From 3c3d5d472e4e0f7bdd750c958581c591e7df5d3d Mon Sep 17 00:00:00 2001
From: Alibek Omarov <a1ba.omarov@gmail.com>
Date: Sun, 17 Nov 2019 18:51:03 +0300
Subject: [PATCH] ref_gl: bring back glDrawRangeElements support

---
 ref_gl/gl_local.h  |  1 +
 ref_gl/gl_opengl.c | 24 +++++++++++++++++++++++-
 2 files changed, 24 insertions(+), 1 deletion(-)

diff --git a/ref_gl/gl_local.h b/ref_gl/gl_local.h
index 9d49cd8c..6549236a 100644
--- a/ref_gl/gl_local.h
+++ b/ref_gl/gl_local.h
@@ -615,6 +615,7 @@ enum
 	GL_DEPTH_TEXTURE,
 	GL_DEBUG_OUTPUT,
 	GL_ARB_VERTEX_BUFFER_OBJECT_EXT,
+	GL_DRAW_RANGEELEMENTS_EXT,
 	GL_EXTCOUNT,		// must be last
 };
 
diff --git a/ref_gl/gl_opengl.c b/ref_gl/gl_opengl.c
index 6f1725d7..6ba77f7d 100644
--- a/ref_gl/gl_opengl.c
+++ b/ref_gl/gl_opengl.c
@@ -243,7 +243,19 @@ static dllfunc_t vbofuncs[] =
 	{ GL_CALL( glUnmapBufferARB ) }, // ,
 	{ GL_CALL( glBufferDataARB ) },
 	{ GL_CALL( glBufferSubDataARB ) },
-	{ NULL, NULL}
+	{ NULL, NULL }
+};
+
+static dllfunc_t drawrangeelementsfuncs[] =
+{
+{ GL_CALL( glDrawRangeElements ) },
+{ NULL, NULL }
+};
+
+static dllfunc_t drawrangeelementsextfuncs[] =
+{
+{ GL_CALL( glDrawRangeElementsEXT ) },
+{ NULL, NULL }
 };
 
 /*
@@ -581,6 +593,7 @@ void GL_InitExtensionsGLES( void )
 		// case GL_ARB_SEAMLESS_CUBEMAP: NOPE
 		// case GL_EXT_GPU_SHADER4: NOPE
 		// case GL_DEPTH_TEXTURE: NOPE
+		// case GL_DRAWRANGEELEMENTS_EXT: NOPE
 		default:
 			GL_SetExtension( extid, false );
 		}
@@ -692,6 +705,15 @@ void GL_InitExtensionsBigGL( void )
 	// rectangle textures support
 	GL_CheckExtension( "GL_ARB_texture_rectangle", NULL, "gl_texture_rectangle", GL_TEXTURE_2D_RECT_EXT );
 
+	if( !GL_CheckExtension( "glDrawRangeElements", drawrangeelementsfuncs, "gl_drawrangeelements", GL_DRAW_RANGEELEMENTS_EXT ) )
+	{
+		if( GL_CheckExtension( "glDrawRangeElementsEXT", drawrangeelementsextfuncs,
+			"gl_drawrangelements", GL_DRAW_RANGEELEMENTS_EXT ) )
+		{
+			pglDrawRangeElements = pglDrawRangeElementsEXT;
+		}
+	}
+
 	// this won't work without extended context
 	if( glw_state.extended )
 		GL_CheckExtension( "GL_ARB_debug_output", debugoutputfuncs, "gl_debug_output", GL_DEBUG_OUTPUT );