Raytracing

本程序是根据Raytracing的要求所写。

该题目要求根据其所给的框架程序来实现raytracing的功能。

该项目已迁移到我的个人github主页，请访问[bin2415]## 题目要求

具体实现

• 环境是virual studio 2015和opengl

• 具体代码及分析如下：

  /*CSCI 480Assignment 3 RaytracerName: <binpang>*/{% highlight c++ %}#define _CRT_SECURE_NO_WARNINGS#define GLUT_DISABLE_ATEXIT_HACK#include <pic.h>#include <windows.h>#include <GL/glu.h>#include <GL/glut.h>#include <stdlib.h>#include <stdio.h>#include <string>#include <math.h>#include <vector>#define MAX_TRIANGLES 2000#define MAX_SPHERES 10#define MAX_LIGHTS 10char *filename=0;#define MODE_DISPLAY 1#define MODE_JPEG 2int mode=MODE_DISPLAY;#define WIDTH 640#define HEIGHT 480#define fov 60.0#define PI 3.1415926int MaxStep = 10;int Steps = 0;//求出投射的屏幕的x和y的最大范围的坐标double yMax = tan((double)PI*fov / (2 * 180));double xMax = yMax*((double)WIDTH) / ((double)HEIGHT);unsigned char buffer[HEIGHT][WIDTH][3];struct Vertex{  double position[3];  double color_diffuse[3];//漫射  double color_specular[3];   //反射  double normal[3];  double shininess;};typedef struct _Triangle{  struct Vertex v[3];} Triangle;typedef struct _Sphere{  double position[3];  double color_diffuse[3];  double color_specular[3];  double shininess;  double radius;} Sphere;typedef struct _Light{  double position[3];  double color[3];} Light;//表示点的结构struct point{    double x;    double y;    double z;};//点在里面还是在外面struct isIn{    bool in;        //当在三角形外面时为0，当在里面时为1    double bary[3];};//交点的结构struct intexPoint{    point p;    double t;    int tID;    //物体在数组中的标号    int tObj;  //如果是1表示点在圆上，如果为2表示在三角形上    isIn iO;    };Triangle triangles[MAX_TRIANGLES];Sphere spheres[MAX_SPHERES];Light lights[MAX_LIGHTS];double ambient_light[3];struct point cam;int num_triangles=0;int num_spheres=0;int num_lights=0;void plot_pixel_display(int x,int y,unsigned char r,unsigned char g,unsigned char b);void plot_pixel_jpeg(int x,int y,unsigned char r,unsigned char g,unsigned char b);void plot_pixel(int x,int y,unsigned char r,unsigned char g,unsigned char b);point reflect(intexPoint p, point dir);point Render(point p, point dir);//两个点进行相减point minusPoint(point A, point B){    point C;    C.x = A.x - B.x;    C.y = A.y - B.y;    C.z = A.z - B.z;    return C;}//向量除以一个数point DivConst(point A, double a){    point B;    B.x = 0.0;    B.y = 0.0;    B.z = 0.0;    if (abs(a) > 1e-10)    {        B.x = A.x / a;        B.y = A.y / a;        B.z = A.z / a;    }    return B;}//计算向量的大小double caculateSize(point A){    double size;    size = sqrt(pow(A.x, 2) + pow(A.y, 2) + pow(A.z, 2));    return size;}//单位化向量point unitize(point A){    point uni;    double size;    size = caculateSize(A);    uni = DivConst(A, size);    return uni;}//点乘double dot(point A, point B){    double C;    C = (A.x*B.x + A.y*B.y + A.z*B.z);    return C;}//叉乘point cross(point A, point B){    point C;    C.x = (A.y*B.z - B.y*A.z);    C.y = (B.x*A.z - A.x*B.z);    C.z = (A.x*B.y - A.y*B.x);    return C;}//求出距离src，方向为dir，长度为t的点point caluPoint(point src, point dir, double t){    point p;    p.x = src.x + t*(dir.x);    p.y = src.y + t*(dir.y);    p.z = src.z + t*(dir.z);    return p;}//与球的交点double intersectSphere(Sphere sphere, point src, point dir){    double b, c, t, t1, t2;    t1 = 0;    t2 = 0;    c = pow((src.x - sphere.position[0]), 2) + pow((src.y - sphere.position[1]), 