I wrote the following code:
int a=0, b=0, c=0, d=0;
sprite[number[0]].setPosition(160, 600);
sprite[number[1]].setPosition(560, 600);
sprite[number[2]].setPosition(360, 400);
sprite[number[3]].setPosition(360, 800);
seiten[number[4]].setPosition(-35, 0);
seiten1[number[4]].setPosition(825, 0);
sprite[number[0]].setOrigin(200,0);
sprite[number[1]].setOrigin(-200,0);
sprite[number[2]].setOrigin(0,-200);
sprite[number[3]].setOrigin(0,-200);
sprite[number[0]].setRotation(a++);
sprite[number[1]].setRotation(b++);
sprite[number[2]].setRotation(c++);
sprite[number[3]].setRotation(d++);
I want to rotate the sprites like:
Unfortunately, this code doesn´t work for this purpose. How can I improve my code?
EDIT:
For better understanding:
I have ten sprites with different colors, four of them are shown on the game screen. The coincidence decides which sprite will be shown, but each sprite of them has a different color. Now I want to rotate the four sprites in the lane which is shown in the image. The four sprites should turn on the pink sprite which in fact doesn´t exist in my code. This pink sprite is just a symbol for the centre of the rotation (P(360|600)). The four sprites rotate all in the same lane.
With my code the four sprites rotate but not in the same lane as it is shown in the image. I hope my question is now more clear.
I guess you could use sprite.rotate() and set the sprite origin to the point you want to rotate about with sprite.setorigin().
Try this :
Sprite sprites[],centralSprite;
float centerX=200,centerY=200,radius=100;
SpriteBatch spriteBatch;
#Override
public void create() {
spriteBatch=new SpriteBatch();
Texture badlogic=new Texture("badlogic.jpg");
centralSprite=new Sprite(badlogic);
centralSprite.setSize(50,50);
centralSprite.setPosition(centerX,centerY);
centralSprite.setOriginCenter();
sprites=new Sprite[4];
for (int i=0;i<sprites.length;i++) {
sprites[i] = new Sprite(badlogic);
sprites[i].setSize(50,50);
sprites[i].setRotation(90 * i);
sprites[i].setPosition(centerX + radius * MathUtils.cosDeg(sprites[i].getRotation()),
centerY + radius * MathUtils.sinDeg(sprites[i].getRotation()));
sprites[i].setOriginCenter();
}
}
#Override
public void render() {
Gdx.gl.glClearColor(1,0,1,1);
Gdx.gl.glClear(GL20.GL_COLOR_BUFFER_BIT);
spriteBatch.begin();
for (int i=0;i<sprites.length;i++) {
sprites[i].rotate(1);
sprites[i].setPosition(centerX + radius * MathUtils.cosDeg(sprites[i].getRotation()),
centerY + radius * MathUtils.sinDeg(sprites[i].getRotation()));
sprites[i].draw(spriteBatch);
}
centralSprite.draw(spriteBatch);
spriteBatch.end();
}
Using accelerometer my sprite image is moving left and right and if I touch my screen the sprite is moving to Y-axis.I want to make a collision detection between different sprites so that if the sprite pass through an object it will stop to hide in that object. I already watch a tutorial this https://www.youtube.com/watch?v=T1aN--vTqLc but nothings happen. What is the proper way to make collition detection? I don't know what's wrong with my coding.Any suggestion or much better tutorial Thank's and Advance
Here is my coding
private Rectangle rectangleCat;
private Rectangle rectangleShoes;
private float yPosition = -40;
Sprite
cat = new Texture(Gdx.files.internal("cat.png"));
catsprite = new Sprite(cat);
catX=300;
catY=0;
sprite_shoes = new Sprite(new Texture("equip/Shoes.png"));
sprite_shoes.setPosition(260,580);
rectangleShoes=new Rectangle(sprite_shoes.getX(),sprite_shoes.getY(),sprite_shoes.getWidth(),sprite_shoes.getHeight());
rectangleCat = new Rectangle(catsprite.getX(),catsprite.getY(),catsprite.getWidth(),catsprite.getHeight());
Render method
boolean isOverlaping = rectangleCat.overlaps(rectangleShoes);
if(!isOverlaping) {
System.out.println("not overlap");
yPosition = yPosition + (20 * delta);
}
My Sprite image and Object is not overlapping
Full source code http://pastebin.com/Dxfx9f65
First of all your sprite is not sharp Rectangle it's looks like polygon so you need to detect collision between two polygon.
Still if you want to detect collision between rectangle then get Bounding Rectangle of your sprite in render() method.
