Add mass, damping and max velocity attributes to a body

5 files changed, 67 insertions, 24 deletions

diff --git a/core/src/org/snoopdesigns/endless/physics/PhysicalBody.java b/core/src/org/snoopdesigns/endless/physics/PhysicalBody.java
index 23ede8d..31204a9 100644
--- a/core/src/org/snoopdesigns/endless/physics/PhysicalBody.java
+++ b/core/src/org/snoopdesigns/endless/physics/PhysicalBody.java
@@ -5,6 +5,7 @@ import com.badlogic.gdx.physics.box2d.Body;
 import com.badlogic.gdx.physics.box2d.BodyDef;
 import com.badlogic.gdx.physics.box2d.BodyDef.BodyType;
 import com.badlogic.gdx.physics.box2d.FixtureDef;
+import com.badlogic.gdx.physics.box2d.MassData;
 import org.snoopdesigns.endless.context.Context;
 
 public abstract class PhysicalBody {
@@ -13,7 +14,9 @@ public abstract class PhysicalBody {
 
     public abstract BodyType getBodyType();
     public abstract FixtureDef getFixture();
-
+    public abstract float getMass();
+    public abstract float getLinearDamping();
+    public abstract float getMaxVelocity();
     public Vector2 getInitialPosition() {
         return new Vector2(0, 0);
     }
@@ -24,6 +27,18 @@ public abstract class PhysicalBody {
         bodyDef.position.set(getInitialPosition());
         body = Context.getInstance().getWorldContext().getWorld().createBody(bodyDef);
         body.createFixture(getFixture());
+
+        final MassData massData = new MassData();
+        massData.mass = getMass();
+        getBody().setMassData(massData);
+
+        getBody().setLinearDamping(getLinearDamping());
+    }
+
+    public void limitVelocity() {
+        if (getBody().getLinearVelocity().len() > getMaxVelocity()) {
+            getBody().setLinearVelocity(getBody().getLinearVelocity().limit(getMaxVelocity()));
+        }
     }
 
     public Body getBody() {
diff --git a/core/src/org/snoopdesigns/endless/renderer/DebugRenderer.java b/core/src/org/snoopdesigns/endless/renderer/DebugRenderer.java
index f31336b..cbf8a07 100644
--- a/core/src/org/snoopdesigns/endless/renderer/DebugRenderer.java
+++ b/core/src/org/snoopdesigns/endless/renderer/DebugRenderer.java
@@ -24,12 +24,12 @@ public class DebugRenderer implements Renderer {
         batch.begin();
         final String debugText = String.format("""
                 window size %d x %d
-                viewport %f %f
-                zoom %f
-                position %f %f
-                angle %f
-                speed %f
-                velocity %f %f
+                viewport %.1f %.1f
+                zoom %.1f
+                position %.1f %.1f
+                angle %.1f
+                speed %.1f m/s
+                velocity %.1f %.1f
                 """,
                 Gdx.graphics.getWidth(),
                 Gdx.graphics.getHeight(),
diff --git a/core/src/org/snoopdesigns/endless/world/ObjectsRenderer.java b/core/src/org/snoopdesigns/endless/world/ObjectsRenderer.java
index f97f05c..628b63a 100644
--- a/core/src/org/snoopdesigns/endless/world/ObjectsRenderer.java
+++ b/core/src/org/snoopdesigns/endless/world/ObjectsRenderer.java
@@ -6,7 +6,6 @@ import java.util.List;
 import com.badlogic.gdx.graphics.g2d.SpriteBatch;
 import org.snoopdesigns.endless.context.Context;
 import org.snoopdesigns.endless.renderer.Renderer;
-import org.snoopdesigns.endless.world.ship.SteerableEnemyShip;
 
 public class ObjectsRenderer implements Renderer {
 
@@ -18,9 +17,9 @@ public class ObjectsRenderer implements Renderer {
     public void create() {
         batch = new SpriteBatch();
         renderables.add(Context.getInstance().getPlayerShip());
-        renderables.add(new SteerableEnemyShip());
-        renderables.add(new SteerableEnemyShip());
-        renderables.add(new SteerableEnemyShip());
+        //renderables.add(new SteerableEnemyShip());
+        //renderables.add(new SteerableEnemyShip());
+        //renderables.add(new SteerableEnemyShip());
 
