Optimized culling solution for skinned meshes (playcanvas#2435)

mvaligursky · web-flow · commit d369b822bc74 · 2020-10-07T10:58:40.000+01:00
* ModelComponent can specify oversize bounding box and disable expensive skinned bounds update

* es5 compatibility
diff --git a/src/framework/components/model/component.js b/src/framework/components/model/component.js
@@ -47,6 +47,8 @@ import { Component } from '../component.js';
  * @property {boolean} lightmapped If true, this model will be lightmapped after using lightmapper.bake().
  * @property {number} lightmapSizeMultiplier Lightmap resolution multiplier.
  * @property {boolean} isStatic Mark model as non-movable (optimization).
+ * @property {pc.BoundingBox} aabb If set, the bounding box is used as a bounding box for visibility culling of attached mesh instances. This is an optimization,
+ * allowing oversized bounding box to be specified for skinned characters in order to avoid per frame bounding box computations based on bone positions.
  * @property {pc.MeshInstance[]} meshInstances An array of meshInstances contained in the component's model. If model is not set or loaded for component it will return null.
  * @property {number} batchGroupId Assign model to a specific batch group (see {@link pc.BatchGroup}). Default value is -1 (no group).
  * @property {number[]} layers An array of layer IDs ({@link pc.Layer#id}) to which this model should belong.
@@ -78,6 +80,9 @@ function ModelComponent(system, entity)   {
     this._layers = [LAYERID_WORLD]; // assign to the default world layer
     this._batchGroupId = -1;
 
+    // bounding box which can be set to override bounding box based on mesh
+    this._aabb = null;
+
     this._area = null;
 
     this._assetOld = 0;
@@ -494,6 +499,26 @@ Object.defineProperty(ModelComponent.prototype, "meshInstances", {
     }
 });
 
+Object.defineProperties(ModelComponent.prototype, {
+
+    'aabb': {
+        get: function () {
+            return this._aabb;
+        },
+        set: function (value) {
+            this._aabb = value;
+
+            // set it on meshInstances
+            var mi = this._model.meshInstances;
+            if (mi) {
+                for (var i = 0; i < mi.length; i++) {
+                    mi[i].setOverrideAabb(this._aabb);
+                }
+            }
+        }
+    }
+});
+
 Object.defineProperty(ModelComponent.prototype, "type", {
     get: function () {
         return this._type;
@@ -683,6 +708,7 @@ Object.defineProperty(ModelComponent.prototype, "model", {
                 meshInstances[i].castShadow = this._castShadows;
                 meshInstances[i].receiveShadow = this._receiveShadows;
                 meshInstances[i].isStatic = this._isStatic;
+                meshInstances[i].setOverrideAabb(this._aabb);
             }
 
             this.lightmapped = this._lightmapped; // update meshInstances
diff --git a/src/scene/batching.js b/src/scene/batching.js
@@ -98,10 +98,10 @@ SkinBatchInstance.prototype = Object.create(SkinBatchInstance.prototype);
 SkinBatchInstance.prototype.constructor = SkinBatchInstance;
 
 Object.assign(SkinBatchInstance.prototype, {
-    updateMatrices: function (rootNode) {
+    updateMatrices: function (rootNode, skinUpdateIndex) {
     },
 
-    updateMatrixPalette: function () {
+    updateMatrixPalette: function (rootNode, skinUpdateIndex) {
         var pe;
         var mp = this.matrixPalette;
         var base;
diff --git a/src/scene/forward-renderer.js b/src/scene/forward-renderer.js
@@ -117,6 +117,8 @@ var skipRenderCamera = null;
 var _skipRenderCounter = 0;
 var skipRenderAfter = 0;
 
+var _skinUpdateIndex = 0;
+
 // The 8 points of the camera frustum transformed to light space
 var frustumPoints = [];
 for (var fp = 0; fp < 8; fp++) {
@@ -1180,19 +1182,22 @@ Object.assign(ForwardRenderer.prototype, {
     },
 
     updateCpuSkinMatrices: function (drawCalls) {
+
+        _skinUpdateIndex++;
+
         var drawCallsCount = drawCalls.length;
         if (drawCallsCount === 0) return;
 
