Compensate PCSS kernel with depth range for directional lights (#5441)

* Compensate PCSS kernel with depth range for directional lights * Copy depth range values to render data and initialize properly. * Save only the depth range compensation we want in the light render data and submit directly.
playcanvas · Jun 28, 2023 · 1855a58 · 1855a58
1 parent c30f8d8
commit 1855a58
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Showing 4 changed files with 8 additions and 5 deletions.
diff --git a/src/scene/light.js b/src/scene/light.js
@@ -65,6 +65,9 @@ class LightRenderData {
         // scissor rectangle for the shadow rendering to the texture (x, y, width, height)
         this.shadowScissor = new Vec4(0, 0, 1, 1);
 
+        // depth range compensation for PCSS with directional lights
+        this.depthRangeCompensation = 0;
+
         // face index, value is based on light type:
         // - spot: always 0
         // - omni: cubemap face, 0..5

diff --git a/src/scene/renderer/forward-renderer.js b/src/scene/renderer/forward-renderer.js
@@ -263,7 +263,7 @@ class ForwardRenderer extends Renderer {
 
                 const cameraParams = directional._shadowCameraParams;
                 cameraParams.length = 4;
-                cameraParams[0] = 0;
+                cameraParams[0] = lightRenderData.depthRangeCompensation;
                 cameraParams[1] = lightRenderData.shadowCamera._farClip;
                 cameraParams[2] = lightRenderData.shadowCamera._nearClip;
                 cameraParams[3] = 1;
@@ -337,7 +337,7 @@ class ForwardRenderer extends Renderer {
             const cameraParams = omni._shadowCameraParams;
 
             cameraParams.length = 4;
-            cameraParams[0] = 0;
+            cameraParams[0] = 1;
             cameraParams[1] = lightRenderData.shadowCamera._farClip;
             cameraParams[2] = lightRenderData.shadowCamera._nearClip;
             cameraParams[3] = 0;
@@ -405,7 +405,7 @@ class ForwardRenderer extends Renderer {
 
             const cameraParams = spot._shadowCameraParams;
             cameraParams.length = 4;
-            cameraParams[0] = 0;
+            cameraParams[0] = 1;
             cameraParams[1] = lightRenderData.shadowCamera._farClip;
             cameraParams[2] = lightRenderData.shadowCamera._nearClip;
             cameraParams[3] = 0;

diff --git a/src/scene/renderer/shadow-renderer-directional.js b/src/scene/renderer/shadow-renderer-directional.js
@@ -173,6 +173,7 @@ class ShadowRendererDirectional {
             // calculate depth range of the caster's AABB from the point of view of the shadow camera
             shadowCamView.copy(shadowCamNode.getWorldTransform()).invert();
             const depthRange = getDepthRange(shadowCamView, visibleSceneAabb.getMin(), visibleSceneAabb.getMax());
+            lightRenderData.depthRangeCompensation = (depthRange.max - depthRange.min) / light.shadowDistance;
 
             // adjust shadow camera's near and far plane to the depth range of casters to maximize precision
             // of values stored in the shadow map. Make it slightly larger to avoid clipping on near / far plane.

diff --git a/src/scene/shader-lib/chunks/lit/frag/shadowPCSS.js b/src/scene/shader-lib/chunks/lit/frag/shadowPCSS.js
@@ -87,13 +87,12 @@ float PCSS(TEXTURE_ACCEPT(shadowMap), vec3 shadowCoords, vec4 cameraParams, vec2
         samplePoints[i] = vogelDisk(i, float(PCSS_SAMPLE_COUNT), noise, pcssPresample);
     }
 
-    // Calculate the ratio of FOV between 45.0 degrees (tan(45) == 1) and the FOV of the camera    
     float averageBlocker = PCSSBlockerDistance(TEXTURE_PASS(shadowMap), samplePoints, shadowCoords.xy, shadowSearchArea, receiverDepth);
     if (averageBlocker == -1.0) {
         return 1.0;
     } else {
 
-        vec2 filterRadius = ((receiverDepth - averageBlocker) / averageBlocker) * shadowSearchArea;
+        vec2 filterRadius = ((receiverDepth - averageBlocker) / averageBlocker) * shadowSearchArea * cameraParams.x;
 
         float shadow = 0.0;