add bias for planar shadow (#16316)

cocos/render-scene/scene/shadows.ts

@@ -255,6 +255,18 @@ export class Shadows {
         this._distance = val;
     }
 
+    /**
+     * @en Positional offset values in planar shading calculations.
+     * @zh 平面阴影计算中的位置偏移值。
+     */
+    get planeBias (): number {
+        return this._planeBias;
+    }
+
+    set planeBias (val: number) {
+        this._planeBias = val;
+    }
+
     /**
      * @en Shadow color.
      * @zh 阴影颜色。
@@ -326,6 +338,7 @@ export class Shadows {
     protected _enabled = false;
     protected _type = SHADOW_TYPE_NONE;
     protected _distance = 0;
+    protected _planeBias = 1.0;
     protected _normal = new Vec3(0, 1, 0);
     protected _shadowColor = new Color(0, 0, 0, 76);
     protected _size: Vec2 = new Vec2(1024, 1024);
@@ -356,6 +369,7 @@ export class Shadows {
 
         this.normal = shadowsInfo.planeDirection;
         this.distance = shadowsInfo.planeHeight;
+        this.planeBias = shadowsInfo.planeBias;
         this.shadowColor = shadowsInfo.shadowColor;
         this.maxReceived = shadowsInfo.maxReceived;
         if (shadowsInfo.shadowMapSize !== this._size.x) {

cocos/rendering/custom/web-pipeline.ts

@@ -625,6 +625,11 @@ function setShadowUBOView (setter: WebSetter, camera: Camera | null, layout = 'd
                 _uboVec.set(_uboVec3.x, _uboVec3.y, _uboVec3.z, -shadowInfo.distance);
                 setter.offsetVec4(_uboVec, uniformOffset);
             }
+            uniformOffset = setter.getUniformOffset('cc_shadowWHPBInfo', Type.FLOAT4);
+            if (setter.hasUniform(uniformOffset)) {
+                _uboVec.set(0, 0, 0, shadowInfo.planeBias);
+                setter.offsetVec4(_uboVec, uniformOffset);
+            }
         }
         if (hasCCShadow) {
             setter.setCurrConstant('CCShadow', layout);

cocos/rendering/pipeline-ubo.ts

@@ -319,6 +319,8 @@ export class PipelineUBO {
                 }
             } else {
                 PipelineUBO.updatePlanarNormalAndDistance(shadowInfo, sv);
+                _vec4ShadowInfo.set(0, 0, 0, shadowInfo.planeBias);
+                Vec4.toArray(sv, _vec4ShadowInfo, UBOShadow.SHADOW_WIDTH_HEIGHT_PCF_BIAS_INFO_OFFSET);
             }
 
             Color.toArray(sv, shadowInfo.shadowColor, UBOShadow.SHADOW_COLOR_OFFSET);

cocos/scene-graph/scene-globals.ts

@@ -930,6 +930,22 @@ export class ShadowsInfo {
         return this._distance;
     }
 
+    /**
+     * @en Positional offset values in planar shading calculations.
+     * @zh 平面阴影计算中的位置偏移值。
+     */
+    @tooltip('i18n:shadow.planeBias')
+    @editable
+    @type(CCFloat)
+    @visible(function (this: ShadowsInfo) { return this._type === ShadowType.Planar; })
+    set planeBias (val: number) {
+        this._planeBias = val;
+        if (this._resource) { this._resource.planeBias = val; }
+    }
+    get planeBias (): number {
+        return this._planeBias;
+    }
+
     /**
      * @en get or set shadow max received
      * @zh 获取或者设置阴影接收的最大光源数量
@@ -972,6 +988,8 @@ export class ShadowsInfo {
     @serializable
     protected _distance = 0;
     @serializable
+    protected _planeBias = 1.0;
+    @serializable
     protected _shadowColor = new Color(0, 0, 0, 76);
     @serializable
     protected _maxReceived = 4;

editor/assets/chunks/common/lighting/functions.chunk

@@ -93,11 +93,11 @@ vec4 CalculatePlanarShadowPos(vec3 meshWorldPos, vec3 cameraPos, vec3 lightDir,
   return vec4(shadowPos, dist);
 }
 // calculate planar clip pos from world pos
-vec4 CalculatePlanarShadowClipPos(vec4 shadowPos, vec3 cameraPos, mat4 matView, mat4 matProj, vec4 nearFar) {
+vec4 CalculatePlanarShadowClipPos(vec4 shadowPos, vec3 cameraPos, mat4 matView, mat4 matProj, vec4 nearFar, float bias) {
   vec4 camPos = matView * vec4(shadowPos.xyz, 1.0);
   // avoid z-fighting with shadow receive plane, add camera bias with perspective correction
   // notice that near plane should not be too small, assume near 1, far 1000
   float lerpCoef = saturate((nearFar.z < 0.0 ? -camPos.z : camPos.z) / (nearFar.y - nearFar.x));
-  camPos.z += mix(nearFar.x * 0.01, nearFar.y * EPSILON_LOWP, lerpCoef);
+  camPos.z += mix(nearFar.x * 0.01, nearFar.y * EPSILON_LOWP * bias, lerpCoef);
   return matProj * camPos;
 }

