MatrixStack modelMatrix = new MatrixStack();
// Render the ground plane.
{
modelMatrix.push();
modelMatrix.scale( 100.0f, 1.0f, 100.0f );
glUseProgram( uniformColor.theProgram );
glUniformMatrix4( uniformColor.modelToWorldMatrixUnif, false,
modelMatrix.top().fillAndFlipBuffer( mat4Buffer ) );