Time for action – initializing OpenGL ES

Let's now see how to implement a sprite batch in DroidBlaster:

1. Modify jni/GraphicsManager.hpp. Create the class GraphicsComponent, which defines a common interface for all rendering techniques starting with sprite batches. Define a few new methods such as:

   • getProjectionMatrix() which provides an OpenGL matrix to project 2D graphics on screen

   • loadShaderProgram() to load a vertex and fragment shader and link them together into an OpenGL program

   • registerComponent() which records a list of GraphicsComponent to initialize and render

   Create the RenderVertex private structure representing the structure of an individual sprite vertex.

   Also, declare a few new member variables such as:

   • mProjectionMatrix to store an orthographic projection (as opposed to a perspective projection used in 3D games).

   • mShaders, mShaderCount, mComponents, and mComponentCount to keep trace of all resources.

   Finally, get rid of all the GraphicsElement stuff used in the previous chapter...