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353 awk 1 
#include "pathtracer.h"
2 
 
3 
using namespace CGLA;
4 
 
355 awk 5 
pathtracer::pathtracer(int w, int h, bool explicit_direct, int subsamples)
6 
: width_(w), height_(h), scene_(0)
353 awk 7 
{
8 
    explicit_direct_ = explicit_direct;
9 
    subsamples_ = subsamples;
10 
}
11 
 
355 awk 12 
void pathtracer::set_scene(scene* s)
353 awk 13 
{
355 awk 14 
    scene_ = s;
15 
}
16 
 
17 
CGLA::Vec3f pathtracer::trace(const ray& r, bool include_emitted)
18 
{
353 awk 19 
    //intersect ray with
20 
    hit_info hi;
21 
    bool hit = scene_->intersect(r, hi);
22 
 
23 
    if (!hit)
24 
        return Vec3f(0.f, 0.f, 0.f);
25 
 
26 
    //Vec3f x, y, z = hi.shading_normal;
27 
    //orthogonal(z, x, y);
28 
    //return (Vec3f(hi.texcoords(0),hi.texcoords(1),0) + Vec3f(0.f)) / 1.f;
29 
 
30 
    //only include emitted light if requested
31 
    CGLA::Vec3f Le(0.f);
32 
    if (include_emitted)
33 
        Le = hi.emitted;
34 
 
35 
    //compute reflectance for each bsdf component
36 
    float rho_diffuse = intensity(hi.diffuse);
37 
    float rho_glossy = intensity(hi.glossy);
38 
    float rho_reflection = intensity(hi.reflection);
39 
    float rho_refraction = intensity(hi.refraction);
40 
    float rho_total = rho_diffuse+rho_glossy+rho_reflection+rho_refraction;
41 
    assert(rho_total < 1.f);
42 
 
43 
    if (rho_total == 0.f)
44 
        return Le;
45 
 
46 
    //compute direct lighting on hit point
47 
    CGLA::Vec3f Ld(0.f);
48 
    Vec3f wo = -r.direction;
49 
    if (explicit_direct_ && rho_diffuse+rho_glossy>0.f)
50 
    {
51 
        size_t nlums = scene_->luminaires();
52 
        for (size_t i=0; i<nlums; ++i)
53 
        {
54 
            const luminaire* lum = scene_->get_luminaire(i);
55 
            int samples = lum->samples();
56 
 
57 
            Vec3f L(0.f);
58 
            for (int j=0; j<samples; ++j)
59 
            {
60 
                Vec3f Li, wi;
61 
                if (lum->sample(r, hi, Li, wi))
62 
                {
63 
                    float cost = std::max(dot(hi.shading_normal, wi),0.f);
64 
                    L += Li * cost * bsdf_evaluate(hi, wi, wo);
65 
                }
66 
 
67 
                Ld += L / float(samples);
68 
            }
69 
        }
70 
    }
71 
 
72 
    //use russian roulette to terminate path
73 
    float prussian = 1.f;
74 
    float rr = mt_random();
75 
 
76 
    if (r.depth > 3)
77 
    {
78 
        prussian = rho_total;
79 
 
80 
        if (rr >= prussian)
81 
            return Ld + Le;
82 
    }
83 
 
84 
    //figure out which bXdf to sample
85 
    float pdiffuse = rho_diffuse/rho_total;
86 
    float pglossy = rho_glossy/rho_total;
87 
    float preflection = rho_reflection/rho_total;
88 
    float prefraction = rho_refraction/rho_total;
89 
 
90 
    Vec3f wi;
91 
    float pwi;
92 
    Vec3f fs;
93 
    bool sample_emitted = !explicit_direct_;
94 
    if (rr <= pdiffuse)
95 
    {
96 
        //sample diffuse
97 
        float pwi = sample_lambertian(hi, wo, wi);
98 
        fs = lambertian_brdf(hi, wi, wo) / (pwi * pdiffuse * prussian);
99 
    }
100 
    else if (rr <= pdiffuse+pglossy)
101 
    {
102 
        //sample glossy part
103 
        float pwi = sample_phong(hi, wo, wi);
104 
 
105 
        if (dot(hi.shading_normal, wi) <= 0.f)
106 
            return Le + Ld;
107 
 
