TPV_P4/Collisions.cpp at master · Filinouns/TPV_P4 · GitHub

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#include "Collisions.h"

Collisions::Collisions() {
}

Collisions::~Collisions() {
}

/// Checks if the two polygons are intersecting.
///
bool Collisions::collidesWithRotation(GameObject* o1, GameObject* o2) {
	Vector2D Ac = o1->getPosition()
			+ Vector2D(o1->getWidth() / 2.0, o1->getHeight() / 2.0);

	double angleA =  o1->getRotation();

	Vector2D Alu = Ac+Vector2D(-o1->getWidth() / 2.0, -o1->getHeight() / 2.0).rotate(angleA);
	Vector2D Aru = Ac+Vector2D(o1->getWidth() / 2.0, -o1->getHeight() / 2.0).rotate(angleA);
	Vector2D All = Ac+Vector2D(-o1->getWidth() / 2.0, o1->getHeight() / 2.0).rotate(angleA);
	Vector2D Arl = Ac+Vector2D(o1->getWidth() / 2.0, o1->getHeight() / 2.0).rotate(angleA);

	double angleB = o2->getRotation();

	Vector2D Bc = o2->getPosition()
			+ Vector2D(o2->getWidth() / 2.0, o2->getHeight() / 2.0);

	Vector2D Blu = Bc+Vector2D(-o2->getWidth() / 2.0, -o2->getHeight() / 2.0).rotate(angleB);
	Vector2D Bru = Bc+Vector2D(o2->getWidth() / 2.0, -o2->getHeight() / 2.0).rotate(angleB);
	Vector2D Bll = Bc+Vector2D(-o2->getWidth() / 2.0, o2->getHeight() / 2.0).rotate(angleB);
	Vector2D Brl = Bc+Vector2D(o2->getWidth() / 2.0, o2->getHeight() / 2.0).rotate(angleB);

	return     PointInRectangle(Alu, Aru, All, Arl, Blu)
			|| PointInRectangle(Alu, Aru, All, Arl, Bru)
			|| PointInRectangle(Alu, Aru, All, Arl, Bll)
			|| PointInRectangle(Alu, Aru, All, Arl, Brl)
			|| PointInRectangle(Blu, Bru, Bll, Brl, Alu)
			|| PointInRectangle(Blu, Bru, Bll, Brl, Aru)
			|| PointInRectangle(Blu, Bru, Bll, Brl, All)
			|| PointInRectangle(Blu, Bru, Bll, Brl, Arl);
}

bool Collisions::PointInRectangle(Vector2D X, Vector2D Y, Vector2D Z,
		Vector2D W, Vector2D P) {
	if (PointInTriangle(X, Y, Z, P))
		return true;
	if (PointInTriangle(X, Z, W, P))
		return true;
	return false;
}

bool Collisions::PointInTriangle(Vector2D A, Vector2D B, Vector2D C,
		Vector2D P) {
// Compute vectors
	Vector2D v0 = C - A;
	Vector2D v1 = B - A;
	Vector2D v2 = P - A;

// Compute dot products
	double dot00 = v0 * v0;
	double dot01 = v0 * v1;
	double dot02 = v0 * v2;
	double dot11 = v1 * v1;
	double dot12 = v1 * v2;

// Compute barycentric coordinates
	double invDenom = 1 / (dot00 * dot11 - dot01 * dot01);
	double u = (dot11 * dot02 - dot01 * dot12) * invDenom;
	double v = (dot00 * dot12 - dot01 * dot02) * invDenom;

// Check if point is in triangle
	if (u >= 0 && v >= 0 && (u + v) < 1) {
		return true;
	} else {
		return false;
	}
}


bool Collisions::collides(GameObject* o1, GameObject* o2) {

	Vector2D o1Pos = o1->getPosition();
	double o1Width = o1->getWidth();
	double o1Height = o1->getHeight();

	Vector2D o2Pos = o2->getPosition();
	double o2Width = o2->getWidth();
	double o2Height = o2->getHeight();

// o1 completely to the left of o2, or vice versa
	if (o1Pos.getX() + o1Width < o2Pos.getX()
			|| o2Pos.getX() + o2Width < o1Pos.getX()) {
		return false;
	}

// o1 completely to the top of o2, or vice versa
	if (o1Pos.getY() + o1Height < o2Pos.getY()
			|| o2Pos.getY() + o2Height < o1Pos.getY()) {
		return false;
	}

	return true;
}