be more conservative and use pure SDL when shader 0 ("none") is selected

src/include/shaders.h

@@ -5,8 +5,7 @@
 
 #ifndef __APPLE__
 extern bool LoadShaderExtensions();
-extern void RenderWithShader(SDL_Renderer *renderer, SDL_Window* win, SDL_Texture* backBuffer);
-extern const char* NextShader();
+extern bool RenderWithShader(SDL_Renderer *renderer, SDL_Window* win, SDL_Texture* backBuffer);
 #else
 #include "stratagus.h"
 
@@ -14,13 +13,8 @@ inline bool LoadShaderExtensions() {
     return false;
 }
 
-inline void RenderWithShader(SDL_Renderer*, SDL_Window*, SDL_Texture*) {
-    fprintf(stderr, "shaders not supported on macOS\n");
-    ExitFatal(-1);
-}
-
-inline const char* NextShader() {
-    return "shaders not supported on macOS";
+inline bool RenderWithShader(SDL_Renderer*, SDL_Window*, SDL_Texture*) {
+    return false;
 }
 #endif
 

src/video/sdl.cpp

@@ -103,8 +103,6 @@ double FrameTicks;     /// Frame length in ms
 
 const EventCallback *Callbacks;
 
-static bool CanUseShaders = false;
-
 bool IsSDLWindowVisible = true;
 
 uint32_t SDL_CUSTOM_KEY_UP;
@@ -378,15 +376,7 @@ void InitVideoSdl()
 	SDL_GetRendererInfo(TheRenderer, &rendererInfo);
 	printf("[Renderer] %s\n", rendererInfo.name);
 	if(!strncmp(rendererInfo.name, "opengl", 6)) {
-		CanUseShaders = LoadShaderExtensions();
-	}
-	if (!CanUseShaders) {
-		puts("[Renderer] Cannot use shaders");
-		SDL_SetHint(SDL_HINT_RENDER_DRIVER, "software");
-		SDL_DestroyRenderer(TheRenderer);
-		TheRenderer = SDL_CreateRenderer(TheWindow, -1, SDL_RENDERER_SOFTWARE);
-		SDL_GetRendererInfo(TheRenderer, &rendererInfo);
-		printf("[Renderer] %s\n", rendererInfo.name);
+		LoadShaderExtensions();
 	}
 	SDL_SetRenderDrawColor(TheRenderer, 0, 0, 0, 255);
 	Video.ResizeScreen(Video.Width, Video.Height);
@@ -747,9 +737,7 @@ void RealizeVideoMemory()
 	if (NumRects) {
 		//SDL_UpdateWindowSurfaceRects(TheWindow, Rects, NumRects);
 		SDL_UpdateTexture(TheTexture, NULL, TheScreen->pixels, TheScreen->pitch);
-		if (CanUseShaders) {
-			RenderWithShader(TheRenderer, TheWindow, TheTexture);
-		} else {
+		if (!RenderWithShader(TheRenderer, TheWindow, TheTexture)) {
 			SDL_RenderClear(TheRenderer);
 			//for (int i = 0; i < NumRects; i++)
 			//    SDL_UpdateTexture(TheTexture, &Rects[i], TheScreen->pixels, TheScreen->pitch);

src/video/shaders.cpp

@@ -88,6 +88,9 @@ static const int MAX_SHADERS = 128;
 static GLuint shaderPrograms[MAX_SHADERS + 1] = { (GLuint) 0 };
 static const char* shaderNames[MAX_SHADERS + 1] = { NULL };
 static char shadersLoaded = -1;
+#define canUseShaders (shadersLoaded == 1)
+#define shadersAreInitialized (shadersLoaded != -1)
+#define setCanUseShaders(x) (shadersLoaded = (x ? 1 : 0))
 static int currentShaderIdx = 0;
 
 static std::regex invalidQuoteReplaceRegex("\"([a-zA-Z0-9 -\\.]+)\"");
@@ -239,7 +242,11 @@ static int loadShaders() {
 	return numShdr;
 }
 
-void RenderWithShader(SDL_Renderer *renderer, SDL_Window* win, SDL_Texture* backBuffer) {
+bool RenderWithShader(SDL_Renderer *renderer, SDL_Window* win, SDL_Texture* backBuffer) {
+	if (!canUseShaders || currentShaderIdx == 0) {
+		return false;
+	}
+
 	GLint oldProgramId;
 	// Detach the texture
 	SDL_SetRenderTarget(renderer, NULL);
@@ -343,14 +350,8 @@ void RenderWithShader(SDL_Renderer *renderer, SDL_Window* win, SDL_Texture* back
 	if (shaderProgram != 0) {
 		glUseProgram(oldProgramId);
 	}
-}
 
-const char* NextShader() {
-	if (shaderPrograms[++currentShaderIdx] == 0) {
-		currentShaderIdx = 0;
-	}
-	std::cout << "NextShader: " << shaderNames[currentShaderIdx] << std::endl;
-	return shaderNames[currentShaderIdx];
+	return true;
 }
 
 static int CclGetShader(lua_State *l) {
@@ -380,6 +381,7 @@ static int CclSetShader(lua_State *l) {
 			break;
 		}
 	}
+	currentShaderIdx = 0;
 	lua_pushboolean(l, 0);
 	return 1;
 }
@@ -395,8 +397,8 @@ static int CclGetShaderNames(lua_State *l) {
 }
 
 bool LoadShaderExtensions() {
-	if (shadersLoaded != -1) {
-		return shadersLoaded == 1;
+	if (shadersAreInitialized) {
+		return canUseShaders;
 	}
 
 	*(void **) (&lazyGlBegin) = SDL_GL_GetProcAddress("glBegin");
@@ -437,16 +439,16 @@ bool LoadShaderExtensions() {
 		glLinkProgram && glValidateProgram && glGetProgramiv && glGetProgramInfoLog &&
 		glUseProgram && glGetUniformLocation && glUniform1i && glUniform1f && glUniform2f &&
 		glUniformMatrix4fv && glGetAttribLocation && glVertexAttrib4f) {
-		shadersLoaded = loadShaders() > 0 ? 1 : 0;
+		setCanUseShaders(loadShaders() > 0);
 	} else {
-		shadersLoaded = 0;
+		setCanUseShaders(false);
 	}
 
 	lua_register(Lua, "GetShaderNames", CclGetShaderNames);
 	lua_register(Lua, "GetShader", CclGetShader);
 	lua_register(Lua, "SetShader", CclSetShader);
 
-	return shadersLoaded == 1;
+	return canUseShaders;
 }
 
 #endif