drawing circles

gistfile1.java

package org.oscim.test;

import static java.lang.Math.random;
import static org.oscim.backend.canvas.Color.fade;
import static org.oscim.utils.ColorUtil.shiftHue;

import org.oscim.backend.canvas.Color;
import org.oscim.core.GeometryBuffer;
import org.oscim.gdx.GdxMapApp;
import org.oscim.layers.GenericLayer;
import org.oscim.renderer.BucketRenderer;
import org.oscim.renderer.GLViewport;
import org.oscim.renderer.bucket.LineBucket;
import org.oscim.renderer.bucket.MeshBucket;
import org.oscim.theme.styles.AreaStyle;
import org.oscim.theme.styles.LineStyle;

public class CircleDemo extends GdxMapApp {

	public static GeometryBuffer makeCircle(float x, float y, float radius, int segments) {
		GeometryBuffer g = new GeometryBuffer(segments, 1);

		g.startPolygon();
		for (int i = 0; i < segments; i++) {
			double rad = Math.toRadians(i * (360f / segments));

			g.addPoint((float) (x + Math.cos(rad) * radius),
			           (float) (y + Math.sin(rad) * radius));

		}
		return g;
	}

	@Override
	public void createLayers() {
		CircleRenderer r = new CircleRenderer();

		MeshBucket mb;
		LineBucket lb;

		GeometryBuffer g;

		int level = 0;
		for (int i = 0; i < 100; i++) {
			AreaStyle style = new AreaStyle(fade(shiftHue(Color.RED, random()), 0.8f));

			mb = r.buckets.addMeshBucket(level++,
			                             style);

			lb = r.buckets.addLineBucket(level++, new LineStyle(Color.BLACK, 1.2f));

			float radius = (float) (random() * 10) + 0.5f;

			g = makeCircle((float) (random() * 400),
			               (float) (random() * 400),
			               radius,
			               60);

			mb.addConvexMesh(g);
			lb.addLine(g);

		}
		mMap.layers().add(new GenericLayer(mMap, r));
	}

	static class CircleRenderer extends BucketRenderer {
		boolean first = true;

		@Override
		public void update(GLViewport v) {
			if (first) {
				/* keep drawing relative to current position */
				mMapPosition.copy(v.pos);

				compile();
				first = false;
			}
		}
	}

	public static void main(String[] args) {
		GdxMapApp.init();
		GdxMapApp.run(new CircleDemo(), null, 400);
	}
}