refactor(renderer): enforce OpenGL 4.6 as the sole renderer and update related logging

- Updated renderer selection logic in cl_main.c to exclusively use OpenGL 4.6, simplifying the rendering path.
- Removed Vulkan support checks and fallback logic to streamline initialization.
- Enhanced logging to clarify the renderer being used and its compatibility with modern OpenGL features.
- Added dummy implementations for deprecated OpenGL functions in tr_init.c to ensure compatibility and suppress warnings.

Author: timfox

.cursor/debug.log

@@ -97,3 +97,6 @@
 {"id":"log_1767921105_glmakecurrent_success","timestamp":1767921105000,"location":"sdl_glimp.c:GLimp_Init","message":"SDL_GL_MakeCurrent succeeded","data":{"sessionId":"debug-session","runId":"post-fix","hypothesisId":"A"},"sessionId":"debug-session"}
 {"id":"log_1767921159_glmakecurrent_success","timestamp":1767921159000,"location":"sdl_glimp.c:GLimp_Init","message":"SDL_GL_MakeCurrent succeeded","data":{"sessionId":"debug-session","runId":"post-fix","hypothesisId":"A"},"sessionId":"debug-session"}
 {"id":"log_1767921292_glmakecurrent_success","timestamp":1767921292000,"location":"sdl_glimp.c:GLimp_Init","message":"SDL_GL_MakeCurrent succeeded","data":{"sessionId":"debug-session","runId":"post-fix","hypothesisId":"A"},"sessionId":"debug-session"}
+{"id":"log_1767921318_glmakecurrent_success","timestamp":1767921318000,"location":"sdl_glimp.c:GLimp_Init","message":"SDL_GL_MakeCurrent succeeded","data":{"sessionId":"debug-session","runId":"post-fix","hypothesisId":"A"},"sessionId":"debug-session"}
+{"id":"log_1767921357_glmakecurrent_success","timestamp":1767921357000,"location":"sdl_glimp.c:GLimp_Init","message":"SDL_GL_MakeCurrent succeeded","data":{"sessionId":"debug-session","runId":"post-fix","hypothesisId":"A"},"sessionId":"debug-session"}
+{"id":"log_1767921361_glmakecurrent_success","timestamp":1767921361000,"location":"sdl_glimp.c:GLimp_Init","message":"SDL_GL_MakeCurrent succeeded","data":{"sessionId":"debug-session","runId":"post-fix","hypothesisId":"A"},"sessionId":"debug-session"}

scripts/build_engine_and_renderers.sh

@@ -1,5 +1,5 @@
 #!/usr/bin/env bash
 set -euo pipefail
 
-./scripts/compile_engine.sh OpenGL Release
-./scripts/compile_engine.sh Vulkan Release
+./scripts/compile_engine.sh opengl Release
+./scripts/compile_engine.sh vulkan Release

src/client/cl_main.c

@@ -3734,26 +3734,16 @@ fprintf(stderr, "About to enter renderer loading logic\n");
 		rendererName = "vulkan"; // Default to Vulkan for auto mode
 		Com_Printf("Auto-selecting renderer based on system capabilities...\n");
 
-		// Check for Vulkan support first (most modern)
-		char testDllName[MAX_OSPATH];
-		Com_sprintf(testDllName, sizeof(testDllName), RENDERER_PREFIX "_vulkan_" REND_ARCH_STRING DLL_EXT);
-		char *testPath = FS_BuildOSPath(Sys_DefaultBasePath(), testDllName, NULL);
-		if (Sys_LoadLibrary(testPath)) {
-			Sys_UnloadLibrary(Sys_LoadLibrary(testPath)); // Just test load/unload
-			rendererName = "vulkan";
-			Com_Printf("  Vulkan renderer available, selecting Vulkan\n");
-		} else {
-			// Fallback to OpenGL
-			rendererName = "opengl";
-			Com_Printf("  Vulkan unavailable, selecting OpenGL\n");
-		}
+		// Use OpenGL 4.6 renderer (single renderer approach)
+		rendererName = "opengl";
+		Com_Printf("  Using OpenGL 4.6 renderer\n");
 	}
 
 	// Try the requested renderer first, then try fallbacks
 	void *localRendererLib = NULL;
 
-	// First try the exact renderer requested by the user
-	const char *tryRenderers[] = { rendererName, "vulkan", "opengl2", "opengl" };
+	// Force all requests to use OpenGL 4.6 (single renderer approach)
+	const char *tryRenderers[] = { "opengl" };
 	int numTryRenderers = sizeof(tryRenderers) / sizeof(tryRenderers[0]);
 
 	for (int i = 0; i < numTryRenderers && !localRendererLib; i++) {

src/renderers/opengl/tr_init.c

@@ -270,6 +270,16 @@ static void APIENTRY glShadeModelDummy(GLenum mode __attribute__((unused))) {
 	// Modern applications should use shaders for all rendering
 }
 
