It would completely miss the pixels.
Rendering a 3D scene without antialiasing (or textures) is for all intents and purpouses the same as casting a single ray through each pixel in a raycaster. Anything that falls between the rays gets missed.
Full screen antialiasing simply renders the scene at 4x the res, and then averages it down to normal res again. So now you have four rays where before you had one, but each of those rays can miss stuff that falls between them just the same.
What you're proposing on the other hand is exactly the opposite of antialiasing. You're proposing to greatly reduce the number of rays being cast to maybe one per every 16x16 pixel square, as that's what happens when you lower the camera's resolution.
Enabling antialising after you've done this will get you some of those rays back, but only as many as you'd get if you rendered at twice the horizontal and vertical res. In the end, even with antialiasing, you're still working with way fewer rays than you had to begin with.
And that means anything small enough to fall between rays, such as things in the distance, will dissapear and reappear as you move around.
Rendering a 3D scene without antialiasing (or textures) is for all intents and purpouses the same as casting a single ray through each pixel in a raycaster. Anything that falls between the rays gets missed.
Full screen antialiasing simply renders the scene at 4x the res, and then averages it down to normal res again. So now you have four rays where before you had one, but each of those rays can miss stuff that falls between them just the same.
What you're proposing on the other hand is exactly the opposite of antialiasing. You're proposing to greatly reduce the number of rays being cast to maybe one per every 16x16 pixel square, as that's what happens when you lower the camera's resolution.
Enabling antialising after you've done this will get you some of those rays back, but only as many as you'd get if you rendered at twice the horizontal and vertical res. In the end, even with antialiasing, you're still working with way fewer rays than you had to begin with.
And that means anything small enough to fall between rays, such as things in the distance, will dissapear and reappear as you move around.