repair ShadowOptions::shadowFar

the shadow far plane (shadowFar) was only partially taken into account

android/filament-android/src/main/java/com/google/android/filament/LightManager.java

@@ -258,6 +258,7 @@ public static class ShadowOptions {
          * shadows that are too far and wouldn't contribute to the scene much, improving
          * performance and quality. This value is always positive.
          * Use 0.0f to use the camera far distance.
+         * This only affect directional lights.
          */
         public float shadowFar = 0.0f;
 

filament/include/filament/LightManager.h

@@ -245,6 +245,7 @@ class UTILS_PUBLIC LightManager : public FilamentAPI {
          * shadows that are too far and wouldn't contribute to the scene much, improving
          * performance and quality. This value is always positive.
          * Use 0.0f to use the camera far distance.
+         * This only affect directional lights.
          */
         float shadowFar = 0.0f;
 

filament/src/ShadowMap.cpp

@@ -131,19 +131,6 @@ ShadowMap::ShaderParameters ShadowMap::updateDirectional(FEngine& engine,
     else            params.options.shadowFarHint = dzf * dz + camera.zf;
 #endif
 
-    // Adjust the camera's projection for the light's shadowFar
-    const mat4f cullingProjection{ [&](auto p) {
-        if (params.options.shadowFar > 0.0f) {
-            float const n = camera.zn;
-            float const f = params.options.shadowFar;
-            // orthographic projection
-            assert_invariant(std::abs(p[2].w) <= std::numeric_limits<float>::epsilon());
-            p[2].z =    2.0f / (n - f);
-            p[3].z = (f + n) / (n - f);
-        }
-        return p;
-    }(camera.cullingProjection) };
-
     const auto direction = params.options.transform * lightData.elementAt<FScene::DIRECTION>(index);
 
     /*
@@ -164,7 +151,7 @@ ShadowMap::ShaderParameters ShadowMap::updateDirectional(FEngine& engine,
 
     // view frustum vertices in world-space
     float3 wsViewFrustumVertices[8];
-    const mat4f worldToClipMatrix = cullingProjection * camera.view;
+    const mat4f worldToClipMatrix = camera.cullingProjection * camera.view;
     const Frustum wsFrustum(worldToClipMatrix);
     computeFrustumCorners(wsViewFrustumVertices, inverse(worldToClipMatrix), sceneInfo.csNearFar);
 
@@ -243,7 +230,7 @@ ShadowMap::ShaderParameters ShadowMap::updateDirectional(FEngine& engine,
         // in stable mode we simply take the view volume bounding sphere, but we calculate it
         // in view space, so that it's perfectly stable.
         float3 vertices[8];
-        computeFrustumCorners(vertices, inverse(cullingProjection), sceneInfo.csNearFar);
+        computeFrustumCorners(vertices, inverse(camera.cullingProjection), sceneInfo.csNearFar);
         viewVolumeBoundingSphere = computeBoundingSphere(vertices, 8);
 
         if (shadowReceiverVolumeBoundingSphere.w < viewVolumeBoundingSphere.w) {
@@ -1081,7 +1068,7 @@ bool ShadowMap::intersectSegmentWithPlanarQuad(float3& UTILS_RESTRICT p,
 }
 
 float ShadowMap::texelSizeWorldSpace(const mat3f& worldToShadowTexture,
-        uint16_t shadowDimension) const noexcept {
+        uint16_t shadowDimension) noexcept {
     // The Jacobian of the transformation from texture-to-world is the matrix itself for
     // orthographic projections. We just need to inverse worldToShadowTexture,
     // which is guaranteed to be orthographic.
@@ -1096,7 +1083,7 @@ float ShadowMap::texelSizeWorldSpace(const mat3f& worldToShadowTexture,
 }
 
 float ShadowMap::texelSizeWorldSpace(const mat4f& Wp, const mat4f& MbMtF,
-        uint16_t shadowDimension) const noexcept {
+        uint16_t shadowDimension) noexcept {
     // Here we compute the Jacobian of inverse(MbMtF * Wp).
     // The expression below has been computed with Mathematica. However, it's not very hard,
     // albeit error-prone, to do it by hand because MbMtF is a linear transform.
@@ -1117,7 +1104,7 @@ float ShadowMap::texelSizeWorldSpace(const mat4f& Wp, const mat4f& MbMtF,
 
