anchor.diff:  
   
   
  -
  
positive.code:     var shader = pass.shader;
      if (!shader.ready) return false;
      pass.prepare(ctx);
      if (shader.uniforms.containsKey(Semantics.viewMat)) ctx.uniformMatrix4fv(shader.uniforms[Semantics.viewMat].location, false, camera.viewMatrix.storage);
      if (shader.uniforms.containsKey(Semantics.projectionMat)) ctx.uniformMatrix4fv(shader.uniforms[Semantics.projectionMat].location, false, camera.projectionMatrix.storage);
      _setupLights();
      return true;
    }
  
negative.code:     shader.uniform(ctx, Semantics.useTextures, false);
  
      if (node is Light) {
        //      _drawLight(node);
      } else if (node is Mesh) {
        _drawMesh(node);
      }
  