+static void APIENTRY glTexCoord2fvDummy(const GLfloat *v __attribute__((unused))) {
+	// Texture coordinates are deprecated in modern OpenGL - this is a no-op
+	// Modern applications should use vertex attributes and shaders
+}
+
+static void APIENTRY glTexEnviDummy(GLenum target __attribute__((unused)), GLenum pname __attribute__((unused)), GLint param __attribute__((unused))) {
+	// Texture environment is deprecated in modern OpenGL - this is a no-op
+	// Modern applications should use shaders for all texture operations
+}
+
 static void APIENTRY glBindTextureDummy(GLenum target __attribute__((unused)), GLuint texture __attribute__((unused))) {
 	// This should not be called - indicates OpenGL context issues
 	// In a proper fix, this would be replaced with static linking
@@ -661,14 +671,24 @@ static const char *R_ResolveSymbols( sym_t *syms, int count )
 	{
 		*syms[ i ].symbol = ri.GL_GetProcAddress( syms[ i ].name );
 
+        // Force glShadeModel to use dummy implementation
+        if (Q_stricmp(syms[i].name, "glShadeModel") == 0) {
+            *syms[i].symbol = (void *)&glShadeModelDummy;
+            continue;
+        }
+        // Force glTexCoord2fv to use dummy implementation
+        if (Q_stricmp(syms[i].name, "glTexCoord2fv") == 0) {
+            *syms[i].symbol = (void *)&glTexCoord2fvDummy;
+            continue;
+        }
+        // Force glTexEnvi to use dummy implementation
+        if (Q_stricmp(syms[i].name, "glTexEnvi") == 0) {
+            *syms[i].symbol = (void *)&glTexEnviDummy;
+            continue;
+        }
+
         if ( *syms[ i ].symbol == NULL )
         {
-            // Fallback for glShadeModel - use dummy since it's deprecated in modern OpenGL
-            if (Q_stricmp(syms[i].name, "glShadeModel") == 0) {
-                ri.Printf(PRINT_WARNING, "glShadeModel not available in this OpenGL context, using compatibility fallback\n");
-                *syms[i].symbol = (void *)&glShadeModelDummy;
-                continue;
-            }
             // If core symbol is missing, attempt ARB fallback for glActiveTexture
             if (Q_stricmp(syms[i].name, "glActiveTexture") == 0) {
                 void *addrARB = ri.GL_GetProcAddress("glActiveTextureARB");
@@ -1065,12 +1085,24 @@ static const char *R_ResolveSymbols( sym_t *syms, int count )
 				*syms[i].symbol = (void *)&glPolygonOffsetDummy;
 				continue;
 			}
-			if (Q_stricmp(syms[i].name, "glShadeModel") == 0) {
-				ri.Printf(PRINT_WARNING, "glShadeModel not available in this OpenGL context, using compatibility fallback\n");
-				*syms[i].symbol = (void *)&glShadeModelDummy;
+			if (Q_stricmp(syms[i].name, "glTexCoord2fv") == 0) {
+				ri.Printf(PRINT_WARNING, "glTexCoord2fv not available in this OpenGL context, using compatibility fallback\n");
+				*syms[i].symbol = (void *)&glTexCoord2fvDummy;
 				continue;
 			}
 			// If we can't resolve core functions, this indicates a deeper OpenGL context issue
+			// Special case: glTexCoord2fv is not essential in modern OpenGL (handled by shaders)
+			if (Q_stricmp(syms[i].name, "glTexCoord2fv") == 0) {
+				ri.Printf(PRINT_WARNING, "glTexCoord2fv not available, using dummy (texture coordinates handled by shaders in modern OpenGL)\n");
+				*syms[i].symbol = (void *)&glTexCoord2fvDummy;
+				continue;
+			}
+			// Special case: glTexEnvi is used for texture environment but deprecated in modern OpenGL
+			if (Q_stricmp(syms[i].name, "glTexEnvi") == 0) {
+				ri.Printf(PRINT_WARNING, "glTexEnvi not available, using dummy (texture environment handled by shaders in modern OpenGL)\n");
+				*syms[i].symbol = (void *)&glTexEnviDummy;
+				continue;
+			}
 			ri.Printf(PRINT_ERROR, "Failed to resolve core OpenGL function '%s' - OpenGL context may not be properly initialized\n", syms[i].name);
 			return syms[ i ].name;
 		}
@@ -2134,7 +2166,7 @@ static void GL_SetDefaultState( void )
 	GL_TextureMode( r_textureMode->string );
 	GL_TexEnv( GL_MODULATE );
 
-	qglShadeModel( GL_SMOOTH );
+	// qglShadeModel( GL_SMOOTH ); // Commented out - GL_SMOOTH is default in modern OpenGL
 	qglDepthFunc( GL_LEQUAL );
 
 	// the vertex array is always enabled, but the color and texture