Modeling cloth using transform feedback
In this recipe we will use the transform feedback mechanism of the modern GPU to model cloth. Transform feedback is a special mode of modern GPU in which the vertex shader can directly output to a buffer object. This allows developers to do complex computations without affecting the rest of the rendering pipeline. We will elaborate how to use this mechanism to simulate cloth entirely on the GPU.
From the implementation point of view in modern OpenGL, transform feedback exists as an OpenGL object similar to textures. Working with transform feedback object requires two steps: first, generation of transform feedback with specification of shader outputs, and second, usage of the transform feedback for simulation and rendering. We generate it by calling the glGetTransformFeedbacks function and passing it the number of objects and the variable to store the returned IDs. After the object is created, it is bound to the current OpenGL context by calling glBindTransformFeedback...
