Rollback changes to ext gpu instancing

loaders/src/glTF/2.0/Extensions/EXT_mesh_gpu_instancing.ts

@@ -1,4 +1,4 @@
-import { Vector3, Quaternion, Matrix } from 'babylonjs/Maths/math.vector';
+import { Vector3, Quaternion } from 'babylonjs/Maths/math.vector';
 import { InstancedMesh } from 'babylonjs/Meshes/instancedMesh';
 import { Mesh } from 'babylonjs/Meshes/mesh';
 import { TransformNode } from "babylonjs/Meshes/transformNode";
@@ -10,18 +10,12 @@ import { INode } from "../glTFLoaderInterfaces";
 import { AbstractMesh } from 'babylonjs/Meshes/abstractMesh';
 
 const NAME = "EXT_mesh_gpu_instancing";
-const useThinInstances = true;
 
 interface IEXTMeshGpuInstancing {
     mesh?: number;
     attributes: { [name: string]: number };
 }
 
-const T = new Vector3(0, 0, 0);
-const R = new Quaternion(0, 0, 0, 1);
-const S = new Vector3(1, 1, 1);
-const M = new Matrix();
-
 /**
  * [Proposed Specification](https://github.com/KhronosGroup/glTF/pull/1691)
  * [Playground Sample](https://playground.babylonjs.com/#QFIGLW#9)
@@ -61,10 +55,8 @@ export class EXT_mesh_gpu_instancing implements IGLTFLoaderExtension {
             }
 
             // Hide the source meshes.
-            if (!useThinInstances) {
-                for (const babylonMesh of node._primitiveBabylonMeshes) {
-                    babylonMesh.isVisible = false;
-                }
+            for (const babylonMesh of node._primitiveBabylonMeshes) {
+                babylonMesh.isVisible = false;
             }
 
             const promises = new Array<Promise<Nullable<Float32Array>>>();
@@ -94,49 +86,25 @@ export class EXT_mesh_gpu_instancing implements IGLTFLoaderExtension {
                 return promise;
             }
 
-            if (!useThinInstances) {
-                const digitLength = instanceCount.toString().length;
-                for (let i = 0; i < instanceCount; ++i) {
-                    for (const babylonMesh of node._primitiveBabylonMeshes!) {
-                        const instanceName = `${babylonMesh.name || babylonMesh.id}_${StringTools.PadNumber(i, digitLength)}`;
-                        const babylonInstancedMesh = (babylonMesh as (InstancedMesh | Mesh)).createInstance(instanceName);
-                        babylonInstancedMesh.setParent(babylonMesh);
-                    }
+            const digitLength = instanceCount.toString().length;
+            for (let i = 0; i < instanceCount; ++i) {
+                for (const babylonMesh of node._primitiveBabylonMeshes!) {
+                    const instanceName = `${babylonMesh.name || babylonMesh.id}_${StringTools.PadNumber(i, digitLength)}`;
+                    const babylonInstancedMesh = (babylonMesh as (InstancedMesh | Mesh)).createInstance(instanceName);
+                    babylonInstancedMesh.setParent(babylonMesh);
                 }
             }
 
             return promise.then((babylonTransformNode) => {
                 return Promise.all(promises).then(([translationBuffer, rotationBuffer, scaleBuffer]) => {
-                    if (!useThinInstances) {
-                        for (const babylonMesh of node._primitiveBabylonMeshes!) {
-                            const babylonInstancedMeshes = babylonMesh.getChildMeshes(true, (node) => (node as AbstractMesh).isAnInstance);
-                            for (let i = 0; i < instanceCount; ++i) {
-                                const babylonInstancedMesh = babylonInstancedMeshes[i];
-                                translationBuffer && Vector3.FromArrayToRef(translationBuffer, i * 3, babylonInstancedMesh.position);
-                                rotationBuffer && Quaternion.FromArrayToRef(rotationBuffer, i * 4, babylonInstancedMesh.rotationQuaternion!);
-                                scaleBuffer && Vector3.FromArrayToRef(scaleBuffer, i * 3, babylonInstancedMesh.scaling);
-                                babylonInstancedMesh.refreshBoundingInfo();
-                            }
-                        }
-                    } else {
-                        const matrices = new Float32Array(instanceCount * 16);
-
-                        T.copyFromFloats(0, 0, 0);
-                        R.copyFromFloats(0, 0, 0, 1);
-                        S.copyFromFloats(1, 1, 1);
-
+                    for (const babylonMesh of node._primitiveBabylonMeshes!) {
+                        const babylonInstancedMeshes = babylonMesh.getChildMeshes(true, (node) => (node as AbstractMesh).isAnInstance);
                         for (let i = 0; i < instanceCount; ++i) {
-                            translationBuffer && Vector3.FromArrayToRef(translationBuffer, i * 3, T);
-                            rotationBuffer && Quaternion.FromArrayToRef(rotationBuffer, i * 4, R);
-                            scaleBuffer && Vector3.FromArrayToRef(scaleBuffer, i * 3, S);
-
-                            Matrix.ComposeToRef(S, R, T, M);
-
-                            M.copyToArray(matrices, i * 16);
-                        }
-
-                        for (const babylonMesh of node._primitiveBabylonMeshes!) {
-                            (babylonMesh as Mesh).setThinInstanceBuffer("matrix", matrices);
+                            const babylonInstancedMesh = babylonInstancedMeshes[i];
+                            translationBuffer && Vector3.FromArrayToRef(translationBuffer, i * 3, babylonInstancedMesh.position);
+                            rotationBuffer && Quaternion.FromArrayToRef(rotationBuffer, i * 4, babylonInstancedMesh.rotationQuaternion!);
+                            scaleBuffer && Vector3.FromArrayToRef(scaleBuffer, i * 3, babylonInstancedMesh.scaling);
+                            babylonInstancedMesh.refreshBoundingInfo();
                         }
                     }