activate method
Implementation
@override
void activate(RenderContextWebGL renderContext) {
super.activate(renderContext);
renderingContext.uniform1i(uniforms['uSampler'], 0);
renderBufferVertex.bindAttribute(attributes['aVertexPosition'], 2, 32, 0);
renderBufferVertex.bindAttribute(attributes['aVertexTextCoord'], 2, 32, 8);
renderBufferVertex.bindAttribute(attributes['aVertexColor'], 4, 32, 16);
}