collisions
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you know in a game like unreal tournament how do they do collision detection?
also how do you check collisions with a 3d triangle?
also can someone please please show me some base code that opens a window and sets up and uses direct input. i've been trying to get direct input working in my game for a long time but it want work.
[edited by - hello_there on October 20, 2002 4:22:09 PM]
as far as the dinput goes, check out a little wrapper class I wrote, it''s on my website. here''s a little snippet I don''t really remember where it''s from, but it''s an example of ray-triangle(plane) intersection and finds the point where it intersects.
I don''t claim this code, but I did use it to write my collision detection stuff. hope it helps.
My Homepage
How many Microsoft employees does it take to screw in a light bulb?
None, they just declare drakness as a new standard.
#define EPSILON 0.000001#define CROSS(dest,v1,v2) \ dest[0]=v1[1]*v2[2]-v1[2]*v2[1]; \ dest[1]=v1[2]*v2[0]-v1[0]*v2[2]; \ dest[2]=v1[0]*v2[1]-v1[1]*v2[0];#define DOT(v1,v2) (v1[0]*v2[0]+v1[1]*v2[1]+v1[2]*v2[2])#define SUB(dest,v1,v2) dest[0]=v1[0]-v2[0]; \ dest[1]=v1[1]-v2[1]; \ dest[2]=v1[2]-v2[2]; /*We present a clean algorithm for determining whether a ray intersects a triangle. The algorithm translates the origin of the ray and then changes the base to yield a vector (t u v)T, where t is the distance to the plane in which the triangle lies and (u,v) represents the coordinates inside the triangle.*/intintersect_triangle(double orig[3], double dir[3], double vert0[3], double vert1[3], double vert2[3], double *t, double *u, double *v){ double edge1[3], edge2[3], tvec[3], pvec[3], qvec[3]; double det,inv_det; /* find vectors for two edges sharing vert0 */ SUB(edge1, vert1, vert0); SUB(edge2, vert2, vert0); /* begin calculating determinant - also used to calculate U parameter */ CROSS(pvec, dir, edge2); /* if determinant is near zero, ray lies in plane of triangle */ det = DOT(edge1, pvec);#ifdef TEST_CULL /* define TEST_CULL if culling is desired */ if (det < EPSILON) return 0; /* calculate distance from vert0 to ray origin */ SUB(tvec, orig, vert0); /* calculate U parameter and test bounds */ *u = DOT(tvec, pvec); if (*u < 0.0 || *u > det) return 0; /* prepare to test V parameter */ CROSS(qvec, tvec, edge1); /* calculate V parameter and test bounds */ *v = DOT(dir, qvec); if (*v < 0.0 || *u + *v > det) return 0; /* calculate t, scale parameters, ray intersects triangle */ *t = DOT(edge2, qvec); inv_det = 1.0 / det; *t *= inv_det; *u *= inv_det; *v *= inv_det;#else /* the non-culling branch */ if (det > -EPSILON && det < EPSILON) return 0; inv_det = 1.0 / det; /* calculate distance from vert0 to ray origin */ SUB(tvec, orig, vert0); /* calculate U parameter and test bounds */ *u = DOT(tvec, pvec) * inv_det; if (*u < 0.0 || *u > 1.0) return 0; /* prepare to test V parameter */ CROSS(qvec, tvec, edge1); /* calculate V parameter and test bounds */ *v = DOT(dir, qvec) * inv_det; if (*v < 0.0 || *u + *v > 1.0) return 0; /* calculate t, ray intersects triangle */ *t = DOT(edge2, qvec) * inv_det;#endif return 1;} I don''t claim this code, but I did use it to write my collision detection stuff. hope it helps.
My Homepage
How many Microsoft employees does it take to screw in a light bulb?
None, they just declare drakness as a new standard.
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