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73 行
3.7 KiB
73 行
3.7 KiB
/*#ifndef SHADERGRAPH_PREVIEW
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real SampleShadowmapDirect(TEXTURE2D_SHADOW_PARAM(ShadowMap, sampler_ShadowMap), SamplerState PointClamp, float4 shadowCoord, ShadowSamplingData samplingData, bool isPerspectiveProjection = true)
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{
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// Compiler will optimize this branch away as long as isPerspectiveProjection is known at compile time
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if (isPerspectiveProjection)
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shadowCoord.xyz /= shadowCoord.w;
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real distance;
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// Instead of getting a value of 0 or 1 depending on a shadowmap comparison, we want to actually sample the shadowmap's values
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distance = SAMPLE_TEXTURE2D_LOD(ShadowMap, PointClamp, shadowCoord.xy, 0);
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//int smWidth, smHeight;
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//ShadowMap.GetDimensions(smWidth, smHeight);
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//shadowCoord = saturate(shadowCoord);
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//distance = ShadowMap[int2(smWidth * shadowCoord.x, smHeight * shadowCoord.y)];
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return distance;
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}
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#endif*/
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void MainLightBlurShadow_half(half rand, half fadeTightness, SamplerState pointClamp, half blurRadius, half3 worldPos, out half shadowAtten)
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{
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#if SHADERGRAPH_PREVIEW
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shadowAtten = 1;
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#else
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const int NUM_STEPS = 40;
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float oneDivNumSteps = 1.0 / NUM_STEPS;
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Light mainLight = GetMainLight();
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shadowAtten = 1;
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ShadowSamplingData shadowSamplingData = GetMainLightShadowSamplingData();
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for (int i = 0; i < NUM_STEPS; i++)
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{
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//Instead of sampling the position of the current pixel, sample a point that's a i steps away, in a semi-randomized direction
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//the starting direction is randomized and then the direction is rotated by "i" radians every iteration
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half3 newWorldPos = worldPos + half3(sin(rand + i), 0, cos(rand + i)) * i * oneDivNumSteps * blurRadius;
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#if SHADOWS_SCREEN
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half4 clipPos = TransformWorldToHClip(newWorldPos);
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half4 shadowCoord = ComputeScreenPos(clipPos);
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#else
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half4 shadowCoord = TransformWorldToShadowCoord(newWorldPos);
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#endif
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#ifdef _MAIN_LIGHT_SHADOWS_CASCADE
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half cascadeIndex = ComputeCascadeIndex(newWorldPos);
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#else
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half cascadeIndex = 0;
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#endif
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float shadowScale = pow(_MainLightWorldToShadow[cascadeIndex], 0.7) * 20; // Some "Magic Math" to try to make transitions between cascades smoother
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//float shadowMapSample = SampleShadowmapDirect(TEXTURE2D_ARGS(_MainLightShadowmapTexture, sampler_MainLightShadowmapTexture), pointClamp, shadowCoord, shadowSamplingData, false);
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float shadowMapSample = SAMPLE_TEXTURE2D_LOD(_MainLightShadowmapTexture, pointClamp, shadowCoord.xy, 0);
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#if defined(SHADER_API_GLES3) || defined(SHADER_API_GLES) || defined(SHADER_API_GLCORE)
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shadowMapSample = 1 - shadowMapSample;
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shadowCoord.z = 1 - shadowCoord.z;
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#endif
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float shadowCoordPos = shadowCoord.z / shadowScale; //Divide by shadowScale to get transitions more close-ish when using shadow cascades
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float shadowMapPos = shadowMapSample / shadowScale;
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//blurAmount is a value between 0 and 1 expressing how much to blur
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float blurAmount = max(0.01, ((shadowMapPos - shadowCoordPos) * fadeTightness));
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float oneDivBlurAmount = 1 / saturate(blurAmount);
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//0 or 1 depending on whether a shadow is being cast
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float isInShadow = step(shadowCoord.z, shadowMapSample);
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// reduce the influence of higher iterations (further out samples) if the sampled shadowmap value is close to our position
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float tightenCloseShadows = clamp((NUM_STEPS - i * oneDivBlurAmount), 0, oneDivBlurAmount * 2);
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// reduce the influence of lower iterations (closer in samples) if the sampled shadowmap value is far way from our position
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float reduceInnerIterations = max(step(saturate(blurAmount) * NUM_STEPS / 4, i + 1), 0.3);
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shadowAtten -= isInShadow * oneDivNumSteps * tightenCloseShadows * reduceInnerIterations;
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// If the position is out of shadow distance, just return 1
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shadowAtten = BEYOND_SHADOW_FAR(shadowCoord) ? 1.0 : saturate(shadowAtten);
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}
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#endif
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}
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