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//-*-c-*-
#include <math_constants.h>
#include "linalg.h"
#include "matrix.h"
#include "rotate.h"
texture<float4, 1, cudaReadModeElementType> mesh;
texture<float4, 1, cudaReadModeElementType> upper_bound_arr;
texture<float4, 1, cudaReadModeElementType> lower_bound_arr;
texture<uint, 1, cudaReadModeElementType> child_map_arr;
texture<uint, 1, cudaReadModeElementType> child_len_arr;
__device__ float3 make_float3(const float4 &a)
{
return make_float3(a.x, a.y, a.z);
}
__device__ bool intersect_triangle(const float3 &origin, const float3 &direction, const float3 &v0, const float3 &v1, const float3 &v2, float3 &intersection)
{
Matrix m = make_matrix(v1-v0, v2-v0, -direction);
float determinant = det(m);
if (determinant == 0.0)
return false;
float3 b = origin-v0;
float u1 = ((m.a11*m.a22 - m.a12*m.a21)*b.x + (m.a02*m.a21 - m.a01*m.a22)*b.y + (m.a01*m.a12 - m.a02*m.a11)*b.z)/determinant;
if (u1 < 0.0)
return false;
float u2 = ((m.a12*m.a20 - m.a10*m.a22)*b.x + (m.a00*m.a22 - m.a02*m.a20)*b.y + (m.a02*m.a10 - m.a00*m.a12)*b.z)/determinant;
if (u2 < 0.0)
return false;
float u3 = ((m.a10*m.a21 - m.a11*m.a20)*b.x + (m.a01*m.a20 - m.a00*m.a21)*b.y + (m.a00*m.a11 - m.a01*m.a10)*b.z)/determinant;
if (u3 < 0.0 || (1-u1-u2) < 0.0)
return false;
intersection = origin + direction*u3;
return true;
}
__device__ int get_color(const float3 &direction, const float3 &v0, const float3& v1, const float3 &v2)
{
int rgb = floorf(255*dot(normalize(cross(v1-v0,v2-v0)),-direction));
return rgb << 16 | rgb << 8 | rgb;
}
__device__ bool intersect_box(const float3 &origin, const float3 &direction, const float3 &lower_bound, const float3 &upper_bound)
{
float kmin, kmax, kymin, kymax, kzmin, kzmax;
if (direction.x >= 0.0)
{
kmin = (lower_bound.x - origin.x)/direction.x;
kmax = (upper_bound.x - origin.x)/direction.x;
}
else
{
kmin = (upper_bound.x - origin.x)/direction.x;
kmax = (lower_bound.x - origin.x)/direction.x;
}
if (kmax < kmin)
return false;
if (direction.y >= 0.0)
{
kymin = (lower_bound.y - origin.y)/direction.y;
kymax = (upper_bound.y - origin.y)/direction.y;
}
else
{
kymin = (upper_bound.y - origin.y)/direction.y;
kymax = (lower_bound.y - origin.y)/direction.y;
}
if (kymax < kymin)
return false;
if (kymin > kmin)
kmin = kymin;
if (kymax < kmax)
kmax = kymax;
if (kmin > kmax)
return false;
if (direction.z >= 0.0)
{
kzmin = (lower_bound.z - origin.z)/direction.z;
kzmax = (upper_bound.z - origin.z)/direction.z;
}
else
{
kzmin = (upper_bound.z - origin.z)/direction.z;
kzmax = (lower_bound.z - origin.z)/direction.z;
}
if (kzmax < kzmin)
return false;
if (kzmin > kmin)
kmin = kzmin;
if (kzmax < kmax)
kmax = kzmax;
if (kmin > kmax)
return false;
if (kmax < 0.0)
return false;
return true;
}
__device__ bool intersect_node(const float3 &origin, const float3 &direction, const int &i)
{
float3 lower_bound = make_float3(tex1Dfetch(lower_bound_arr, i));
float3 upper_bound = make_float3(tex1Dfetch(upper_bound_arr, i));
return intersect_box(origin, direction, lower_bound, upper_bound);
}
extern "C"
{
__global__ void translate(int max_idx, float3 *pt, float3 v)
{
int idx = blockIdx.x*blockDim.x + threadIdx.x;
if (idx > max_idx)
return;
pt[idx] += v;
}
__global__ void rotate(int max_idx, float3 *pt, float phi, float3 axis)
{
int idx = blockIdx.x*blockDim.x + threadIdx.x;
if (idx > max_idx)
return;
pt[idx] = rotate(pt[idx], phi, axis);
}
__global__ void intersect_mesh(int max_idx, float3 *origin_arr, float3 *direction_arr, int *pixel_arr, int first_leaf)
{
int idx = blockIdx.x*blockDim.x + threadIdx.x;
if (idx > max_idx)
return;
float3 origin = origin_arr[idx];
float3 direction = direction_arr[idx];
int *pixel = pixel_arr+idx;
bool hit = false;
float distance, min_distance;
float3 intersection, min_intersection;
if (!intersect_node(origin, direction, 0))
{
*pixel = 0;
return;
}
int stack[100];
int *head = &stack[0];
int *node = &stack[1];
*node = 0;
int i;
do
{
int child_map = tex1Dfetch(child_map_arr, *node);
int child_len = tex1Dfetch(child_len_arr, *node);
if (*node < first_leaf)
{
for (i=0; i < child_len; i++)
if (intersect_node(origin, direction, child_map+i))
*node++ = child_map+i;
if (node == head)
break;
node--;
}
else // node is a leaf
{
for (i=0; i < child_len; i++)
{
int mesh_idx = child_map + 3*i;
float3 v0 = make_float3(tex1Dfetch(mesh, mesh_idx));
float3 v1 = make_float3(tex1Dfetch(mesh, mesh_idx+1));
float3 v2 = make_float3(tex1Dfetch(mesh, mesh_idx+2));
if (intersect_triangle(origin, direction, v0, v1, v2, intersection))
{
if (!hit)
{
*pixel = get_color(direction, v0, v1, v2);
min_distance = norm(intersection-origin);
min_intersection = intersection;
hit = true;
continue;
}
distance = norm(intersection-origin);
if (distance < min_distance)
{
*pixel = get_color(direction, v0, v1, v2);
min_distance = distance;
min_intersection = intersection;
}
}
} // triangle loop
node--;
} // node is a leaf
} // while loop
while (node != head);
if (!hit)
*pixel = 0;
} // intersect mesh
} // extern "c"
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