Implement MSAA #1480

VReaperV · 2024-12-27T15:40:33Z

Implements #532.

Add r_msaa. When set to > 0, an MSAA FBO will be created with that many samples. This FBO will be used for rendering, other than when it requires sampling from current render/depth image. When such rendering is required the MSAA FBO will be blit into the main FBO and vice versa, to resolve the MSAA texture.

plat23:
No MSAA:

MSAA 4x:

thunder:
No MSAA:

MSAA 4x:

MSAA 16x:

MSAA 32x:

illwieckz · 2024-12-28T23:14:57Z

Nice! Finally some antialiasing!

It looks like when MSAA is enabled the heathaze from back surface is applied on front surfaces too:
https://imgsli.com/MzMyODgx

illwieckz · 2024-12-30T00:01:06Z

My previous comment was about screenshots from the original post.

When I try the branch and enable MSAA I get a black screen (AMD Radeon with Mesa radeonsi driver).

VReaperV · 2024-12-31T11:10:49Z

When I try the branch and enable MSAA I get a black screen (AMD Radeon with Mesa radeonsi driver).

That's interesting. Can you try with effects that use the main render target disabled, like heatHaze, bloom etc (or just use the lowest profile to make sure)? Also, does it work in the main menu?

slipher · 2025-01-05T05:27:06Z

I get a completely black screen (other than 2D drawing) with r_msaa 4 or 16 on Spacetracks. Plat23, on the other hand, renders. I tested with Nvidia on Windows; default cvars except with reliefmapping enabled.

slipher · 2025-01-11T01:06:39Z

Actually it's just black from whenever the 2nd map is loaded. Must be some cleanup bug

illwieckz · 2025-03-17T21:08:46Z

Can this be rebased on current master? 🙂️

VReaperV · 2025-03-17T23:09:50Z

Can this be rebased on current master? 🙂️

Done... but I haven't tested it after rebase, so I don't know if it still works lol.

illwieckz · 2025-03-17T23:34:17Z

It looks like the rebase went wrong! 😅️

/home/vsts/work/1/s/src/engine/renderer/tr_backend.cpp:3105:1: error: expected expression
<<<<<<< HEAD
^

VReaperV · 2025-08-31T10:50:45Z

I get a completely black screen (other than 2D drawing) with r_msaa 4 or 16 on Spacetracks. Plat23, on the other hand, renders. I tested with Nvidia on Windows; default cvars except with reliefmapping enabled.

Actually it's just black from whenever the 2nd map is loaded. Must be some cleanup bug

It looks like the rebase went wrong! 😅️

/home/vsts/work/1/s/src/engine/renderer/tr_backend.cpp:3105:1: error: expected expression
<<<<<<< HEAD
^

All fixed.

VReaperV · 2025-08-31T11:00:19Z

Nice! Finally some antialiasing!

It looks like when MSAA is enabled the heathaze from back surface is applied on front surfaces too: https://imgsli.com/MzMyODgx

The heatHaze is wrong because the heatHaze itself is drawn into the regular framebuffer, so this is an aliasing issue. It might be possible to make heatHaze render into an MSAA FBO, but I'm not sure it's worth the performance hit, since heatHaze with MSAA currently works as:
Resolve MSAA into main -> use main to render heatHaze surfaces into the other main FBO -> bind the other main FBO -> render distorted heatHaze surface from the first main FBO -> transition back into the MSAA FBO

To fix it, it would have to be:
At the start, create another MSAA FBO
Resolve MSAA into main -> use main to render heatHaze surfaces into the extra MSAA FBO -> resolve the extra FBO into other main FBO -> bind main FBO -> render distorted heatHaze surface from the other main FBO -> transition back into the MSAA FBO
Which adds more rendering into MSAA targets and extra resolves (the extra resolves could also be more of an issue if material system is disabled, since the core renderer doesn't group drawcalls anywhere as efficiently).

slipher · 2025-09-01T03:48:14Z

Works great on my favorite jaggies test case from Spacetracks!

Default:

With r_msaa 1 - somehow a lot better already. Is that even supposed to be different from having it off?

r_msaa 64

VReaperV · 2025-09-01T07:02:29Z

With r_msaa 1 - somehow a lot better already. Is that even supposed to be different from having it off?

It's most likely that the driver is actually using a higher value. The spec says:

samples represents a request for a desired minimum number of samples.
Since different implementations may support different sample counts for multisampled textures, the actual number of samples allocated for the texture image is
implementation-dependent. However, the resulting value for TEXTURE_SAMPLES
is guaranteed to be greater than or equal to samples and no more than the next
larger sample count supported by the implementation.

illwieckz · 2025-09-01T09:48:32Z

On my end it now works. I still get a black screen on AMD and Mesa when I use values higher than 8, but maybe we can cap that.

