Bloom fixes

[VReaperV]

• Removed mip-levels from contrast and bloom FBOs, other than the base one since that's the only one that we use.
• NUKED one of the blur shaders and moved everything into just one of them, since the difference was only the components of a vec2 being switched, which is better done with a uniform.
• Fixes Bloom has no effect #1438.

[slipher]

It doesn't seem to do the same thing as in 0.54.0. Here's map "zandronum" -175 -2529 -82 -97 3. I tested this scene since bloom has a very large effect on it. For testing the PR I set r_overbrightDefaultClamp 1 for fair comparison.

0.54.0:

This PR:

There is a lot of added brightness around the top left corner of the photograph that shouldn't be there.

While reviewing the first commit, I noticed that in the old code a "contrast" shader is the first one executed, while the commit changes it so that a "blur" shader is first.

[VReaperV]

It's still executed first, at lines #3075-3090. Both use the blur shader(s) after the contrast one.

There is a lot of added brightness around the top left corner of the photograph that shouldn't be there.

Could it be due to framebuffer format changes?

[slipher]

It's still executed first, at lines #3075-3090. Both use the blur shader(s) after the contrast one.

I see.

Could it be due to framebuffer format changes?

I tried reverting 483d83d and setting r_highPrecisionRendering 0 and there wasn't any difference.

[VReaperV]

Hmm, that's weird. I'll look at what the issue is later. On my end on the same map + viewpos the effect is not as strong as on the 2nd screenshot, but still brighter than the 1st one.

[VReaperV]

It doesn't seem to do the same thing as in 0.54.0. Here's map "zandronum" -175 -2529 -82 -97 3. I tested this scene since bloom has a very large effect on it. For testing the PR I set r_overbrightDefaultClamp 1 for fair comparison.

0.54.0:

This PR:

There is a lot of added brightness around the top left corner of the photograph that shouldn't be there.

While reviewing the first commit, I noticed that in the old code a "contrast" shader is the first one executed, while the commit changes it so that a "blur" shader is first.

Fixed, both look the same now:
0.54.1:

This pr:

[slipher]

LGTM