/// <summary> Called before Render (normally by RenderList::Render) to set up data for the render.
/// currentstate may be null, meaning, don't apply
/// RenderState may be null, meaning don't change</summary>
public void Bind(GLRenderState currentstate, IGLProgramShader shader, GLMatrixCalc matrixcalc)
{
if (currentstate != null && RenderState != null) // if either null, it means the last render state applied is the same as our render state, so no need to apply
{
currentstate.ApplyState(RenderState); // else go to this state
}
VertexArray?.Bind(); // give the VA a chance to bind to GL
RenderData?.Bind(this, shader, matrixcalc); // optional render data supplied by the user to bind
ElementBuffer?.BindElement(); // if we have an element buffer, give it a chance to bind
IndirectBuffer?.BindIndirect(); // if we have an indirect buffer, give it a chance to bind
ParameterBuffer?.BindParameter(); // if we have a parameter buffer, give it a chance to bind
}