     constexpr bool JACOBIAN_ESTIMATE = false;
     if constexpr (JACOBIAN_ESTIMATE) {
-        // this estimates the Jacobian -- this is a lot heavier. This is mostly for reference
+        // This estimates the Jacobian -- this is a lot heavier. This is mostly for reference
         // and testing.
         const mat4f Si(inverse(MbMtF * Wp));
         const float3 p0 = mat4f::project(Si, p);

filament/src/ShadowMap.h

@@ -283,11 +283,11 @@ class ShadowMap {
 
     math::float4 getClampToEdgeCoords(ShadowMapInfo const& shadowMapInfo) const noexcept;
 
-    float texelSizeWorldSpace(const math::mat3f& worldToShadowTexture,
-            uint16_t shadowDimension) const noexcept;
+    static float texelSizeWorldSpace(const math::mat3f& worldToShadowTexture,
+            uint16_t shadowDimension) noexcept;
 
-    float texelSizeWorldSpace(const math::mat4f& W, const math::mat4f& MbMtF,
-            uint16_t shadowDimension) const noexcept;
+    static float texelSizeWorldSpace(const math::mat4f& W, const math::mat4f& MbMtF,
+            uint16_t shadowDimension) noexcept;
 
     static constexpr const Segment sBoxSegments[12] = {
             { 0, 1 }, { 1, 3 }, { 3, 2 }, { 2, 0 },

filament/src/ShadowMapManager.cpp

@@ -435,15 +435,34 @@ FrameGraphId<FrameGraphTexture> ShadowMapManager::render(FEngine& engine, FrameG
 }
 
 ShadowMapManager::ShadowTechnique ShadowMapManager::updateCascadeShadowMaps(FEngine& engine,
-        FView& view, CameraInfo const& cameraInfo, FScene::RenderableSoa& renderableData,
+        FView& view, CameraInfo cameraInfo, FScene::RenderableSoa& renderableData,
         FScene::LightSoa const& lightData, ShadowMap::SceneInfo sceneInfo) noexcept {
+
     FScene* scene = view.getScene();
     auto& lcm = engine.getLightManager();
 
     FLightManager::Instance const directionalLight = lightData.elementAt<FScene::LIGHT_INSTANCE>(0);
     FLightManager::ShadowOptions const& options = lcm.getShadowOptions(directionalLight);
     FLightManager::ShadowParams const& params = lcm.getShadowParams(directionalLight);
 
+    // Adjust the camera's projection for the light's shadowFar
+
+    cameraInfo.zf = params.options.shadowFar > 0.0f ? params.options.shadowFar : cameraInfo.zf;
+    if (UTILS_UNLIKELY(params.options.shadowFar > 0.0f)) {
+        cameraInfo.zf = params.options.shadowFar;
+        float const n = cameraInfo.zn;
+        float const f = cameraInfo.zf;
+        if (std::abs(cameraInfo.cullingProjection[2].w) > std::numeric_limits<float>::epsilon()) {
+            // perspective projection
+            cameraInfo.cullingProjection[2].z = (f + n) / (n - f);
+            cameraInfo.cullingProjection[3].z = (2 * f * n) / (n - f);
+        } else {
+            // orthographic projection
+            cameraInfo.cullingProjection[2].z = 2.0f / (n - f);
+            cameraInfo.cullingProjection[3].z = (f + n) / (n - f);
+        }
+    }
+
     const ShadowMap::ShadowMapInfo shadowMapInfo{
             .atlasDimension      = mTextureAtlasRequirements.size,
             .textureDimension    = uint16_t(options.mapSize),

filament/src/ShadowMapManager.h

@@ -109,7 +109,7 @@ class ShadowMapManager {
 
 private:
     ShadowMapManager::ShadowTechnique updateCascadeShadowMaps(FEngine& engine,
-            FView& view, CameraInfo const& cameraInfo, FScene::RenderableSoa& renderableData,
+            FView& view, CameraInfo cameraInfo, FScene::RenderableSoa& renderableData,
             FScene::LightSoa const& lightData, ShadowMap::SceneInfo sceneInfo) noexcept;
 
     ShadowMapManager::ShadowTechnique updateSpotShadowMaps(FEngine& engine,