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simplify + cleanups

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This commit is contained in:
Hannes Janetzek 2013-02-11 10:07:43 +01:00
parent 114eb91084
commit fab415057e
2 changed files with 40 additions and 34 deletions
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60
src/org/oscim/utils/OBB2D.java
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@ -14,22 +14,22 @@
*/
package org.oscim.utils;
/**
* from http://www.flipcode.com/archives/2D_OBB_Intersection.shtml
*
* @author Morgan McGuire morgan@cs.brown.edu
* @author Hannes Janetzek
*/
public class OBB2D {
// Corners of the box, where 0 is the lower left.
private final float[] corner = new float[4 * 2];
public final float[] corner = new float[4 * 2];
// Two edges of the box extended away from corner[0].
private final float[] axis = new float[2 * 2];
public final float[] axis = new float[2 * 2];
// origin[a] = corner[0].dot(axis[a]);
private final float[] origin = new float[2];
public final float[] origin = new float[2];
// Returns true if other overlaps one dimension of this.
private boolean overlaps1Way(OBB2D other) {
@ -69,30 +69,28 @@ public class OBB2D {
// Updates the axes after the corners move. Assumes the
// corners actually form a rectangle.
private void computeAxes() {
//axis[0] = corner[1] - corner[0];
//axis[1] = corner[3] - corner[0];
Vec2.sub(axis, 0, corner, 1, corner, 0);
Vec2.sub(axis, 1, corner, 3, corner, 0);
// Make the length of each axis 1/edge length so we know any
// dot product must be less than 1 to fall within the edge.
for (int a = 0; a < 2; a++) {
Vec2.normalizeSquared(axis, a);
origin[a] = Vec2.dot(corner, 0, axis, a);
}
Vec2.normalizeSquared(axis, 0);
origin[0] = Vec2.dot(corner, 0, axis, 0);
Vec2.normalizeSquared(axis, 1);
origin[1] = Vec2.dot(corner, 0, axis, 1);
}
public OBB2D(float cx, float cy, float w, float h, float angle) {
float rcos = (float) Math.cos(angle);
float rsin = (float) Math.sin(angle);
float[] tmp = new float[4*2];
float[] tmp = new float[4 * 2];
Vec2.set(tmp, 0, rcos, rsin);
Vec2.set(tmp, 1, -rsin, rcos);
Vec2.mul(tmp, 0, w/2);
Vec2.mul(tmp, 1, h/2);
Vec2.mul(tmp, 0, w / 2);
Vec2.mul(tmp, 1, h / 2);
Vec2.add(tmp, 2, tmp, 0, tmp, 1);
Vec2.sub(tmp, 3, tmp, 0, tmp, 1);
@ -130,7 +128,8 @@ public class OBB2D {
computeAxes();
}
public OBB2D(float cx, float cy, float vx, float vy, float width, float height, boolean normalized) {
public OBB2D(float cx, float cy, float vx, float vy, float width, float height,
boolean normalized) {
float ux = -vy;
float uy = vx;
@ -164,33 +163,30 @@ public class OBB2D {
float vx = cx - dx;
float vy = cy - dy;
float a = (float) (1.0 / Math.sqrt(vx * vx + vy * vy));
vx *= a;
vy *= a;
float ux = -vy;
float uy = vx;
float a = (float) Math.sqrt(vx * vx + vy * vy);
vx /= a;
vy /= a;
float hw = width / 2;
float hh = height / 2;
float ux = vy * hh;
float uy = -vx * hh;
vx *= hw;
vy *= hw;
ux *= hh;
uy *= hh;
corner[0] = cx - vx - ux;
corner[1] = cy - vy - uy;
corner[0] = cx + (vx - ux);
corner[1] = cy + (vy - uy);
corner[2] = cx + vx - ux;
corner[3] = cy + vy - uy;
corner[2] = cx + (-vx - ux);
corner[3] = cy + (-vy - uy);
corner[4] = cx + vx + ux;
corner[5] = cy + vy + uy;
corner[4] = cx + (-vx + ux);
corner[5] = cy + (-vy + uy);
corner[6] = cx + (vx + ux);
corner[7] = cy + (vy + uy);
corner[6] = cx - vx + ux;
corner[7] = cy - vy + uy;
computeAxes();
}

14
src/org/oscim/utils/Vec2.java
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@ -27,8 +27,18 @@ public final class Vec2 {
float length = x * x + y * y;
v[(pos << 1) + 0] /= length;
v[(pos << 1) + 1] /= length;
v[(pos << 1) + 0] = x / length;
v[(pos << 1) + 1] = y / length;
}
public final static void normalize(float[] v, int pos) {
float x = v[(pos << 1) + 0];
float y = v[(pos << 1) + 1];
double length = Math.sqrt(x * x + y * y);
v[(pos << 1) + 0] = (float)(x / length);
v[(pos << 1) + 1] = (float)(y / length);
}
public final static float length(float[] v, int pos) {