45 lines
1.5 KiB
Markdown
45 lines
1.5 KiB
Markdown
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---
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title: 深度相关
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date: 2024-09-09 16:49:08
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excerpt:
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tags:
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rating: ⭐
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---
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# 相关代码
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位于common.ush
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```c++
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#define NearDepthValue (HAS_INVERTED_Z_BUFFER ? 1.0f : 0.0f)
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#define FarDepthValue (HAS_INVERTED_Z_BUFFER ? 0.0f : 1.0f)
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```
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可以通过**DeviceZ == FarDepthValue**来判断是否处于最远端。
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```c++
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float DeviceZ = DepthReadDisabled ? FarDepthValue : LookupDeviceZ(UvBuffer);
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#endif
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if (DeviceZ == FarDepthValue)
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{
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// Get the light disk luminance to draw
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LuminanceScale = SkyAtmosphere.SkyLuminanceFactor;
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#if SOURCE_DISK_ENABLED
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if (SourceDiskEnabled > 0)
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{
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PreExposedL += GetLightDiskLuminance(WorldPos, WorldDir, 0);
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#if SECOND_ATMOSPHERE_LIGHT_ENABLED
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PreExposedL += GetLightDiskLuminance(WorldPos, WorldDir, 1);
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#endif
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}
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#endif
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#if RENDERSKY_ENABLED==0
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// We should not render the sky and the current pixels are at far depth, so simply early exit.
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// We enable depth bound when supported to not have to even process those pixels.
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OutLuminance = PrepareOutput(float3(0.0f, 0.0f, 0.0f), float3(1.0f, 1.0f, 1.0f));
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//Now the sky pass can ignore the pixel with depth == far but it will need to alpha clip because not all RHI backend support depthbound tests.
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// And the depthtest is already setup to avoid writing all the pixel closer than to the camera than the start distance (very good optimisation).
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// Since this shader does not write to depth or stencil it should still benefit from EArlyZ even with the clip (See AMD depth-in-depth documentation)
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clip(-1.0f);
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return;
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#endif
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```
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