tionLocation);
const colorLocation = gl.getUniformLocation(program, 'u_color');
gl.useProgram(program);

const SMALL = 2;
// Changing this size to something smaller produces
// different results. Sometimes wrong, sometimes correct.
const LARGE = 1200;

gl.uniform4fv(colorLocation, [0.0, 1.0, 0.0, 1.0]);

// -

debug('\nResize then render.');
gl.canvas.width = gl.canvas.height = SMALL;
gl.viewport(0, 0, SMALL, SMALL);

gl.clear(gl.COLOR_BUFFER_BIT);
wtu.drawUnitQuad(gl);

wtu.checkCanvasRect(gl, 0, 0, 1, 1, 