本文主要参照 Ray Tracing: The Next Week，其中只是主要精炼光追相关理论，具体实现可参照原文。

一、长方体

首先，实现一个轴对齐的长方体box，同样继承自hittable，轴对齐长方体有6个面，放到一个hittable_list并在里面，这6个面的合并构成了一个box。

class box: public hittable  {public:box() {}box(const vec3& p0, const vec3& p1, material *ptr);virtual bool hit(const ray& r, float t0, float t1, hit_record& rec) const;virtual bool bounding_box(float t0, float t1, aabb& box) const {box =  aabb(pmin, pmax);return true; }vec3 pmin, pmax;hittable *list_ptr;
};box::box(const vec3& p0, const vec3& p1, material *ptr) {pmin = p0;pmax = p1;hittable **list = new hittable*[6];list[0] = new xy_rect(p0.x(), p1.x(), p0.y(), p1.y(), p1.z(), ptr);list[1] = new flip_normals(new xy_rect(p0.x(), p1.x(), p0.y(), p1.y(), p0.z(), ptr));list[2] = new xz_rect(p0.x(), p1.x(), p0.z(), p1.z(), p1.y(), ptr);list[3] = new flip_normals(new xz_rect(p0.x(), p1.x(), p0.z(), p1.z(), p0.y(), ptr));list[4] = new yz_rect(p0.y(), p1.y(), p0.z(), p1.z(), p1.x(), ptr);list[5] = new flip_normals(new yz_rect(p0.y(), p1.y(), p0.z(), p1.z(), p0.x(), ptr));list_ptr = new hittable_list(list,6);
}bool box::hit(const ray& r, float t0, float t1, hit_record& rec) const {return list_ptr->hit(r, t0, t1, rec);
}

场景中增加两个轴对准长方体：

list[i++] = new box(vec3(130, 0, 65), vec3(295, 165, 230), white);
list[i++] = new box(vec3(265, 0, 295), vec3(430, 330, 460), white);

每个像素采样1000个点：

二、平移

平移是相对的，如果要射线采样一个平移的box，只需要在射线命中检测之前，将射线反向平移。

举个例子：如果要对一个box在x轴上平移2个单位，从(1,1)平移到(3,1)，并不需要老老实实地平移box，只需要在检查射线是否命中之前，将射线反向平移，然后再做真正的射线命中判断。若命中，则将命中点正向平移。

代码中，需要包多一层translate，用反向平移后的射线moved_r来进行命中检测：

class translate : public hittable {public:translate(hittable *p, const vec3& displacement): ptr(p), offset(displacement) {}virtual bool hit(const ray& r, float t_min, float t_max, hit_record& rec) const;virtual bool bounding_box(float t0, float t1, aabb& box) const;hittable *ptr;vec3 offset;
};bool translate::hit(const ray& r, float t_min, float t_max, hit_record& rec) const {ray moved_r(r.origin() - offset, r.direction(), r.time());if (ptr->hit(moved_r, t_min, t_max, rec)) {rec.p += offset;return true;}elsereturn false;
}bool translate::bounding_box(float t0, float t1, aabb& box) const {if (ptr->bounding_box(t0, t1, box)) {box = aabb(box.min() + offset, box.max() + offset);return true;}elsereturn false;
}

三、旋转

接下来实现旋转，旋转的原理跟平移非常相似。下面以绕z轴旋转为例：

绕z轴逆时针旋转θ，则x和y分量的变化公式为：

同理，绕y轴旋转公式为：

绕x轴旋转公式为：

如果反向旋转，则只需要将 θ 替换成 − θ ，同时运用 cos(θ) = cos(−θ) 和 sin(−θ) = − sin(θ) 即可。

如果要旋转射线，则同样要在射线命中检测之前，同时反向旋转射线的起点和方向。若命中，则跟平移类似，变换命中点的坐标，此外，还需要额外对法线执行旋转。绕y轴旋转写成代码如下：