         renderables.forEach(Renderable::create);
     }
diff --git a/core/src/org/snoopdesigns/endless/world/player/PlayerShip.java b/core/src/org/snoopdesigns/endless/world/player/PlayerShip.java
index 3670d6f..1393d02 100644
--- a/core/src/org/snoopdesigns/endless/world/player/PlayerShip.java
+++ b/core/src/org/snoopdesigns/endless/world/player/PlayerShip.java
@@ -32,26 +32,47 @@ public final class PlayerShip extends PhysicalBody implements Controllable, Rend
     @Override
     public FixtureDef getFixture() {
         final CircleShape circle = new CircleShape();
-        circle.setRadius(7f);
+        circle.setRadius(5f);
         final FixtureDef fixtureDef = new FixtureDef();
         fixtureDef.shape = circle;
-        fixtureDef.density = 1f; // weight of body
         return fixtureDef;
     }
 
     @Override
+    public float getMass() {
+        return 10000; // 10 tons
+    }
+
+    @Override
+    public float getLinearDamping() {
+        return 1.5f;
+    }
+
+    @Override
+    public float getMaxVelocity() {
+        return 100f; // meters per second
+    }
+
+    @Override
     public void create() {
         initBody();
 
         final Texture texture = new Texture(Gdx.files.internal("ship.png"));
         sprite = new Sprite(texture);
-        sprite.setScale(0.1f);
+
+        final float expectedSizeInMeters = 15f;
+        final Vector2 scale = new Vector2(
+                expectedSizeInMeters / sprite.getHeight(),
+                expectedSizeInMeters / sprite.getWidth());
+
+        sprite.setScale(scale.x, scale.y);
     }
 
     @Override
     public void render(SpriteBatch batch) {
         handleInput();
         handleMousePosition();
+
         final float x = getBody().getPosition().x;
         final float y = getBody().getPosition().y;
         Context.getInstance().getCameraContext().getPosition().set(x, y);
@@ -73,6 +94,8 @@ public final class PlayerShip extends PhysicalBody implements Controllable, Rend
         sprite.draw(batch);
         effects.forEach(effect ->
                 effect.draw(batch, Gdx.graphics.getDeltaTime()));
+
+        limitVelocity();
     }
 
     @Override
@@ -104,22 +127,14 @@ public final class PlayerShip extends PhysicalBody implements Controllable, Rend
     }
 
     private void speedUp() {
-        final float force = 100000.0f;
+        final float force = getBody().getMass() * 200; // force 200x times more than self mass
         final Vector2 impulse = new Vector2(force, 0).rotateRad(getBody().getAngle());
         getBody().applyForceToCenter(impulse, true);
     }
 
-    private void slowDown() {
-        getBody().setLinearVelocity(
-                getBody().getLinearVelocity().x * 0.98f,
-                getBody().getLinearVelocity().y * 0.98f);
-    }
-
     private void handleInput() {
         if (Gdx.input.isKeyPressed(Keys.SPACE)) {
             speedUp();
-        } else {
-            slowDown();
         }
     }
 
diff --git a/core/src/org/snoopdesigns/endless/world/ship/SteerableEnemyShip.java b/core/src/org/snoopdesigns/endless/world/ship/SteerableEnemyShip.java
index 4c24408..40db5d4 100644
--- a/core/src/org/snoopdesigns/endless/world/ship/SteerableEnemyShip.java
+++ b/core/src/org/snoopdesigns/endless/world/ship/SteerableEnemyShip.java
@@ -41,11 +41,25 @@ public class SteerableEnemyShip extends SteerablePhysicalBody implements Rendera
         circle.setRadius(7f);
         final FixtureDef fixtureDef = new FixtureDef();
         fixtureDef.shape = circle;
-        fixtureDef.density = 1f;
         return fixtureDef;
     }
 
     @Override
+    public float getMass() {
+        return 10000;
+    }
+
+    @Override
+    public float getLinearDamping() {
+        return 1.5f;
+    }
+
+    @Override
+    public float getMaxVelocity() {
+        return 50;
+    }
+
+    @Override
     public Vector2 getInitialPosition() {
         return new Vector2(MathUtils.random(50), MathUtils.random(50));
     }