Fixed bug 3169 - GLES2_CreateRenderer does not check SDL_GL_GetAttribute result, causing use of uninitialized data
Yann Dirson
When attempting to force use of opengles2 renderer with:
int wanted_renderer = -1;
for (int i = 0; i < numrenderers; i++) {
SDL_RendererInfo renderer_info;
if (SDL_GetRenderDriverInfo(i, &renderer_info) != 0) {
SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, "Couldn't get renderer driver info: %s\n",
SDL_GetError());
quit(2);
}
std::cerr << "Renderer " << i << " '" << renderer_info.name << "': flags=0x"
<< std::hex << renderer_info.flags << std::dec
<< ", " << renderer_info.num_texture_formats << " texture formats, max="
<< renderer_info.max_texture_width << "x"
<< renderer_info.max_texture_height << "\n";
if (!strcmp(renderer_info.name, "opengles2")) {
std::cerr << " selecting!\n";
wanted_renderer = i;
}
}
renderer = SDL_CreateRenderer(window, wanted_renderer, 0);
... on banana pi or raspberry pi I get an error like the following (the actual
context profile value varies, being used uninitialized)
ERROR: Couldn't create renderer: Unknown OpenGL context profile 900
With this patch I get the following, which should help more pointing to a real problem:
ERROR: Couldn't create renderer: Failed getting OpenGL glGetString entry point
I pushed a patch (based on master branch of unofficial git mirror):
https://github.com/O-Computers/SDL/commit/550389c89f4e73a0a5294f95b9f6e6c18ba48509
I'll be opening a different bug for the underlying issue.
diff --git a/src/render/opengles2/SDL_render_gles2.c b/src/render/opengles2/SDL_render_gles2.c
index 30d761a..c419c0f 100644
--- a/src/render/opengles2/SDL_render_gles2.c
+++ b/src/render/opengles2/SDL_render_gles2.c
@@ -1969,9 +1969,15 @@
int profile_mask = 0, major = 0, minor = 0;
SDL_bool changed_window = SDL_FALSE;
- SDL_GL_GetAttribute(SDL_GL_CONTEXT_PROFILE_MASK, &profile_mask);
- SDL_GL_GetAttribute(SDL_GL_CONTEXT_MAJOR_VERSION, &major);
- SDL_GL_GetAttribute(SDL_GL_CONTEXT_MINOR_VERSION, &minor);
+ if (SDL_GL_GetAttribute(SDL_GL_CONTEXT_PROFILE_MASK, &profile_mask) < 0) {
+ goto error;
+ }
+ if (SDL_GL_GetAttribute(SDL_GL_CONTEXT_MAJOR_VERSION, &major) < 0) {
+ goto error;
+ }
+ if (SDL_GL_GetAttribute(SDL_GL_CONTEXT_MINOR_VERSION, &minor) < 0) {
+ goto error;
+ }
window_flags = SDL_GetWindowFlags(window);
if (!(window_flags & SDL_WINDOW_OPENGL) ||