In render method
rectangleShoes=sprite_shoes.getBoundingRectangle();
rectangleCat=catsprite.getBoundingRectangle();
boolean isOverlaping = rectangleCat.overlaps(rectangleShoes);
if(!isOverlaping) {
System.out.println("not overlap");
yPosition = yPosition + (20 * delta);
}
I'm using LibGDX with Scene2D for my java game. I know my issue is connected to Scene2D, because I used the EXACT same class passing it normally to SpriteBatch (not through Stage instance) and it worked as expected.
I let Stage manage all of my drawables entities which are actors. It draws everything using implementor of Batch; SpriteBatch is the default. And it was working until I wanted to draw a polygon, which has to be drawn by PolygonSpriteBatch, not SpriteBatch.. So during one Stage.draw() call I need to use them both.
I made a CheckedPolygon class which is basically two PolygonSprites drawn on top of each other (one is semi-transparent). SpriteBatch passed in draw() method is temporarily ended to enable PolygonSpriteBatch for a moment, draw the polygon and disable it.
And the output is empty screen, I get nothing. Again, it worked when I wasn't using Stage class.
Here's the class, so you get a better understanding.
NOTE: I know this is bad in terms of performance, because I don't dispose of Texture and keep Batch for one object but it's for the sake of simplicity.
NOTE2: Yes, I passed it properly to stage, the code is executed, I checked through debugging.
public class CheckedPolygon extends Actor {
private final PolygonSprite mBackground, mCross;
private final PolygonSpriteBatch mPolygonSpriteBatch;
private final Camera mCamera;
public CheckedPolygon(Camera camera, float[] vertices, short[] triangles) {
super();
mCamera = camera;
mPolygonSpriteBatch = new PolygonSpriteBatch();
Texture textureBack = new Texture(Gdx.files.internal("source/back.png"));
textureBack.setWrap(Texture.TextureWrap.Repeat, Texture.TextureWrap.Repeat);
PolygonRegion regionBack = new PolygonRegion(new TextureRegion(textureBack), vertices, triangles);
mBackground = new PolygonSprite(regionBack);
Texture textureCross = new Texture(Gdx.files.internal("source/cross.png"));
textureCross.setWrap(Texture.TextureWrap.Repeat, Texture.TextureWrap.Repeat);
PolygonRegion regionCross = new PolygonRegion(new TextureRegion(textureCross), vertices, triangles);
mCross = new PolygonSprite(regionCross);
}
#Override
public void draw(Batch batch, float parentAlpha) {
batch.end();
mPolygonSpriteBatch.setProjectionMatrix(mCamera.combined);
mPolygonSpriteBatch.begin();
mBackground.draw(mPolygonSpriteBatch);
mCross.draw(mPolygonSpriteBatch);
mPolygonSpriteBatch.end();
batch.begin();
}
}
And I use it like this:
CheckedPolygon polygon = new CheckedPolygon(mStage.getCamera(), mTextureAtlas, new float[]{0, 500, 0, 0, 0, 500}, new short[]{0, 1, 2});
mStage.addActor(polygon);
I checked values from methods PolygonSprite.getVertices() and PolygonSprite.getBoundingRectangle() and got some weird outputs...
You create an invalid polygon with 0,500 being the first and last point.
So you need to chose valid vertices, for example:
new float[] {0, 0, 0, 500, 500, 500}
I created a small image to visualize it. The line on top is your "polygon", the triangle below is a polygon with the vertices from above:
The vertices you get back from the polygon sprite are otherwise ok, since they contain x, y, color, u, v.
I have a player setup with box2d and I am trying to draw a sprite over the player. The player spawns in the middle of the screen, while the sprite spawns in the lower left hand corner of the screen but does move along with the player entity, just starting at a different location.
GameScreen snippet:
#Override
public void render(float delta) {
super.render(delta);
player.update();
world.step(TIMESTEP, VELOCITY_ITERATIONS, POSITION_ITERATIONS);
}
#Override
public void show() {
player = new Player(world, 0, 0);
}
Player class snippet:
public Player(World world, float x, float y) {
texture = new Texture(Gdx.files.internal("sprites/Player.png"));
sprite = new Sprite(texture);
}
public void update() {
batch = new SpriteBatch();
batch.begin();
sprite.draw();
sprite.setPosition(body.getPosition().x, body.getPosition().y);
batch.end();
body.setLinearVelocity(impulse);
}
I tried setting the position of the sprite in the constructor based on the body's coordinates but it doesn't seem to be working. I have removed body & fixture code. Any push in the right direction is appreciated.
