Implementing per-vertex and per-fragment point lighting

To give more realism to 3D graphic scenes, we add lighting. In OpenGL's fixed function pipeline, per-vertex lighting is provided (which is deprecated in OpenGL v3.3 and above). Using shaders, we can not only replicate the per-vertex lighting of fixed function pipeline but also go a step further by implementing per-fragment lighting. The per-vertex lighting is also known as Gouraud shading and the per-fragment shading is known as Phong shading. So, without further ado, let's get started.

Getting started

In this recipe, we will render many cubes and a sphere. All of these objects are generated and stored in the buffer objects. For details, refer to the CreateSphere and CreateCube functions in Chapter4/PerVertexLighting/main.cpp. These functions generate both vertex positions as well as per-vertex normals, which are needed for the lighting calculations. All of the lighting calculations take place in the vertex shader of the per...