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https://github.com/EsotericSoftware/spine-runtimes.git
synced 2026-02-11 09:38:44 +08:00
[libgdx] Added SutherlandHodgmanClipper and corresponding SoftwareClippingTest
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badlogic
parent
9a086a5c18
commit
b3ac8a7f72
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package com.esotericsoftware.spine;
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import org.lwjgl.opengl.GL11;
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import com.badlogic.gdx.ApplicationAdapter;
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import com.badlogic.gdx.Gdx;
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import com.badlogic.gdx.Input.Buttons;
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import com.badlogic.gdx.backends.lwjgl.LwjglApplication;
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import com.badlogic.gdx.backends.lwjgl.LwjglApplicationConfiguration;
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import com.badlogic.gdx.graphics.Color;
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import com.badlogic.gdx.graphics.GL20;
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import com.badlogic.gdx.graphics.OrthographicCamera;
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import com.badlogic.gdx.graphics.glutils.ShapeRenderer;
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import com.badlogic.gdx.graphics.glutils.ShapeRenderer.ShapeType;
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import com.badlogic.gdx.math.Vector3;
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import com.badlogic.gdx.utils.FloatArray;
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import com.esotericsoftware.spine.utils.SutherlandHodgmanClipper;
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public class SoftwareClippingTest extends ApplicationAdapter {
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OrthographicCamera sceneCamera;
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ShapeRenderer shapes;
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float[] triangle = {100, 100, 300, 100, 200, 300};
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FloatArray clippingPolygon = new FloatArray();
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FloatArray clippedPolygon = new FloatArray();
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boolean isCreatingClippingArea = false;
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Vector3 tmp = new Vector3();
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SutherlandHodgmanClipper clipper;
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@Override
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public void create () {
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sceneCamera = new OrthographicCamera();
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shapes = new ShapeRenderer();
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clipper = new SutherlandHodgmanClipper();
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}
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@Override
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public void resize (int width, int height) {
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sceneCamera.setToOrtho(false);
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}
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@Override
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public void render () {
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Gdx.gl.glClearColor(0.3f, 0.3f, 0.3f, 1);
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Gdx.gl.glClear(GL20.GL_COLOR_BUFFER_BIT);
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processInput();
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renderScene();
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}
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private void processInput () {
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tmp.set(Gdx.input.getX(), Gdx.input.getY(), 0);
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sceneCamera.unproject(tmp);
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if (Gdx.input.justTouched()) {
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if (!isCreatingClippingArea) {
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clippingPolygon.clear();
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isCreatingClippingArea = true;
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}
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clippingPolygon.add(tmp.x);
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clippingPolygon.add(tmp.y);
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if (Gdx.input.isButtonPressed(Buttons.RIGHT)) {
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isCreatingClippingArea = false;
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clip();
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}
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}
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}
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private void renderScene () {
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sceneCamera.update();
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shapes.setProjectionMatrix(sceneCamera.combined);
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shapes.begin(ShapeType.Line);
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// triangle
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shapes.setColor(Color.GREEN);
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shapes.polygon(triangle);
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// clipped polygons
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shapes.setColor(Color.RED);
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if (isCreatingClippingArea) {
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tmp.set(Gdx.input.getX(), Gdx.input.getY(), 0);
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sceneCamera.unproject(tmp);
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clippingPolygon.add(tmp.x);
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clippingPolygon.add(tmp.y);
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}
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switch (clippingPolygon.size) {
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case 0:
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break;
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case 2:
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shapes.end();
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shapes.begin(ShapeType.Point);
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GL11.glPointSize(4);
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shapes.point(clippingPolygon.get(0), clippingPolygon.get(1), 0);
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shapes.end();
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shapes.begin(ShapeType.Line);
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break;
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case 4:
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shapes.line(clippingPolygon.get(0), clippingPolygon.get(1), clippingPolygon.get(2), clippingPolygon.get(3));
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break;
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default:
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shapes.polygon(clippingPolygon.items, 0, clippingPolygon.size);
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}
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// edge normals
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shapes.setColor(Color.YELLOW);
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if (clippingPolygon.size > 2) {
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boolean clockwise = SutherlandHodgmanClipper.clockwise(clippingPolygon);
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for (int i = 0; i < clippingPolygon.size; i += 2) {
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float x = clippingPolygon.get(i);
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float y = clippingPolygon.get(i + 1);
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float x2 = clippingPolygon.get((i + 2) % clippingPolygon.size);
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float y2 = clippingPolygon.get((i + 3) % clippingPolygon.size);
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float mx = x + (x2 - x) / 2;
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float my = y + (y2 - y) / 2;
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float nx = (y2 - y);
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float ny = -(x2 - x);
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if (!clockwise) {
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nx = -nx;
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ny = -ny;
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}
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float l = 1 / (float)Math.sqrt(nx * nx + ny * ny);
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nx *= l * 20;
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ny *= l * 20;
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shapes.line(mx, my, mx + nx, my + ny);
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}
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}
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if (isCreatingClippingArea) {
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clippingPolygon.setSize(clippingPolygon.size - 2);
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}
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// clipped polygon
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shapes.setColor(Color.PINK);
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if (clippedPolygon.size > 0) {
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shapes.polygon(clippedPolygon.items, 0, clippedPolygon.size);
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}
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shapes.end();
