Fix #4476: Assertion Failed

Disable track preview for OpenGL drawing until a later time where we can use a different drawing engine for track preview alongside OpenGL.

src/drawing/NewDrawing.cpp

@@ -43,6 +43,11 @@ extern "C"
 
 extern "C"
 {
+    sint32 drawing_engine_get_type()
+    {
+        return _drawingEngineType;
+    }
+
     void drawing_engine_init()
     {
         assert(_drawingEngine == nullptr);

src/drawing/NewDrawing.h

@@ -23,6 +23,7 @@ extern "C"
 
 extern rct_string_id DrawingEngineStringIds[3];
 
+sint32 drawing_engine_get_type();
 void drawing_engine_init();
 void drawing_engine_resize();
 void drawing_engine_set_palette(SDL_Color * colours);

src/windows/track_list.c

@@ -15,6 +15,7 @@
 #pragma endregion
 
 #include "../audio/audio.h"
+#include "../config.h"
 #include "../editor.h"
 #include "../interface/themes.h"
 #include "../interface/widget.h"
@@ -623,7 +624,7 @@ static bool track_list_load_design_for_preview(utf8 *path)
 	_loadedTrackDesign = NULL;
 
 	_loadedTrackDesign = track_design_open(path);
-	if (_loadedTrackDesign != NULL) {
+	if (_loadedTrackDesign != NULL && drawing_engine_get_type() != DRAWING_ENGINE_OPENGL) {
 		track_design_draw_preview(_loadedTrackDesign, _trackDesignPreviewPixels);
 		return true;
 	}