108 
        fs = phong_brdf(hi, wi, wo) / (pwi * pglossy * prussian);
109 
    }
110 
    else if (rr <= pdiffuse+pglossy+preflection)
111 
    {
112 
        //sample perfect specular reflection
113 
        wi = reflect(hi.shading_normal, wo);
114 
        pwi = 1.f;
115 
        float cost = dot(hi.shading_normal, wo);
116 
        fs = hi.reflection / (pwi * preflection * cost);
117 
        sample_emitted = true;
118 
    }
119 
    else if (rr <= pdiffuse+pglossy+preflection+prefraction)
120 
    {
121 
        //sample perfect specular refraction
122 
        bool not_tir = refract(hi.shading_normal, wo, 1.f/hi.ior, wi);
123 
        assert(not_tir);
124 
        pwi = 1.f;
125 
        float cost = std::abs(dot(hi.shading_normal, wi));
126 
        fs = hi.refraction / (pwi * prefraction * cost);
127 
        sample_emitted = true;
128 
    }
129 
    else
130 
        assert(false);
131 
 
132 
    //create aux ray
133 
    ray s;
134 
    s.origin = hi.position + epsilon * wi;
135 
    s.direction = wi;
136 
    s.depth = r.depth + 1;
137 
    s.distance = std::numeric_limits<float>::infinity();
138 
    float cost = std::abs(dot(hi.shading_normal, wi));
139 
    Vec3f Li = cost * fs * trace(s, sample_emitted);
140 
 
141 
    //returm sum of emitted + direct + indirect
142 
    return Le + Ld + Li;
143 
}
144 
 
355 awk 145 
Vec3f pathtracer::compute_pixel(int w, int h)
353 awk 146 
{
147 
    assert(scene_);
148 
 
149 
    //supersample
150 
    Vec3f L(0.f);
151 
    for (int j=0; j<subsamples_; ++j)
152 
    {
153 
        float y  = h + (j + 0.5f) / subsamples_;
154 
 
155 
        for (int i=0; i<subsamples_; ++i)
156 
        {
157 
            float x  = w + (i + 0.5f) / subsamples_;
158 
 
159 
            //ask camera for initial ray..
160 
            Vec2f uv(x/width_, y/height_);
161 
            ray r = scene_->get_camera()->generate(uv);
162 
 
163 
            //trace ray
164 
            L += trace(r, true);
165 
        }
166 
    }
167 
 
168 
    return L / float(subsamples_ * subsamples_);
169 
}
170 
 
346 awk 171 
//02566 framework, Anders Wang Kristensen, awk@imm.dtu.dk, 2007
172 
 
353 awk 173 
#if 0
174 
//02566 framework, Anders Wang Kristensen, awk@imm.dtu.dk, 2007
175 
 
346 awk 176 
#include <stdlib.h>
177 
#include <GL/glut.h>
178 
 
179 
#include <CGLA/Vec2i.h>
180 
#include <CGLA/Vec3uc.h>
181 
 
353 awk 182 
#include "scene.h"
183 
#include "camera.h"
184 
#include "mesh.h"
185 
#include "omni.h"
346 awk 186 
 
353 awk 187 
#include "matte.h"
188 
#include "plastic.h"
189 
#include "metal.h"
190 
#include "glass.h"
346 awk 191 
 
355 awk 192 
#include "pathtracer.h"
346 awk 193 
 
194 
using namespace CGLA;
195 
 
196 
//global pointer to the active scene
197 
scene* current;
198 
 
355 awk 199 
static pathtracer* renderer;
346 awk 200 
 
201 
const int width = 64*8;
202 
const int height = 64*8;
203 
 
204 
static Vec3f* film;
205 
static Vec3uc* image;
206 
static Vec2i pixel(0);
207 
static bool done = false;
208 
 
347 awk 209 
static float dgamma = 2.2f;
210 
static float dexposure = 0.f;
346 awk 211 
 
212 
Vec3uc tonemap(const Vec3f& v)
213 
{
347 awk 214 
    Vec3f u = v * std::pow(2.f, dexposure);
348 awk 215 
    float r = mt_random() - 0.5f;
346 awk 216 
 
