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avoid sqrt, just flip that vector

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This commit is contained in:
Hannes Janetzek 2013-01-04 12:54:35 +01:00
parent 6681247215
commit 3484110e08
1 changed files with 17 additions and 28 deletions
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45
src/org/oscim/renderer/layer/LineLayer.java
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@ -61,7 +61,7 @@ public final class LineLayer extends Layer {
* whether to connect start- and end-point
*/
public void addLine(float[] points, short[] index, boolean closed) {
float x, y, nextX, nextY, prevX, prevY;
float x, y, nextX, nextY;
float a, ux, uy, vx, vy, wx, wy;
int tmax = Tile.TILE_SIZE + 10;
@ -219,21 +219,23 @@ public final class LineLayer extends Layer {
// outside means line is probably clipped
// TODO should align ending with tile boundary
// for now, just extend the line a little
float tx = vx;
float ty = vy;
if (squared) {
vx = 0;
vy = 0;
tx = 0;
ty = 0;
} else if (!outside) {
vx *= 0.5;
vy *= 0.5;
tx *= 0.5;
ty *= 0.5;
}
if (rounded)
verticesCnt -= 2;
// add first vertex twice
ddx = (int) ((ux - vx) * DIR_SCALE);
ddy = (int) ((uy - vy) * DIR_SCALE);
ddx = (int) ((ux - tx) * DIR_SCALE);
ddy = (int) ((uy - ty) * DIR_SCALE);
dx = (short) (0 | ddx & DIR_MASK);
dy = (short) (1 | ddy & DIR_MASK);
@ -259,8 +261,8 @@ public final class LineLayer extends Layer {
opos = 0;
}
ddx = (int) (-(ux + vx) * DIR_SCALE);
ddy = (int) (-(uy + vy) * DIR_SCALE);
ddx = (int) (-(ux + tx) * DIR_SCALE);
ddy = (int) (-(uy + ty) * DIR_SCALE);
v[opos++] = ox;
v[opos++] = oy;
@ -269,11 +271,12 @@ public final class LineLayer extends Layer {
}
prevX = x;
prevY = y;
x = nextX;
y = nextY;
boolean flip = false;
// Unit vector pointing back to previous node
vx *= -1;
vy *= -1;
for (;;) {
if (ipos < pos + length) {
@ -287,13 +290,6 @@ public final class LineLayer extends Layer {
} else
break;
// Unit vector pointing back to previous node
vx = prevX - x;
vy = prevY - y;
a = (float) Math.sqrt(vx * vx + vy * vy);
vx = (vx / a);
vy = (vy / a);
// Unit vector pointing forward to next node
wx = nextX - x;
wy = nextY - y;
@ -361,20 +357,13 @@ public final class LineLayer extends Layer {
v[opos++] = (short) (2 | -ddx & DIR_MASK);
v[opos++] = (short) (1 | -ddy & DIR_MASK);
prevX = x;
prevY = y;
x = nextX;
y = nextY;
vx = -1 * wx;
vy = -1 * wy;
}
vx = prevX - x;
vy = prevY - y;
a = (float) Math.sqrt(vx * vx + vy * vy);
vx = (vx / a);
vy = (vy / a);
ux = vy;
uy = -vx;