editor/assets/chunks/shading-entries/main-functions/render-planar-shadow/vs.chunk

@@ -22,7 +22,7 @@ void main()
   In.worldPos = shadowPos.xyz;
 
   // Clip Space
-  In.clipPos = CalculatePlanarShadowClipPos(shadowPos, cc_cameraPos.xyz, cc_matView, cc_matProj, cc_nearFar);
+  In.clipPos = CalculatePlanarShadowClipPos(shadowPos, cc_cameraPos.xyz, cc_matView, cc_matProj, cc_nearFar, cc_shadowWHPBInfo.w);
   In.clipPos = SurfacesVertexModifyClipPos(In);
 
   // Other Surfaces Function

editor/assets/effects/builtin-unlit.effect

@@ -224,7 +224,7 @@ CCProgram planar-shadow-vs %{
     CCGetWorldMatrixFull(matWorld, matWorldIT);
     vec3 worldPos = (matWorld * position).xyz;
     vec4 shadowPos = CalculatePlanarShadowPos(worldPos, cc_cameraPos.xyz, cc_mainLitDir.xyz, cc_planarNDInfo);
-    position  = CalculatePlanarShadowClipPos(shadowPos, cc_cameraPos.xyz, cc_matView, cc_matProj, cc_nearFar);
+    position = CalculatePlanarShadowClipPos(shadowPos, cc_cameraPos.xyz, cc_matView, cc_matProj, cc_nearFar, cc_shadowWHPBInfo.w);
     v_dist = shadowPos.w;
     return position;
   }

editor/assets/effects/legacy/standard.effect

@@ -479,7 +479,7 @@ CCProgram planar-shadow-vs %{
     CCGetWorldMatrixFull(matWorld, matWorldIT);
     vec3 worldPos = (matWorld * position).xyz;
     vec4 shadowPos = CalculatePlanarShadowPos(worldPos, cc_cameraPos.xyz, cc_mainLitDir.xyz, cc_planarNDInfo);
-    position  = CalculatePlanarShadowClipPos(shadowPos, cc_cameraPos.xyz, cc_matView, cc_matProj, cc_nearFar);
+    position = CalculatePlanarShadowClipPos(shadowPos, cc_cameraPos.xyz, cc_matView, cc_matProj, cc_nearFar, cc_shadowWHPBInfo.w);
     v_dist = shadowPos.w;
     return position;
   }

editor/assets/effects/legacy/toon.effect

@@ -383,7 +383,7 @@ CCProgram planar-shadow-vs %{
     CCGetWorldMatrixFull(matWorld, matWorldIT);
     vec3 worldPos = (matWorld * position).xyz;
     vec4 shadowPos = CalculatePlanarShadowPos(worldPos, cc_cameraPos.xyz, cc_mainLitDir.xyz, cc_planarNDInfo);
-    position  = CalculatePlanarShadowClipPos(shadowPos, cc_cameraPos.xyz, cc_matView, cc_matProj, cc_nearFar);
+    position = CalculatePlanarShadowClipPos(shadowPos, cc_cameraPos.xyz, cc_matView, cc_matProj, cc_nearFar, cc_shadowWHPBInfo.w);
     v_dist = shadowPos.w;
     return position;
   }

editor/assets/effects/pipeline/planar-shadow.effect

@@ -42,7 +42,7 @@ CCProgram planar-shadow-vs %{
     CCGetWorldMatrixFull(matWorld, matWorldIT);
     vec3 worldPos = (matWorld * position).xyz;
     vec4 shadowPos = CalculatePlanarShadowPos(worldPos, cc_cameraPos.xyz, cc_mainLitDir.xyz, cc_planarNDInfo);
-    position  = CalculatePlanarShadowClipPos(shadowPos, cc_cameraPos.xyz, cc_matView, cc_matProj, cc_nearFar);
+    position = CalculatePlanarShadowClipPos(shadowPos, cc_cameraPos.xyz, cc_matView, cc_matProj, cc_nearFar, cc_shadowWHPBInfo.w);
     v_dist = shadowPos.w;
     return position;
   }

