Let's now see how to implement a sprite batch in DroidBlaster:
Modify
jni/GraphicsManager.hpp. Create the classGraphicsComponent, 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 screenloadShaderProgram()to load a vertex and fragment shader and link them together into an OpenGL programregisterComponent()which records a list ofGraphicsComponentto initialize and render
Create the
RenderVertexprivate structure representing the structure of an individual sprite vertex.Also, declare a few new member variables such as:
mProjectionMatrixto store an orthographic projection (as opposed to a perspective projection used in 3D games).mShaders,mShaderCount,mComponents, andmComponentCountto keep trace of all resources.
Finally, get rid of all the
GraphicsElementstuff used in the previous chapter...