OpenGL: GLSL always supported

In gpu lib:
- GPU_glsl_support() always returns true
- internal cleanup & comments

Outside gpu lib:
- remove check from various code, remove the “else” path

- sprinkled a few C99-isms

We can remove GPU_glsl_support() when BGE stops calling it.

source/blender/editors/space_view3d/drawmesh.c

@@ -1151,7 +1151,7 @@ void draw_mesh_textured(Scene *scene, View3D *v3d, RegionView3D *rv3d,
 		Mesh *me = ob->data;
 		TexMatCallback data = {scene, ob, me, dm};
 		bool (*set_face_cb)(void *, int);
-		bool glsl, picking = (G.f & G_PICKSEL) != 0;
+		bool picking = (G.f & G_PICKSEL) != 0;
 		
 		/* face hiding callback depending on mode */
 		if (ob == scene->obedit)
@@ -1162,7 +1162,7 @@ void draw_mesh_textured(Scene *scene, View3D *v3d, RegionView3D *rv3d,
 			set_face_cb = NULL;
 
 		/* test if we can use glsl */
-		glsl = (v3d->drawtype == OB_MATERIAL) && GPU_glsl_support() && !picking;
+		bool glsl = (v3d->drawtype == OB_MATERIAL) && !picking;
 
 		GPU_begin_object_materials(v3d, rv3d, scene, ob, glsl, NULL);
 

source/blender/editors/space_view3d/drawobject.c

@@ -289,8 +289,6 @@ static bool check_ob_drawface_dot(Scene *sce, View3D *vd, char dt)
 
 bool draw_glsl_material(Scene *scene, Object *ob, View3D *v3d, const char dt)
 {
-	if (!GPU_glsl_support())
-		return false;
 	if (G.f & G_PICKSEL)
 		return false;
 	if (!check_object_draw_texture(scene, v3d, dt))

source/blender/editors/space_view3d/view3d_draw.c

@@ -2969,17 +2969,16 @@ void ED_view3d_draw_offscreen_init(Scene *scene, View3D *v3d)
 static void view3d_main_area_clear(Scene *scene, View3D *v3d, ARegion *ar)
 {
 	if (scene->world && (v3d->flag3 & V3D_SHOW_WORLD)) {
-		bool glsl = GPU_glsl_support() && BKE_scene_use_new_shading_nodes(scene) && scene->world->nodetree && scene->world->use_nodes;
+		bool glsl = BKE_scene_use_new_shading_nodes(scene) && scene->world->nodetree && scene->world->use_nodes;
 		
 		if (glsl) {
 			RegionView3D *rv3d = ar->regiondata;
 			GPUMaterial *gpumat = GPU_material_world(scene, scene->world);
-			bool material_not_bound;
 
 			/* calculate full shader for background */
 			GPU_material_bind(gpumat, 1, 1, 1.0, false, rv3d->viewmat, rv3d->viewinv, rv3d->viewcamtexcofac, (v3d->scenelock != 0));
 			
-			material_not_bound = !GPU_material_bound(gpumat);
+			bool material_not_bound = !GPU_material_bound(gpumat);
 
 			if (material_not_bound) {
 				glMatrixMode(GL_PROJECTION);

source/blender/gpu/intern/gpu_extensions.c

@@ -109,12 +109,9 @@ static struct GPUGlobal {
 	GLint maxtexsize;
 	GLint maxtextures;
 	GLuint currentfb;
-	int glslsupport;
+	bool extdisabled;
-	int extdisabled;
 	int colordepth;
 	int samples_color_texture_max;
-	int npotdisabled; /* ATI 3xx-5xx (and more) chipsets support NPoT partially (== not enough) */
-	int dlistsdisabled; /* Legacy ATI driver does not support display lists well */
 	GPUDeviceType device;
 	GPUOSType os;
 	GPUDriverType driver;
@@ -148,7 +145,7 @@ bool GPU_type_matches(GPUDeviceType device, GPUOSType os, GPUDriverType driver)
 
 void GPU_extensions_disable(void)
 {
-	GG.extdisabled = 1;
+	GG.extdisabled = true;
 }
 
 int GPU_max_texture_size(void)
@@ -163,9 +160,6 @@ void GPU_get_dfdy_factors(float fac[2])
 
 void gpu_extensions_init(void)
 {
-	GLint r, g, b;
-	const char *vendor, *renderer, *version;
-
 	/* BLI_assert(GLEW_VERSION_2_1); */
 	/* ^-- maybe a bit extreme? */
 
