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.
--- 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);