class rotate_y : public hittable {public:rotate_y(hittable *p, float angle);virtual bool hit(const ray& r, float t_min, float t_max, hit_record& rec) const;virtual bool bounding_box(float t0, float t1, aabb& box) const {box = bbox; return hasbox;}hittable *ptr;float sin_theta;float cos_theta;bool hasbox;aabb bbox;
};rotate_y::rotate_y(hittable *p, float angle) : ptr(p) {float radians = (M_PI / 180.) * angle;sin_theta = sin(radians);cos_theta = cos(radians);hasbox = ptr->bounding_box(0, 1, bbox);vec3 min(FLT_MAX, FLT_MAX, FLT_MAX);vec3 max(-FLT_MAX, -FLT_MAX, -FLT_MAX);for (int i = 0; i < 2; i++) {for (int j = 0; j < 2; j++) {for (int k = 0; k < 2; k++) {float x = i*bbox.max().x() + (1-i)*bbox.min().x();float y = j*bbox.max().y() + (1-j)*bbox.min().y();float z = k*bbox.max().z() + (1-k)*bbox.min().z();float newx = cos_theta*x + sin_theta*z;float newz = -sin_theta*x + cos_theta*z;vec3 tester(newx, y, newz);for ( int c = 0; c < 3; c++ ){if ( tester[c] > max[c] )max[c] = tester[c];if ( tester[c] < min[c] )min[c] = tester[c];}}}}bbox = aabb(min, max);
}   bool rotate_y::hit(const ray& r, float t_min, float t_max, hit_record& rec) const {vec3 origin = r.origin();vec3 direction = r.direction();origin[0] = cos_theta*r.origin()[0] - sin_theta*r.origin()[2];origin[2] =  sin_theta*r.origin()[0] + cos_theta*r.origin()[2];direction[0] = cos_theta*r.direction()[0] - sin_theta*r.direction()[2];direction[2] = sin_theta*r.direction()[0] + cos_theta*r.direction()[2];ray rotated_r(origin, direction, r.time());if (ptr->hit(rotated_r, t_min, t_max, rec)) {vec3 p = rec.p;vec3 normal = rec.normal;p[0] = cos_theta*rec.p[0] + sin_theta*rec.p[2];    //命中点坐标需要旋转p[2] = -sin_theta*rec.p[0] + cos_theta*rec.p[2];normal[0] = cos_theta*rec.normal[0] + sin_theta*rec.normal[2];   //命中点法线也要旋转normal[2] = -sin_theta*rec.normal[0] + cos_theta*rec.normal[2];rec.p = p;rec.normal = normal;return true;}else return false;
}

四、旋转与平移

在场景中，应用刚刚实现的平移和变换：

 hittable *box1 = new box(vec3(0,0,0), vec3(165,165,165), white);hittable *box2 = new box(vec3(0,0,0), vec3(165,330,165), white);list[i++] = new translate(new rotate_y(box1, -18), vec3(130,0,65));list[i++] = new translate(new rotate_y(box2, 15), vec3(265,0,295));

