.programGrey = gl.compileProgram( VERT_SOURCE_DEFAULT, FRAG_SOURCE_GREY );
            this.programBlur = gl.compileProgram( VERT_SOURCE_DEFAULT, FRAG_SOURCE_BLUR, { radiusLocation: 'u_radius' } );
            this.programHarris = gl.compileProgram( VERT_SOURCE_DEFAULT, FRAG_SOURCE_HARRIS, { thresholdLocation: 'u_threshold', kLocation: 'u_k', stepLocation: 'u_step' } );
            this.programNonmax = gl.compileProgram( VERT_SOURCE_DEFAULT, FRAG_SOURCE_NONMAX, { radiusLocation: 'u_radius' } );
            