Render handles refouncing of meshes (playcanvas#3328)

mvaligursky · Martin Valigursky · web-flow · commit b46c7e556cbb · 2021-07-12T08:48:31.000-07:00
Co-authored-by: Martin Valigursky &lt;mvaligursky@snapchat.com&gt;
diff --git a/src/resources/parser/glb-parser.js b/src/resources/parser/glb-parser.js
@@ -767,6 +767,8 @@ const createMesh = function (device, gltfMesh, accessors, bufferViews, callback,
                 mesh.primitive[0].count = vertexBuffer.numVertices;
             }
 
+            // TODO: Refactor, we should not store temporary data on the mesh.
+            // The container should store some mapping table instead.
             mesh.materialIndex = primitive.material;
 
             let accessor = accessors[primitive.attributes.POSITION];
diff --git a/src/resources/render.js b/src/resources/render.js
@@ -35,7 +35,7 @@ function onContainerAssetRemoved(containerAsset) {
     renderAsset.registry.off('load:' + containerAsset.id, onContainerAssetLoaded, renderAsset);
 
     if (renderAsset.resource) {
-        renderAsset.resource.meshes = null;
+        renderAsset.resource.destroy();
     }
 }
 
diff --git a/src/scene/render.js b/src/scene/render.js
@@ -20,15 +20,58 @@ import { EventHandler } from '../core/event-handler.js';
 class Render extends EventHandler {
     constructor() {
         super();
+
+        // meshes are reference counted, and this class owns the references and is responsible
+        // for releasing the meshes when they are no longer referenced
         this._meshes = null;
     }
 
+    destroy() {
+        this.meshes = null;
+    }
+
+    // decrement references to meshes, destroy the ones with zero references
+    decRefMeshes() {
+        if (this._meshes) {
+            const count = this._meshes.length;
+            for (let i = 0; i < count; i++) {
+                const mesh = this._meshes[i];
+                if (mesh) {
+                    mesh.decRefCount();
+                    if (mesh.getRefCount() < 1) {
+                        mesh.destroy();
+                        this._meshes[i] = null;
+                    }
+                }
+            }
+        }
+    }
+
+    // increments ref count on all meshes
+    incRefMeshes() {
+        if (this._meshes) {
+            const count = this._meshes.length;
+            for (let i = 0; i < count; i++) {
+                if (this._meshes[i]) {
+                    this._meshes[i].incRefCount();
+                }
+            }
+        }
+    }
+
     get meshes() {
         return this._meshes;
     }
 
     set meshes(value) {
+
+        // decrement references on the existing meshes
+        this.decRefMeshes();
+
+        // assign new meshes
         this._meshes = value;
+        this.incRefMeshes();
+
         this.fire('set:meshes', value);
     }
 }

Original file line number	Diff line number	Diff line change
`@@ -767,6 +767,8 @@ const createMesh = function (device, gltfMesh, accessors, bufferViews, callback,`
`767`	`767`	`mesh.primitive[0].count = vertexBuffer.numVertices;`
`768`	`768`	`}`
`769`	`769`
	`770`	`+ // TODO: Refactor, we should not store temporary data on the mesh.`
	`771`	`+ // The container should store some mapping table instead.`
`770`	`772`	`mesh.materialIndex = primitive.material;`
`771`	`773`
`772`	`774`	`let accessor = accessors[primitive.attributes.POSITION];`
Original file line number	Diff line number	Diff line change
`@@ -35,7 +35,7 @@ function onContainerAssetRemoved(containerAsset) {`
`35`	`35`	`renderAsset.registry.off('load:' + containerAsset.id, onContainerAssetLoaded, renderAsset);`
`36`	`36`
`37`	`37`	`if (renderAsset.resource) {`
`38`		`- renderAsset.resource.meshes = null;`
	`38`	`+ renderAsset.resource.destroy();`
`39`	`39`	`}`
`40`	`40`	`}`
`41`	`41`