2)        + pow((src.z - sphere.position[2]), 2) - pow(sphere.radius, 2);    b = 2 * (dir.x*(src.x - sphere.position[0])        + dir.y*(src.y - sphere.position[1])        + dir.z*(src.z - sphere.position[2])        );    //检查判别式是否大于0    if ((pow(b, 2) - 4 * c) > 0)    {        t1 = (((-1)*b) + sqrt(pow(b, 2) - 4 * c)) / 2;        t2 = (((-1)*b) - sqrt(pow(b, 2) - 4 * c)) / 2;        if (t1 <= t2)            t = t1;        else            t = t2;        if (t < 0)            t = -1;        else if (t<1e-10)        {            if (t1<1e-15 && t2>1e-15)                t = t2;            else if (t2<1e-15 && t1>1e-15)                t = t1;            else t = -1;         }    }    else t = -1;     return t;}//获得两个顶点之间的边point getSide(Vertex v1, Vertex v2){    point c;    c.x = v1.position[0] - v2.position[0];    c.y = v1.position[1] - v2.position[1];    c.z = v1.position[2] - v2.position[2];    return c;}//判断两个点是否相等bool checkEqual(point A, point B){    bool equ;    if ((abs(A.x - B.x)<1e-10) && (abs(A.y - B.y)<1e-10) && (abs(A.z - B.z)<1e-10))        equ = 1;    else        equ = 0;    return equ;}double intersectTriangle(Triangle triangle, point src, point dir,isIn* iO){    point AB, AC, DirxAC;    float u, v, t;    //isIn iO;    AB = getSide(triangle.v[1], triangle.v[0]);    AC = getSide(triangle.v[2], triangle.v[0]);    DirxAC = cross(dir, AC);    float det = dot(AB, DirxAC);    point T;    point p1;    p1.x = triangle.v[0].position[0];    p1.y = triangle.v[0].position[1];    p1.z = triangle.v[0].position[2];    if (det >0)   {       T = minusPoint(src, p1);}    else    {        T = minusPoint(p1, src);    det = -det; }    if (det < 1e-10)    {        iO->in = -1;        return -1;    }    u = dot(T, DirxAC);    if (u < 0.0f || u > det)    {        iO->in = -1;        return -1;    }    point Q = cross(T, AB);    v = dot(dir, Q);    if (v < 0.0f || u + v > det)    {        iO->in = -1;        return -1;    }    t = dot(AC, Q);    //t = -t;    float fInvDet = 1.0f / det;    t *= fInvDet;    u *= fInvDet;    v *= fInvDet;    iO->in = 1;    iO->bary[0] = u;    iO->bary[1] = v;    iO->bary[2] = 1 - u - v;    return t;}//找到p点在圆上的的法向量，tID为spheres数组中的标号point findSphereNormal(point p, int tID){    point n;    // based on the equation    n.x = (p.x - spheres[tID].position[0]) / spheres[tID].radius;    n.y = (p.y - spheres[tID].position[1]) / spheres[tID].radius;    n.z = (p.z - spheres[tID].position[2]) / spheres[tID].radius;    return n;}//三角形的线性插值,如果ID为0则表示法线插值,如果ID为1则表示漫反射，如果为2则表示镜面反射point chazhi(Triangle triangle, isIn iO, int ID){    point P;    if (ID == 0)    {        P.x = iO.bary[0] * triangle.v[0].normal[0]            + iO.bary[1] * triangle.v[1].normal[1]            + iO.bary[2] * triangle.v[2].normal[2];        P.y = iO.bary[0] * triangle.v[0].normal[1]            + iO.bary[1] * triangle.v[1].normal[1]            + iO.bary[2] * triangle.v[2].normal[1];        P.z = iO.bary[0] * triangle.v[0].normal[2]            + iO.bary[1] * triangle.v[1].normal[2]            + iO.bary[2] * triangle.v[2].normal[2];    }    else if (ID == 1)    {        P.x = iO.bary[0] * triangle.v[0].color_diffuse[0]            + iO.bary[1] * triangle.v[1].color_diffuse[0]            + iO.bary[2] * triangle.v[2].color_diffuse[0];        