If you enable box2d debug render, you'll probably find that both the texture and the body are starting at the left corner of the screen. Actually, 0, 0 are supposed to be the coordinates for the left bottom corner. In order to set your body in the center of the screen, you should set something like
(SCREEN_WIDTH / 2) / PTM_RATIO, (SCREEN_HEIGHT / 2) / PTM_RATIO
as your body initial position.
I want to draw some (filled) polygons with libGDX. It shoudn't be filled with a graphic/texture. I have only the vertices of the polygon (closed path) and tried to visualize with meshes but at some point this is not the best solution, I think.
My code for an rectangle is:
private Mesh mesh;
#Override
public void create() {
if (mesh == null) {
mesh = new Mesh(
true, 4, 0,
new VertexAttribute(Usage.Position, 3, "a_position")
);
mesh.setVertices(new float[] {
-0.5f, -0.5f, 0
0.5f, -0.5f, 0,
-0.5f, 0.5f, 0,
0.5f, 0.5f, 0
});
}
}
// ...
#Override
public void render() {
Gdx.gl.glClear(GL10.GL_COLOR_BUFFER_BIT);
mesh.render(GL10.GL_TRIANGLE_STRIP, 0, 4);
}
is there a function or something to draw filled polygons in an easier way?
Since recent updates of LibGDX, #Rus answer is using deprecated functions. However, I give him/her credits for the new updated version below:
PolygonSprite poly;
PolygonSpriteBatch polyBatch = new PolygonSpriteBatch(); // To assign at the beginning
Texture textureSolid;
// Creating the color filling (but textures would work the same way)
Pixmap pix = new Pixmap(1, 1, Pixmap.Format.RGBA8888);
pix.setColor(0xDEADBEFF); // DE is red, AD is green and BE is blue.
pix.fill();
textureSolid = new Texture(pix);
PolygonRegion polyReg = new PolygonRegion(new TextureRegion(textureSolid),
new float[] { // Four vertices
0, 0, // Vertex 0 3--2
100, 0, // Vertex 1 | /|
100, 100, // Vertex 2 |/ |
0, 100 // Vertex 3 0--1
}, new short[] {
0, 1, 2, // Two triangles using vertex indices.
0, 2, 3 // Take care of the counter-clockwise direction.
});
poly = new PolygonSprite(polyReg);
poly.setOrigin(a, b);
polyBatch = new PolygonSpriteBatch();
For good triangulating algorithms if your polygon is not convex, see the almost-linear earclipping algorithm from Toussaint (1991)
Efficient triangulation of simple polygons, Godfried Toussaint, 1991
Here is a libGDX example which draws a 2D concave polygon.
Define class members for PolygonSprite PolygonSpriteBatch
PolygonSprite poly;
PolygonSpriteBatch polyBatch;
Texture textureSolid;
Create instances, 1x1 size texture used with red pixel as workaround. An array of coordinates (x, y) is used for initialization of the polygon.
ctor() {
textureSolid = makeTextureBox(1, 0xFFFF0000, 0, 0);
float a = 100;
float b = 100;
PolygonRegion polyReg = new PolygonRegion(new TextureRegion(textureSolid),
new float[] {
a*0, b*0,
a*0, b*2,
a*3, b*2,
a*3, b*0,
a*2, b*0,
a*2, b*1,
a*1, b*1,
a*1, b*0,
});
poly = new PolygonSprite(polyReg);
poly.setOrigin(a, b);
polyBatch = new PolygonSpriteBatch();
}
Draw and rotate polygon
void draw() {
super.draw();
polyBatch.begin();
poly.draw(polyBatch);
polyBatch.end();
poly.rotate(1.1f);
}
I believe the ShapeRenderer class now has a polygon method for vertex defined polygons:
ShapeRenderer.polygon()
You can use the ShapeRenderer API to draw simple, solid-color shapes with Libgdx.
The code you've given is a reasonable way to draw solid color polygons too. Its much more flexible than ShapeRenderer, but is a good bit more complicated. You'll need to use glColor4f to set the color, or add a Usage.Color attribute to each vertex. See the SubMeshColorTest example for more details on the first approach and the MeshColorTexture example for details on the second approach.
Another option to think about is using sprite textures. If you're only interested in simple solid colors objects, you can use very simple 1x1 textures of a single color and let the system stretch that across the sprite. Much of Libgdx and the underlying hardware are really optimized for rendering textures, so you may find it easier to use even if you're not really taking advantage of the texture contents. (You can even use a 1x1 white texture, and then use a SpriteBatch with setColor and draw()
to draw different color rectangles easily.)
You can also mix and match the various approaches, too.
