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 Triangle fill algorithm  (Read 7081 times) 0 Members and 1 Guest are viewing this topic.
bestwarrior2001

Senior Newbie

Exp: 3 years

 « Posted 2017-05-31 20:19:58 »

Hi guys

I need a fast algorithm that fills a 2D triangle. I'm not using Graphics or Graphics2D for this.
This is what I want:
 1  2  3  4  5  6  7  8  9  10  11  12  13  14 `class ColorBuffer {   private int[][] data;   public void plot(int x,int y,int color) {      data[x][y]=color;   }   // some other methods}class Renderer {   public ColorBuffer buffer;   // [...]   public void fillTriangle(Point v1,Point v2,Point v3) {      // that's what I need   }}`

Please include a source code if you can.
Riven

« JGO Overlord »

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 « Reply #1 - Posted 2017-05-31 20:41:47 »

And I want a pony.

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KaiHH

JGO Kernel

Medals: 482

 « Reply #2 - Posted 2017-05-31 21:22:41 »

http://bfy.tw/C6uZ
Archive
 « Reply #3 - Posted 2017-05-31 22:49:57 »

If you're looking for speed, the first thing you should fix is your ColorBuffer. 2D arrays are slower than a 1D array. Plot the pixel at (x,y) by indexing into a 1D array of length (width*height) by using this formula (x + y * width)

ddyer
 « Reply #4 - Posted 2017-06-01 15:52:53 »

Decompose the triangle into two segments, "top half" and "bottom half" with appropriate
special cases.

Use the Bresenham algorithm to describe the left and right edges, draw one row at a time
from left to right.

This can be very fast (requires no multiplies) if implemented carefully, but be warned
that for extremely acute triangles, it can produce counterintuitive "triangles" that are
not one blob.

For extra credit, get the edge conditions correct so drawing a mesh of triangles
draws each pixel exactly once.  Otherwise, attempts to draw a mesh will leave
stray pixels undrawn.

bestwarrior2001

Senior Newbie

Exp: 3 years

 « Reply #5 - Posted 2017-06-01 15:58:49 »

That's exactly what I need. Thanks!
Damocles
 « Reply #6 - Posted 2017-06-06 12:29:59 »

http://www.sunshine2k.de/coding/java/TriangleRasterization/TriangleRasterization.html

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