VReaperV · 2025-09-01T11:35:11Z

On my end it now works. I still get a black screen on AMD and Mesa when I use values higher than 8, but maybe we can cap that.

Does it say in the log that the samples requested were too high and it's falling back on some other value? According to https://opengl.gpuinfo.org/displaycapability.php?name=GL_MAX_COLOR_TEXTURE_SAMPLES, 8 is indeed the max for AMD, but the renderer should be automatically using that value if you specify a higher one.

illwieckz · 2025-09-01T11:41:37Z

Using 4 dynamic light layers, 64 dynamic lights available per tile 
Warn: MSAA samples 9 > 8, setting to 8 
The change to r_msaa will take effect after restart. 
Warn: R_CheckFBO: (msaa) Framebuffer incomplete attachment

After another vid_restart it works. So I guess we face some mess with the latching.

illwieckz · 2025-09-01T11:43:19Z

We probably need something similar to this, but for r_MSAA:

	// HACK: We want to set the current value, not the latched value
	Cvar::ClearFlags("r_customwidth", CVAR_LATCH);
	Cvar::ClearFlags("r_customheight", CVAR_LATCH);
	Cvar_Set( "r_customwidth", va("%d", windowConfig.vidWidth ) );
	Cvar_Set( "r_customheight", va("%d", windowConfig.vidHeight ) );
	Cvar::AddFlags("r_customwidth", CVAR_LATCH);
	Cvar::AddFlags("r_customheight", CVAR_LATCH);

VReaperV · 2025-09-01T11:45:09Z

Ah, yes. I'll add that a bit later.

slipher · 2025-09-01T11:47:02Z

We probably need something similar to this, but for r_MSAA:

Well that's only needed if you really want to use the cvar as a status display for the currently used value. Normally we try to avoid modifying cvars, and would store the current value in glConfig.msaa or something like that.

VReaperV · 2025-09-01T11:49:32Z

That's an option too.

illwieckz · 2025-09-01T12:05:38Z

The glConfig.msaa way is fine.

src/engine/renderer/tr_image.cpp

VReaperV · 2025-09-02T12:02:00Z

The glConfig.msaa way is fine.

That part is done now.

VReaperV · 2025-12-27T16:25:52Z

SSAO does not work.

Fixed.

VReaperV · 2025-12-27T16:26:43Z

Turning on r_msaa causes tone mapping to be disabled in my tests. This is the same issue as I saw in #1684 (comment) (but this time I took screenshots with r_toneMapping 0 to confirm that this is what is happening). I can't reproduce it manually, only in scripted tests, so I need to do more investigation on how to reproduce it.
Also color grading is missing in my tests so it's like the whole cameraEffects shader is skipped?

I'm unable to reproduce this on NV and on Intel Arc (both with proprietary drivers).

VReaperV · 2025-12-27T17:05:35Z

With conservative rasterisation I get seams with or without MSAA:

So perhaps there's an issue with the fog code as well.

slipher · 2025-12-28T08:31:47Z

Figured out what the tonemapping issue is. Nothing to do with my scripts; the problem is that screenshots are not the same as what you seen is on-screen. It seems to show the 3D drawing framebuffer before any color effects or 2D drawing.

VReaperV · 2025-12-28T14:56:57Z

Figured out what the tonemapping issue is. Nothing to do with my scripts; the problem is that screenshots are not the same as what you seen is on-screen. It seems to show the 3D drawing framebuffer before any color effects or 2D drawing.

I suppose it's down to the order in which console commands are processed. The screenshots could be deferred such that the screenshot command is always inserted before the end of list command (the console commands just raising a flag instead).

slipher · 2025-12-29T09:03:56Z

Yeah looks like RB_ReadPixels doesn't bother to select which framebuffer to read from. So it depends on the correct one being active by accident and this could depend on the sequence of RenderCommands.

src/engine/renderer/tr_backend.cpp

slipher

No regressions now and it looks great on my AMD card. Just a few nits.

src/engine/renderer/tr_backend.cpp

src/engine/renderer/tr_shade.cpp

slipher · 2026-01-03T08:40:44Z

src/engine/renderer/tr_image.cpp

+						GL_TexImage2D( target, 0, internalFormat, scaledWidth, scaledHeight, 0, format, GL_UNSIGNED_BYTE, scaledBuffer, isSRGB );
+					}
 				}
+				GL_CheckErrors();


GL_CheckErrors not needed here since it is done after the switch statement.