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}
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private void clip () {
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FloatArray input = new FloatArray();
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input.addAll(triangle, 0, triangle.length);
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clippedPolygon.clear();
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System.out.println("Clipped: " + (clipper.clip(input, clippingPolygon, clippedPolygon) != null));
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}
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public static void main (String[] args) {
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LwjglApplicationConfiguration config = new LwjglApplicationConfiguration();
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new LwjglApplication(new SoftwareClippingTest(), config);
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}
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}
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@ -0,0 +1,129 @@
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package com.esotericsoftware.spine.utils;
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import com.badlogic.gdx.math.Intersector;
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import com.badlogic.gdx.math.Vector2;
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import com.badlogic.gdx.utils.FloatArray;
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public class SutherlandHodgmanClipper {
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Vector2 tmp = new Vector2();
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public FloatArray clip (FloatArray input, FloatArray clippingArea, FloatArray output) {
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boolean isClockwise = clockwise(clippingArea);
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FloatArray originalOutput = output;
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boolean clipped = false;
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for (int i = 0; i < clippingArea.size; i += 2) {
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float edgeX = clippingArea.items[i];
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float edgeY = clippingArea.items[i + 1];
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float edgeX2 = clippingArea.items[(i + 2) % clippingArea.size];
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float edgeY2 = clippingArea.items[(i + 3) % clippingArea.size];
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if (!isClockwise) {
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float tmp = edgeX;
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edgeX = edgeX2;
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edgeX2 = tmp;
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tmp = edgeY;
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edgeY = edgeY2;
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edgeY2 = tmp;
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}
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System.out.println("-- Edge " + i / 2 + ": (" + edgeX + ", " + edgeY + ")-(" + edgeX2 + ", " + edgeY2 + ")");
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for (int j = 0; j < input.size; j += 2) {
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float inputX = input.items[j % input.size];
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float inputY = input.items[(j + 1) % input.size];
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float inputX2 = input.items[(j + 2) % input.size];
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float inputY2 = input.items[(j + 3) % input.size];
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System.out.println("\tinput " + j / 2 + ": (" + inputX + ", " + inputY + ")-(" + inputX2 + ", " + inputY2 + ")");
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int side = Intersector.pointLineSide(edgeX2, edgeY2, edgeX, edgeY, inputX, inputY);
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int side2 = Intersector.pointLineSide(edgeX2, edgeY2, edgeX, edgeY, inputX2, inputY2);
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System.out.println("\tv1: " + (side < 0 ? "outside" : "inside" ) + ", v2: " + (side2 < 0 ? "outside" : "inside"));
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// v1 inside, v2 inside
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if (side >= 0 && side2 >= 0) {
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output.add(inputX2);
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output.add(inputY2);
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}
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// v1 inside, v2 outside
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else if (side >= 0 && side2 < 0) {
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if (!Intersector.intersectLines(edgeX, edgeY, edgeX2, edgeY2, inputX, inputY, inputX2, inputY2, tmp)) {
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throw new RuntimeException("Lines should intersect, but didn't");
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}
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output.add(tmp.x);
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output.add(tmp.y);
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clipped = true;
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}
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// v1 outside, v2 outside
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else if (side < 0 && side2 < 0) {
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// no output
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clipped = true;
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}
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// v1 outside, v2 inside
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else if (side < 0 && side2 >= 0) {
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if (!Intersector.intersectLines(edgeX, edgeY, edgeX2, edgeY2, inputX, inputY, inputX2, inputY2, tmp)) {
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throw new RuntimeException("Lines should intersect, but didn't");
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}
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output.add(tmp.x);
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output.add(tmp.y);
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output.add(inputX2);
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output.add(inputY2);
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clipped = true;
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}
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}
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if (i < clippingArea.size - 2) {
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FloatArray tmp = output;
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output = input;
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output.clear();
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input = tmp;
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}
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}
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if (originalOutput != output) {
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originalOutput.clear();
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originalOutput.addAll(output.items, 0, output.size);
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}
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return clipped ? output : null;
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}
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private int pointLineSide(float lineX, float lineY, float lineX2, float lineY2, float pointX, float pointY) {
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return (int)Math.signum((lineX2 - lineX) * (pointY - lineY) - (lineY2 - lineY) * (pointX - lineX));
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}
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public static boolean intersectLines (float x1, float y1, float x2, float y2, float x3, float y3, float x4, float y4,
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Vector2 intersection) {
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float d = (y4 - y3) * (x2 - x1) - (x4 - x3) * (y2 - y1);
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if (d == 0) return false;
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if (intersection != null) {
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float ua = ((x4 - x3) * (y1 - y3) - (y4 - y3) * (x1 - x3)) / d;
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intersection.set(x1 + (x2 - x1) * ua, y1 + (y2 - y1) * ua);
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}
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return true;
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}
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public static boolean clockwise (FloatArray poly) {
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return area(poly) < 0;
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}
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public static float area (FloatArray poly) {
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float area = 0;
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for (int i = 0; i < poly.size; i += 2) {
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float x = poly.items[i];
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float y = poly.items[i + 1];
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float x2 = poly.items[(i + 2) % poly.size];
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float y2 = poly.items[(i + 3) % poly.size];
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area += x * y2 - y * x2;
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}
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return area;
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}
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}
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