The problem with rendering a larger image, and then scaling it down (as ED Supersampling does, as I understand it) is, it take MORE video memory to hold that large extra video buffer i.e. 4K at 2.0 super-sample, required a 4K and 8K image buffer. You render to 8K and then resize to 4K and display. If you think about it, this ONLY gives 4 more sample per pixel. So to me, it does not seem efficient. And it also uses a LOT of extra Video RAM.
If however you render to 4K, but render multiple samples per pixel, then you could possible use 8 or 16 samples, with a similar speed. But using 4x or 8x mem PER pixel, BEFORE those samples were combined and the result used for the pixel. You are, kind of, rendering 8k or 16ks worth of image, but its more memory efficient, as the extra data is thrown away once combined, per pixel.
Hey, at the end of the day, Im not a hard nut GFX pipe coder. So what I am saying may not make sense. Im just guessing to some extent.
You know, thinking about it, re-using samples for a given surface point from an earlier frame, actually makes a lot of sense. Some shading, like Ambient Occlusion, and Diffuse shading, by its nature, is generally directionally independent. This basically means, the shading on a chalk sphere looks the same, whether looking at it from its left, right, or above. indeed, if you have combined multiple diffuse samples for a pixel, and then do so on the next frame. Combining those samples would be relatively cheap.
However, reflective shading, IS very much dependant on your view. Small changes in view, can mean large changes in the reflection, especially on curved surfaces. However, again, these samples from previous frame ARE quite cheap to keep, and would tend to reduce dark/bright flicker when combined, as they average out the shift over time.
So I guess Temporal AA may make more sense than it seems at first. As its kind of recycling previous, expensively aquired samples on subsequent frames, getting better value PER sample.
If however you render to 4K, but render multiple samples per pixel, then you could possible use 8 or 16 samples, with a similar speed. But using 4x or 8x mem PER pixel, BEFORE those samples were combined and the result used for the pixel. You are, kind of, rendering 8k or 16ks worth of image, but its more memory efficient, as the extra data is thrown away once combined, per pixel.
Hey, at the end of the day, Im not a hard nut GFX pipe coder. So what I am saying may not make sense. Im just guessing to some extent.
You know, thinking about it, re-using samples for a given surface point from an earlier frame, actually makes a lot of sense. Some shading, like Ambient Occlusion, and Diffuse shading, by its nature, is generally directionally independent. This basically means, the shading on a chalk sphere looks the same, whether looking at it from its left, right, or above. indeed, if you have combined multiple diffuse samples for a pixel, and then do so on the next frame. Combining those samples would be relatively cheap.
However, reflective shading, IS very much dependant on your view. Small changes in view, can mean large changes in the reflection, especially on curved surfaces. However, again, these samples from previous frame ARE quite cheap to keep, and would tend to reduce dark/bright flicker when combined, as they average out the shift over time.
So I guess Temporal AA may make more sense than it seems at first. As its kind of recycling previous, expensively aquired samples on subsequent frames, getting better value PER sample.
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