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//-*-c-*-
#include <math_constants.h>
#include <curand_kernel.h>
#include "linalg.h"
#include "matrix.h"
#include "rotate.h"
#include "mesh.h"
#include "geometry.h"
#include "photon.h"
__device__ void
fAtomicAdd(float *addr, float data)
{
while (data)
data = atomicExch(addr, data+atomicExch(addr, 0.0f));
}
__device__ void
to_diffuse(Photon &p, State &s, Geometry *g, curandState &rng, int max_steps)
{
int steps = 0;
while (steps < max_steps) {
steps++;
int command;
fill_state(s, p, g);
if (p.last_hit_triangle == -1)
break;
command = propagate_to_boundary(p, s, rng);
if (command == BREAK)
break;
if (command == CONTINUE)
continue;
if (s.surface_index != -1) {
command = propagate_at_surface(p, s, rng, g);
if (p.history & REFLECT_DIFFUSE)
break;
if (command == BREAK)
break;
if (command == CONTINUE)
continue;
}
propagate_at_boundary(p, s, rng);
} // while (steps < max_steps)
} // to_diffuse
extern "C"
{
__global__ void
update_xyz_lookup(int nthreads, int total_threads, int offset, float3 position,
curandState *rng_states, float wavelength, float3 xyz,
float3 *xyz_lookup1, float3 *xyz_lookup2, int max_steps,
Geometry *g)
{
int kernel_id = blockIdx.x*blockDim.x + threadIdx.x;
int id = kernel_id + offset;
if (kernel_id >= nthreads || id >= total_threads)
return;
curandState rng = rng_states[kernel_id];
Triangle t = get_triangle(g, id);
float a = curand_uniform(&rng);
float b = uniform(&rng, 0.0f, (1.0f - a));
float c = 1.0f - a - b;
float3 direction = a*t.v0 + b*t.v1 + c*t.v2 - position;
direction /= norm(direction);
float distance;
int triangle_index = intersect_mesh(position, direction, g, distance);
if (triangle_index != id) {
rng_states[kernel_id] = rng;
return;
}
float3 v01 = t.v1 - t.v0;
float3 v12 = t.v2 - t.v1;
float3 surface_normal = normalize(cross(v01,v12));
float cos_theta = dot(surface_normal,-direction);
if (cos_theta < 0.0f)
cos_theta = dot(-surface_normal,-direction);
Photon p;
p.position = position;
p.direction = direction;
p.wavelength = wavelength;
p.polarization = uniform_sphere(&rng);
p.last_hit_triangle = -1;
p.time = 0;
p.history = 0;
State s;
to_diffuse(p, s, g, rng, max_steps);
if (p.history & REFLECT_DIFFUSE) {
if (s.inside_to_outside) {
fAtomicAdd(&xyz_lookup1[p.last_hit_triangle].x, cos_theta*xyz.x);
fAtomicAdd(&xyz_lookup1[p.last_hit_triangle].y, cos_theta*xyz.y);
fAtomicAdd(&xyz_lookup1[p.last_hit_triangle].z, cos_theta*xyz.z);
}
else {
fAtomicAdd(&xyz_lookup2[p.last_hit_triangle].x, cos_theta*xyz.x);
fAtomicAdd(&xyz_lookup2[p.last_hit_triangle].y, cos_theta*xyz.y);
fAtomicAdd(&xyz_lookup2[p.last_hit_triangle].z, cos_theta*xyz.z);
}
}
rng_states[kernel_id] = rng;
} // update_xyz_lookup
__global__ void
update_xyz_image(int nthreads, curandState *rng_states, float3 *positions,
float3 *directions, float wavelength, float3 xyz,
float3 *xyz_lookup1, float3 *xyz_lookup2, float3 *image,
int nlookup_calls, int max_steps, Geometry *g)
{
int id = blockIdx.x*blockDim.x + threadIdx.x;
if (id >= nthreads)
return;
curandState rng = rng_states[id];
Photon p;
p.position = positions[id];
p.direction = directions[id];
p.direction /= norm(p.direction);
p.wavelength = wavelength;
p.polarization = uniform_sphere(&rng);
p.last_hit_triangle = -1;
p.time = 0;
p.history = 0;
State s;
to_diffuse(p, s, g, rng, max_steps);
if (p.history & REFLECT_DIFFUSE) {
if (s.inside_to_outside)
image[id] += xyz*xyz_lookup1[p.last_hit_triangle]/nlookup_calls;
else
image[id] += xyz*xyz_lookup2[p.last_hit_triangle]/nlookup_calls;
}
rng_states[id] = rng;
} // update_xyz_image
__global__ void
process_image(int nthreads, float3 *image, unsigned int *pixels, int nimages)
{
int id = blockIdx.x*blockDim.x + threadIdx.x;
if (id >= nthreads)
return;
float3 rgb = image[id]/nimages;
if (rgb.x < 0.0f)
rgb.x = 0.0f;
if (rgb.y < 0.0f)
rgb.y = 0.0f;
if (rgb.z < 0.0f)
rgb.z = 0.0f;
if (rgb.x > 1.0f)
rgb.x = 1.0f;
if (rgb.y > 1.0f)
rgb.y = 1.0f;
if (rgb.z > 1.0f)
rgb.z = 1.0f;
unsigned int r = floorf(rgb.x*255.0f);
unsigned int g = floorf(rgb.y*255.0f);
unsigned int b = floorf(rgb.z*255.0f);
pixels[id] = 255 << 24 | r << 16 | g << 8 | b;
} // process_image
} // extern "c"
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