editor/i18n/en/localization.js

@@ -239,6 +239,7 @@ module.exports = link(mixin({
         shadowColor: 'The planar shadow color',
         planeDirection: 'The normal vector of the plane which receives shadow.',
         planeHeight: 'The height from the origin of the plane which receives shadow.',
+        planeBias:'Positional offset values in planar shading calculations.',
         shadowMapSize: 'Shadowmap resolutions.',
         maxReceived: 'Number of the effective light sources that produce shadows.',
     },

editor/i18n/zh/localization.js

@@ -239,6 +239,7 @@ module.exports = link(mixin({
         shadowColor: '平面阴影颜色',
         planeDirection: '阴影接收平面的法线，垂直于阴影，用于调整阴影的倾斜度',
         planeHeight: '阴影接收平面距离原点的高度',
+        planeBias: '平面阴影计算中的位置偏移值',
         shadowMapSize: '阴影贴图分辨率，目前支持 Low_256x256、Medium_512x512、High_1024x1024、Ultra_2048x2048 四种精度的纹理',
         maxReceived: '产生阴影的有效光源数量',
     },

native/cocos/renderer/pipeline/PipelineUBO.cpp

@@ -301,6 +301,8 @@ void PipelineUBO::updateShadowUBOView(const RenderPipeline *pipeline, ccstd::arr
             }
         } else if (mainLight && shadowInfo->getType() == scene::ShadowType::PLANAR) {
             PipelineUBO::updatePlanarNormalAndDistance(shadowInfo, shadowBufferView);
+            const float shadowWHPBInfos[4] = {0, 0, 0, shadowInfo->getPlaneBias()};
+            memcpy(sv.data() + UBOShadow::SHADOW_WIDTH_HEIGHT_PCF_BIAS_INFO_OFFSET, &shadowWHPBInfos, sizeof(shadowWHPBInfos));
         }
 
         memcpy(sv.data() + UBOShadow::SHADOW_COLOR_OFFSET, shadowInfo->getShadowColor4f().data(), sizeof(float) * 4);

native/cocos/renderer/pipeline/custom/NativeBuiltinUtils.cpp

@@ -357,6 +357,10 @@ void setShadowUBOView(
             setVec4Impl(data, layoutGraph,
                         "cc_planarNDInfo",
                         Vec4(tempVec3.x, tempVec3.y, tempVec3.z, -shadowInfo.getDistance()));
+            vec4ShadowInfo.set(
+                0, 0,
+                0, shadowInfo.getPlaneBias());
+            setVec4Impl(data, layoutGraph, "cc_shadowWHPBInfo", vec4ShadowInfo);
         }
         {
             const auto &color = shadowInfo.getShadowColor4f();

native/cocos/scene/Shadow.cpp

@@ -76,6 +76,13 @@ void ShadowsInfo::setPlaneHeight(float val) {
     }
 }
 
+void ShadowsInfo::setPlaneBias(float val) {
+    _planeBias = val;
+    if (_resource != nullptr) {
+        _resource->setPlaneBias(val);
+    }
+}
+
 void ShadowsInfo::setMaxReceived(uint32_t val) {
     _maxReceived = val;
     if (_resource != nullptr) {
@@ -112,6 +119,7 @@ void Shadows::initialize(const ShadowsInfo &shadowsInfo) {
     setType(shadowsInfo.getType());
     setNormal(shadowsInfo.getPlaneDirection());
     setDistance(shadowsInfo.getPlaneHeight());
+    setPlaneBias(shadowsInfo.getPlaneBias());
     setMaxReceived(shadowsInfo.getMaxReceived());
     if (fabsf(shadowsInfo.getShadowMapSize() - _size.x) > 0.1F) {
         setSize(Vec2(shadowsInfo.getShadowMapSize(), shadowsInfo.getShadowMapSize()));

native/cocos/scene/Shadow.h

@@ -247,6 +247,15 @@ class ShadowsInfo : public RefCounted {
         return _distance;
     }
 
+    /**
+     * @en Positional offset values in planar shading calculations.
+     * @zh 平面阴影计算中的位置偏移值
+     */
+    void setPlaneBias(float val);
+    inline float getPlaneBias() const {
+        return _planeBias;
+    }
+
     /**
      * @en get or set shadow max received
      * @zh 获取或者设置阴影接收的最大光源数量
@@ -275,14 +284,21 @@ class ShadowsInfo : public RefCounted {
     void activate(Shadows *resource);
 
     bool _enabled{false};
+
     ShadowType _type{ShadowType::PLANAR};
-    Vec3 _normal{0.F, 1.F, 0.F};
-    float _distance{0.F};
-    Color _shadowColor{0, 0, 0, 76};
+
+    Shadows *_resource{nullptr};
+
     uint32_t _maxReceived{4};
+
+    float _distance{0.F};
+    float _planeBias{1.0F};
+
     Vec2 _size{1024.F, 1024.F};
 
