If you just need to read what i’ve done to fix MSAA go into LoST section.

Story

One day one of my friends send me a message with a two simple sentances:

Why your screenshots so jittery and aliased? Fix it!

Without any arguing that i was lazy for that i chose MSAA for my main AA alghorithm. I Thought that it would be easy to implement it! Just add some checks, change some things here add some code here and should be working!

Right?

Wrong!

When i started digging i saw how many things must be done in order to enable and use MSAA. I’ll skip a whole story about how i rage each time when i fail to make MSAA work, so bear with me.

Last day i was reading an article written by Turanszkij and i saw a link to his discord server.

This guy helped me a lot and saved a lot of time for future me.

In case you barly see image or can barely read what he wrote:

@SweetLuna Check the debug layer if it outputs anything when you render to MSAA texture. Also check that you have set a proper sample mask with OMSetBlendState that allows all samples to be written

So thanks to him i finally made MSAA work.

Results

Without MSAA

MSAA x8

Close look at bridge without MSAA

MSAA x8

LoST for MSAA

List of several things that i encountered with when i tried integrating MSAA into my own engine.

1. Check if current device/hardware/software can handle MSAA for this exact DXGI_FORMAT.
   • If yes, then what is max level?
   • If returned Quality > 0 and SampleCount > 1
     • This device/hardware/software supports MSAA for this format with SampleCount levels.

The way how i check for MSAA support can be found here and here.

1. Each RTV that has type of Texture2DMS must have exact RTV but with type of Texture2D.
2. For DSV that has SampleCount > 1 must have:
   • Must have same DSV with No MSAA and No UAV.
   • Must have same DSV with No MSAA, W/ UAV, and without DSV/RTV.
3. Enable MSAA in RasterState.

   MultisampleEnable = true;
   

4. Set Sample Mask for BlendState to 0xFFFFFFFF.

   Mine was always set to 1, and i always wondered why only 1st sample had data, when rest of them - don’t?

5. For each RTV MSAA reolve is simple. Just call

   ID3D11DeviceContext::ResolveSubresource(ID3D11Resource *Dest, UINT DestSubres, 
                                        ID3D11Resource *Src, UINT SrcSubres, 
                                        DXGI_FORMAT format);
   

6. For depth you do this by hand. I use similar technique as described by Turanszkij for WikedEngine.
   • Bind no MSAA depth buffer (the one with UAV) to UAV slot for compute shader.
   • Bind original depth buffer with MSAA to SRV slot.
   • Dispatch * Shader can be found here * Depth MSAA resolving function in my RenderTarget class can be found here
7. Add SV_SampleIndex for input into rendering shader.

   GBuffer main(PS In, bool bIsFront : SV_IsFrontFace, uint SampleIndex : SV_SampleIndex) {
   

8. Replace in every shader where you sample original SRV (with MSAA) Texture2D with Texture2DMS.
9. Store for each RTV and DSV(for 3rd one you don’t need this) created their SampleCount.

References

• How to resolve an MSAA depthbuffer from wickedengine
• How to sample a SRV when enable msaa x4?DirectX11
• How to enable MSAA in DirectX 11
• Cannot enable 4X MSAA Anti-Aliasing in DirectX 11
• dx12 open 4x msaa failed
• Enable MSAA in DirectX 11
• Sampling MSAA from DirectX 11
• Multisampling (MSAA) for DirectX11/DirectX10 with D3DImage shared resource
• Get the MSAA sample number inside pixelshader for OIT
• Custom MSAA in pixel shader with DX11
• D3D11 Render to Texture Transparency/MSAA Issue
• DX9, rendertargets and MSAA
• Deferred rendering + MRT + MSAA
• How to enable MSAA in DirectX 11
• Deferred Shading MSAA Sample
• DeferredShadingMSAA.cpp
• Lighting_FS.glsl
• Deferred MSAA Artifacting
• Deferred Rendering w/ MSAA - MSAA Z Prepass Idea
• MSAA in Deferred shading
• MSAA with Deferred shading
• Single Pass MSAA Deferred Rendering - Dithered Deferred Rendering Idea
• Deferred MSAA
• Beware of SV_Coverage
• Semantics for HLSL at MSDN