I am trying to programmatically figure out how many "texture2d " calls the gpu can make before the fps drops below 60fps.
My current way of doing this is to have a fragment shader with a for loop that will run a specified number of times based on a passed in uniform. So each frame the for loop will run more times, each time sampling the texture more times.
Then on the cpu I can monitor the fps and see when it drops.
My problem is if this shader runs on more then one pixel then the test is worth nothing.
How can I ensure from the cpu code and vertex shader that the fragment program only runs once?