注意：上述旋转是对物体的局部坐标的旋转，要等局部变换执行完之后才平移到世界坐标。（也就是说，旋转和平移的顺序不能搞反，作者没有提到这个潜规则，特此补充）

平移和旋转的效果如下（每个像素采样500个点）：

完整代码如下：

#include "imgui.h"
#include "imgui_impl_glfw.h"
#include "imgui_impl_opengl.h"
#include <stdio.h>
//#include <sys/time.h> // for gettimeofday()
#include <ctime>
//#include <unistd.h>
#include "vec3.h"
#include "draw.h"
#include <cstdlib>
#include <thread>
#include <fstream>
#include <vector>
#include <ctime>
#define STB_IMAGE_IMPLEMENTATION
#include "stb_image.h"//#include <sys/time.h>
#include<string>
#ifdef __APPLE__
#define GL_SILENCE_DEPRECATION
#endif
#include <GLFW/glfw3.h>#if defined(_MSC_VER) && (_MSC_VER >= 1900) && !defined(IMGUI_DISABLE_WIN32_FUNCTIONS)
#pragma comment(lib, "legacy_stdio_definitions")
#endifstatic void glfw_error_callback(int error, const char *description)
{fprintf(stderr, "Glfw Error %d: %s\n", error, description);
}using namespace std;long curTime;
long totTime;
float timeRemaining;//全局变量ImVec4 clear_color = ImVec4(0.0f, 0.0f, 0.00f, 1.00f);
float progressDone = 0.0f, progressDir = 1.0f;
bool gRayTracingBegin = false;int numPixelTotal;
int numThread = 5;
int numPixelRendered = 0;
int doneRecord = 0;
int framebufferInited = false;
int gFrameFinished = false;int *lastFrameBuffer;int gFov = 40;//vec3 lookfrom(22, 2, 3);
//vec3 lookat(0, 2.5, 0);
vec3 lookfrom(278, 278, -800);
vec3 lookat(278, 278, 0);
float dist_to_focus = 10.0;
float aperture = 0.0;
float M_PI = 3.1415926;static int speedFactor = 1;#pragma region Rayclass ray
{public:vec3 A; //起点vec3 B; //方向float _time;ray() {}ray(const vec3 &a, const vec3 &b, float ti = 0.0f){A = a;B = b;_time = ti;}float time() const { return _time; }vec3 origin() const { return A; }vec3 direction() const { return B; }vec3 point_at_parameter(float t) const { return A + t * B; } //终点的坐标
};#pragma endregion#pragma region BVHinline float ffmin(float a, float b) { return a < b ? a : b; }
inline float ffmax(float a, float b) { return a > b ? a : b; }class aabb {public:vec3 _min; //左下角顶点vec3 _max; //右上角顶点aabb() {}aabb(const vec3& a, const vec3& b) { _min = a; _max = b; }vec3 min() const { return _min; }vec3 max() const { return _max; }//判断射线是否在t区间bool hit(const ray &r, float tmin, float tmax) const{for (int a = 0; a < 3; a++){float invD = 1.0f / r.direction()[a];float t0 = (min()[a] - r.origin()[a]) * invD;float t1 = (max()[a] - r.origin()[a]) * invD;if (invD < 0.0f)std::swap(t0, t1);tmax = t1 < tmax ? t1 : tmax;   //F为两者终点的最小值tmin = t0 > tmin ? t0 : tmin;   //f为两者起点的最大值if (tmax <= tmin)       //F <= freturn false;}return true;}
};//计算2个box的包围盒
aabb surrounding_box(aabb box0, aabb box1)
{vec3 small(ffmin(box0.min().x(), box1.min().x()),ffmin(box0.min().y(), box1.min().y()),ffmin(box0.min().z(), box1.min().z()));vec3 big(ffmax(box0.max().x(), box1.max().x()),ffmax(box0.max().y(), box1.max().y()),ffmax(box0.max().z(), box1.max().z()));return aabb(small, big);
}#pragma endregion#pragma region objstruct hit_record;class material
{public://r_in为入射光线, scattered为散射光线, attenuation 意思为衰减量，实际为各通道的反射率virtual bool scatter(const ray &r_in, const hit_record &rec, vec3 &attenuation, ray &scattered) const = 0;virtual vec3 emitted(float u, float v, const vec3& p) const {return vec3(0, 0, 0);}
};class texture {public://返回一个三通道的颜色值，p为命中终点坐标virtual vec3 value(float u, float v, const vec3& p) const = 0;
};class constant_texture : public texture {public:vec3 color;constant_texture() { }constant_texture(vec3 c) : color(c) { }//返回一个三通道的colorvirtual vec3 value(float u, float v, const vec3& p) const {return color;}
};//棋盘纹理
class checker_texture : public texture {public:texture *odd;texture *even;checker_texture() { }checker_texture(texture *t0, texture *t1) : even(t0), odd(t1) { }virtual vec3 value(float u, float v, const vec3& p) const {float sines = sin(10 * p.x())*sin(10 * p.y())*sin(10 * p.z());if (sines < 0)return odd->value(u, v, p);elsereturn even->value(u, v, p);}
};//记录命中信息
struct hit_record
{float t;     //命中射线的长度vec3 p;      //命中终点坐标vec3 normal; //命中点的法向量material *mat_ptr; //newfloat u = 1;float v = 1;
};#define pi 3.1415926//物体的虚基类
class hittable
