一. lq的解码过程 lightmapCommon.ush GetLightMapColorLQ()函数:
1. 纹理采样:
2. 亮度、颜色还原
3. 还原亮度
4. 还原最大贡献方向
5. 最终颜色还原
二、 hq解码过程 lightmapCommon.ush GetLightMapColorHQ()函数
1. 纹理采样:分为有vt和没有vt:
2. 亮度还原
3. 颜色还原
4. 还原方向,是否定义方向,是否是双向植被:
5. 最终颜色:
三、 skyOcclusion和aomaterialMask的解码
float4 GetSkyBentNormalAndOcclusion(VTPageTableResult LightmapVTPageTableResult, float2 LightmapUV, uint LightmapDataIndex, float2 SvPositionXY) { float4 TextureValue; #if LIGHTMAP_VT_ENABLED TextureValue = SampleLightmapVT( LightmapVTPageTableResult, 3u, LightmapDataIndex, LightmapResourceCluster.VTSkyOcclusionTexture, LIGHTMAP_SHARED_SAMPLER(SkyOcclusionSampler)); #else TextureValue = Texture2DSample( LightmapResourceCluster.SkyOcclusionTexture, LIGHTMAP_SHARED_SAMPLER(SkyOcclusionSampler), LightmapUV ); #endif // Unpack vector TextureValue.rgb = TextureValue.rgb * 2 - 1; // Undo sqrt which allocated more precision toward 0 TextureValue.a = TextureValue.a * TextureValue.a; return TextureValue; } float GetAOMaterialMask(VTPageTableResult LightmapVTPageTableResult, float2 LightmapUV, uint LightmapDataIndex, float2 SvPositionXY) { float TextureValue; #if LIGHTMAP_VT_ENABLED TextureValue = SampleLightmapVT( LightmapVTPageTableResult, 4u, LightmapDataIndex, LightmapResourceCluster.VTAOMaterialMaskTexture, LIGHTMAP_SHARED_SAMPLER(AOMaterialMaskSampler)).x; #else TextureValue = Texture2DSample( LightmapResourceCluster.AOMaterialMaskTexture, LIGHTMAP_SHARED_SAMPLER(AOMaterialMaskSampler), LightmapUV ).x; #endif // Undo sqrt which allocated more precision toward 0 return TextureValue * TextureValue; }
四、 ue4 lightmap编码特点的思考:
1. 好处:
2. 不足: