So I have a custom Shape object with intersection for points, but I want to test the shapes for collision with a rotated rectangle. I have looked all over, including AffineTransform, Path2D, etc. but I couldn’t find a solution to my problem.
Here is the Shape class. create() finalizes the shape:
package game.util;
import java.awt.geom.Line2D;
import java.util.ArrayList;
import static org.lwjgl.opengl.GL11.*;
public class Shape {
private ArrayList<Coordinate> points = new ArrayList<Coordinate>();
private ArrayList<Line2D.Float> intersectionTest = new ArrayList<Line2D.Float>();
public Shape(){
}
public void addPoint(float x, float y){
points.add(new Coordinate(x, y));
if(points.size() >= 2){
Coordinate last = points.get(points.size() - 2);
intersectionTest.add(new Line2D.Float(last.x, last.y, x, y));
}
}
public void create(){
// last point
Coordinate last = points.get(points.size() - 1);
Coordinate first = points.get(0);
intersectionTest.add(new Line2D.Float(last.x, last.y, first.x, first.y));
}
public boolean intersects(float x, float y){
int intersections = 0;
Line2D.Float original = new Line2D.Float(x - 1000, y - 1000, x, y);
for(Line2D.Float intersectionTestLine : intersectionTest){
if(original.intersectsLine(intersectionTestLine)){
intersections++;
}
}
return intersections > 0 && intersections % 2 == 1;
}
public boolean intersects(Shape shape){
for(Line2D.Float intersectionTestLine : intersectionTest){
for(Line2D.Float intersectionOtherLine : shape.intersectionTest){
if(intersectionOtherLine.intersectsLine(intersectionTestLine)){
return true;
}
}
}
return false;
}
private static class Coordinate {
private float x, y;
public Coordinate(float x, float y){
this.x = x;
this.y = y;
}
}
public void debug(){
glColor3f(0.0f, 0.0f, 1.0f);
glBegin(GL_LINE_STRIP);
for(int index = 0; index < intersectionTest.size(); index++){
Line2D.Float line = intersectionTest.get(index);
drawLine(line);
}
glEnd();
glColor3f(1.0f, 1.0f, 1.0f);
}
private void drawLine(Line2D.Float line){
glVertex2f(line.x1, line.y1);
glVertex2f(line.x2, line.y2);
}
}
And here is what I have so far for my rotated rectangle, however it doesn’t seem to work…
package game.util;
import java.awt.geom.Line2D;
import static org.lwjgl.opengl.GL11.*;
public class RotatingRectangle {
private float x1, x2, x3, x4, y1, y2, y3, y4, x, y, width, height;
private Line2D.Float line1, line2, line3, line4;
private Shape shape;
public RotatingRectangle(float x, float y, float width, float height){
x1 = x;
x2 = x + width;
x3 = x + width;
x4 = x;
y1 = y;
y2 = y;
y3 = y + height;
y4 = y + height;
this.x = x;
this.y = y;
this.width = width;
this.height = height;
}
public void setCenterX(float cx){
x = cx - (width / 2);
}
public void setCenterY(float cy){
y = cy - (height / 2);
}
public void debug(){
glColor3f(1.0f, 0.0f, 0.0f);
glBegin(GL_LINE_STRIP);
glVertex2f(x1, y1);
glVertex2f(x2, y2);
glVertex2f(x3, y3);
glVertex2f(x4, y4);
glVertex2f(x1, y1);
glEnd();
glColor3f(1.0f, 1.0f, 1.0f);
}
public RotatingRectangle rotate(float radians){
// rotate each point
Point p1 = rotate(radians, x, y);
x1 = p1.x;
y1 = p1.y;
Point p2 = rotate(radians, x + width, y);
x2 = p2.x;
y2 = p2.y;
Point p3 = rotate(radians, x + width, y + height);
x3 = p3.x;
y3 = p3.y;
Point p4 = rotate(radians, x, y + height);
x4 = p4.x;
y4 = p4.y;
createShape();
return this;
}
public void createShape(){
shape = new Shape();
shape.addPoint(x1, y1);
shape.addPoint(x2, y2);
shape.addPoint(x3, y3);
shape.addPoint(x4, y4);
shape.create();
}
public boolean intersects(Shape shape_){
return shape.intersects(shape_);
}
// You can only rotate a shape once
public Point rotate(float radians, float x, float y){
float cx = this.x + (width / 2);
float cy = this.y + (height / 2);
float dx = cx - x;
float dy = cy - y;
float hypotenuse = (float) StrictMath.sqrt(dx * dx + dy * dy);
float oldAngle = (float) Math.tan(dx / dy);
float ndx = hypotenuse * (float) Math.sin(oldAngle + radians);
float ndy = hypotenuse * (float) Math.cos(oldAngle + radians);
float nx = ndx + cx;
float ny = ndy + cy;
return new Point(nx, ny);
}
private static class Point {
private float x, y;
public Point(float x, float y){
this.x = x;
this.y = y;
}
}
}
Sorry that the code is so all over the place. Any help with the collision would be appreciated. (Also, the Shape object collision seems to work 100% correctly, rotated rectangle seems to be where the problem lies)
CopyableCougar4
