reset method
Implementation
@override
void reset() {
final viewportWidth = _canvasElement.width!;
final viewportHeight = _canvasElement.height!;
_activeRenderFrameBuffer = null;
_renderingContext.bindFramebuffer(gl.WebGL.FRAMEBUFFER, null);
_renderingContext.viewport(0, 0, viewportWidth, viewportHeight);
_projectionMatrix.setIdentity();
_projectionMatrix.scale(2.0 / viewportWidth, -2.0 / viewportHeight, 1.0);
_projectionMatrix.translate(-1.0, 1.0, 0.0);
_activeRenderProgram.projectionMatrix = _projectionMatrix;
}