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//-*-c-*-
__device__ __host__ Matrix inv(const Matrix&m, float& determinant)
{
determinant = det(m);
return make_matrix(m.a11*m.a22 - m.a12*m.a21,
m.a02*m.a21 - m.a01*m.a22,
m.a01*m.a12 - m.a02*m.a11,
m.a12*m.a20 - m.a10*m.a22,
m.a00*m.a22 - m.a02*m.a20,
m.a02*m.a10 - m.a00*m.a12,
m.a10*m.a21 - m.a11*m.a20,
m.a01*m.a20 - m.a00*m.a21,
m.a00*m.a11 - m.a01*m.a10)/determinant;
}
__device__ bool intersect_triangle(const float3 &x, const float3 &p, float3 *vertex, float3 &intersection)
{
float determinant;
float3 u = inv(make_matrix(vertex[0]-vertex[2],vertex[1]-vertex[2],-p), determinant)*(x-vertex[2]);
if (determinant == 0.0)
return false;
if (u.x < 0.0 || u.y < 0.0 || u.z < 0.0 || (1-u.x-u.y) < 0.0)
return false;
intersection = x + p*u.z;
return true;
}
extern "C"
{
__global__ void intersect_triangle_mesh(float3 *x, float3 *p, int n, float3 *mesh, int *state, float3 *w)
{
int idx = blockIdx.x*blockDim.x + threadIdx.x;
bool hit = false;
float distance, min_distance;
float3 intersection, min_intersection;
int i;
for (i=0; i < n; i++)
{
if (intersect_triangle(x[idx], p[idx], mesh+3*i, intersection))
{
if (!hit)
{
state[idx] = 1;
min_distance = norm(intersection-x[idx]);
min_intersection = intersection;
continue;
}
distance = norm(w[idx]-x[idx]);
if (distance < min_distance)
{
state[idx] = 1;
min_distance = distance;
min_intersection = intersection;
}
}
}
}
} // extern "c"
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