/** Disposes all resources associated with this shader. Must be called when the shader is no longer used. */
public void dispose () {
GL20 gl = Gdx.graphics.getGL20();
gl.glUseProgram(0);
gl.glDeleteShader(vertexShaderHandle);
gl.glDeleteShader(fragmentShaderHandle);
gl.glDeleteProgram(program);
if (shaders.get(Gdx.app) != null) shaders.get(Gdx.app).remove(this);
}
/** Disables the vertex attribute with the given name