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flat assembler > Windows > CPU raytracing draw triangle.

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Roman



Joined: 21 Apr 2012
Posts: 497
I found c++ example draw sphere.
RayIntersectSphere. Work fine. I not use camera. Very simple raytracing.

But i try use RayIntersectTriangle and not see triangle.
Code:
rayTriangleIntersect (Ray * r, Vec3 * v0, Vec3 * v1, Vec3 * v2){
  Vec3 v0v1 = sub (*v1, *v0);
  Vec3 v0v2 = sub (*v2, *v0);

  Vec3 pvec = cross (r->dir, v0v2);

  float det = dot (v0v1, pvec);
  if (det < 0.000001)
    return -INFINITY;

  float invDet = 1.0 / det;

  Vec3 tvec = sub (r->orig, *v0);

  float u = dot (tvec, pvec) * invDet;

  if (u < -0.0001 || u > 1.0001)
    return -INFINITY;

  Vec3 qvec = cross (tvec, v0v1);

  float v = dot (r->dir, qvec) * invDet;

  if (v < -0.0001 || u + v > 1.0001)
    return -INFINITY;

  return dot (v0v2, qvec) * invDet;   }
    

I check this code and my both work equally.
My RayOrigin.xyz = 0
My RayDir.xyz=(float 2DX,float 2DY ,-1.0);
I draw in BMP image size 500x500 and save to disk and look result.
Draw simple.
Code:
v0 = (0.0,0.0,0.1);
v1 = (0.01,0.0,0.1);
v2 = (0.002,0.01,0.1);
for int 2DY = 0 to 500; ++2DY {
for int 2DX = 0 to 500; ++2DX {
RayDir.xyz=(float 2DX,float 2DY ,-1.0); 
float r = rayTriangleIntersect(Ray,v0,v1,v2);
if (r != -INFINITY) drawone_pixel(2DX,2DY) }
}

    


Last edited by Roman on 14 Jan 2019, 07:10; edited 1 time in total
Post 13 Jan 2019, 13:40
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bitRAKE



Joined: 21 Jul 2003
Posts: 2795
Location: dank orb
Relative to your screen projection that is a very small triangle?
Post 13 Jan 2019, 22:01
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Roman



Joined: 21 Apr 2012
Posts: 497
In code need:
Code:
vec2 f = float(2DX,2DY);
f = (2.0 * f / 500.0 - 1.0);
RayDir.xyz=(f.x,f.y ,-1.0);
    

And i get small triangle in BMP file. On center of screen.
Post 14 Jan 2019, 07:04
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macgub



Joined: 11 Jan 2006
Posts: 232
Location: Poland
Post 27 May 2019, 17:48
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