comments and cleanups

src/ACGL/OpenGL/glloaders/KHR_debug_emulator.cc

 
+// include your OpenGL header here:
 #include <ACGL/OpenGL/GL.hh>
 
-//#include <iostream>
-//using namespace std;
+/*
+ * Simulates KHR_debug
+ *
+ * Use-cases:
+ * ----------
+ *
+ * Use this as a fallback on systems that don't implement KHR_debug for debugging only,
+ * don't use this code in shipping release builds - it will slow down the application!
+ * Using a debug callback instead of lots of glGetError() calls should work fine,
+ * MessageControl, DebugGroups and DebugLabels are only implemented as fallbacks, in case
+ * you have to rely on those features, you want to reimplement them in a more efficient way.
+ *
+ *
+ * Known restrictions:
+ * -------------------
+ *
+ *    Wrong behavior:
+ *    ---------------
+ *
+ *    * Does not support multiple OpenGL contexts, all errors from all contexts are mixed.
+ *      All settings (including the debug callback) are set for all contexts.
+ *
+ *    * glObjectLabel and glObjectPtrLabel do not check if the object to label exists and thus
+ *      will not generate a GL_INVALID_VALUE.
+ *
+ *    * glObjectLabel can label GL_DISPLAY_LIST even in Core profiles.
+ *
+ *    Inefficiency:
+ *    -------------
+ *
+ *    * Using this, the number of GL calls doubles as each call will get followed by a glGetError.
+ *    * This will also force OpenGL to run synchronous which will reduce the performance!
+ *    * ObjectLabels are implemented inefficiently and are not used internally. The functionality is
+ *      only present to be compatible with KHR_debug.
+ *    * DebugGroups and glDebugMessageControl are not efficiently implemented.
+ *    * Some memory will not get released.
+ *
+ *    Implementation dependent limits:
+ *    --------------------------------
+ *
+ *    * GL_MAX_DEBUG_MESSAGE_LENGTH and Gl_MAX_LABEL_LENGTH are arbitrary and can be changed.
+ *    * GL_MAX_DEBUG_GROUP_STACK_DEPTH is set to the lowest allowed value of 64 but can be changed
+ *    * GL_DEBUG_LOGGED_MESSAGES is set to 1 - increasing this will be more work.
+ *
+ *    * This implementation always behaves synchronous, even if GL_DEBUG_OUTPUT_SYNCHRONOUS is
+ *      disabled (the default btw.). This is legal by the spec.
+ */
 
 #include <string.h>
 #include <stdio.h>
@@ -264,15 +310,27 @@ GLuint KHR_DEBUG_EMULATOR_GetDebugMessageLog(GLuint count, GLsizei bufsize, GLen
     return 1;
 }
 
+///////////////////////////////////////////////////////////////////////////////////////////////////
+///
+/// Handling of ObjectLabels:
+/// ( not very pretty, just for compatibility )
+///
+///////////////////////////////////////////////////////////////////////////////////////////////////
+
 #ifndef GL_TRANSFORM_FEEDBACK
 #define GL_TRANSFORM_FEEDBACK 0x8E22
 #endif
 
+#ifndef GL_DISPLAY_LIST
+#define GL_DISPLAY_LIST 0x82E7
+#endif
+
 GLboolean isValidObjectLabelNamespace( GLenum e )
 {
     if (e == GL_BUFFER || e == GL_SHADER || e == GL_PROGRAM || e == GL_VERTEX_ARRAY
             || e == GL_QUERY || e == GL_PROGRAM_PIPELINE || e == GL_TRANSFORM_FEEDBACK
-            || e == GL_SAMPLER || e == GL_TEXTURE || e == GL_RENDERBUFFER || e == GL_FRAMEBUFFER ) {
+            || e == GL_SAMPLER || e == GL_TEXTURE || e == GL_RENDERBUFFER || e == GL_FRAMEBUFFER
+            || e == GL_DISPLAY_LIST ) {
         return true;
     }
 
@@ -407,6 +465,12 @@ void KHR_DEBUG_EMULATOR_GetObjectLabel(GLenum identifier, GLuint name, GLsizei b
     *length = size;
 }
 
