OpenGL – Build high performance graphics

Dynamically subdividing a plane using the geometry shader with instanced rendering

In order to avoid pushing the same data multiple times, we can exploit the instanced rendering functions. We will now see how we can omit the multiple glDrawElements calls in the previous recipe with a single glDrawElementsInstanced call.

Getting ready

Before doing this, we assume that the reader knows how to use the geometry shader in the OpenGL 3.3 core profile. The code for this recipe is in the Chapter1\SubdivisionGeometryShader_Instanced directory.

How to do it…

Converting the previous recipe to use instanced rendering requires the following steps:

1. Change the vertex shader to handle the instance modeling matrix and output world space positions (shaders/shader.vert ...