ClippingNaan.java

package com.esotericsoftware.spine;

import com.badlogic.gdx.ApplicationAdapter;
import com.badlogic.gdx.Gdx;
import com.badlogic.gdx.backends.lwjgl.LwjglApplication;
import com.badlogic.gdx.graphics.GL20;
import com.badlogic.gdx.graphics.OrthographicCamera;
import com.badlogic.gdx.graphics.glutils.ShapeRenderer;
import com.badlogic.gdx.graphics.glutils.ShapeRenderer.ShapeType;
import com.badlogic.gdx.utils.FloatArray;
import com.badlogic.gdx.utils.ShortArray;
import com.esotericsoftware.spine.attachments.ClippingAttachment;
import com.esotericsoftware.spine.utils.SkeletonClipping;

public class ClipNaan extends ApplicationAdapter {
	ShapeRenderer renderer;
	OrthographicCamera camera;
	private ClippingAttachment clipping;
	private float[] vertices;
	private short[] triangles;
	private FloatArray clippedVertices;
	private ShortArray clippedTriangles;
	private SkeletonClipping clipper;
	private Skeleton skeleton;

	@Override
	public void create () {
		SkeletonData skeletonData = new SkeletonData();

		BoneData boneData = new BoneData(0, "bone", null);
		skeletonData.getBones().add(boneData);

		SlotData slotData = new SlotData(0, "slot", boneData);
		slotData.setAttachmentName("clipping");
		skeletonData.getSlots().add(slotData);

		skeleton = new Skeleton(skeletonData);
		skeleton.updateWorldTransform();

		camera = new OrthographicCamera();
		renderer = new ShapeRenderer();
		renderer.setAutoShapeType(true);
	}

	@Override
	public void render () {
		clipping = new ClippingAttachment("clipping");
		clipping.setBones(new int[] {1, 0, 1, 0, 1, 0, 1, 0});
		clipping.setVertices(
			new float[] {-300.72156f, 708.0388f, 1, -300.72153f, 168.0389f, 1, 137.288f, 8.616486f, 1, 137.28796f, 548.61633f, 1});
		clipping.setWorldVerticesLength(8);

		clipper = new SkeletonClipping();
		clipper.clipStart(skeleton.getSlots().first(), clipping);

		vertices = new float[] {137.288f, 8.616455f, -300.72153f, 168.03888f, -300.7216f, 708.0388f, 137.28793f, 548.61633f};
		float[] uvs = vertices;
		triangles = new short[] {1, 2, 3, 1, 3, 0};
		clipper.clipTriangles(vertices, vertices.length, triangles, triangles.length, uvs, 0, 0, false);

		clippedVertices = clipper.getClippedVertices();
		clippedTriangles = clipper.getClippedTriangles();

		Gdx.gl.glClear(GL20.GL_COLOR_BUFFER_BIT);
		camera.setToOrtho(false);
		camera.zoom = 2f;
		camera.position.x = -200;
		camera.position.y = 250;
		camera.update();
		renderer.setProjectionMatrix(camera.combined);

		renderer.begin();
		renderer.setColor(1, 1, 1, 1);
		drawTriangles(vertices, 2, triangles, triangles.length);
		renderer.setColor(0, 1, 0, 1);
		FloatArray clippingPolygon = clipper.clippingPolygons.get(0);
		polyline(clippingPolygon.items, clippingPolygon.size, 2);
		renderer.setColor(1, 0, 0, 1);
		drawTriangles(clippedVertices.items, 5, clippedTriangles.items, clippedTriangles.size);
		renderer.end();
	}

	public void drawTriangles (float[] vertices, int stride, short[] triangles, int trianglesLength) {
		for (int i = 0; i < trianglesLength; i += 3) {
			int idx1 = triangles[i] * stride, idx2 = triangles[i + 1] * stride, idx3 = triangles[i + 2] * stride;
			renderer.line(vertices[idx1], vertices[idx1 + 1], vertices[idx2], vertices[idx2 + 1]);
			renderer.line(vertices[idx2], vertices[idx2 + 1], vertices[idx3], vertices[idx3 + 1]);
			renderer.line(vertices[idx3], vertices[idx3 + 1], vertices[idx1], vertices[idx1 + 1]);
		}
	}

	/** Draws a polyline in the x/y plane using {@link ShapeType#Line}. The vertices must contain at least 2 points (4 floats
	 * x,y). */
	public void polyline (float[] vertices, int length, int stride) {
		for (int i = 0, n = length - stride; i < n; i += stride) {
			float x1 = vertices[i];
			float y1 = vertices[i + 1];

			float x2;
			float y2;

			x2 = vertices[i + 2];
			y2 = vertices[i + 3];

			renderer.line(x1, y1, x2, y2);
		}
	}

	static public void main (String[] args) throws Exception {
		new LwjglApplication(new ClipNaan());
	}
}