVertexAnimation = qtrue;
+	} else {
+		ri.Printf(PRINT_ALL, "Using CPU vertex animation\n");
+		glRefConfig.gpuVertexAnimation = qfalse;
+	}
+
 	for (i = 0; i < GENERICDEF_COUNT; i++) {
 		if ((i & GENERICDEF_USE_VERTEX_ANIMATION) && (i & GENERICDEF_USE_BONE_ANIMATION))
 			continue;
@@ -883,6 +892,9 @@ void GLSL_InitGPUShaders(void) {
 		}
 
 		if (i & GENERICDEF_USE_VERTEX_ANIMATION) {
+			if (!glRefConfig.gpuVertexAnimation)
+				continue;
+
 			Q_strcat(extradefines, 1024, "#define USE_VERTEX_ANIMATION\n");
 			attribs |= ATTR_POSITION2 | ATTR_NORMAL2;
 		} else if (i & GENERICDEF_USE_BONE_ANIMATION) {
@@ -931,6 +943,9 @@ void GLSL_InitGPUShaders(void) {
 		if ((i & FOGDEF_USE_VERTEX_ANIMATION) && (i & FOGDEF_USE_BONE_ANIMATION))
 			continue;
 
+		if ((i & FOGDEF_USE_VERTEX_ANIMATION) && !glRefConfig.gpuVertexAnimation)
+			continue;
+
 		if ((i & FOGDEF_USE_BONE_ANIMATION) && !glRefConfig.glslMaxAnimatedBones)
 			continue;
 
@@ -1094,11 +1109,15 @@ void GLSL_InitGPUShaders(void) {
 		}
 
 		if (i & LIGHTDEF_ENTITY_VERTEX_ANIMATION) {
-			Q_strcat(extradefines, 1024, "#define USE_VERTEX_ANIMATION\n#define USE_MODELMATRIX\n");
-			attribs |= ATTR_POSITION2 | ATTR_NORMAL2;
+			Q_strcat(extradefines, 1024, "#define USE_MODELMATRIX\n");
 
-			if (r_normalMapping->integer) {
-				attribs |= ATTR_TANGENT2;
+			if (glRefConfig.gpuVertexAnimation) {
+				Q_strcat(extradefines, 1024, "#define USE_VERTEX_ANIMATION\n");
+				attribs |= ATTR_POSITION2 | ATTR_NORMAL2;
+
+				if (r_normalMapping->integer) {
+					attribs |= ATTR_TANGENT2;
+				}
 			}
 		} else if (i & LIGHTDEF_ENTITY_BONE_ANIMATION) {
 			Q_strcat(extradefines, 1024, "#define USE_MODELMATRIX\n");
@@ -1131,6 +1150,9 @@ void GLSL_InitGPUShaders(void) {
 		if ((i & SHADOWMAPDEF_USE_VERTEX_ANIMATION) && (i & SHADOWMAPDEF_USE_BONE_ANIMATION))
 			continue;
 
+		if ((i & SHADOWMAPDEF_USE_VERTEX_ANIMATION) && !glRefConfig.gpuVertexAnimation)
+			continue;
+
 		if ((i & SHADOWMAPDEF_USE_BONE_ANIMATION) && !glRefConfig.glslMaxAnimatedBones)
 			continue;
 
@@ -1373,7 +1395,7 @@ void GLSL_ShutdownGPUShaders(void) {
 
 	ri.Printf(PRINT_ALL, "------- GLSL_ShutdownGPUShaders -------\n");
 
-	for (i = 0; i < ATTR_INDEX_COUNT; i++)
+	for (i = 0; i < ATTR_INDEX_COUNT && i < glRefConfig.maxVertexAttribs; i++)
 		qglDisableVertexAttribArray(i);
 
 	GL_BindNullProgram();

code/renderergl2/tr_init.c

@@ -272,6 +272,9 @@ static void InitOpenGL(void) {
 		qglGetIntegerv(GL_MAX_TEXTURE_IMAGE_UNITS, &temp);
 		glConfig.numTextureUnits = temp;
 