Use triangulation algorithm and then draw all triangles as GL_TRIANGLE_STRIP
http://www.personal.psu.edu/cxc11/AERSP560/DELAUNEY/13_Two_algorithms_Delauney.pdf
just wanted to share my related solution with you, namely for implementing and drawing a walkZone with scene2d. I basically had to put together the different suggestions of the others' posts:
1) The WalkZone:
import com.badlogic.gdx.graphics.Pixmap;
import com.badlogic.gdx.graphics.Texture;
import com.badlogic.gdx.graphics.g2d.PolygonRegion;
import com.badlogic.gdx.graphics.g2d.TextureRegion;
import com.badlogic.gdx.math.EarClippingTriangulator;
import com.badlogic.gdx.math.Polygon;
import com.mygdx.game.MyGame;
public class WalkZone extends Polygon {
private PolygonRegion polygonRegion = null;
public WalkZone(float[] vertices) {
super(vertices);
if (MyGame.DEBUG) {
Pixmap pix = new Pixmap(1, 1, Pixmap.Format.RGBA8888);
pix.setColor(0x00FF00AA);
pix.fill();
polygonRegion = new PolygonRegion(new TextureRegion(new Texture(pix)),
vertices, new EarClippingTriangulator().computeTriangles(vertices).toArray());
}
}
public PolygonRegion getPolygonRegion() {
return polygonRegion;
}
}
2) The Screen:
you can then add a listener in the desired Stage:
myStage.addListener(new InputListener() {
#Override
public boolean touchDown(InputEvent event, float x, float y, int pointer, int button) {
if (walkZone.contains(x, y)) player.walkTo(x, y);
// or even directly: player.addAction(moveTo ...
return super.touchDown(event, x, y, pointer, button);
}
});
3) The implementation:
The array passed to te WZ constructor is a set of x,y,x,y... points. If you put them counter-clockwise, it works (I didn't check the other way, nor know how it exactly works); for example this generates a 100x100 square:
yourScreen.walkZone = new WalkZone(new int[]{0, 0, 100, 0, 100, 100, 0, 100});
In my project it works like a charm, even with very intricated polygons. Hope it helps!!
Most answers suggest triangulation, which is fine, but you can also do it using the stencil buffer. It handles both convex and concave polygons. This may be a better solution if your polygon changes a lot, since otherwise you'd have to do triangulation every frame. Also, this solution properly handles self intersecting polygons, which EarClippingTriangulator does not.
FloatArray vertices = ... // The polygon x,y pairs.
Color color = ... // The color to draw the polygon.
ShapeRenderer shapes = ...
ImmediateModeRenderer renderer = shapes.getRenderer();
Gdx.gl.glClearStencil(0);
Gdx.gl.glClear(GL20.GL_STENCIL_BUFFER_BIT);
Gdx.gl.glEnable(GL20.GL_STENCIL_TEST);
Gdx.gl.glStencilFunc(GL20.GL_NEVER, 0, 1);
Gdx.gl.glStencilOp(GL20.GL_INVERT, GL20.GL_INVERT, GL20.GL_INVERT);
Gdx.gl.glColorMask(false, false, false, false);
renderer.begin(shapes.getProjectionMatrix(), GL20.GL_TRIANGLE_FAN);
renderer.vertex(vertices.get(0), vertices.get(1), 0);
for (int i = 2, n = vertices.size; i < n; i += 2)
renderer.vertex(vertices.get(i), vertices.get(i + 1), 0);
renderer.end();
Gdx.gl.glColorMask(true, true, true, true);
Gdx.gl.glStencilOp(GL20.GL_ZERO, GL20.GL_ZERO, GL20.GL_ZERO);
Gdx.gl.glStencilFunc(GL20.GL_EQUAL, 1, 1);
Gdx.gl.glEnable(GL20.GL_BLEND);
shapes.setColor(color);
shapes.begin(ShapeType.Filled);
shapes.rect(-9999999, -9999999, 9999999 * 2, 9999999 * 2);
shapes.end();
Gdx.gl.glDisable(GL20.GL_STENCIL_TEST);
To use the stencil buffer, you must specify the number of bits for the stencil buffer when your app starts. For example, here is how to do that using the LWJGL2 backend:
LwjglApplicationConfiguration config = new LwjglApplicationConfiguration();
config.stencil = 8;
new LwjglApplication(new YourApp(), config);
For more information on this technique, try one of these links:
http://commaexcess.com/articles/7/concave-polygon-triangulation-shortcut
http://glprogramming.com/red/chapter14.html#name13
http://what-when-how.com/opengl-programming-guide/drawing-filled-concave-polygons-using-the-stencil-buffer-opengl-programming/