Where after the switch statement?

Maybe I should say after the outermost if/else. Right before the new location of switch ( image->internalFormat )

slipher · 2026-01-03T16:00:12Z

Also there should be an extension or version check for the needed OpenGL features. https://registry.khronos.org/OpenGL-Refpages/gl4/html/glTexImage2DMultisample.xhtml just says it is available from version 3.2.

VReaperV · 2026-01-04T00:16:28Z

Also there should be an extension or version check for the needed OpenGL features. https://registry.khronos.org/OpenGL-Refpages/gl4/html/glTexImage2DMultisample.xhtml just says it is available from version 3.2.

Jesus h. w. Christ

slipher · 2026-01-04T08:53:58Z

For some other cases where the GL version needs to be checked, I have done it like this:

if ( std::make_pair( glConfig.glMajor, glConfig.glMinor ) >= std::make_pair( 3, 2 ) )

VReaperV · 2026-01-04T20:00:34Z

For some other cases where the GL version needs to be checked, I have done it like this:
if ( std::make_pair( glConfig.glMajor, glConfig.glMinor ) >= std::make_pair( 3, 2 ) )

i added that.

slipher

Unfortunately I found another bug when trying a different graphics preset... when MSAA is on and SSAO is off, depth fade doesn't work (no alpha modification occurs). I reproduced it with Nvidia so you should hopefully be able to see it.

src/engine/renderer/tr_shade.cpp

VReaperV · 2026-01-09T01:17:12Z

Unfortunately I found another bug when trying a different graphics preset... when MSAA is on and SSAO is off, depth fade doesn't work (no alpha modification occurs). I reproduced it with Nvidia so you should hopefully be able to see it.

Fixed I think. Also added the missing MSAA resolve to global fog.

Add `r_msaa`. When set to > 0, an MSAA FBO will be created with that many samples. This FBO will be used for rendering, other than when it requires sampling from current render/depth image. When such rendering is required the MSAA FBO will be blit into the main FBO and vice versa, to resolve the MSAA texture.

VReaperV added A-Renderer T-Feature-Request Proposed new feature labels Dec 27, 2024

VReaperV force-pushed the msaa branch from d4fdbdd to 9e131a9 Compare March 17, 2025 23:08

VReaperV force-pushed the msaa branch 2 times, most recently from 27484ca to a80b19e Compare August 31, 2025 10:50

VReaperV force-pushed the msaa branch from a80b19e to 5b6b719 Compare August 31, 2025 11:01

slipher reviewed Sep 1, 2025

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VReaperV force-pushed the msaa branch from 5b6b719 to 1e91eb0 Compare September 2, 2025 12:01

VReaperV force-pushed the msaa branch from fe88177 to 55cef7b Compare September 5, 2025 01:09

VReaperV force-pushed the msaa branch from e281d9c to e224c48 Compare December 27, 2025 16:25

slipher mentioned this pull request Dec 29, 2025

Implement PushBuffer #1684

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slipher reviewed Jan 2, 2026

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slipher reviewed Jan 3, 2026

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slipher mentioned this pull request Jan 3, 2026

Fix screenshots with read-only depth buffer #1882

Merged

VReaperV force-pushed the msaa branch from 69a6655 to 0fdcaff Compare January 4, 2026 00:13

VReaperV force-pushed the msaa branch from 850fdd5 to 76339ca Compare January 6, 2026 12:36

slipher reviewed Jan 8, 2026

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src/engine/renderer/tr_shade.cpp Show resolved Hide resolved

VReaperV force-pushed the msaa branch from 76339ca to b80e615 Compare January 9, 2026 00:47

VReaperV force-pushed the msaa branch from 90d86b3 to 0d7ec88 Compare January 9, 2026 01:17

VReaperV added 8 commits January 9, 2026 04:38

R_UploadImage(): early return for MSAA images

b2f51b6

MSAA clean-up and fixes

bb3dee8

Fix fog and transparent surfaces with MSAA

d201588

MSAA: clean-up FBO bindings

7b07434

Clean-up Render_generic3D() MSAA resolve

2cdcc89

Add a GL version check for MSAA

353b2ce

Fix MSAA with depth-fade and global fog

26720f5

VReaperV force-pushed the msaa branch from 0d7ec88 to 26720f5 Compare January 9, 2026 01:38

Implement MSAA #1480

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Implement MSAA #1480

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