int d,mx,my;
d = 3 - (2< </pre>
"this one time at computer camp..." bresenham circle algorithm help?
Author
can anyone point me in the right direction here (i''m trying to write a primitives library, i based this code on the code found in this article http://www.gamedev.net/reference/articles/article767.asp
but for some reason i draw a + rather than any sort of circle.. does anyone know what i did wrong?
This is the algorithm my ''graphics algorithm book'' has for circles (editted somewhat so that I can type it quicker). It isn''t exactly like yours, but it has the same basic idea, so you can probably compare them.
Let''s hope I didn''t typo
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void circlePlotPoints(int xC, int yC, int x, iny y) { setPixel(xC + x, yC + y); setPixel(xC - x, yC + y); setPixel(xC + x, yC - y); setPixel(xC - x, yC - y); setPixel(xC + y, yC + x); setPixel(xC - y, yC + x); setPixel(xC + y, yC - x); setPixel(xC - y, yC - x);}void circleMidPoint(int xC, int yC, int Rad) { int x = 0; int y = Rad; int p = 1 - Rad; circlePlotPoints(xC,yC,x,y); while(x < y) { ++x; if(p < 0) p += 2 * x + 1; else { --y; p += 2 * (x-y) + 1; } circlePlotPoints(xC,xY,x,y); }} Let''s hope I didn''t typo
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Author
hey, that worked real well, who is the author of that book? I think i should look for it, thanks for all your help.
quote:Original post by cozman
hey, that worked real well, who is the author of that book? I think i should look for it, thanks for all your help.
It''s Computer Graphics: C Version by Donald Hearn and M. Pauline Baker. I don''t know if there are non-hardback versions of it, so it''s somewhat expensive ($60 US). It''s basically an equation reference with occasional code for simple things (mostly 2D). It''s lacking a lot of modern 3D stuff, unless you want to make a software renderer.
Author
here is my algorithm now
void DrawCircle(SDL_Surface *surface, Uint32 x, Uint32 y, Uint32 radius, Uint32 color){ int p,mx,my; p = 1 - radius; mx = 0; my = radius; while(mx <= my) { DrawPixel(surface,x+mx,y+my,color); DrawPixel(surface,x+mx,y-my,color); DrawPixel(surface,x-mx,y+my,color); DrawPixel(surface,x-mx,y-my,color); DrawPixel(surface,x+my,y+mx,color); DrawPixel(surface,x+my,y-mx,color); DrawPixel(surface,x-my,y+mx,color); DrawPixel(surface,x-my,y-mx,color); mx++; if(p < 0) p += 2*mx +1; else { my--; p += 2*(mx-my) +1; } }} This topic is closed to new replies.
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