347 awk 217 
    Vec3uc I;
218 
    for (int i=0; i<3; ++i)
219 
    {
220 
        float c = std::pow(u[i], 1.f / dgamma);
221 
        c = 255.f * c + 0.5f + r;
222 
        I[i] = clamp(int(c), 0, 255);
223 
    }
224 
    return I;
346 awk 225 
}
226 
 
227 
void display(void)
228 
{
347 awk 229 
    glClear(GL_COLOR_BUFFER_BIT);
346 awk 230 
 
347 awk 231 
    for (int j=0; j<height; ++j)
232 
        for (int i=0; i<width; ++i)
233 
            image[i + j*width] = tonemap(film[i + j*width]);
346 awk 234 
 
347 awk 235 
    glDrawPixels(width, height, GL_RGB, GL_UNSIGNED_BYTE, image);
236 
    glutSwapBuffers();
237 
 
238 
    GLenum e = glGetError();
239 
    if (e != GL_NO_ERROR)
240 
    {
241 
        printf("OpenGL error: %s\n", gluErrorString(e));
242 
        exit(EXIT_FAILURE);
243 
    }
346 awk 244 
}
245 
 
246 
void reshape(GLint width, GLint height)
247 
{
347 awk 248 
    glMatrixMode(GL_PROJECTION);
249 
    glLoadIdentity();
250 
    gluOrtho2D(0, width, 0, height);
251 
    glMatrixMode(GL_MODELVIEW);
252 
    glLoadIdentity();
346 awk 253 
}
254 
 
255 
void special(int key, int x, int y)
256 
{
347 awk 257 
    switch (key)
258 
    {
259 
    case GLUT_KEY_LEFT:
260 
        dgamma = std::max(dgamma - 0.1f, 0.5f);
261 
        break;
346 awk 262 
 
347 awk 263 
    case GLUT_KEY_RIGHT:
264 
        dgamma = std::min(dgamma + 0.1f, 5.f);
265 
        break;
346 awk 266 
 
347 awk 267 
    case GLUT_KEY_DOWN:
268 
        dexposure = std::max(dexposure - 0.1f, -10.f);
269 
        break;
346 awk 270 
 
347 awk 271 
    case GLUT_KEY_UP:
272 
        dexposure = std::min(dexposure + 0.1f, 10.f);
273 
        break;
274 
    }
346 awk 275 
 
347 awk 276 
    printf("gamma: %.2f, exposure: %.2f\n", dgamma, dexposure);
277 
    glutPostRedisplay();
346 awk 278 
}
279 
 
280 
void keyboard(unsigned char key, int x, int y)
281 
{
347 awk 282 
    switch (key)
283 
    {
284 
    case 27: //ESCAPE key
285 
        exit(0);
286 
        break;
287 
    }
346 awk 288 
}
289 
 
290 
void idle(void)
291 
{
347 awk 292 
    for (int i=0; i<width*8 && !done; ++i)
293 
    {
294 
        Vec3f L = renderer->compute_pixel(pixel[0], pixel[1]);
295 
        film[pixel[0] + pixel[1] * width] = L;
346 awk 296 
 
347 awk 297 
        //advance
298 
        ++pixel[0];
346 awk 299 
 
347 awk 300 
        if (pixel[0] == width)
301 
        {
302 
            pixel[0] = 0;
303 
            ++pixel[1];
346 awk 304 
 
347 awk 305 
            if (pixel[1] == height)
306 
            {
307 
                done = true;
308 
                glutIdleFunc(NULL);
309 
            }
310 
        }
311 
    }
346 awk 312 
 
347 awk 313 
    glutPostRedisplay();
346 awk 314 
}
315 
 
316 
int main(int argc, char* argv[])
317 
{
347 awk 318 
    //make the scene
319 
    current = new scene;
346 awk 320 
 
347 awk 321 
    //setup some materials
322 
    matte dull_white(Vec3f(0.5f, 0.5f, 0.5f));
323 
    matte dull_gray(Vec3f(0.4f, 0.4f, 0.4f));
324 
    matte dull_red(Vec3f(0.6f, 0.3f, 0.2f));
325 
    matte dull_green(Vec3f(0.3f, 0.6f, 0.2f));
326 
    matte dull_blue(Vec3f(0.2f, 0.2f, 0.6f));
346 awk 327 
 
