From 545554989bf17036e78d7b5ea2379b70269d4b30 Mon Sep 17 00:00:00 2001
From: bones_was_here <bones_was_here@xa.org.au>
Date: Fri, 22 Jul 2022 09:49:16 +1000
Subject: [PATCH] Improve DEBUGGL

glGetError() must be called in a loop to retrieve and reset
multiple error flags.

Signed-off-by: bones_was_here <bones_was_here@xa.org.au>
---
 gl_backend.c |  4 +---
 glquake.h    | 35 +++++++++++++++++++++--------------
 2 files changed, 22 insertions(+), 17 deletions(-)

diff --git a/gl_backend.c b/gl_backend.c
index ad4a0cdc..3b511704 100644
--- a/gl_backend.c
+++ b/gl_backend.c
@@ -27,9 +27,7 @@ float gl_modelviewprojection16f[16];
 qbool gl_modelmatrixchanged;
 
 #ifdef DEBUGGL
-int gl_errornumber = 0;
-
-void GL_PrintError(int errornumber, const char *filename, int linenumber)
+void GL_PrintError(GLenum errornumber, const char *filename, unsigned int linenumber)
 {
 	switch(errornumber)
 	{
diff --git a/glquake.h b/glquake.h
index 21da68bc..e3f8f6d0 100644
--- a/glquake.h
+++ b/glquake.h
@@ -29,20 +29,6 @@
 
 //====================================================
 
-//#define DEBUGGL
-
-#ifdef DEBUGGL
-#ifdef USE_GLES2
-#define CHECKGLERROR {if (gl_paranoid.integer){if (gl_printcheckerror.integer) Con_Printf("CHECKGLERROR at %s:%d\n", __FILE__, __LINE__);gl_errornumber = glGetError();if (gl_errornumber) GL_PrintError(gl_errornumber, __FILE__, __LINE__);}}
-#else
-#define CHECKGLERROR {if (gl_paranoid.integer){if (gl_printcheckerror.integer) Con_Printf("CHECKGLERROR at %s:%d\n", __FILE__, __LINE__);gl_errornumber = qglGetError ? qglGetError() : 0;if (gl_errornumber) GL_PrintError(gl_errornumber, __FILE__, __LINE__);}}
-#endif //USE_GLES2
-extern int gl_errornumber;
-void GL_PrintError(int errornumber, const char *filename, int linenumber);
-#else
-#define CHECKGLERROR
-#endif //DEBUGGL
-
 #ifndef USE_GLES2
 // this is defined if the SDL_opengl.h is included
 #ifndef GL_ZERO
@@ -1050,4 +1036,25 @@ extern void (GLAPIENTRY *qglViewport)(GLint x, GLint y, GLsizei width, GLsizei h
 #define GL_HALF_FLOAT                                    0x140B
 #define GL_NUM_EXTENSIONS                 0x821D
 
+
+//====================================================
+
+//#define DEBUGGL
+
+#ifdef DEBUGGL
+void GL_PrintError(GLenum errornumber, const char *filename, unsigned int linenumber);
+#define CHECKGLERROR { \
+	if (gl_paranoid.integer) { \
+		GLenum gl_errornumber; \
+		if (gl_printcheckerror.integer) \
+			Con_Printf("CHECKGLERROR at %s:%d\n", __FILE__, __LINE__); \
+		if (qglGetError) /* bones_was_here: is this pointer check still necessary? */ \
+			while ((gl_errornumber = qglGetError())) \
+				GL_PrintError(gl_errornumber, __FILE__, __LINE__); \
+	}}
+#else
+#define CHECKGLERROR
+#endif //DEBUGGL
+
+
 #endif //GLQUAKE_H
-- 
2.39.2