https://bugs.freedesktop.org/show_bug.cgi?id=91656
--- Comment #9 from Daniel Scharrer daniel@constexpr.org --- This looks like an application bug to me - here's what the game does with the minimap fog of war in the apitrace (right at the start of each frame, so it's easy to find):
1. Uploads the fog of war to GL_ALPHA texture 2487 2. Binds framebuffer 2 3. Attaches texture 6613 as the color0 buffer 4. Clears color to (0, 0, 0, 0) 5. Unbinds framebuffer 2 6. Binds framebuffer 2 7. Attaches texture 6613 as the color0 buffer 8. Binds 6613 as texture0 9. Binds 2487 as texture1 10. Draws a full-screen quad with a shader that boils down to a = pow(texture1.a, 8); color0 = a * (0, 0, 0, 1) + (1 - a) * texture0;
Reading from and writing to the same texture in this way is undefined without inserting the appropriate memory barriers.