flutter/examples/game/lib/game_world.dart

192 lines
5.7 KiB
Dart

part of game;
class GameWorld extends TransformNode {
World world;
List<Body> bodies = [];
Body _bodyShip;
Image _imgBg;
Image _imgAsteroid;
Image _imgShip;
double _steeringInput;
double _thrustInput;
double _lastSteeringSpeed = 0.0;
GameWorld(ImageMap images) {
this.width = 1024.0;
this.height = 1024.0;
// Fetch images
_imgBg = images["https://raw.githubusercontent.com/slembcke/GalacticGuardian.spritebuilder/GDC/Packages/SpriteBuilder%20Resources.sbpack/resources-auto/BurnTexture.png"];
_imgAsteroid = images["https://raw.githubusercontent.com/slembcke/GalacticGuardian.spritebuilder/GDC/Packages/SpriteBuilder%20Resources.sbpack/Sprites/resources-auto/asteroid_big_002.png"];
_imgShip = images["https://raw.githubusercontent.com/slembcke/GalacticGuardian.spritebuilder/GDC/Packages/SpriteBuilder%20Resources.sbpack/Sprites/resources-auto/GG_blueship_Lv3.png"];
// Create the physics world
world = new World.withGravity(new Vector2(0.0, 0.0));
// Add a background
addBackground();
// Add some asteroids to the game world
for (int i = 0; i < 5; i++) {
addAsteroid(10.0);
}
for (int i = 0; i < 5; i++) {
addAsteroid(20.0);
}
// Add ship
addShip();
}
void addBackground() {
SpriteNode sprtBg = new SpriteNode.withImage(_imgBg);
sprtBg.width = width;
sprtBg.height = height;
sprtBg.pivot = new Vector2(0.0, 0.0);
this.children.add(sprtBg);
}
void addAsteroid([double radius=20.0]) {
// Create shape
final CircleShape shape = new CircleShape();
shape.radius = radius;
// Define fixture (links body and shape)
final FixtureDef activeFixtureDef = new FixtureDef();
activeFixtureDef.restitution = 1.0;
activeFixtureDef.density = 0.05;
activeFixtureDef.shape = shape;
// Define body
final BodyDef bodyDef = new BodyDef();
bodyDef.type = BodyType.DYNAMIC;
bodyDef.position = new Vector2(0.0, 30.0);
bodyDef.linearDamping = 0.0;
bodyDef.angularDamping = 0.0;
// Create body and fixture from definitions
final Body body = world.createBody(bodyDef);
body.createFixtureFromFixtureDef(activeFixtureDef);
// Set position of object
Math.Random rand = new Math.Random();
body.setTransform(new Vector2(rand.nextDouble() * this.width, rand.nextDouble() * this.height), 0.0);
body.applyLinearImpulse(new Vector2(rand.nextDouble()*10000.0-5000.0, rand.nextDouble()*10000.0-5000.0), new Vector2(0.0, 0.0), true);
// Add to list
bodies.add(body);
// Create sprite
SpriteNode sprt = new SpriteNode.withImage(_imgAsteroid);
sprt.width = radius*2;
sprt.height = radius*2;
// sprt.colorOverlay = new Color(0x33ff0000);
// sprt.transferMode = TransferMode.plusMode;
body.userData = sprt;
this.children.add(sprt);
}
void addShip() {
double radius = 30.0;
// Create shape
final CircleShape shape = new CircleShape();
shape.radius = radius;
// Define fixture (links body and shape)
final FixtureDef activeFixtureDef = new FixtureDef();
activeFixtureDef.restitution = 1.0;
activeFixtureDef.density = 0.05;
activeFixtureDef.shape = shape;
// Define body
final BodyDef bodyDef = new BodyDef();
bodyDef.type = BodyType.DYNAMIC;
bodyDef.position = new Vector2(0.0, 30.0);
bodyDef.linearDamping = 0.0;
bodyDef.angularDamping = 0.95;
// Create body and fixture from definitions
final Body body = world.createBody(bodyDef);
body.createFixtureFromFixtureDef(activeFixtureDef);
// Center on screen
body.setTransform(new Vector2(width/2.0, height/2.0), 90.0);
// Add to list
bodies.add(body);
_bodyShip = body;
// Create sprite
SpriteNode sprt = new SpriteNode.withImage(_imgShip);
sprt.width = radius*2;
sprt.height = radius*2;
sprt.position = new Vector2(width/2.0, height/2.0);
body.userData = sprt;
this.children.add(sprt);
}
void update(double dt) {
// Apply thrust
if (_thrustInput != null) {
double force = _thrustInput*10000.0;
double rad = degrees2radians(_bodyShip.getAngle());
_bodyShip.applyLinearImpulse(new Vector2(Math.cos(rad)*force, Math.sin(rad)*force), new Vector2(0.0, 0.0), true);
}
// Simulate world
world.stepDt(1.0/60.0, 10, 10); // Pass in dt
// Apply stearing
if (_steeringInput != null) {
_lastSteeringSpeed = _steeringInput * 4.0;
}
else {
_lastSteeringSpeed *= 0.75;
}
_bodyShip.setTransform(_bodyShip.position, _bodyShip.getAngle() + _lastSteeringSpeed);
// Update all sprites
bodies.forEach(updateBody);
}
void updateBody(Body body) {
SpriteNode sprt = body.userData;
double rot = 0.0; //body.getRotation();
// Check bounds and warp objects
if (body.position[0] < -sprt.width/2) {
body.setTransform(new Vector2(body.position[0] + this.width + sprt.width, body.position[1]), rot);
}
if (body.position[0] > this.width + sprt.width/2) {
body.setTransform(new Vector2(body.position[0] - (this.width + sprt.width), body.position[1]), rot);
}
if (body.position[1] < -sprt.height/2) {
body.setTransform(new Vector2(body.position[0], body.position[1] + this.height + sprt.height), rot);
}
if (body.position[1] > this.height + sprt.height/2) {
body.setTransform(new Vector2(body.position[0], body.position[1] - (this.height + sprt.height)), rot);
}
// Update sprite
sprt.position = body.position;
sprt.rotation = body.getAngle();
}
void controlSteering(double input) {
_steeringInput = input;
}
void controlThrust(double input) {
_thrustInput = input;
}
void controlFire() {
}
}