optimize transforms

Author: peteroupc

glutil-transform.js

@@ -83,7 +83,14 @@ Transform.prototype.setMatrix=function(value){
 }
 Transform.prototype.isIdentity=function(){
  if(this._matrixDirty){
-  this.getMatrix();
+  if(this.complexMatrix){
+   this.getMatrix();
+  } else {
+   return this.position[0]==0 && this.position[1]==0 &&
+    this.position[2]==0 && this.scale[0]==1 &&
+    this.scale[1]==1 && this.scale[2]==1 &&
+    GLMath.quatIsIdentity(this.rotation);
+  }
  }
  return this._isIdentity;
 }
@@ -303,26 +310,35 @@ Transform.prototype.multOrientation=function(angle, v,vy,vz){
 Transform.prototype.getMatrix=function(){
   if(this._matrixDirty){
    this._matrixDirty=false;
-   // for best results, multiply in this order:
-   // 1. translation
+   if(GLMath.quatIsIdentity(this.rotation)){
+    this.matrix=[this.scale[0],0,0,0,0,
+     this.scale[1],0,0,0,0,
+     this.scale[2],0,
+     this.position[0],
+     this.position[1],
+     this.position[2],1]; 
+    this._isIdentity=(this.position[0]==0 && this.position[1]==0 &&
+     this.position[2]==0 && this.scale[0]==1 &&
+     this.scale[1]==1 && this.scale[2]==1);
+   } else {
+    // for best results, multiply in this order:
+    // 1. translation
    this.matrix=[1,0,0,0,0,1,0,0,0,0,1,0,
     this.position[0],
     this.position[1],
     this.position[2],1];
-   // 2. rotation
-   if(!GLMath.quatIsIdentity(this.rotation)){
+    // 2. rotation
     this.matrix=GLMath.mat4multiply(this.matrix,
       GLMath.quatToMat4(this.rotation));
+    // 3. scaling
+    GLMath.mat4scaleInPlace(this.matrix,this.scale);
+    this._isIdentity=(
+     m[0]==1 && m[1]==0 && m[2]==0 && m[3]==0 &&
+     m[4]==0 && m[5]==1 && m[6]==0 && m[7]==0 &&
+     m[8]==0 && m[9]==0 && m[10]==1 && m[11]==0 &&
+     m[12]==0 && m[13]==0 && m[14]==0 && m[15]==1
+    );
    }
-   // 3. scaling
-   GLMath.mat4scaleInPlace(this.matrix,this.scale);
-   var m=this.matrix
-   this._isIdentity=(
-    m[0]==1 && m[1]==0 && m[2]==0 && m[3]==0 &&
-    m[4]==0 && m[5]==1 && m[6]==0 && m[7]==0 &&
-    m[8]==0 && m[9]==0 && m[10]==1 && m[11]==0 &&
-    m[12]==0 && m[13]==0 && m[14]==0 && m[15]==1
-   );
   } else if(this._isIdentity){
    return GLMath.mat4identity();
   }

glutil.js

@@ -883,6 +883,7 @@ Texture.loadTexture=function(name, textureCache){
   });
 }
 
+
 /**
 *  Creates a texture from a byte array specifying the texture data.
 * @param {Uint8Array} array A byte array containing the texture data,
@@ -1906,11 +1907,30 @@ Scene3D.prototype.setPointLight=function(index,position,diffuse,specular){
  return this;
 }
 /** @private */
+Scene3D._isIdentityExceptTranslate=function(mat){
+return (
+    mat[0]==1 && mat[1]==0 && mat[2]==0 && mat[3]==0 &&
+    mat[4]==0 && mat[5]==1 && mat[6]==0 && mat[7]==0 &&
+    mat[8]==0 && mat[9]==0 && mat[10]==1 && mat[11]==0 &&
+    mat[15]==1
+ );
+};
+/** @private */
 Scene3D.prototype._setupMatrices=function(shape,program){
   var uniforms={};
   var currentMatrix=shape.getMatrix();
-  var viewWorld=GLMath.mat4multiply(this._viewMatrix,
+  var viewWorld;
+  if(Scene3D._isIdentityExceptTranslate(this._viewMatrix)){
+   // view matrix is just a translation matrix, so that getting the model-view
+   // matrix amounts to simply adding the view's position
+   viewWorld=currentMatrix.slice(0,16);
+   viewWorld[13]+=this._viewMatrix[13];
+   viewWorld[14]+=this._viewMatrix[14];
+   viewWorld[15]+=this._viewMatrix[15];
+  } else {
+   viewWorld=GLMath.mat4multiply(this._viewMatrix,
     currentMatrix);
+  }
   var invTrans=GLMath.mat4inverseTranspose3(viewWorld);
   uniforms["world"]=currentMatrix;
   uniforms["modelMatrix"]=currentMatrix;