No matter how stunning the content you’re rendering, isn’t it a set amount of colored pixels per frame, per second? Or is it different than that
In: 3
To a certain extent, you’re right. On a 4K screen there are approximately 8 million pixels. One of the basic functions of a GPU is to draw those pixels to the screen. But, the real hard work becomes deciding what color each pixel should be.
In a 3D game, there may be hundreds or thousands of objects inside the frame. Each of those objects is made of thousands or tens of thousands of triangles. The GPU figures out where all of those triangles are in relation to the camera for every frame.
Next, it draws a texture on each of those objects. This is a two-dimensional picture that is mapped onto a 3D surface. The size of the original texture is never exactly the size that it will be on screen. So, the GPU has to figure out how to best draw the texture onto the object so that it looks right.
The last big thing the GPU has to do is figure out lighting. Without any lights the scene is simply black. If everything is at full brightness it all looks flat and ugly. Correctly figuring out how all of the lights in a scene illuminate every object, and sometimes how that light bounces off one object and onto another, requires a TON of calculation. This step used to take hours for every frame of animation for a movie like Toy Story. Today it can be done sixty times per second (or more)!
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