X-Git-Url: https://git.ralfj.de/gltest.git/blobdiff_plain/dac0dad539be501c94cb8646d979e6e7787e1992..ce1b46da645fdcac80fc9c71082bb5cb40166576:/glxbackend.cpp

diff --git a/glxbackend.cpp b/glxbackend.cpp
index 3ebc878..e40e90c 100644
--- a/glxbackend.cpp
+++ b/glxbackend.cpp
@@ -25,20 +25,32 @@
 #include <GL/glxext.h>
 #include <string>
 
-#if !defined(CON_GL1)
-#error "Valid GL contexts for GLX are: GL1"
+#if !defined(CON_GL1) && !defined(CON_GL3)
+#error "Valid GL contexts for GLX are: GL1, GL3"
 #endif
 
-// attributes for a double buffered visual in RGBA format with at least 4 bits per color
-static int attrList[] =                                             
+// attributes for a double buffered framebuffer in RGBA format with at least 4 bits per color
+static int configAttribs[] =                                             
 {
-	GLX_RGBA, GLX_DOUBLEBUFFER,
+	GLX_RENDER_TYPE, GLX_RGBA_BIT,
+	GLX_DOUBLEBUFFER, True,
 	GLX_RED_SIZE, 4,
 	GLX_GREEN_SIZE, 4,
 	GLX_BLUE_SIZE, 4,
 	None
 };
 
+#ifdef CON_GL3
+// attributes for a GL3 context
+static int contextAttribs[] =
+{
+	GLX_CONTEXT_MAJOR_VERSION_ARB,               3,
+	GLX_CONTEXT_MINOR_VERSION_ARB,               0,
+	GLX_CONTEXT_FLAGS_ARB,                       GLX_CONTEXT_FORWARD_COMPATIBLE_BIT_ARB,
+	None
+};
+#endif
+
 VisualID GLXBackend::initialize(Display *display)
 {
 	if (this->display == NULL) { // this implies that the context is also unitialized
@@ -47,26 +59,46 @@ VisualID GLXBackend::initialize(Display *display)
 		int glxMajor, glxMinor;
 		glXQueryVersion(display, &glxMajor, &glxMinor);
 		printf("Using GLX version: %d.%d\n", glxMajor, glxMinor);
-		// check for swap control functions
-		const char *extensions = glXQueryExtensionsString(display, DefaultScreen(display));
-		if (std::string(extensions).find("GLX_MESA_swap_control") != std::string::npos) {
-			funSwapIntervalMesa = (PFNGLXSWAPINTERVALMESAPROC)glXGetProcAddress((const GLubyte*)"glXSwapIntervalMESA");
-			if (funSwapIntervalMesa) printf("glXSwapIntervalMESA is present\n");
+		if (glxMajor < 1 || (glxMajor == 1 && glxMinor < 3)) {
+			// glXChooseFBConfig and glXCreateNewContext require GLX 1.3
+			fprintf(stderr, "Need at least GLX 1.3 to function properly\n");
+			exit(1);
 		}
-		else {
-			funSwapIntervalMesa = 0;
+		// check for extension-based functions
+		funSwapIntervalMesa = (PFNGLXSWAPINTERVALMESAPROC)resolveGLXFunction("GLX_MESA_swap_control", "glXSwapIntervalMESA");
+		funSwapIntervalExt = (PFNGLXSWAPINTERVALEXTPROC)resolveGLXFunction("GLX_EXT_swap_control", "glXSwapIntervalEXT");
+		funCreateContextAttribsARB = (PFNGLXCREATECONTEXTATTRIBSARBPROC)resolveGLXFunction("GLX_ARB_create_context", "glXCreateContextAttribsARB");
+		// get the first usable framebuffer configuration
+		int count = 0;
+		GLXFBConfig *configs = glXChooseFBConfig(display, DefaultScreen(display), configAttribs, &count);
+		if (count < 1) {
+			fprintf(stderr, "Failed to choose framebuffer configuration\n");
+			exit(1);
 		}
-		if (std::string(extensions).find("GLX_EXT_swap_control") != std::string::npos) {
-			funSwapIntervalExt = (PFNGLXSWAPINTERVALEXTPROC)glXGetProcAddress((const GLubyte*)"glXSwapIntervalEXT");
-			if (funSwapIntervalExt) printf("glXSwapIntervalEXT is present\n");
-		}
-		else {
-			funSwapIntervalExt = 0;
-		}
-		// get the visual
-		vi = glXChooseVisual(display, DefaultScreen(display), attrList);
+		config = configs[0];
+		XFree(configs);
 	}
-	return vi->visualid;
+	// return visual ID
+	XVisualInfo *vi = glXGetVisualFromFBConfig(display, config);
+	VisualID visualid = vi->visualid;
+	XFree(vi);
+	return visualid;
+}
+
+bool GLXBackend::haveGLXExtension(const std::string &name)
+{
+	assert(display != NULL);
+	std::string extensions = glXQueryExtensionsString(display, DefaultScreen(display));
+	return (std::string(" "+extensions+" ").find(" "+name+" ") != std::string::npos);
+}
+
+T_proc GLXBackend::resolveGLXFunction(const char *extension, const char *function)
+{
+	if (!haveGLXExtension(extension)) return NULL;
+	T_proc f = glXGetProcAddress((const GLubyte*)function);
+	if (f)
+		printf("%s is supported, using it for %s\n", extension, function);
+	return f;
 }
 
 void GLXBackend::createContext(Window window)
@@ -74,7 +106,19 @@ void GLXBackend::createContext(Window window)
 	assert(display != NULL && context == None);
 	this->window = window;
 	// create context with that window
-	context = glXCreateContext(display, vi, 0, GL_TRUE);                             
+#ifdef CON_GL1
+	context = glXCreateNewContext(display, config, GLX_RGBA_TYPE, NULL, GL_TRUE);
+#else
+	if (!funCreateContextAttribsARB) {
+		fprintf(stderr, "Cannot create GL3 context: GLX_ARB_create_context not supported\n");
+		exit(1);
+	}
+	context = funCreateContextAttribsARB(display, config, NULL, GL_TRUE, contextAttribs);
+#endif
+	if (!context) {
+		fprintf(stderr, "Error creating context\n");
+		exit(1);
+	}
 	glXMakeCurrent(display, window, context);                                      
 	assert(glXIsDirect(display, context));
 	printf("Using GL version: %s\n", glGetString(GL_VERSION));
@@ -89,7 +133,6 @@ GLXBackend::~GLXBackend()
 			glXMakeCurrent(display, None, NULL);
 			glXDestroyContext(display, context);
 		}
-		XFree(vi);
 	}
 }
 
@@ -102,12 +145,18 @@ void GLXBackend::swapBuffers() const
 void GLXBackend::setSwapInterval(int i) const
 {
 	assert(context != None);
+	// check if swap interval value is supported
+	if (i < 0) {
+		fprintf(stderr, "Cannot set swap interval to %d, must not be negative\n", i);
+		exit(1);
+	}
+	// set it
 	if (funSwapIntervalExt)
 		funSwapIntervalExt(display, window, i);
 	else if (funSwapIntervalMesa)
 		funSwapIntervalMesa(i);
 	else {
-		fprintf(stderr, "At least one of glXSwapIntervalMESA, glXSwapIntervalEXT must be provided by the system\n");
+		fprintf(stderr, "At least one of GLX_EXT_swap_control, GLX_MESA_swap_control must be supported by the system\n");
 		abort();
 	}
 }