Fixed bug 2575 - Current GL context tracking fails
authorSam Lantinga <slouken@libsdl.org>
Sun, 15 Jun 2014 18:09:39 -0700
changeset 8869 553e9f7cd10e
parent 8868 55b16e3a3fc4
child 8870 cd1113741ade
Fixed bug 2575 - Current GL context tracking fails Ronie Salgado The GL Renderer current context tracking fails when one window is used with an SDL renderer but another separate window is used with a user handled OpenGL context. Attached is a small program that reproduces this bug, at least in some Linux machines where an OpenGL renderer is provided by default. Expected Output: -"First window" should be blue. -"Second window" should be green. Gotten Output: - "First window" black. - "Second window" blue. What happened: The renderer created for the "first window" ends rendering into the "second window" OpenGL context. Bug location: SDL_render_gl.c - line 286 on hg: static SDL_GLContext SDL_CurrentContext = NULL; When making SDL_GL_MakeCurrent from the user perspective, that variable or the GL renderer is not notified about the OpenGL context change. Solution proposal: - Move the current GL context cache into another place global.
src/render/opengl/SDL_render_gl.c
--- a/src/render/opengl/SDL_render_gl.c	Sun Jun 15 17:37:35 2014 -0700
+++ b/src/render/opengl/SDL_render_gl.c	Sun Jun 15 18:09:39 2014 -0700
@@ -290,7 +290,8 @@
 {
     GL_RenderData *data = (GL_RenderData *) renderer->driverdata;
 
-    if (SDL_CurrentContext != data->context) {
+    if (SDL_CurrentContext != data->context ||
+        SDL_GL_GetCurrentContext() != data->context) {
         if (SDL_GL_MakeCurrent(renderer->window, data->context) < 0) {
             return -1;
         }
@@ -310,7 +311,7 @@
 {
     GL_RenderData *data = (GL_RenderData *) renderer->driverdata;
 
-    if (SDL_CurrentContext == data->context) {
+    if (SDL_GL_GetCurrentContext() == data->context) {
         GL_UpdateViewport(renderer);
     } else {
         GL_ActivateRenderer(renderer);