GL Debug Output Message Callback Guide

GLDebugMessageCallback.c

// This is free and unencumbered software released into the public domain.
// 
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// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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// WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
// 
// For more information, please refer to <http://unlicense.org/>

// REQUIREMENTS: OpenGL version with the KHR_debug extension available.

// Callback function for printing debug statements
void APIENTRY GLDebugMessageCallback(GLenum source, GLenum type, GLuint id,
                            GLenum severity, GLsizei length,
                            const GLchar *message, const void *param)
{
	const char *source_, *type_, *severity_;

	switch (source)
	{
	case GL_DEBUG_SOURCE_API:             source_ = "API";             break;
	case GL_DEBUG_SOURCE_WINDOW_SYSTEM:   source_ = "WINDOW_SYSTEM";   break;
	case GL_DEBUG_SOURCE_SHADER_COMPILER: source_ = "SHADER_COMPILER"; break;
	case GL_DEBUG_SOURCE_THIRD_PARTY:     source_ = "THIRD_PARTY";     break;
	case GL_DEBUG_SOURCE_APPLICATION:     source_ = "APPLICATION";     break;
	case GL_DEBUG_SOURCE_OTHER:           source_ = "OTHER";           break;
	default:                              source_ = "<SOURCE>";        break;
	}

	switch (type)
	{
	case GL_DEBUG_TYPE_ERROR:               type_ = "ERROR";               break;
	case GL_DEBUG_TYPE_DEPRECATED_BEHAVIOR: type_ = "DEPRECATED_BEHAVIOR"; break;
	case GL_DEBUG_TYPE_UNDEFINED_BEHAVIOR:  type_ = "UDEFINED_BEHAVIOR";   break;
	case GL_DEBUG_TYPE_PORTABILITY:         type_ = "PORTABILITY";         break;
	case GL_DEBUG_TYPE_PERFORMANCE:         type_ = "PERFORMANCE";         break;
	case GL_DEBUG_TYPE_OTHER:               type_ = "OTHER";               break;
	case GL_DEBUG_TYPE_MARKER:              type_ = "MARKER";              break;
	default:                                type_ = "<TYPE>";              break;
	}

	switch (severity)
	{
	case GL_DEBUG_SEVERITY_HIGH:         severity_ = "HIGH";         break;
	case GL_DEBUG_SEVERITY_MEDIUM:       severity_ = "MEDIUM";       break;
	case GL_DEBUG_SEVERITY_LOW:          severity_ = "LOW";          break;
	case GL_DEBUG_SEVERITY_NOTIFICATION: severity_ = "NOTIFICATION"; break;
	default:                             severity_ = "<SEVERITY>";   break;
	}

	printf("%d: GL %s %s (%s): %s\n",
		   id, severity_, type_, source_, message);
}

// =============== INIT DEBUG OUTPUT ================
// The following function calls should be made directly after OpenGL
// initialization.

// Enable the debugging layer of OpenGL
//
// GL_DEBUG_OUTPUT - Faster version but not useful for breakpoints
// GL_DEBUG_OUTPUT_SYNCHRONUS - Callback is in sync with errors, so a breakpoint
// can be placed on the callback in order to get a stacktrace for the GL error.

glEnable(GL_DEBUG_OUTPUT_SYNCHRONOUS);

// Set the function that will be triggered by the callback, the second parameter
// is the data parameter of the callback, it can be useful for different
// contexts but isn't necessary for our simple use case.
glDebugMessageCallback(GLDebugMessageCallback, NULL);