Fastest method of referencing all pixels in a line?

[counterp]

Currently, to find all pixels in a line I am using Bresenham's line algorithm. I converted the method from pseudo-code (on wikipedia) to java, but it's rather slow. Here is the code:

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private void getPixelsInLine(int x0, int y0, int x1, int y1) {       boolean steep = Math.abs(y1 - y0) > Math.abs(x1 - x0);       if (steep) {          int tmp = x0;          x0 = y0;          y0 = tmp;          tmp = x1;          x1 = y1;          y1 = tmp;       }       if (x0 > x1) {          int tmp = x0;          x0 = x1;          x1 = tmp;          tmp = y0;          y0 = y1;          y1 = tmp;       }       int deltax = x1 - x0;       int deltay = Math.abs(y1 - y0);       int error = deltax / 2;       int ystep = -1;       int y = y0;       if (y0 < y1)          ystep = 1;       for (int x = x0; x <= x1; x++) {          if (steep)             mark(y, x);          else             mark(x, y);          error -= deltay;          if (error < 0) {             y += ystep;             error += deltax;          }       }    }

I was wondering if there is a faster method of obtaining all pixels in a line/better implementation?

[avm1979]

That should be very fast. Fast enough that you could do it thousands of times a second and not worry about at all.

Unless you're doing something hideously slow in the "mark" function. If this were actually slow, that's where I'd look...

[Roquen]

You're leaving out the most important piece of information: what do you really want to do?

Games published by our own members! Check 'em out!

[counterp]

yes it is fast, it seems the problem is linked to the other thread I posted (with the images)

[pitbuller]

int error = deltax / 2;

Could be:

int error = deltax >>1;



I have allways thinked do Java found these kind of bit shift optimizations automatically?

[Roquen]

Not the same if negative.

[zoto]

1	int error = deltax >>>1;

http://en.wikipedia.org/wiki/Arithmetic_shift
http://en.wikipedia.org/wiki/Logical_shift

[counterp]

1	int error = deltax >>>1;

http://en.wikipedia.org/wiki/Arithmetic_shift
http://en.wikipedia.org/wiki/Logical_shift

see post above yours

[Roquen]

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int i = -1;   int r0 = i/2;   int r1 = i>>1;

Shifting (alone) isnt't the same for negative.  The result depends on the sub-bit, so compilers won't convert division into a shift unless it can statically determine that all values are positive or zero.