         // #ifdef PROFILER
         var skinTime = now();
         // #endif
 
-        var i, skin;
+        var i, si;
         for (i = 0; i < drawCallsCount; i++) {
-            skin = drawCalls[i].skinInstance;
-            if (skin) {
-                skin.updateMatrices(drawCalls[i].node);
-                skin._dirty = true;
+            si = drawCalls[i].skinInstance;
+            if (si) {
+                si.updateMatrices(drawCalls[i].node, _skinUpdateIndex);
+                si._dirty = true;
             }
         }
 
@@ -1213,7 +1218,7 @@ Object.assign(ForwardRenderer.prototype, {
             skin = drawCalls[i].skinInstance;
             if (skin) {
                 if (skin._dirty) {
-                    skin.updateMatrixPalette();
+                    skin.updateMatrixPalette(drawCalls[i].node, _skinUpdateIndex);
                     skin._dirty = false;
                 }
             }
diff --git a/src/scene/mesh-instance.js b/src/scene/mesh-instance.js
@@ -294,6 +294,8 @@ Object.defineProperty(MeshInstance.prototype, 'skinInstance', {
         for (var i = 0; i < this._shader.length; i++) {
             this._shader[i] = null;
         }
+
+        this._setupSkinUpdate();
     }
 });
 
@@ -512,6 +514,23 @@ Object.assign(MeshInstance.prototype, {
                 parameter.scopeId.setValue(parameter.data);
             }
         }
+    },
+
+    setOverrideAabb: function (aabb) {
+        this._updateAabb = !aabb;
+        if (aabb) {
+            this.aabb.copy(aabb);
+        }
+
+        this._setupSkinUpdate();
+    },
+
+    _setupSkinUpdate: function () {
+
+        // set if bones need to be updated before culling
+        if (this._skinInstance) {
+            this._skinInstance._updateBeforeCull = this._updateAabb;
+        }
     }
 });
 
diff --git a/src/scene/skin-instance.js b/src/scene/skin-instance.js
@@ -18,6 +18,12 @@ var _invMatrix = new Mat4();
 function SkinInstance(skin) {
     this._dirty = true;
 
+    // sequencial index of when the bone update was performed the last time
+    this._skinUpdateIndex = -1;
+
+    // true if bones need to be updated before the frustum culling (bones are needed to update bounds of the MeshInstance)
+    this._updateBeforeCull = true;
+
     if (skin) {
         this.initSkin(skin);
     }
@@ -77,16 +83,33 @@ Object.assign(SkinInstance.prototype, {
         }
     },
 
-    updateMatrices: function (rootNode) {
+    _updateMatrices: function (rootNode, skinUpdateIndex) {
+
+        // if not already up to date
+        if (this._skinUpdateIndex !== skinUpdateIndex) {
+            this._skinUpdateIndex = skinUpdateIndex;
 
-        _invMatrix.copy(rootNode.getWorldTransform()).invert();
-        for (var i = this.bones.length - 1; i >= 0; i--) {
-            this.matrices[i].mulAffine2(_invMatrix, this.bones[i].getWorldTransform()); // world space -> rootNode space
-            this.matrices[i].mulAffine2(this.matrices[i], this.skin.inverseBindPose[i]); // rootNode space -> bind space
+            _invMatrix.copy(rootNode.getWorldTransform()).invert();
+            for (var i = this.bones.length - 1; i >= 0; i--) {
+                this.matrices[i].mulAffine2(_invMatrix, this.bones[i].getWorldTransform()); // world space -> rootNode space
+                this.matrices[i].mulAffine2(this.matrices[i], this.skin.inverseBindPose[i]); // rootNode space -> bind space
+            }
         }
     },
 
-    updateMatrixPalette: function () {
+    updateMatrices: function (rootNode, skinUpdateIndex) {
+
+        if (this._updateBeforeCull) {
+            this._updateMatrices(rootNode, skinUpdateIndex);
+        }
+    },
+
+    updateMatrixPalette: function (rootNode, skinUpdateIndex) {
+
+        // make sure matrices are up to date
+        this._updateMatrices(rootNode, skinUpdateIndex);
+
+        // copy matrices to palette
         var pe;
         var mp = this.matrixPalette;
         var base;