P.y = iO.bary[0] * triangle.v[0].color_diffuse[1]            + iO.bary[1] * triangle.v[1].color_diffuse[1]            + iO.bary[2] * triangle.v[2].color_diffuse[1];        P.z = iO.bary[0] * triangle.v[0].color_diffuse[2]            + iO.bary[1] * triangle.v[1].color_diffuse[2]            + iO.bary[2] * triangle.v[2].color_diffuse[2];    }    else if (ID == 2)    {        P.x = iO.bary[0] * triangle.v[0].color_specular[0]            + iO.bary[1] * triangle.v[1].color_specular[0]            + iO.bary[2] * triangle.v[2].color_specular[0];        P.y = iO.bary[0] * triangle.v[0].color_specular[1]            + iO.bary[1] * triangle.v[1].color_specular[1]            + iO.bary[2] * triangle.v[2].color_specular[1];        P.z = iO.bary[0] * triangle.v[0].color_specular[2]            + iO.bary[1] * triangle.v[1].color_specular[2]            + iO.bary[2] * triangle.v[2].color_specular[2];    }    return P;}//公式模型I_spec = k_z * I_l(V • ((2N • L)N - L))^n_s//其中R = (2N • L)N - Lpoint phong(point p, int id, int Obj, isIn iO, Light light, point camera){    point n, l, v, r, kd, ks;    point po;    double lDotN, rDotV, n_s;    //用point表示light的位置    l.x = light.position[0];    l.y = light.position[1];    l.z = light.position[2];    //l = l - p;    //入射光线    l = unitize(minusPoint(l, p));    //v = camera - p;    //观察者到p点的射线    v = unitize(minusPoint(camera, p));    if (Obj == 1)    {        n = findSphereNormal(p, id);        kd.x = spheres[id].color_diffuse[0];        kd.y = spheres[id].color_diffuse[1];        kd.z = spheres[id].color_diffuse[2];        ks.x = spheres[id].color_specular[0];        ks.y = spheres[id].color_specular[1];        ks.z = spheres[id].color_specular[2];        n_s = spheres[id].shininess;    }    else        if (Obj == 2)        {            n = unitize(chazhi(triangles[id], iO, 0));            kd = chazhi(triangles[id], iO, 1);            ks = chazhi(triangles[id], iO, 2);            n_s = iO.bary[0] * triangles[id].v[0].shininess                + iO.bary[1] * triangles[id].v[1].shininess                + iO.bary[2] * triangles[id].v[2].shininess;        }    lDotN = dot(l, n);    if (lDotN<0)        lDotN = 0;    else if (lDotN>1.f)        lDotN = 1.f;    //R = (2N • L)N - L    r.x = 2 * lDotN*n.x - l.x;    r.y = 2 * lDotN*n.y - l.y;    r.z = 2 * lDotN*n.z - l.z;    rDotV = dot(r, v);    if (rDotV<0)        rDotV = 0;    else if (rDotV>1.f)        rDotV = 1.f;    //计算该点的颜色r,g,b    po.x = light.color[0] * ((kd.x)*lDotN + ((ks.x)*pow((rDotV), (n_s)))); // r    po.y = light.color[1] * ((kd.y)*lDotN + ((ks.y)*pow((rDotV), (n_s)))); // g     po.z = light.color[2] * ((kd.z)*lDotN + ((ks.z)*pow((rDotV), (n_s)))); // b    return po;}/*与物体相交*/intexPoint intersectObjects(point p1, point p2, point dir, int flag){    point p, q,raySrc, pixPoint;    intexPoint intxObj;    isIn iO;    iO.in = -1;    double t, t1, t2, tS, tT;    int id, Obj;    q = p1;    t1 = 0;    id = -1;    Obj = -1;    raySrc = p1;    //找到最近的交点    for (int i = 0; i < num_spheres; i++)    {        tS = intersectSphere(spheres[i], raySrc, dir);        if (t1 == 0 && tS > 1e-10)        {            t1 = tS;            id = i;            Obj = 1;        }        else if (tS <= t1 && tS > 1e-10)        {            t1 = tS;            