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// - _ENABLE_FOG_ON_TRANSPARENT if fog is enable on transparent surface |
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//----------------------------------------------------------------------------- |
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// ApplyBlendMode function |
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//----------------------------------------------------------------------------- |
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float4 ApplyBlendMode(float3 diffuseLighting, float3 specularLighting, float opacity) |
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{ |
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// ref: http://advances.realtimerendering.com/other/2016/naughty_dog/NaughtyDog_TechArt_Final.pdf |
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// Lit transparent object should have reflection and tramission. |
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// Transmission when not using "rough refraction mode" (with fetch in preblured background) is handled with blend mode. |
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// However reflection should not be affected by blend mode. For example a glass should still display reflection and not lose the highlight when blend |
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// This is the purpose of following function, "Cancel" the blend mode effect on the specular lighting but not on the diffuse lighting |
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#ifdef _BLENDMODE_PRESERVE_SPECULAR_LIGHTING |
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// In the case of _BLENDMODE_ALPHA the code should be float4(diffuseLighting + (specularLighting / max(opacity, 0.01)), opacity) |
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// However this have precision issue when reaching 0, so we change the blend mode and apply src * src_a inside the shader instead |
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#if defined(_BLENDMODE_ADD) || defined(_BLENDMODE_ALPHA) |
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return float4(diffuseLighting * opacity + specularLighting, opacity); |
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#else // defined(_BLENDMODE_MULTIPLY) || defined(_BLENDMODE_PRE_MULTIPLY) |
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return float4(diffuseLighting + specularLighting, opacity); |
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#endif |
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#else |
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#if defined(_BLENDMODE_ADD) || defined(_BLENDMODE_ALPHA) |
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return float4((diffuseLighting + specularLighting) * opacity, opacity); |
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#else // defined(_BLENDMODE_MULTIPLY) || defined(_BLENDMODE_PRE_MULTIPLY) |
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return float4(diffuseLighting + specularLighting, opacity); |
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#endif |
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#endif |
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} |
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float4 ApplyBlendMode(float3 color, float opacity) |
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{ |
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return ApplyBlendMode(color, float3(0.0, 0.0, 0.0), opacity); |
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} |
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//----------------------------------------------------------------------------- |
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// This must be call after ApplyBlendMode to work correctly |
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float4 EvaluateAtmosphericScattering(PositionInputs posInput, float4 inputColor) |
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{ |
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float4 result = inputColor; |
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#if defined(_BLENDMODE_ALPHA) |
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// Regular alpha blend only need a lerp to work |
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result.rgb = lerp(result.rgb, fog.rgb, fog.a); |
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// Regular alpha blend need to multiply fog color by opacity (as we do src * src_a inside the shader) |
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result.rgb = lerp(result.rgb, fog.rgb * result.a, fog.a); |
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#elif defined(_BLENDMODE_ADD) |
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// For additive, we just need to fade to black with fog density (black + background == background color == fog color) |
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result.rgb = result.rgb * (1.0 - fog.a); |
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// For Pre-Multiplied Alpha Blend, we need to multiply fog color by src alpha to match regular alpha blending formula. |
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result.rgb = lerp(result.rgb, fog.rgb * result.a, fog.a); |
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#endif |
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#else |
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// Evaluation of fog for opaque objects is currently done in a full screen pass independent from any material parameters. |
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// but this funtction is called in generic forward shader code so we need it to be neutral in this case. |
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GitHub
7 年前