-    Shadows *_resource{nullptr};
+    Vec3 _normal{0.F, 1.F, 0.F};
+
+    Color _shadowColor{0, 0, 0, 76};
 };
 
 class Shadows final {
@@ -332,6 +348,13 @@ class Shadows final {
     inline float getDistance() const { return _distance; }
     inline void setDistance(float val) { _distance = val; }
 
+    /**
+     * @en Positional offset values in planar shading calculations.
+     * @zh 平面阴影计算中的位置偏移值
+     */
+    inline float getPlaneBias() const { return _planeBias; }
+    inline void setPlaneBias(float val) { _planeBias = val; }
+
     /**
      * @en Shadow color.
      * @zh 阴影颜色。
@@ -398,30 +421,38 @@ class Shadows final {
     void createInstanceMaterial();
     void createMaterial();
 
-    /**
-     * @en The bounding sphere of the shadow map.
-     * @zh 用于计算固定区域阴影 Shadow map 的场景包围球.
-     */
-    geometry::Sphere _fixedSphere{0.0F, 0.0F, 0.0F, 0.01F};
+    bool _enabled{false};
+    bool _shadowMapDirty{false};
+
+    ShadowType _type{ShadowType::NONE};
+
+    IntrusivePtr<Material> _material{nullptr};
+    IntrusivePtr<Material> _instancingMaterial{nullptr};
+
+    float _distance{0.F};
+    float _planeBias{1.0F};
 
     /**
      * @en get or set shadow max received.
      * @zh 阴影接收的最大灯光数量。
      */
     uint32_t _maxReceived{4};
 
+    /**
+     * @en The bounding sphere of the shadow map.
+     * @zh 用于计算固定区域阴影 Shadow map 的场景包围球.
+     */
+    geometry::Sphere _fixedSphere{0.0F, 0.0F, 0.0F, 0.01F};
+
+    Vec2 _size{1024.F, 1024.F};
+
     // public properties of shadow
     Vec3 _normal{0.F, 1.F, 0.F};
+
     Color _shadowColor{0, 0, 0, 76};
     ccstd::array<float, 4> _shadowColor4f{0.F, 0.F, 0.F, 76.F / 255.F};
+
     Mat4 _matLight;
-    IntrusivePtr<Material> _material{nullptr};
-    IntrusivePtr<Material> _instancingMaterial{nullptr};
-    Vec2 _size{1024.F, 1024.F};
-    bool _enabled{false};
-    float _distance{0.F};
-    ShadowType _type{ShadowType::NONE};
-    bool _shadowMapDirty{false};
 };
 
 } // namespace scene

native/tools/swig-config/scene.i

@@ -531,13 +531,15 @@ using namespace cc;
 %attribute(cc::scene::ShadowsInfo, cc::Color&, shadowColor, getShadowColor, setShadowColor);
 %attribute(cc::scene::ShadowsInfo, cc::Vec3&, planeDirection, getPlaneDirection, setPlaneDirection);
 %attribute(cc::scene::ShadowsInfo, float, planeHeight, getPlaneHeight, setPlaneHeight);
+%attribute(cc::scene::ShadowsInfo, float, planeBias, getPlaneBias, setPlaneBias);
 %attribute(cc::scene::ShadowsInfo, uint32_t, maxReceived, getMaxReceived, setMaxReceived);
 %attribute(cc::scene::ShadowsInfo, float, shadowMapSize, getShadowMapSize, setShadowMapSize);
 
 %attribute(cc::scene::Shadows, bool, enabled, isEnabled, setEnabled);
 %attribute(cc::scene::Shadows, cc::scene::ShadowType, type, getType, setType);
 %attribute(cc::scene::Shadows, cc::Vec3&, normal, getNormal, setNormal);
 %attribute(cc::scene::Shadows, float, distance, getDistance, setDistance);
+%attribute(cc::scene::Shadows, float, planeBias, getPlaneBias, setPlaneBias);
 %attribute(cc::scene::Shadows, cc::Color&, shadowColor, getShadowColor, setShadowColor);
 %attribute(cc::scene::Shadows, uint32_t, maxReceived, getMaxReceived, setMaxReceived);
 %attribute(cc::scene::Shadows, cc::Vec2&, size, getSize, setSize);