support drawing circles.

yay! next up, spheres.

js/pixl/public/trixl.html

@@ -61,6 +61,15 @@
			}
			return m;
		}
		var range = function(lo, hi) {
			var both = hi !== undefined,
			    l = both ? lo : 0,
			    h = both ? hi : lo;
			return Array.apply(null, Array(h - l)).map(function(_, i) {
				return l + i;
			});
		}
	</script>
	<script>
		window.trixl = {};
@@ -182,6 +191,18 @@
			trixl.generate.many(1000, -100, 100);
		}
		trixl.geometry = {};
		trixl.geometry.circle = function(pos, radius, color) {
			range(0, 2 * radius).map(function(i) {
				trixl.world.set([
					pos[0] + radius * Math.sin(i * Math.PI / radius),
					pos[1] + radius * Math.cos(i * Math.PI / radius),
					pos[2]
				], {color: color || trixl.color});
			});
		}
		var angle = {x: 0, y: 0, z: 0};
		var offset = {x: 0, y: 0, z: 0};
		program.transform = gl.getUniformLocation(program, 'transform');