README.md

raytracing-render

Developing ray tracing render from scratch.

Key Features

• Using k-d tree for fast traversal of 3D scene objects
• Using Surface Area Heuristic for building optimal k-d tree
• Rendering entire scene in parallel (using OpenMP)
• Texture mapping (using libpng)
• Saving rendered image to file (using libpng)
• Loading 3D models from *.obj format
• Phong shading
• Antialiasing: throwing 4 rays per each pixel, which belongs to edge (using Sobel operator to detect edges)
• Phong reflection model
• Two types of primitives: triangle and sphere
• Reflections, shadows, fog effect, multiple light sources

Requirements

Requires libpng to be installed.
Tested on Mac OS 10.8 with gcc 4.2, gcc 4.7, gcc 4.9 and gcc 5 (as far as OpenMP is required - currently, Clang can't be used).

Demo with GLUT front-end

All rendering routines are performing by this render, not OpenGL. Just using GLUT to display rendered image.

make run_demo_gl

or something like this (in case if Homebrew installed GCC 5 - under its own alias):

make CC=gcc-5 run_demo_gl

• Use controls ← ↑ → ↓ to rotate camera
• Use CTRL + ↑ or CTRL + ↓ to move camera forward or backward
• Use SHIFT + ↑ or SHIFT + ↓ to move camera up or down
• Use SHIFT + ← or SHIFT + → to move camera left or right
• Use ALT + ↑ or ALT + ↓ to change focus of camera
• Use ESC to exit

Create demo from scratch

Lets create example application from scratch :) You will get following image:

#include <stdio.h>

#include <canvas.h>
#include <render.h>
#include <obj_loader.h>

#define CANVAS_W 400
#define CANVAS_H 400

// Boost by rendering in parallel
#define THREADS_NUM 4

#define BACKGROUND_COLOR rgb(255, 255, 255)

#define MAX_OBJECTS_NUMBER 10000
#define MAX_LIGHT_SOURCES_NUMBER 5

int
main(void) {
    // Allocating scene
    Scene * scene = new_scene(MAX_OBJECTS_NUMBER,
                              MAX_LIGHT_SOURCES_NUMBER,
                              BACKGROUND_COLOR);
    
    // Allocating new sphere
    Float radius = 100;
    Point3d center = point3d(0, 0, 0);
    Color sphere_color = rgb(250, 30, 30);
    Material sphere_material = material(1, 5, 5, 10, 0, 10);
    Object3d * sphere = new_sphere(center,
                                   radius,
                                   sphere_color,
                                   sphere_material);
    
    // Adding sphere to the scene
    add_object(scene,
               sphere);
    
    // Allocating new triangle
    Object3d * triangle = new_triangle(point3d(-700, -700, -130), // vertex 1
                                       point3d( 700, -700, -130), // vertex 2
                                       point3d(   0,  400, -130), // vertex 3
                                       rgb(100, 255, 30),         // color
                                       material(1, 6, 0, 2, 0, 0) // surface params
                                       );
    
    // Adding triangle to the scene
    add_object(scene,
               triangle);
    
    // Loading 3D model of cow from *.obj file
    // defining transformations and parameters of 3D model
    // TODO: must be refactored...
    SceneFaceHandlerParams load_params =
    new_scene_face_handler_params(scene,
                                  // scale:
                                  40,
                                  // move dx, dy, dz:
                                  -150, -100, 30,
                                  // rotate around axises x, y, z:
                                  0, 0, 0,
                                  // color
                                  rgb(200, 200, 50),
                                  // surface params
                                  material(2, 3, 0, 0, 0, 0)
                                  );
    
    load_obj("./demo/models/cow.obj",
             // default handler which adding polygons of 3D model to scene:
             scene_face_handler,
             &load_params);
    
    // This function is requried (bulding k-d tree of entire scene)
    prepare_scene(scene);
    
    printf("\nNumber of polygons: %i\n", scene->last_object_index + 1);
    
    // Allocating new light source
    Color light_source_color = rgb(255, 255, 255);
    Point3d light_source_location = point3d(-300, 300, 300);
    LightSource3d * light_source = new_light_source(light_source_location,
                                                    light_source_color);
    // Adding light source to the scene
    add_light_source(scene,
                     light_source);
    
    // Adding fog
    Float density = 0.002;
    set_exponential_fog(scene, density);
    
    // Allocating camera
    // TODO: It's a pity, but quaternions are not implemented yet :(
    Point3d camera_location = point3d(0, 500, 0);
    Float focus = 320;
    Float x_angle = -1.57;
    Float y_angle = 0;
    Float z_angle = 3.14;
    Camera * camera = new_camera(camera_location,
                                 x_angle,
                                 y_angle,
                                 z_angle,
                                 focus);
    
    // Rotate camera if needed
    // rotate_camera(camera, d_x_angle, d_y_angle, d_z_angle);
    
    // Move camera if needed
    // move_camera(camera, vector3df(d_x, d_y, d_z));
    
    // Alocate new canvas, to render scene on it
    Canvas * canvas = new_canvas(CANVAS_W,
                                 CANVAS_H);
    
    render_scene(scene,
                 camera,
                 canvas,
                 THREADS_NUM);
    
    // Saving rendered image in PNG format
    write_png("example.png",
              canvas);
    
    release_canvas(canvas);
    release_scene(scene);
    release_camera(camera);
    
    return 0;
}

Launch it

make example && ./example

Average number of intersections per pixel

Define different values of maximal depth of Kd-tree and track average number of ray intersections per pixel:

make DEF="-DRAY_INTERSECTIONS_STAT -DMAX_TREE_DEPTH=25" run_demo_gl

make DEF="-DRAY_INTERSECTIONS_STAT -DMAX_TREE_DEPTH=25" example && ./example

Benchamrks

Illustration of kd-tree boosting:

1. Without kd-tree, and without bounding box:

make clean > /dev/null
make DEF="-DRAY_INTERSECTIONS_STAT -DNO_BOUNDING_BOX -DMAX_TREE_DEPTH=0" benchmark > /dev/null &&
./benchmark
make clean > /dev/null

2. Without kd-tree, but with bounding box:

make clean > /dev/null
make DEF="-DRAY_INTERSECTIONS_STAT -DMAX_TREE_DEPTH=0" benchmark > /dev/null &&
./benchmark
make clean > /dev/null

3. With kd-tree, but without bounding box:

make clean > /dev/null
make DEF="-DRAY_INTERSECTIONS_STAT -DNO_BOUNDING_BOX -DMAX_TREE_DEPTH=20" benchmark > /dev/null &&
./benchmark
make clean > /dev/null

4. With kd-tree, and with bounding box:

make clean > /dev/null
make DEF="-DRAY_INTERSECTIONS_STAT -DMAX_TREE_DEPTH=20" benchmark > /dev/null &&
./benchmark
make clean > /dev/null