id = i;            Obj = 1;        }    }    for (int i = 0; i < num_triangles; i++)    {        tT = intersectTriangle(triangles[i], raySrc, dir, &iO);        p = caluPoint(raySrc, dir, tT); //找到交点                                       //iO = isInTest(triangles[i], p); //判断p点是否在三角形内        if (iO.in == 1)        {            if (t1 == 0 && tT > 1e-5)            {                t1 = tT;                id = i;                Obj = 2;                if (flag == 0)                    q = p;                intxObj.iO.bary[0] = iO.bary[0];                intxObj.iO.bary[1] = iO.bary[1];                intxObj.iO.bary[2] = iO.bary[2];            }            else if (tT<t1 && tT>1e-5)            {                t1 = tT;                id = i;                Obj = 2;                if (flag == 0)                    q = p;                intxObj.iO.bary[0] = iO.bary[0];                intxObj.iO.bary[1] = iO.bary[1];                intxObj.iO.bary[2] = iO.bary[2];            }        }    }    if (flag == 1)    {        //如果为1则计算从light到p点的距离t2        if (dir.x != 0)        {            t2 = (p2.x - raySrc.x) / dir.x;        }        else if (dir.y != 0)        {            t2 = (p2.y - raySrc.y) / dir.y;        }        else if (dir.z != 0)        {            t2 = (p2.z - raySrc.z) / dir.z;        }        else t2 = 0;        //t2和t1进行比较，如果t1小于t2则说明没有物体挡住光线         if (t1 >= t2)        {            Obj = -1;            id = -1;        }    }    else if ((t1 >= 0) && (Obj == 1))        q = caluPoint(raySrc, dir, t1);    intxObj.p = q;    intxObj.t = t1;    intxObj.tID = id;    intxObj.tObj = Obj;    return intxObj;}point findColor(int x, int y){    //point p, q, dir, light, lightS;    //point black, pixColor, temp, tempN;    //intexPoint intxObj, intxFlag;    point black, pixColor, p;    black.x = 0.0;    black.y = 0.0;    black.z = 0.0;    pixColor = black;    //将像素点转换为世界坐标    p.x = (((double)x / (double)WIDTH) * 2 * xMax) - xMax;    p.y = (((double)y / (double)HEIGHT) * 2 * yMax) - yMax;    p.z = -1;    point dir1, p1 = p;    dir1 = minusPoint(p, cam);    dir1 = unitize(dir1);    pixColor = Render(p, dir1);    if (pixColor.x > 1) pixColor.x = 1.f;    if (pixColor.y > 1) pixColor.y = 1.f;    if (pixColor.z > 1) pixColor.z = 1.f;    return pixColor;}//迭代渲染point Render(point p, point dir){    Steps++;    point blackColor, pixColor, q, light, dir1, temp, temp1;    point reflect_ray;    intexPoint intxObj, intxFlag;    blackColor.x = 0.0;    blackColor.y = 0.0;    blackColor.z = 0.0;    pixColor = blackColor;    if (Steps > MaxStep)    {        Steps = 0;        return blackColor;    }    point p1 = p;    intxObj = intersectObjects(p, p1, dir, 0);    //如果和一个物体有交点        if (intxObj.tID != -1)        {            q = intxObj.p;            reflect_ray = reflect(intxObj, dir);            pixColor.x += ambient_light[0];            pixColor.y += ambient_light[1];            pixColor.z += ambient_light[2];            for (int h = 0; h < num_lights; h++)            {                light.x = lights[h].position[0];                light.y = lights[h].position[1];                light.z = lights[h].position[2];                dir1 = minusPoint(light, q);                dir1 = unitize(dir1);                intxFlag = intersectObjects(q, light, dir1, 1);                //如果没有物体遮挡                if (intxFlag.tID == -1)                {                    //phong模型求出颜色                    temp = phong(q, intxObj.tID, intxObj.tObj, intxObj.iO, lights[h], cam);                    pixColor.x += temp.x;                    pixColor.y += temp.y;                    pixColor.z += temp.z;                }            }            temp1 = Render(q, reflect_ray);            int id = intxObj.tID;            if (intxObj.tObj == 1)            {                pixColor.x += temp1.x * spheres[id].color_specular[0];                pixColor.y += temp1.y * spheres[id].color_specular[1];                pixColor.z += temp1.z * spheres[id].color_specular[2];            }            else            {                point tp = chazhi(triangles[id], intxObj.iO, 2);                pixColor.x += temp1.x * tp.x;                pixColor.y += temp1.y * tp.y;                pixColor.z += temp1.z * tp.z;            }        }        else        {            pixColor = blackColor;            Steps = 0;        }        return pixColor;}//反射的光线的方向point reflect(intexPoint intx, point dir){    point result;    point n;    if (intx.tObj == 1)    {        n = findSphereNormal(intx.p, intx.tID);    }    else    {        n = unitize(chazhi(triangles[intx.tID], intx.iO, 0));    }    dir.x = -dir.x;    dir.y = -dir.y;    dir.z = -dir.z;    double r1 = dot(n, dir);    point n2;    n2.x = n.x * 2 * r1;    n2.y = n.y * 2 * r1;    n2.z = n.z * 2 * r1;    result = n2;    return result;}void drawColor(){    unsigned int x, y;    point pixColor;    for (x = 0; x < WIDTH; x++)    {        for (y = 0; y < HEIGHT; y++)        {            pixColor = findColor(x, y);            plot_pixel_jpeg(x, y, abs(pixColor.x) * 255, abs(pixColor.y) * 255, abs(pixColor.z) * 255);        }    }}//MODIFY THIS FUNCTIONvoid draw_scene(){  unsigned int x,y;  //glPointSize(2.0);  //glBegin(GL_POINTS);  //simple output  for(x=0; x<WIDTH; x++)  {glPointSize(2.0);  glBegin(GL_POINTS);for(y=0;y < HEIGHT;y++){ // plot_pixel(x,y,x%256,y%256,(x+y)%256);        plot_pixel_display(x, y, buffer[HEIGHT - y - 1][x][0], buffer[HEIGHT - y - 1][x][1], buffer[HEIGHT - y - 1][x][2]);}glEnd();glFlush();  }  printf("Done!\n"); fflush(stdout);}void plot_pixel_display(int x,int y,unsigned char r,unsigned char g,unsigned char b){  glColor3f(((double)r)/256.f,((double)g)/256.f,((double)b)/256.f);  glVertex2i(x,y);}void plot_pixel_jpeg(int x,int y,unsigned char r,unsigned char g,unsigned char b){  buffer[HEIGHT-y-1][x][0]=r;  buffer[HEIGHT-y-1][x][1]=g;  buffer[HEIGHT-y-1][x][2]=b;}void plot_pixel(int x,int y,unsigned char r,unsigned char g, unsigned char b){  plot_pixel_display(x,y,r,g,b);  if(mode == MODE_JPEG)  plot_pixel_jpeg(x,y,r,g,b);}/*void save_jpg(){  Pic *in = NULL;  in = pic_alloc(640, 480, 3, NULL);  printf("Saving JPEG file: %s\n", filename);  memcpy(in->pix,buffer,3*WIDTH*HEIGHT);  if (jpeg_write(filename, in))printf("File saved Successfully\n");  elseprintf("Error in Saving\n");  pic_free(in);  }*/void parse_check(char *expected,char *found){  if(stricmp(expected,found)){  char error[100];  printf("Expected '%s ' found '%s '\n",expected,found);  printf("Parse error, abnormal abortion\n");  exit(0);}}void