/**
* Copyright 2008 - 2015 The Loon Game Engine Authors
*
* Licensed under the Apache License, Version 2.0 (the "License"); you may not
* use this file except in compliance with the License. You may obtain a copy of
* the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations under
* the License.
*
* @project loon
* @author cping
* @email：javachenpeng@yahoo.com
* @version 0.5
*/
package loon.geom;
import loon.utils.MathUtils;
public class Line extends Shape {
/**
*
*/
private static final long serialVersionUID = 1L;
private Vector2f start;
private Vector2f end;
private Vector2f vec;
private Vector2f loc = new Vector2f(0, 0);
private Vector2f closest = new Vector2f(0, 0);
public Line(float x, float y, boolean inner, boolean outer) {
this(0, 0, x, y);
}
public Line(float x, float y) {
this(x, y, true, true);
}
public Line(Point p1, Point p2) {
this(p1.x, p1.y, p2.x, p2.y);
}
public Line(float x1, float y1, float x2, float y2) {
this(new Vector2f(x1, y1), new Vector2f(x2, y2));
}
public Line(float x1, float y1, float dx, float dy, boolean dummy) {
this(new Vector2f(x1, y1), new Vector2f(x1 + dx, y1 + dy));
}
public Line(float[] start, float[] end) {
super();
set(start, end);
}
public Line(Vector2f start, Vector2f end) {
super();
set(start, end);
}
public void set(float[] start, float[] end) {
set(start[0], start[1], end[0], end[1]);
}
public Vector2f getStart() {
return start;
}
public Vector2f getEnd() {
return end;
}
public float length() {
return vec.len();
}
public float lengthSquared() {
return vec.lengthSquared();
}
public void set(Vector2f start, Vector2f end) {
super.pointsDirty = true;
if (this.start == null) {
this.start = new Vector2f();
}
this.start.set(start);
if (this.end == null) {
this.end = new Vector2f();
}
this.end.set(end);
vec = new Vector2f(end);
vec.sub(start);
}
public void set(float sx, float sy, float ex, float ey) {
super.pointsDirty = true;
start.set(sx, sy);
end.set(ex, ey);
float dx = (ex - sx);
float dy = (ey - sy);
vec.set(dx, dy);
}
public float getDX() {
return end.getX() - start.getX();
}
public float getDY() {
return end.getY() - start.getY();
}
public float getX() {
return getX1();
}
public float getY() {
return getY1();
}
public float getX1() {
return start.getX();
}
public float getY1() {
return start.getY();
}
public float getX2() {
return end.getX();
}
public float getY2() {
return end.getY();
}
public float distance(Vector2f point) {
return MathUtils.sqrt(distanceSquared(point));
}
public boolean on(Vector2f point) {
getClosestPoint(point, closest);
return point.equals(closest);
}
public float distanceSquared(Vector2f point) {
getClosestPoint(point, closest);
closest.sub(point);
float result = closest.lengthSquared();
return result;
}
public void getClosestPoint(Vector2f point, Vector2f result) {
loc.set(point);
loc.sub(start);
float projDistance = vec.dot(loc);
projDistance /= vec.lengthSquared();
if (projDistance < 0) {
result.set(start);
return;
}
if (projDistance > 1) {
result.set(end);
return;
}
result.x = start.getX() + projDistance * vec.getX();
result.y = start.getY() + projDistance * vec.getY();
}
public Vector2f intersect(Line other) {
return intersect(other, false);
}
public Vector2f intersect(Line other, boolean limit) {
Vector2f temp = new Vector2f();
if (!intersect(other, limit, temp)) {
return null;
}
return temp;
}
public boolean intersect(Line other, boolean limit, Vector2f result) {
float dx1 = end.getX() - start.getX();
float dx2 = other.end.getX() - other.start.getX();
float dy1 = end.getY() - start.getY();
float dy2 = other.end.getY() - other.start.getY();
float denom = (dy2 * dx1) - (dx2 * dy1);
if (denom == 0) {
return false;
}
float ua = (dx2 * (start.getY() - other.start.getY()))
- (dy2 * (start.getX() - other.start.getX()));
ua /= denom;
float ub = (dx1 * (start.getY() - other.start.getY()))
- (dy1 * (start.getX() - other.start.getX()));
ub /= denom;
if ((limit) && ((ua < 0) || (ua > 1) || (ub < 0) || (ub > 1))) {
return false;
}
float u = ua;
float ix = start.getX() + (u * (end.getX() - start.getX()));
float iy = start.getY() + (u * (end.getY() - start.getY()));
result.set(ix, iy);
return true;
}
protected void createPoints() {
points = new float[4];
points[0] = getX1();
points[1] = getY1();
points[2] = getX2();
points[3] = getY2();
}
public float ptSegDistSq(Point pt) {
return ptSegDistSq(getX1(), getY1(), getX2(), getY2(), pt.getX(),
pt.getY());
}
public float ptSegDistSq(float px, float py) {
return ptSegDistSq(getX1(), getY1(), getX2(), getY2(), px, py);
}
public static float ptSegDist(float x1, float y1, float x2, float y2,
float px, float py) {
return MathUtils.sqrt(ptSegDistSq(x1, y1, x2, y2, px, py));
}
public static float ptSegDistSq(float x1, float y1, float x2, float y2,
float px, float py) {
x2 -= x1;
y2 -= y1;
px -= x1;
py -= y1;
float dotprod = px * x2 + py * y2;
float projlenSq;
if (dotprod <= 0.0) {
projlenSq = 0.0f;
} else {
px = x2 - px;
py = y2 - py;
dotprod = px * x2 + py * y2;
if (dotprod <= 0.0) {
projlenSq = 0.0f;
} else {
projlenSq = dotprod * dotprod / (x2 * x2 + y2 * y2);
}
}
float lenSq = px * px + py * py - projlenSq;
if (lenSq < 0) {
lenSq = 0;
}
return lenSq;
}
public static float ptLineDist(float x1, float y1, float x2, float y2,
float px, float py) {
return MathUtils.sqrt(ptLineDistSq(x1, y1, x2, y2, px, py));
}
public float ptLineDist(Point pt) {
return ptLineDist(getX1(), getY1(), getX2(), getY2(), pt.getX(),
pt.getY());
}
public float ptLineDistSq(float px, float py) {
return ptLineDistSq(getX1(), getY1(), getX2(), getY2(), px, py);
}
public float ptLineDistSq(Point pt) {
return ptLineDistSq(getX1(), getY1(), getX2(), getY2(), pt.getX(),
pt.getY());
}
public static float ptLineDistSq(float x1, float y1, float x2, float y2,
float px, float py) {
x2 -= x1;
y2 -= y1;
px -= x1;
py -= y1;
float dotprod = px * x2 + py * y2;
float projlenSq = dotprod * dotprod / (x2 * x2 + y2 * y2);
float lenSq = px * px + py * py - projlenSq;
if (lenSq < 0) {
lenSq = 0;
}
return lenSq;
}
public Shape transform(Matrix3 transform) {
float[] temp = new float[4];
createPoints();
transform.transform(points, 0, temp, 0, 2);
return new Line(temp[0], temp[1], temp[2], temp[3]);
}
public boolean closed() {
return false;
}
}