347 awk 328 
    plastic glossy_white(Vec3f(0.4f, 0.4f, 0.4f), Vec3f(0.5f), 20.f);
329 
    plastic glossy_purple(Vec3f(0.3f, 0.1f, 0.3f), Vec3f(0.65f), 8.f);
330 
    plastic glossy_yellow(Vec3f(0.3f, 0.3f, 0.0f), Vec3f(0.65f), 32.f);
346 awk 331 
 
347 awk 332 
    //for exercise 2
333 
    glass clear(Vec3f(0.99f, 0.99f, 0.99f), 1.5f);
334 
    metal silver(Vec3f(0.9f, 0.9f, 0.9f), 22.f, 0.177f, 3.638f);
346 awk 335 
 
347 awk 336 
    //setup cornell box 1mx1mx1m
337 
    mesh floor("../../data/cornell_box/floor.obj");
338 
    floor.set_material(&glossy_white);
339 
    current->insert(&floor);
346 awk 340 
 
347 awk 341 
    mesh ceiling("../../data/cornell_box/ceiling.obj");
342 
    ceiling.set_material(&dull_gray);
343 
    current->insert(&ceiling);
346 awk 344 
 
347 awk 345 
    mesh back("../../data/cornell_box/back.obj");
346 
    back.set_material(&silver);
347 
    current->insert(&back);
346 awk 348 
 
347 awk 349 
    mesh left("../../data/cornell_box/left.obj");
350 
    left.set_material(&dull_red);
351 
    current->insert(&left);
346 awk 352 
 
347 awk 353 
    mesh right("../../data/cornell_box/right.obj");
354 
    right.set_material(&dull_blue);
355 
    current->insert(&right);
346 awk 356 
 
347 awk 357 
    //add some objects to the box
358 
    Mat4x4f tmp;
346 awk 359 
 
347 awk 360 
    mesh box1("../../data/cornell_box/box1.obj");
361 
    tmp = rotation_Mat4x4f(YAXIS, -float(M_PI)/8.f);
362 
    tmp = translation_Mat4x4f(Vec3f(-0.3f,0.f,-0.05f)) * tmp;
363 
    box1.set_transform(tmp);
364 
    box1.set_material(&dull_green);
365 
    current->insert(&box1);
346 awk 366 
 
347 awk 367 
    mesh box2("../../data/cornell_box/box2.obj");
368 
    tmp = translation_Mat4x4f(Vec3f(0.25f,0.f, -0.05f));
369 
    box2.set_transform(tmp);
370 
    box2.set_material(&glossy_purple);
371 
    current->insert(&box2);
346 awk 372 
 
347 awk 373 
    mesh teapot("../../data/cornell_box/teapot1.obj");
374 
    tmp = rotation_Mat4x4f(YAXIS, float(M_PI/4.f));
375 
    tmp = translation_Mat4x4f(Vec3f(-0.25f,0.25f, -0.05)) * tmp;
376 
    teapot.set_transform(tmp);
377 
    teapot.set_material(&silver);
378 
    current->insert(&teapot);
346 awk 379 
 
347 awk 380 
    mesh sphere1("../../data/cornell_box/sphere2.obj");
381 
    tmp = translation_Mat4x4f(Vec3f(0.25f,0.45f,-0.05f));
382 
    sphere1.set_transform(tmp);
383 
    sphere1.set_material(&clear);
384 
    current->insert(&sphere1);
346 awk 385 
 
347 awk 386 
    mesh sphere2("../../data/cornell_box/sphere2.obj");
387 
    tmp = translation_Mat4x4f(Vec3f(0.22f,0.15f,0.25f));
388 
    sphere2.set_transform(tmp);
389 
    sphere2.set_material(&glossy_yellow);
390 
    //current->insert(&sphere2);
346 awk 391 
 
347 awk 392 
    //light sources
393 
    mesh quad_light("../../data/cornell_box/quad.obj");
394 
    tmp = rotation_Mat4x4f(XAXIS, float(M_PI));
395 
    tmp = translation_Mat4x4f(Vec3f(0.f,0.99f,0.2f)) * tmp;
396 
    quad_light.set_transform(tmp);
397 
    quad_light.set_exitance(Vec3f(300,300,300));
398 
    current->insert(&quad_light);
346 awk 399 
 
