-------------------------------------------------------------------
            gl.uniform1i( this.programHarris.stepLocation, 1 );
            gl.uniform1f( this.programHarris.kLocation, harrisK );
            gl.uniform1f( this.programHarris.thresholdLocation, harrisThr );
            gl.runProgram( this.programHarris, this.ping.tex, this.pong.fbo );
            //-------------------------------------------------------------------------------

            // compute non-maximum suppression
            //-