@@ -173,8 +167,7 @@ void gpu_extensions_init(void)
 
 	glGetIntegerv(GL_MAX_TEXTURE_SIZE, &GG.maxtexsize);
 
-	GG.glslsupport = 1;
+	GLint r, g, b;
-
 	glGetIntegerv(GL_RED_BITS, &r);
 	glGetIntegerv(GL_GREEN_BITS, &g);
 	glGetIntegerv(GL_BLUE_BITS, &b);
@@ -184,9 +177,9 @@ void gpu_extensions_init(void)
 		glGetIntegerv(GL_MAX_COLOR_TEXTURE_SAMPLES , &GG.samples_color_texture_max);
 	}
 
-	vendor = (const char *)glGetString(GL_VENDOR);
+	const char *vendor = (const char *)glGetString(GL_VENDOR);
-	renderer = (const char *)glGetString(GL_RENDERER);
+	const char *renderer = (const char *)glGetString(GL_RENDERER);
-	version = (const char *)glGetString(GL_VERSION);
+	const char *version = (const char *)glGetString(GL_VERSION);
 
 	if (strstr(vendor, "ATI")) {
 		GG.device = GPU_DEVICE_ATI;
@@ -274,18 +267,23 @@ void gpu_extensions_exit(void)
 
 bool GPU_glsl_support(void)
 {
-	return GG.glslsupport;
+	/* always supported, still queried by game engine */
+	return true;
 }
 
 bool GPU_non_power_of_two_support(void)
 {
-	/* still relevant for OpenGL ES */
+	/* always supported on full GL but still relevant for OpenGL ES */
-	return !GG.npotdisabled;
+	return true;
 }
 
 bool GPU_display_list_support(void)
 {
-	return !GG.dlistsdisabled;
+	/* deprecated in GL 3
+	 * supported on older GL and compatibility profile
+	 * still queried by game engine
+	 */
+	return true;
 }
 
 bool GPU_bicubic_bump_support(void)

source/blender/gpu/intern/gpu_material.c

@@ -2278,9 +2278,6 @@ GPUShaderExport *GPU_shader_export(struct Scene *scene, struct Material *ma)
 	GLint lastbindcode;
 	int i, liblen, fraglen;
 
-	if (!GPU_glsl_support())
-		return NULL;
-
 	/* TODO(sergey): How to detemine whether we need OSD or not here? */
 	mat = GPU_material_from_blender(scene, ma, false);
 	pass = (mat)? mat->pass: NULL;

source/blender/gpu/intern/gpu_simple_shader.c

@@ -173,29 +173,10 @@ static GPUShader *gpu_simple_shader(int options)
 
 void GPU_simple_shader_bind(int options)
 {
-	if (GPU_glsl_support()) {
 	GPUShader *shader = gpu_simple_shader(options);
 
 	if (shader)
 		GPU_shader_bind(shader);
-	}
-	else {
-		// XXX where does this fit, depends on ortho/persp?
-
-		if (options & GPU_SHADER_LIGHTING)
-			glEnable(GL_LIGHTING);
-
-		if (options & GPU_SHADER_TWO_SIDED)
-			glLightModeli(GL_LIGHT_MODEL_TWO_SIDE, GL_TRUE);
-
-		if (options & GPU_SHADER_OVERRIDE_DIFFUSE) {
-			glEnable(GL_COLOR_MATERIAL);
-			glColorMaterial(GL_FRONT_AND_BACK, GL_DIFFUSE);
-		}
-
-		if (options & GPU_SHADER_TEXTURE_2D)
-			glEnable(GL_TEXTURE_2D);
-	}
 
 	/* temporary hack, should be solved outside of this file */
 	GPU_MATERIAL_STATE.need_normals = (options & GPU_SHADER_LIGHTING);
@@ -203,16 +184,8 @@ void GPU_simple_shader_bind(int options)
 
 void GPU_simple_shader_unbind(void)
 {
-	if (GPU_glsl_support()) {
 	GPU_shader_unbind();
 }
-	else {
-		glDisable(GL_LIGHTING);
-		glDisable(GL_COLOR_MATERIAL);
-		glDisable(GL_TEXTURE_2D);
-		glLightModeli(GL_LIGHT_MODEL_TWO_SIDE, GL_FALSE);
-	}
-}
 
 /* Material Colors */