fix a name collision on Ubuntu, allow forcing shaders off by passing -1 as shader

src/include/video.h

@@ -55,6 +55,7 @@ class CFont;
 extern char ForceUseOpenGL;
 extern bool UseOpenGL;
 extern bool ZoomNoResize;
+extern bool GLShaderPipelineSupported;
 #endif
 
 class CGraphic : public gcn::Image

src/stratagus/stratagus.cpp

@@ -480,6 +480,7 @@ static void Usage()
 		"\t-x\t\tControls fullscreen scaling if your graphics card supports shaders.\n"\
 		"\t  \t\tPass 1 for nearest-neigubour, 2 for EPX/AdvMame, 3 for HQx, 4 for SAL, 5 for SuperEagle\n"\
 		"\t  \t\tYou can also use Ctrl+Alt+/ to cycle between these scaling algorithms at runtime.\n"
+		"\t  \t\tPass -1 to force old-school nearest neighbour scaling without shaders\n"\
 		"\t-Z\t\tUse OpenGL to scale the screen to the viewport (retro-style). Implies -O.\n"
 #endif
 		"map is relative to StratagusLibPath=datapath, use ./map for relative to cwd\n",
@@ -634,6 +635,9 @@ void ParseCommandLine(int argc, char **argv, Parameters &parameters)
 #if defined(USE_OPENGL) || defined(USE_GLES)
 			case 'x':
 				ShaderIndex = atoi(optarg) % MAX_SHADERS;
+				if (atoi(optarg) == -1) {
+					GLShaderPipelineSupported = false;
+				}
 				continue;
 			case 'Z':
 				ForceUseOpenGL = 1;

src/video/sdl.cpp

@@ -123,7 +123,6 @@ GLint GLMaxTextureSize = 256;   /// Max texture size supported on the video card
 GLint GLMaxTextureSizeOverride;     /// User-specified limit for ::GLMaxTextureSize
 bool GLTextureCompressionSupported; /// Is OpenGL texture compression supported
 bool UseGLTextureCompression;       /// Use OpenGL texture compression
-bool GLShaderPipelineSupported;
 #endif
 
 static std::map<int, std::string> Key2Str;
@@ -259,7 +258,7 @@ static void InitOpenGLExtensions()
 		GLTextureCompressionSupported = false;
 	}
 
-	GLShaderPipelineSupported = LoadShaderExtensions();
+	GLShaderPipelineSupported = GLShaderPipelineSupported && LoadShaderExtensions();
 #else
 	GLTextureCompressionSupported = false;
 	GLShaderPipelineSupported = false;

src/video/shaders.cpp

@@ -335,7 +335,7 @@ PFNGLGETPROGRAMIVPROC glGetProgramiv;
 PFNGLGETSHADERINFOLOGPROC glGetShaderInfoLog;
 PFNGLGETPROGRAMINFOLOGPROC glGetProgramInfoLog;
 PFNGLGETUNIFORMLOCATIONPROC glGetUniformLocation;
-PFNGLACTIVETEXTUREPROC glActiveTexture;
+PFNGLACTIVETEXTUREPROC glActiveTextureProc;
 PFNGLUNIFORM1FPROC glUniform1f;
 PFNGLUNIFORM1IPROC glUniform1i;
 
@@ -385,7 +385,7 @@ void printProgramInfoLog(GLuint obj, const char* prefix)
 	}
 }
 
-extern unsigned ShaderIndex = 0;
+unsigned ShaderIndex = 0;
 
 extern void LoadShaders() {
 	GLuint vs, fs;
@@ -427,7 +427,7 @@ extern bool LoadShaderExtensions() {
 	glDeleteShader = (PFNGLDELETESHADERPROC)(uintptr_t)SDL_GL_GetProcAddress("glDeleteShader");
 
 	glGetUniformLocation = (PFNGLGETUNIFORMLOCATIONPROC)(uintptr_t)SDL_GL_GetProcAddress("glGetUniformLocation");
-	glActiveTexture = (PFNGLACTIVETEXTUREPROC)(uintptr_t)SDL_GL_GetProcAddress("glActiveTexture");
+	glActiveTextureProc = (PFNGLACTIVETEXTUREPROC)(uintptr_t)SDL_GL_GetProcAddress("glActiveTexture");
 	glUniform1f = (PFNGLUNIFORM1FPROC)(uintptr_t)SDL_GL_GetProcAddress("glUniform1f");
 	glUniform1i = (PFNGLUNIFORM1IPROC)(uintptr_t)SDL_GL_GetProcAddress("glUniform1i");
 
@@ -441,7 +441,7 @@ extern bool LoadShaderExtensions() {
 	glDrawBuffers = (PFNGLDRAWBUFFERSPROC)(uintptr_t)SDL_GL_GetProcAddress("glDrawBuffers");
 	glCheckFramebufferStatus = (PFNGLCHECKFRAMEBUFFERSTATUSEXTPROC)(uintptr_t)SDL_GL_GetProcAddress("glCheckFramebufferStatus");
 
-	if (glCreateShader && glGenFramebuffers && glGetUniformLocation && glActiveTexture) {
+	if (glCreateShader && glGenFramebuffers && glGetUniformLocation && glActiveTextureProc) {
 		LoadShaders();
 		return true;
 	} else {
@@ -482,7 +482,7 @@ extern void RenderFramebufferToScreen() {
 	glUniform1f(widthrelloc, (float)Video.Width / (float)Video.ViewportWidth);
 	glUniform1f(heightrelloc, (float)Video.Height / (float)Video.ViewportHeight);
 	glUniform1i(textureloc, 0);
-	glActiveTexture(GL_TEXTURE0);
+	glActiveTextureProc(GL_TEXTURE0);
 	// render the framebuffer texture to a fullscreen quad on the real display
 	glBindTexture(GL_TEXTURE_2D, fullscreenTexture);
 	glBegin(GL_QUADS);
@@ -499,4 +499,4 @@ extern void RenderFramebufferToScreen() {
 	glUseProgram(0); // Disable shaders again, and render to framebuffer again
 	glBindFramebuffer(GL_FRAMEBUFFER_EXT, fullscreenFramebuffer);
 }
-#endif
+#endif

src/video/video.cpp

@@ -170,6 +170,7 @@ CVideo Video;
 char ForceUseOpenGL;
 bool UseOpenGL;                      /// Use OpenGL
 bool ZoomNoResize;
+bool GLShaderPipelineSupported = true;
 #endif
 
 char VideoForceFullScreen;           /// fullscreen set from commandline