In this article I will discuss how you can use OpenGL textures and buffers in a CUDA kernel. I will demonstrate a simple post-process effect that can be applied to off-screen textures and then rendered to the screen using a full-screen quad. I will assume the reader has some basic knowledge of C/C++ programming, OpenGL, and CUDA. If you lack OpenGL knowledge, you can refer to my previous article titled Introduction to OpenGL or if you have never done anything with CUDA, you can follow my previous article titled Introduction to CUDA.
In this article, I will show how to implement projective shadow mapping in OpenGL using Cg shaders.
The basis of this post comes from the article titled [Transformation and Lighting in Cg]. I will assume the reader has a basic understanding of OpenGL and already knows how to setup an application that uses OpenGL. If you require a refresher on setting up an application using OpenGL, you can refer to my previous article titled [Introduction to OpenGL for Game Programmers].
I will take advantage of a few OpenGL extensions such as GL_ARB_framebuffer_object to create a offscreen framebuffer to render to and and GL_ARB_texture_border_clamp for clamping to the border color of the projective textures.
In this article, I will discuss a technique called normal mapping. Normal mapping is a shader technique that encodes pre-computed surface normals in a texture that can be used to add extra detail to a surface without the requirement of adding extra geometry. Before reading this article, you should have a basic understanding of OpenGL and you should know how to setup a Cg shader. For a review on OpenGL, you can refer to my previous article titled [Introduction to OpenGL for Game Programmers] and to learn how to incorporate Cg shaders in your own applications, you can refer to my article titled [Introduction to Cg Runtime with OpenGL].
This tutorial builds upon the previous article titled [Loading and Animating MD5 Models with OpenGL]. It is highly recommended that you read the previous article before following this one. In this tutorial, I will extend the MD5 model rendering to provide support for GPU skinning. I will also provide an example shader that will perform the vertex skinning in the vertex shader and do per-fragment lighting on the model using a single point light. For a complete discussion on lighting in CgFX, you can refer to my previous article titled [Transformation and Lighting in Cg].
In this article I will demonstrate one possible way to generate multi-textured terrain using only the OpenGL rendering pipeline. This demo uses the GL_ARB_multitexture and GL_ARB_texture_env_combine OpenGL extensions to do the multi-textured blending based on the height of the vertex in the terrain. I will also use the GL_ARB_vertex_buffer_object extension to store the terrain’s vertex information in the GPU memory for optimized rendering.
I will not show how to setup an application that uses OpenGL. If you would like to review how to setup an OpenGL application you can refer to my previous article titled “Introduction to OpenGL for Game Programmers“.