{public:virtual bool hit(const ray &r, float t_min, float t_max, hit_record &rec) const = 0;virtual bool bounding_box(float t0, float t1, aabb& box) const = 0;
};#pragma endregion#pragma region uvclass image_texture : public texture
{public:unsigned char* data;int nx, ny;image_texture() {}image_texture(unsigned char* pixels, int A, int B) : data(pixels), nx(A), ny(B) {}//输入u和v，输出对应图片像素的rgb值virtual vec3 value(float u, float v, const vec3 &p) const{int i = int((u)* nx);//求出像素索引int j = int((1 - v)*ny - 0.001f);if (i < 0) i = 0;if (j < 0) j = 0;if (i > nx - 1) i = nx - 1;if (j > ny - 1) j = ny - 1;float r = int(data[3 * i + 3 * nx*j]) / 255.0f;float g = int(data[3 * i + 3 * nx*j + 1]) / 255.0f;float b = int(data[3 * i + 3 * nx*j + 2]) / 255.0f;return vec3(r, g, b);}
};#pragma endregion#pragma region bvHint box_x_compare(const void * a, const void * b) {aabb box_left, box_right;hittable *ah = *(hittable**)a;hittable *bh = *(hittable**)b;if (!ah->bounding_box(0, 0, box_left) || !bh->bounding_box(0, 0, box_right))std::cerr << "no bounding box in bvh_node constructor\n";if (box_left.min().x() - box_right.min().x() < 0.0)return -1;elsereturn 1;
}int box_y_compare(const void * a, const void * b) {aabb box_left, box_right;hittable *ah = *(hittable**)a;hittable *bh = *(hittable**)b;if (!ah->bounding_box(0, 0, box_left) || !bh->bounding_box(0, 0, box_right))std::cerr << "no bounding box in bvh_node constructor\n";if (box_left.min().y() - box_right.min().y() < 0.0)return -1;elsereturn 1;
}int box_z_compare(const void * a, const void * b) {aabb box_left, box_right;hittable *ah = *(hittable**)a;hittable *bh = *(hittable**)b;if (!ah->bounding_box(0, 0, box_left) || !bh->bounding_box(0, 0, box_right))std::cerr << "no bounding box in bvh_node constructor\n";if (box_left.min().z() - box_right.min().z() < 0.0)return -1;elsereturn 1;
}class bvh_node : public hittable
{public:bvh_node() {}hittable *left;hittable *right;aabb box;bool bounding_box(float t0, float t1, aabb &b) const{b = box;return true;}bool hit(const ray &r, float t_min, float t_max, hit_record &rec) const{if (box.hit(r, t_min, t_max)){hit_record left_rec, right_rec;bool hit_left = left->hit(r, t_min, t_max, left_rec);bool hit_right = right->hit(r, t_min, t_max, right_rec);if (hit_left && hit_right){if (left_rec.t < right_rec.t)rec = left_rec;elserec = right_rec;return true;}else if (hit_left){rec = left_rec;return true;}else if (hit_right){rec = right_rec;return true;}elsereturn false;}elsereturn false;}bvh_node(hittable **l, int n, float time0, float time1){int axis = int(3 * random_double());if (axis == 0)qsort(l, n, sizeof(hittable *), box_x_compare);else if (axis == 1)qsort(l, n, sizeof(hittable *), box_y_compare);elseqsort(l, n, sizeof(hittable *), box_z_compare);if (n == 1){left = right = l[0];}else if (n == 2){left = l[0];right = l[1];}else{left = new bvh_node(l, n / 2, time0, time1);right = new bvh_node(l + n / 2, n - n / 2, time0, time1);}aabb box_left, box_right;if (!left->bounding_box(time0, time1, box_left) ||!right->bounding_box(time0, time1, box_right)){std::cerr << "no bounding box in bvh_node constructor\n";}box = surrounding_box(box_left, box_right);}
};#pragma endregionvec3 random_in_unit_sphere()
{vec3 p;do{p = 2.0 * vec3(random_double(), random_double(), random_double()) - vec3(1, 1, 1);} while (p.squared_length() >= 1.0);return p;
}void DrawFrame(int *fb)
{glMatrixMode(GL_PROJECTION);glLoadIdentity();glOrtho(0.0, display_w, 0.0, display_h, 0.0, 1.0);glBegin(GL_POINTS);for (int i = 0; i < display_h; i++){int r, g, b;for (int j = 0; j < display_w; j++){Color2RGB(fb[i * display_w + j], r, g, b);glColor3f((float)r / 255, (float)g / 255, (float)b / 255);glVertex3f(j + 20, display_h - i - 300, 0);}}glEnd();
}
//记录进度和时间
void RecordProgressAndTime()
{progressDone = float(numPixelRendered) / (numPixelTotal);// totTime = (GetCurrentTimeMs() - curTime);// timeRemaining = totTime * (1 - progressDone) / progressDone / 1000; //根据过去的平均时间来计算剩余时间 x/t=pTodo/pDone -> x= t*pTodo/pDone = t*(1-pDone) /pDone
}class camera