347 awk 400 
    mesh quad_light1("../../data/cornell_box/quad.obj");
401 
    tmp = rotation_Mat4x4f(XAXIS, float(M_PI));
402 
    tmp = translation_Mat4x4f(Vec3f(0.f,0.99f,0.2f)) * tmp;
403 
    quad_light1.set_transform(tmp);
404 
    quad_light1.set_exitance(Vec3f(0,400,0));
405 
//  current->insert(&quad_light1);
346 awk 406 
 
347 awk 407 
    mesh quad_light2("../../data/cornell_box/quad.obj");
408 
    tmp = rotation_Mat4x4f(XAXIS, float(M_PI));
409 
    tmp = translation_Mat4x4f(Vec3f(-0.2f,0.99f,0.2f)) * tmp;
410 
    quad_light2.set_transform(tmp);
411 
    quad_light2.set_exitance(Vec3f(400,0,0));
412 
//  current->insert(&quad_light2);
346 awk 413 
 
347 awk 414 
    mesh quad_light3("../../data/cornell_box/quad.obj");
415 
    tmp = rotation_Mat4x4f(XAXIS, float(M_PI));
416 
    tmp = translation_Mat4x4f(Vec3f(0.2f,0.99f,0.2f)) * tmp;
417 
    quad_light3.set_transform(tmp);
418 
    quad_light3.set_exitance(Vec3f(0,0,400));
419 
//  current->insert(&quad_light3);
346 awk 420 
 
347 awk 421 
    omni omni_light(Vec3f(30.f));
422 
    omni_light.set_transform(translation_Mat4x4f(Vec3f(0.0f,0.95f,0.0f)));
423 
    //current->insert(&omni_light);
346 awk 424 
 
347 awk 425 
    mesh sphere_light("../../data/cornell_box/small_sphere.obj");
426 
    sphere_light.set_transform(translation_Mat4x4f(Vec3f(0.f,0.95f,0.f)));
427 
    sphere_light.set_exitance(Vec3f(30.f/(4.f*float(M_PI)*0.01f*0.01f)));
428 
    //current->insert(&sphere_light);
346 awk 429 
 
347 awk 430 
    //setup camera (eye, center, up, focal length)
431 
    camera pentax(
432 
        Vec3f(0.f,0.5f,2.0f),
433 
        Vec3f(0.f,0.5f,0.5f),
434 
        Vec3f(0,1,0),
435 
        0.035f);
346 awk 436 
 
347 awk 437 
    current->set_camera(&pentax);
346 awk 438 
 
347 awk 439 
    //build acceleration structure
440 
    current->initialize(8, 25);
346 awk 441 
 
347 awk 442 
    //create the renderer
355 awk 443 
    renderer = new pathtracer(width, height, true, 1);
347 awk 444 
    renderer->set_scene(current);
346 awk 445 
 
347 awk 446 
    //create the film
447 
    film = new Vec3f[width * height];
448 
    std::fill(film, film+width*height, Vec3f(0.3f));
449 
    image = new Vec3uc[width * height];
450 
    std::fill(image, image+width*height, Vec3uc(32,32,32));
346 awk 451 
 
347 awk 452 
    //init glut
453 
    glutInit(&argc, argv);
454 
    glutInitWindowSize(width, height);
455 
    glutInitDisplayMode(GLUT_RGB | GLUT_DOUBLE | GLUT_DEPTH);
456 
    glutCreateWindow("Course 02566 - IMM DTU");
346 awk 457 
 
347 awk 458 
    glutDisplayFunc(display);
459 
    glutReshapeFunc(reshape);
460 
    glutKeyboardFunc(keyboard);
461 
    glutSpecialFunc(special);
346 awk 462 
 
347 awk 463 
    glutIdleFunc(idle);
346 awk 464 
 
347 awk 465 
    //Turn the flow of control over to GLUT
466 
    glutMainLoop();
346 awk 467 
 
347 awk 468 
    //clean up
469 
    delete current;
470 
    delete renderer;
471 
 
472 
    return EXIT_SUCCESS;
473 
}
353 awk 474 
#endif