+///////////////////////////////////////////////////////////////////////////////////////////////////
+///
+/// Handling of ObjectPtrLabels:
+/// ( not very pretty, just for compatibility )
+///
+///////////////////////////////////////////////////////////////////////////////////////////////////
 
 void KHR_DEBUG_EMULATOR_ObjectPtrLabel(const void * ptr, GLsizei length, const GLchar * label)
 {
@@ -418,6 +482,12 @@ void KHR_DEBUG_EMULATOR_GetObjectPtrLabel(const void * ptr, GLsizei bufSize, GLs
     KHR_DEBUG_EMULATOR_insertMissingFeatureError( "function not simulated yet - ignored" );
 }
 
+///////////////////////////////////////////////////////////////////////////////////////////////////
+///
+/// Handling of DebugGroups
+///
+///////////////////////////////////////////////////////////////////////////////////////////////////
+
 struct DebugGroupDescription {
     GLenum source;
     GLuint id;
@@ -529,6 +599,12 @@ GLboolean isValidSource( GLenum e )
     return false;
 }
 
+///////////////////////////////////////////////////////////////////////////////////////////////////
+///
+/// Generating errors:
+///
+///////////////////////////////////////////////////////////////////////////////////////////////////
+
 const char* KHR_DEBUG_EMULATOR_GET_ERROR_STRING( GLenum _errorCode )
 {
     if      (_errorCode == GL_INVALID_ENUM)                  { return (char*) "OpenGL error: GL_INVALID_ENUM"; }
@@ -628,21 +704,27 @@ GLboolean KHR_DEBUG_EMULATOR_IsEnabled(GLenum cap){
 //   needs to recognize a few new tokens
 //
 void KHR_DEBUG_EMULATOR_GetIntegerv(GLenum pname, GLint * params){
-   if (pname == GL_CONTEXT_FLAGS) {
-     _original_glGetIntegerv(pname, params);
-     *params |= GL_CONTEXT_FLAG_DEBUG_BIT; // we make this a debug context ;-)
-   } else if (pname == GL_MAX_DEBUG_MESSAGE_LENGTH) {
-     *params = KHR_DEBUG_EMULATOR_MAX_DEBUG_MESSAGE_LENGTH;
-   } else if (pname == GL_MAX_DEBUG_LOGGED_MESSAGES) {
-     *params = KHR_DEBUG_EMULATOR_MAX_DEBUG_LOGGED_MESSAGES;
-   } else if (pname == GL_MAX_DEBUG_GROUP_STACK_DEPTH) {
-     *params = KHR_DEBUG_EMULATOR_MAX_DEBUG_GROUP_STACK_DEPTH;
-   } else if (pname == GL_MAX_LABEL_LENGTH) {
-     *params = KHR_DEBUG_EMULATOR_MAX_LABEL_LENGTH;
-   } else {
-     _original_glGetIntegerv(pname, params);
-   }
-   KHR_DEBUG_EMULATOR_CHECK_GL_ERROR();
+    if (pname == GL_CONTEXT_FLAGS) {
+        _original_glGetIntegerv(pname, params);
+        *params |= GL_CONTEXT_FLAG_DEBUG_BIT; // we make this a debug context ;-)
+    } else if (pname == GL_MAX_DEBUG_MESSAGE_LENGTH) {
+        *params = KHR_DEBUG_EMULATOR_MAX_DEBUG_MESSAGE_LENGTH;
+    } else if (pname == GL_MAX_DEBUG_LOGGED_MESSAGES) {
+        *params = KHR_DEBUG_EMULATOR_MAX_DEBUG_LOGGED_MESSAGES;
+    } else if (pname == GL_MAX_DEBUG_GROUP_STACK_DEPTH) {
+        *params = KHR_DEBUG_EMULATOR_MAX_DEBUG_GROUP_STACK_DEPTH;
+    } else if (pname == GL_MAX_LABEL_LENGTH) {
+        *params = KHR_DEBUG_EMULATOR_MAX_LABEL_LENGTH;
+    } else if (pname == GL_DEBUG_NEXT_LOGGED_MESSAGE_LENGTH) {
+        if (g_LastDebugMessageEmpty) {
+            *params = 0;
+        } else {
+            *params = g_LastDebugMessage.length;
+        }
+    } else {
+        _original_glGetIntegerv(pname, params);
+    }
+    KHR_DEBUG_EMULATOR_CHECK_GL_ERROR();
 }
 
 //