private void initializePrograms() {
smoothInterp = loadProgram( "SmoothVertexColors.vert", "SmoothVertexColors.frag" );
linearInterp = loadProgram( "NoCorrectVertexColors.vert", "NoCorrectVertexColors.frag" );
MatrixStack persMatrix = new MatrixStack();
persMatrix.perspective( 60.0f, 1.0f, zNear, zFar );
glUseProgram( smoothInterp.theProgram );
glUniformMatrix4( smoothInterp.cameraToClipMatrixUnif, false,
persMatrix.top().fillAndFlipBuffer( mat4Buffer ) );
glUseProgram( linearInterp.theProgram );