+		qglGetIntegerv( GL_MAX_VERTEX_ATTRIBS, &temp );
+		glRefConfig.maxVertexAttribs = temp;
+
 		// reserve 160 components for other uniforms
 		qglGetIntegerv(GL_MAX_VERTEX_UNIFORM_COMPONENTS, &temp);
 		glRefConfig.glslMaxAnimatedBones = Com_Clamp(0, IQM_MAX_JOINTS, (temp - 160) / 16);

code/renderergl2/tr_local.h

@@ -1337,6 +1337,9 @@ typedef struct {
 	qboolean vertexArrayObject;
 	qboolean directStateAccess;
 
+	int maxVertexAttribs;
+	qboolean gpuVertexAnimation;
+
 	GLenum vaoCacheGlIndexType; // GL_UNSIGNED_INT or GL_UNSIGNED_SHORT
 	size_t vaoCacheGlIndexSize; // must be <= sizeof( vaoCacheGlIndex_t )
 

code/renderergl2/tr_mesh.c

@@ -253,6 +253,7 @@ void R_AddMD3Surfaces(trRefEntity_t *ent) {
 	int i;
 	mdvModel_t *model = NULL;
 	mdvSurface_t *surface = NULL;
+	void *drawSurf;
 	shader_t *shader = NULL;
 	int cull;
 	int lod;
@@ -347,23 +348,29 @@ void R_AddMD3Surfaces(trRefEntity_t *ent) {
 			shader = tr.shaders[surface->shaderIndexes[ent->e.skinNum % surface->numShaderIndexes]];
 		}
 
+		if (model->numVaoSurfaces > 0) {
+			drawSurf = &model->vaoSurfaces[i];
+		} else {
+			drawSurf = surface;
+		}
+
 		// we will add shadows even if the main object isn't visible in the view
 
 		// stencil shadows can't do personal models unless I polyhedron clip
 		if (!personalModel && r_shadows->integer == 2 && fogNum == 0 &&
 			!(ent->e.renderfx & (RF_NOSHADOW | RF_DEPTHHACK)) && shader->sort == SS_OPAQUE) {
-			R_AddDrawSurf((void *)&model->vaoSurfaces[i], tr.shadowShader, 0, qfalse, qfalse, 0);
+			R_AddDrawSurf(drawSurf, tr.shadowShader, 0, qfalse, qfalse, 0);
 		}
 
 		// projection shadows work fine with personal models
 		if (r_shadows->integer == 3 && fogNum == 0 && (ent->e.renderfx & RF_SHADOW_PLANE) &&
 			shader->sort == SS_OPAQUE) {
-			R_AddDrawSurf((void *)&model->vaoSurfaces[i], tr.projectionShadowShader, 0, qfalse, qfalse, 0);
+			R_AddDrawSurf(drawSurf, tr.projectionShadowShader, 0, qfalse, qfalse, 0);
 		}
 
 		// don't add third_person objects if not viewing through a portal
 		if (!personalModel) {
-			R_AddDrawSurf((void *)&model->vaoSurfaces[i], shader, fogNum, qfalse, qfalse, cubemapIndex);
+			R_AddDrawSurf(drawSurf, shader, fogNum, qfalse, qfalse, cubemapIndex);
 		}
 
 		surface++;

code/renderergl2/tr_model.c

@@ -607,6 +607,12 @@ static qboolean R_LoadMD3(model_t *mod, int lod, void *buffer, int bufferSize, c
 		surf++;
 	}
 
+	if (mdvModel->numFrames > 1 && !glRefConfig.gpuVertexAnimation)
+	{
+		mdvModel->numVaoSurfaces = 0;
+		mdvModel->vaoSurfaces = NULL;
+	}
+	else
 	{
 		srfVaoMdvMesh_t *vaoSurf;