e, yScale];
                gl.bindBuffer( gl.ARRAY_BUFFER, gl.createBuffer() );
                gl.bufferData( gl.ARRAY_BUFFER, new Float32Array( positions ), gl.STATIC_DRAW );
                gl.vertexAttribPointer( program.posLocation, 2, gl.FLOAT, false, 0, 0 );

                const texCoords = [0, 0, 1, 0, 0, 1, 1, 1];
                gl.bindBuffer( gl.ARRAY_BUFFER, gl.createBuffer() );
                gl.bufferData( gl.ARRAY_BUFFER, new Float32Array( texCoords ), gl.STATIC_DRAW );
                gl