#94 Add some improvements

core/src/main/java/com/github/introfog/pie/core/collisions/broadphase/AbstractBroadPhase.java

@@ -78,7 +78,7 @@ public Set<IShape> getUnmodifiableShapes() {
      * <p>
      * Note, before calling the {@link #domesticCalculateAabbCollisions()} method, which calculates collisions,
      * the {@link IShape#computeAabb()} method is called for all shapes from the {@link #shapes}, because the
-     * broad phase needs the up-to-date Aabbs.
+     * broad phase needs the up-to-date aabbs.
      *
      * @return the {@link ShapePair} set in which each item represents
      * a unique shape pair and the Aabb of those shapes intersect
@@ -93,7 +93,7 @@ public final Set<ShapePair> calculateAabbCollisions() {
      * Domestic method for calculating the shape Aabb collisions.
      *
      * <p>
-     * Note, when this method is called, all shapes from {@link #shapes} have an up-to-date Aabb.
+     * Note, when this method is called, all shapes from {@link #shapes} have an up-to-date aabb.
      *
      * @return the {@link ShapePair} set in which each item represents
      * a unique shape pair and the Aabb of those shapes intersect

core/src/main/java/com/github/introfog/pie/core/collisions/narrowphase/impl/CirclePolygonCollisionHandler.java

@@ -68,7 +68,7 @@ public Manifold handleCollision(IShape aShape, IShape bShape, Context context) {
         Vector2f projection = new Vector2f();
         Vector2f realProjection = new Vector2f();
         Vector2f tmpV = new Vector2f();
-        for (int i = 0; i < polygonB.getVertexCount(); i++) {
+        for (int i = 0; i < polygonB.getVertices().length; i++) {
             tmpV.set(centerA);
             tmpV.sub(polygonB.getVertices()[i]);
             dotProduct = Vector2f.dotProduct(polygonB.getNormals()[i], tmpV);
@@ -113,7 +113,7 @@ public Manifold handleCollision(IShape aShape, IShape bShape, Context context) {
         // Found the nearest edge to the center of the circle, and the center of the circle lies outside the polygon.
         // Now define the Voronoi region in which the center of the circle is located relative to the nearest edge of the polygon
         Vector2f v1 = new Vector2f(polygonB.getVertices()[indexFaceNormal]);
-        Vector2f v2 = new Vector2f(polygonB.getVertices()[(indexFaceNormal + 1) % polygonB.getVertexCount()]);
+        Vector2f v2 = new Vector2f(polygonB.getVertices()[(indexFaceNormal + 1) % polygonB.getVertices().length]);
 
         float dot1 = Vector2f.dotProduct(Vector2f.sub(centerA, v1), Vector2f.sub(v2, v1));
         float dot2 = Vector2f.dotProduct(Vector2f.sub(centerA, v2), Vector2f.sub(v1, v2));

core/src/main/java/com/github/introfog/pie/core/collisions/narrowphase/impl/PolygonPolygonCollisionHandler.java

@@ -93,7 +93,7 @@ public Manifold handleCollision(IShape aShape, IShape bShape, Context context) {
 
         // Setup reference face vertices
         Vector2f v1 = new Vector2f(refPoly.getVertices()[referenceIndex]);
-        referenceIndex = referenceIndex + 1 == refPoly.getVertexCount() ? 0 : referenceIndex + 1;
+        referenceIndex = referenceIndex + 1 == refPoly.getVertices().length ? 0 : referenceIndex + 1;
         Vector2f v2 = new Vector2f(refPoly.getVertices()[referenceIndex]);
 
         // Transform vectors to world coordinates
@@ -189,7 +189,7 @@ private void findIncidentFace(Vector2f[] v, Polygon refPoly, Polygon incPoly, in
         // Find most anti-normal face on incident polygon
         int incidentFace = 0;
         float minDot = Float.MAX_VALUE;
-        for (int i = 0; i < incPoly.getVertexCount(); ++i) {
+        for (int i = 0; i < incPoly.getVertices().length; ++i) {
             // real dot = Dot( referenceNormal, IncPoly->m_normals[i] );
             float dotProduct = Vector2f.dotProduct(referenceNormal, incPoly.getNormals()[i]);
 
@@ -208,7 +208,7 @@ private void findIncidentFace(Vector2f[] v, Polygon refPoly, Polygon incPoly, in
         // IncPoly->body->position;
         incPoly.getRotateMatrix().mul(incPoly.getVertices()[incidentFace], v[0]);
         v[0].add(incPoly.getBody().position);
-        incidentFace = incidentFace + 1 >= incPoly.getVertexCount() ? 0 : incidentFace + 1;
+        incidentFace = incidentFace + 1 >= incPoly.getVertices().length ? 0 : incidentFace + 1;
         incPoly.getRotateMatrix().mul(incPoly.getVertices()[incidentFace], v[1]);
         v[1].add(incPoly.getBody().position);
     }
@@ -261,7 +261,7 @@ private static float findAxisLeastPenetration(int[] faceIndex, Polygon polygonA,
         float bestDistance = -Float.MAX_VALUE;
         int bestIndex = 0;
 
-        for (int i = 0; i < polygonA.getVertexCount(); ++i) {
+        for (int i = 0; i < polygonA.getVertices().length; ++i) {
             // Retrieve a face normal from A
             // Vec2 n = A->m_normals[i];
             // Vec2 nw = A->u * n;

core/src/main/java/com/github/introfog/pie/core/math/RotationMatrix2x2.java

@@ -17,12 +17,16 @@
 
 import java.util.StringJoiner;
 
