VAOs, VBOs, Vertex and Fragment Shaders

关于Vertex Array Objects(VAOs), Vertex Buffer Objects(VBOs), Vertex and Fragment Shaders的概念还是看官方说明理解的好！

The OpenGL 3.2 core specification removes the majority of the fixed function pipeline previously used, and replaces it with a completely programmable architecture using shaders. Our tutorial will make use of VAOs and VBOs to provide our shaders with data.

A Vertex Array Object (VAO) is an object which contains one or more Vertex Buffer Objects（VBOs） and is designed to store the information for a complete rendered object.

A Vertex Buffer Object (VBO) is a memory buffer in the high speed memory of your video card designed to hold information about vertices. VBOs can also store information such as normals, texcoords, indicies, etc.

A Vertex Shader in OpenGL is a piece of C like code written to the GLSL specification which influences the attributes of a vertex. Vertex shaders can be used to modify properties of the vertex such as position, color, and texture coordinates.

A Fragment Shader is similar to a Vertex Shader, but is used for calculating individual fragment colors. This is where lighting and bump-mapping effects are performed.

There is another shader type called Geometry Shaders which we will be using in a later tutorial. They are used to create additional vertices.

The shader pipeline behaves as follows: Vertex Shaders -> Geometry Shaders -> (Rasterizing Engine) -> Fragment Shaders.

The shaders are compilied and then chained together into a Shader Program.

The shaders receive input data from our VAO through a process of attribute binding, allowing us to perform the needed computations to provide us with the desired results.