设置颜色到材质球时的注意事项

设置颜色到材质球时的注意事项

00 前置知识

在非材质球面板上的颜色, 都是Gamma颜色, 在传入材质或Shader全局变量的时候, 需要根据当前项目的空间进行转化.

在Library/PackageCache/com.unity.render-pipelines.universal@12.1.10/Runtime/UniversalRenderPipeline.cs文件中

static void SetupPerFrameShaderConstants()
{
    using var profScope = new ProfilingScope(null, Profiling.Pipeline.setupPerFrameShaderConstants);

    // When glossy reflections are OFF in the shader we set a constant color to use as indirect specular
    SphericalHarmonicsL2 ambientSH = RenderSettings.ambientProbe;
    Color linearGlossyEnvColor = new Color(ambientSH[0, 0], ambientSH[1, 0], ambientSH[2, 0]) * RenderSettings.reflectionIntensity;
    Color glossyEnvColor = CoreUtils.ConvertLinearToActiveColorSpace(linearGlossyEnvColor);
    Shader.SetGlobalVector(ShaderPropertyId.glossyEnvironmentColor, glossyEnvColor);

    // Used as fallback cubemap for reflections
    Shader.SetGlobalVector(ShaderPropertyId.glossyEnvironmentCubeMapHDR, ReflectionProbe.defaultTextureHDRDecodeValues);
    Shader.SetGlobalTexture(ShaderPropertyId.glossyEnvironmentCubeMap, ReflectionProbe.defaultTexture);

    // Ambient
    Shader.SetGlobalVector(ShaderPropertyId.ambientSkyColor, CoreUtils.ConvertSRGBToActiveColorSpace(RenderSettings.ambientSkyColor));
    Shader.SetGlobalVector(ShaderPropertyId.ambientEquatorColor, CoreUtils.ConvertSRGBToActiveColorSpace(RenderSettings.ambientEquatorColor));
    Shader.SetGlobalVector(ShaderPropertyId.ambientGroundColor, CoreUtils.ConvertSRGBToActiveColorSpace(RenderSettings.ambientGroundColor));

    // Used when subtractive mode is selected
    Shader.SetGlobalVector(ShaderPropertyId.subtractiveShadowColor, CoreUtils.ConvertSRGBToActiveColorSpace(RenderSettings.subtractiveShadowColor));

    // Required for 2D Unlit Shadergraph master node as it doesn't currently support hidden properties.
    Shader.SetGlobalColor(ShaderPropertyId.rendererColor, Color.white);
}

注意这几段关于环境颜色的设置

	// Ambient
    Shader.SetGlobalVector(ShaderPropertyId.ambientSkyColor, CoreUtils.ConvertSRGBToActiveColorSpace(RenderSettings.ambientSkyColor));
    Shader.SetGlobalVector(ShaderPropertyId.ambientEquatorColor, CoreUtils.ConvertSRGBToActiveColorSpace(RenderSettings.ambientEquatorColor));
    Shader.SetGlobalVector(ShaderPropertyId.ambientGroundColor, CoreUtils.ConvertSRGBToActiveColorSpace(RenderSettings.ambientGroundColor));

这里都是使用了CoreUtils.ConvertSRGBToActiveColorSpace()函数对颜色进行转换的.

具体方法在Library/PackageCache/com.unity.render-pipelines.core@12.1.10/Runtime/Utilities/CoreUtils.cs文件中

// Color space utilities
/// <summary>
/// Converts the provided sRGB color to the current active color space.
/// </summary>
/// <param name="color">Input color.</param>
/// <returns>Linear color if the active color space is ColorSpace.Linear, the original input otherwise.</returns>
public static Color ConvertSRGBToActiveColorSpace(Color color)
{
    return (QualitySettings.activeColorSpace == ColorSpace.Linear) ? color.linear : color;
}

01 实施

对于任何的HDR颜色, 都要通过Vector进行传入, 且传入前都要调用Api进行CoreUtils.ConvertSRGBToActiveColorSpace()进行颜色空间适配.

参考网页