parse_doubles(FILE*file, char *check, double p[3]){  char str[100];  fscanf(file,"%s",str);  parse_check(check,str);  fscanf(file,"%lf %lf %lf",&p[0],&p[1],&p[2]);  printf("%s %lf %lf %lf\n",check,p[0],p[1],p[2]);}void parse_rad(FILE*file,double *r){  char str[100];  fscanf(file,"%s",str);  parse_check("rad:",str);  fscanf(file,"%lf",r);  printf("rad: %f\n",*r);}void parse_shi(FILE*file,double *shi){  char s[100];  fscanf(file,"%s",s);  parse_check("shi:",s);  fscanf(file,"%lf",shi);  printf("shi: %f\n",*shi);}int loadScene(char *argv){  FILE *file = fopen(argv,"r");  int number_of_objects;  char type[50];  int i;  Triangle t;  Sphere s;  Light l;  fscanf(file,"%i",&number_of_objects);  printf("number of objects: %i\n",number_of_objects);  char str[200];  parse_doubles(file,"amb:",ambient_light);  for(i=0;i < number_of_objects;i++){  fscanf(file,"%s\n",type);  printf("%s\n",type);  if(stricmp(type,"triangle")==0)    {      printf("found triangle\n");      int j;      for(j=0;j < 3;j++)    {      parse_doubles(file,"pos:",t.v[j].position);      parse_doubles(file,"nor:",t.v[j].normal);      parse_doubles(file,"dif:",t.v[j].color_diffuse);      parse_doubles(file,"spe:",t.v[j].color_specular);      parse_shi(file,&t.v[j].shininess);    }      if(num_triangles == MAX_TRIANGLES)    {      printf("too many triangles, you should increase MAX_TRIANGLES!\n");      exit(0);    }      triangles[num_triangles++] = t;    }  else if(stricmp(type,"sphere")==0)    {      printf("found sphere\n");      parse_doubles(file,"pos:",s.position);      parse_rad(file,&s.radius);      parse_doubles(file,"dif:",s.color_diffuse);      parse_doubles(file,"spe:",s.color_specular);      parse_shi(file,&s.shininess);      if(num_spheres == MAX_SPHERES)    {      printf("too many spheres, you should increase MAX_SPHERES!\n");      exit(0);    }      spheres[num_spheres++] = s;    }  else if(stricmp(type,"light")==0)    {      printf("found light\n");      parse_doubles(file,"pos:",l.position);      parse_doubles(file,"col:",l.color);      if(num_lights == MAX_LIGHTS)    {      printf("too many lights, you should increase MAX_LIGHTS!\n");      exit(0);    }      lights[num_lights++] = l;    }  else    {      printf("unknown type in scene description:\n%s\n",type);      exit(0);    }}  return 0;}void display(){    cam.x = 0.0;    cam.y = 0.0;    cam.z = 0.0;    glLoadIdentity();    drawColor();    draw_scene();}void init(){  glMatrixMode(GL_PROJECTION);  glOrtho(0,WIDTH,0,HEIGHT,1,-1);  glMatrixMode(GL_MODELVIEW);  glLoadIdentity();  glClearColor(0,0,0,0);  glClear(GL_COLOR_BUFFER_BIT);}void idle(){  //hack to make it only draw once  static int once=0;  if (!once)  {      draw_scene();//    if (mode == MODE_JPEG)//        save_jpg();  }  once=1;}int main (int argc, char ** argv){  if (argc<2 || argc > 3)  {  printf ("usage: %s <scenefile> [jpegname]\n", argv[0]);exit(0);  }  if(argc == 3){  mode = MODE_JPEG;  filename = argv[2];}  else if(argc == 2)mode = MODE_DISPLAY;  glutInit(&argc,argv);  loadScene(argv[1]);  glutInitDisplayMode(GLUT_RGBA | GLUT_SINGLE);  glutInitWindowPosition(0,0);  glutInitWindowSize(WIDTH,HEIGHT);  int window = glutCreateWindow("Ray Tracer");  glutDisplayFunc(display);  glutIdleFunc(idle);  init();  glutMainLoop();}

• 运行结果如图所示