simple lighting from a static directional source + ambient.

https://developer.mozilla.org/en-US/docs/Web/WebGL/Lighting_in_WebGL

js/pixl/public/geometry.js

	];
};
geometry.cube.normals = function() {
	var front = [0.0, 0.0, 1.0],
	    back = [0.0, 0.0, -1.0],
	    left = [-1.0, 0.0, 0.0],
	    right = [1.0, 0.0, 0.0],
	    top = [0.0, 1.0, 0.0],
	    bottom = [0.0, -1.0, 0.0];
	return [].concat(
		front, front, front, front, front, front,
		back, back, back, back, back, back,
		left, left, left, left, left, left,
		right, right, right, right, right, right,
		top, top, top, top, top, top,
		bottom, bottom, bottom, bottom, bottom, bottom);
}

js/pixl/public/trixl.html

	<span id="debug"></span>
	<script type="gl/vertex-shader">
		attribute vec3 pos;
		attribute vec3 normal;
		varying vec3 world_pos;
		varying vec3 lighting;
		uniform mat4 transform;
		void main() {
			world_pos = pos;
			gl_Position = vec4(transform * vec4(pos, 1));
			highp vec3 ambientLight = vec3(0.6, 0.6, 0.6);
			highp vec3 directionalLightColor = vec3(0.5, 0.5, 0.75);
			highp vec3 directionalVector = vec3(0.85, 0.8, 0.75);
			// FIXME: transform should only be transform w/o view & perspective
			highp vec4 transformedNormal = transform * vec4(normal, 1.0);
			highp float directional = max(dot(normal, directionalVector), 0.0);
			lighting = ambientLight + (directionalLightColor * directional);
		}
	</script>
	<script type="gl/fragment-shader">
		precision mediump float;
		uniform vec4 color;
		varying vec3 world_pos;
		varying vec3 lighting;
		void main() {
			if (color.x >= 0.0 && color.x <= 1.0) {
				gl_FragColor = color;
				gl_FragColor = vec4(color.rgb * lighting, color.a);
			} else {
				gl_FragColor = vec4(world_pos.x, world_pos.y, world_pos.z, 1);
			}
			vec3.add(trixl.camera.focus, trixl.camera.pos, front);
		}
		var vertexPosBuffer = gl.createBuffer();
		gl.bindBuffer(gl.ARRAY_BUFFER, vertexPosBuffer);
		gl.bufferData(gl.ARRAY_BUFFER, new Float32Array(geometry.cube()), gl.STATIC_DRAW);
		var vs = document.querySelector("script[type='gl/vertex-shader']").textContent;
		var fs = document.querySelector("script[type='gl/fragment-shader']").textContent;
		var program = createProgram(vs, fs);
		gl.useProgram(program);
		var vertexPosBuffer = gl.createBuffer();
		gl.bindBuffer(gl.ARRAY_BUFFER, vertexPosBuffer);
		gl.bufferData(gl.ARRAY_BUFFER, new Float32Array(geometry.cube()), gl.STATIC_DRAW);
		program.vertexPosAttrib = gl.getAttribLocation(program, 'pos');
		gl.enableVertexAttribArray(program.vertexPosAttrib);
		gl.vertexAttribPointer(program.vertexPosBuffer, 3, gl.FLOAT, false, 0, 0);
		gl.vertexAttribPointer(program.vertexPosAttrib, 3, gl.FLOAT, false, 0, 0);
		var vertexNormalBuffer = gl.createBuffer();
		gl.bindBuffer(gl.ARRAY_BUFFER, vertexNormalBuffer);
		gl.bufferData(gl.ARRAY_BUFFER, new Float32Array(geometry.cube.normals()), gl.STATIC_DRAW);
		program.vertexNormalAttrib = gl.getAttribLocation(program, 'normal');
		gl.enableVertexAttribArray(program.vertexNormalAttrib);
		gl.vertexAttribPointer(program.vertexNormalAttrib, 3, gl.FLOAT, false, 0, 0);
		program.color = gl.getUniformLocation(program, 'color');
		gl.uniform4f(program.color, -1, -1, -1, -1);