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dungeon-gunner/source/abstract/CollisionModel.cpp

130 lines
4.7 KiB
C++

/*
* CollisionModel.cpp
*
* Created on: 07.05.2013
* Author: Felix
*/
#include "CollisionModel.h"
#include <SFML/System.hpp>
#include <Thor/Vectors.hpp>
#include "Circle.h"
#include "Rectangle.h"
#include "../util/Interval.h"
CollisionModel::~CollisionModel() {
}
/**
* Tests for collision between a circle and a rectangle. Offset is the maximum
* value between zero and the original value of previous, for which the
* objects do not collide. Rectangles are assumed to be axis aligned.
*
* @param [in,out] offset The movement offset of the circle.
* @param offsetSecond Movement offset of the rectangle.
* @return True if a collision occured.
*/
bool
CollisionModel::testCollision(const Circle& circle, const Rectangle& rect,
Vector2f& offsetFirst, const Vector2f& offsetSecond) {
Vector2f halfSize = rect.getSize() / 2.0f;
Vector2f rectNewPos = rect.getPosition() + offsetSecond;
Vector2f circleRotatedPos = circle.getPosition() + offsetFirst - rectNewPos;
circleRotatedPos = thor::rotatedVector(circleRotatedPos, -rect.mShape.getRotation());
circleRotatedPos += rectNewPos;
// If circle center is inside rect on x plane, we just take y direction result.
if (Interval::IntervalFromRadius(rectNewPos.x, halfSize.x)
.isInside(circleRotatedPos.x)) {
float overlapY =
Interval::IntervalFromRadius(circleRotatedPos.y, circle.getRadius())
.getOverlap(Interval::IntervalFromRadius(rectNewPos.y, halfSize.y))
.getLength();
offsetFirst += ((circleRotatedPos.y > rectNewPos.y) ? 1.0f : - 1.0f) *
thor::rotatedVector(Vector2f(0, overlapY), rect.mShape.getRotation());
return overlapY > 0;
}
// Same here (just switched x/y).
else if (Interval::IntervalFromRadius(rectNewPos.y, halfSize.y)
.isInside(circleRotatedPos.y)) {
float overlapX =
Interval::IntervalFromRadius(circleRotatedPos.x, circle.getRadius())
.getOverlap(Interval::IntervalFromRadius(rectNewPos.x, halfSize.x))
.getLength();
offsetFirst += ((circleRotatedPos.x > rectNewPos.x) ? 1.0f : - 1.0f) *
thor::rotatedVector(Vector2f(overlapX, 0), rect.mShape.getRotation());
return overlapX > 0;
}
// Test if the circle is colliding with a corner of the rectangle, using
// the same method as circle-circle collision (distance to corner instead
// of radius.
else {
Vector2f axis(thor::unitVector(rectNewPos - circleRotatedPos));
// Use correct vector for corner projections (positive/negative
// direction does not matter).
float rectHalfSizeProjected;
if ((circleRotatedPos.x > rectNewPos.x && circleRotatedPos.y > rectNewPos.y) ||
(circleRotatedPos.x < rectNewPos.x && circleRotatedPos.y < rectNewPos.y))
rectHalfSizeProjected = thor::dotProduct(axis, halfSize);
else
rectHalfSizeProjected = thor::dotProduct(axis,
Vector2f(halfSize.x, -halfSize.y));
Interval projectedCircle = Interval::IntervalFromRadius(
thor::dotProduct(axis, circleRotatedPos),
circle.getRadius());
Interval projectedRect = Interval::IntervalFromRadius(
thor::dotProduct(axis, rectNewPos),
rectHalfSizeProjected);
// using -5: works perfectly going between corner/side
// without -5 works perfectly on corner, but skips when going in between tiles
float overlap = projectedCircle.getOverlap(projectedRect).getLength() - 5;
if (overlap > 0)
offsetFirst -= thor::rotatedVector(overlap * axis, rect.mShape.getRotation());
return overlap > 0;
}
}
/**
* Tests for collision between two circles. Offset is the maximum value between
* zero and the original value of previous, for which the objects do
* not collide.
*
* @param [in,out] offset The movement offset of the first circle.
* @param offsetSecond Movement offset of the second circle.
* @return True if a collision occured.
*/
bool
CollisionModel::testCollision(const Circle& first, const Circle& second,
Vector2f& offsetFirst, const Vector2f& offsetSecond) {
Vector2f axis(thor::unitVector(second.getPosition() + offsetFirst -
(first.getPosition() + offsetSecond)));
Interval projectedFirst = Interval::IntervalFromRadius(
thor::dotProduct(axis, first.getPosition() + offsetFirst),
first.getRadius());
Interval projectedSecond = Interval::IntervalFromRadius(
thor::dotProduct(axis, second.getPosition() + offsetSecond),
second.getRadius());
float overlap = projectedFirst.getOverlap(projectedSecond).getLength();
if (overlap > 0)
offsetFirst -= overlap * axis;
return overlap > 0;
}
/**
* Tests for collision between two rectangles. Always returns false as
* these can't occur (rectangles can't move).
*
* @return True if a collision occured.
*/
bool
CollisionModel::testCollision(const Rectangle& first, const Rectangle& second,
Vector2f& offsetFirst, const Vector2f& offsetSecond) {
return false;
}