-public class RotationMatrix2x2 {
+public final class RotationMatrix2x2 {
     public float m00;
     public float m01;
     public float m10;
     public float m11;
 
+    public RotationMatrix2x2() {
+        setAngle(0);
+    }
+
     public void setAngle(float radian) {
         float cos = (float) Math.cos(radian);
         float sin = (float) Math.sin(radian);

core/src/main/java/com/github/introfog/pie/core/shape/Body.java

@@ -25,29 +25,29 @@
  */
 public class Body {
     /** The density. */
-    public float density;
+    public final float density;
     /** The restitution. */
-    public float restitution;
+    public final float restitution;
     /** The inverted mass. */
     public float invertedMass;
     /** The static friction. */
-    public float staticFriction;
+    public final float staticFriction;
     /** The dynamic friction. */
-    public float dynamicFriction;
+    public final float dynamicFriction;
     /** The torque. */
-    public float torque;
+    public final float torque;
     /** The body orientation in radians. */
     public float orientation;
     /** The angular velocity. */
     public float angularVelocity;
     /** The inverted inertia. */
     public float invertedInertia;
     /** The position. */
-    public Vector2f position;
+    public final Vector2f position;
     /** The force. */
-    public Vector2f force;
+    public final Vector2f force;
     /** The velocity. */
-    public Vector2f velocity;
+    public final Vector2f velocity;
 
     /**
      * Instantiates a new {@link Body} instance.

core/src/main/java/com/github/introfog/pie/core/shape/Circle.java

@@ -22,7 +22,7 @@
  */
 public class Circle extends IShape {
     /** The radius of circle. */
-    protected final float radius;
+    private final float radius;
 
     /**
      * Instantiates a new {@link Circle} instance based on radius, coordinates of center, density and restitution.
@@ -50,30 +50,30 @@ public Circle(float radius, float centreX, float centreY, float density, float r
      *
      * @return the radius
      */
-    public float getRadius() {
+    public final float getRadius() {
         return radius;
     }
 
     @Override
     public void computeAabb() {
-        aabb.min.set(body.position.x - radius, body.position.y - radius);
-        aabb.max.set(body.position.x + radius, body.position.y + radius);
+        getAabb().min.set(getBody().position.x - radius, getBody().position.y - radius);
+        getAabb().max.set(getBody().position.x + radius, getBody().position.y + radius);
     }
 
     @Override
     public String toString() {
         return new StringJoiner("; ", "{", "}")
-                .add("center=" + body.position)
+                .add("center=" + getBody().position)
                 .add("radius=" + radius)
                 .toString();
     }
 
     @Override
     protected void computeMassAndInertia() {
-        float mass = (float) Math.PI * radius * radius * body.density;
-        body.invertedMass = (mass == 0f) ? 0f : 1f / mass;
+        float mass = (float) Math.PI * radius * radius * getBody().density;
+        getBody().invertedMass = (mass == 0f) ? 0f : 1f / mass;
 
-        float inertia = radius * radius / (body.invertedMass == 0 ? 1 : body.invertedMass);
-        body.invertedInertia = (inertia != 0.0f) ? 1.0f / inertia : 0.0f;
+        float inertia = radius * radius / (getBody().invertedMass == 0 ? 1 : getBody().invertedMass);
+        getBody().invertedInertia = (inertia != 0.0f) ? 1.0f / inertia : 0.0f;
     }
 }

core/src/main/java/com/github/introfog/pie/core/shape/IShape.java

@@ -27,14 +27,13 @@
 public abstract class IShape {
     private static final AtomicInteger lastShapeId = new AtomicInteger(Integer.MIN_VALUE);
 
+    private final int shapeId;
     /** The shape axis aligned bounding box. */
-    protected final Aabb aabb;
+    private final Aabb aabb;
     /** The body that stores shape physical parameters. */
-    protected final Body body;
+    private final Body body;
     /** The rotation matrix. */
-    protected final RotationMatrix2x2 rotateMatrix;
-
-    private final int shapeId;
+    private final RotationMatrix2x2 rotateMatrix;
 
     /**
      * Instantiates a new {@link IShape} instance.
@@ -44,7 +43,6 @@ public IShape(float centreX, float centreY, float density, float restitution) {
         aabb = new Aabb();
         body = new Body(centreX, centreY, density, restitution);
         rotateMatrix = new RotationMatrix2x2();
-        rotateMatrix.setAngle(0f);
     }
 
     /**
@@ -73,7 +71,7 @@ public void applyImpulse(Vector2f impulse, Vector2f contactVector) {
      *
      * @return the axis aligned bounding box
      */
-    public Aabb getAabb() {
+    public final Aabb getAabb() {
         return aabb;
     }
 
@@ -82,7 +80,7 @@ public Aabb getAabb() {
      *
      * @return the body
      */
-    public Body getBody() {
+    public final Body getBody() {
         return body;
     }
 
@@ -91,7 +89,7 @@ public Body getBody() {
      *
      * @return the rotation matrix
      */
-    public RotationMatrix2x2 getRotateMatrix() {
+    public final RotationMatrix2x2 getRotateMatrix() {
         return rotateMatrix;
     }
 
@@ -114,7 +112,7 @@ public RotationMatrix2x2 getRotateMatrix() {
      * @return {@inheritDoc}
      */
     @Override
-    public boolean equals(Object o) {
+    public final boolean equals(Object o) {
         return this == o;
     }
 
@@ -125,7 +123,7 @@ public boolean equals(Object o) {
      * @return {@inheritDoc}
      */
     @Override
-    public int hashCode() {
+    public final int hashCode() {
         return shapeId;
     }