{public:vec3 origin;vec3 lower_left_corner;vec3 horizontal;vec3 vertical;vec3 u, v, w;float lens_radius;float time0, time1;//lookfrom为相机位置，lookat为观察位置，vup传(0,1,0)，vfov为视野角度，aspect为屏幕宽高比//aperture为光圈大小，focus_dist为相机到观察点的距离camera(vec3 lookfrom, vec3 lookat, vec3 vup, float vfov, float aspect, float aperture, float focus_dist, float t0, float t1){time0 = t0;time1 = t1;lens_radius = aperture / 2;float theta = vfov * M_PI / 180;float half_height = tan(theta / 2);float half_width = aspect * half_height;origin = lookfrom;w = unit_vector(lookfrom - lookat);u = unit_vector(cross(vup, w));v = cross(w, u);lower_left_corner = origin - half_width * focus_dist * u - half_height * focus_dist * v - focus_dist * w;horizontal = 2 * half_width * focus_dist * u;vertical = 2 * half_height * focus_dist * v;}ray get_ray(float s, float t){vec3 rd = lens_radius * random_in_unit_disk();vec3 offset = u * rd.x() + v * rd.y();float time = time0 + random_double() * (time1 - time0);return ray(origin + offset, lower_left_corner + s * horizontal + t * vertical - origin - offset, time);}};//输入命中点p的坐标，输出纹理坐标u,v
void get_sphere_uv(const vec3& p, float& u, float& v) {auto phi = atan2(p.z(), p.x());auto theta = asin(p.y());u = 1 - (phi + pi) / (2 * pi);v = (theta + pi / 2) / pi;
}//aarect.h
class xy_rect : public hittable {public:xy_rect() {}xy_rect(float _x0, float _x1, float _y0, float _y1, float _k, material *mat) : x0(_x0), x1(_x1), y0(_y0), y1(_y1), k(_k), mp(mat) {};virtual bool hit(const ray& r, float t0, float t1, hit_record& rec) const;virtual bool bounding_box(float t0, float t1, aabb& box) const {box = aabb(vec3(x0, y0, k - 0.0001), vec3(x1, y1, k + 0.0001));return true;}material  *mp;float x0, x1, y0, y1, k;
};bool xy_rect::hit(const ray& r, float t0, float t1, hit_record& rec) const {float t = (k - r.origin().z()) / r.direction().z();if (t < t0 || t > t1)        return false;float x = r.origin().x() + t * r.direction().x();float y = r.origin().y() + t * r.direction().y();if (x < x0 || x > x1 || y < y0 || y > y1)         return false;rec.u = (x - x0) / (x1 - x0);rec.v = (y - y0) / (y1 - y0);rec.t = t;rec.mat_ptr = mp;rec.p = r.point_at_parameter(t);rec.normal = vec3(0, 0, 1);   //默认法线为(0,0,1)，但会有潜在的朝向问题return true;
}class xz_rect : public hittable {public:xz_rect() {}xz_rect(float _x0, float _x1, float _z0, float _z1, float _k, material *mat) :x0(_x0), x1(_x1), z0(_z0), z1(_z1), k(_k), mp(mat) {};virtual bool hit(const ray& r, float t_min, float t_max, hit_record& rec) const override;virtual bool bounding_box(float time0, float time1, aabb& output_box) const override {// The bounding box must have non-zero width in each dimension, so pad the Y// dimension a small amount.output_box = aabb(vec3(x0, k - 0.0001, z0), vec3(x1, k + 0.0001, z1));return true;}material  *mp;double x0, x1, z0, z1, k;
};bool xz_rect::hit(const ray& r, float t_min, float t_max, hit_record& rec) const {auto t = (k - r.origin().y()) / r.direction().y();if (t < t_min || t > t_max)return false;auto x = r.origin().x() + t * r.direction().x();auto z = r.origin().z() + t * r.direction().z();if (x < x0 || x > x1 || z < z0 || z > z1)return false;rec.u = (x - x0) / (x1 - x0);rec.v = (z - z0) / (z1 - z0);rec.t = t;rec.normal = vec3(0, 1, 0);rec.mat_ptr = mp;rec.p = r.point_at_parameter(t);return true;
}class yz_rect : public hittable {public:yz_rect(float _y0, float _y1, float _z0, float _z1, float _k,material *mat): y0(_y0), y1(_y1), z0(_z0), z1(_z1), k(_k), mp(mat) {};virtual bool hit(const ray& r, float t_min, float t_max, hit_record& rec) const override;virtual bool bounding_box(float time0, float time1, aabb& output_box) const override {// The bounding box must have non-zero width in each dimension, so pad the X// dimension a small amount.output_box = aabb(vec3(k - 0.0001, y0, z0), vec3(k + 0.0001, y1, z1));return true;}material  *mp;double y0, y1, z0, z1, k;
};bool yz_rect::hit(const ray& r, float t_min, float t_max, hit_record& rec) const {auto t = (k - r.origin().x()) / r.direction().x();if (t < t_min || t > t_max)return false;auto y = r.origin().y() + t * r.direction().y();auto z = r.origin().z() + t * r.direction().z();if (y < y0 || y > y1 || z < z0 || z > z1)return false;rec.u = (y - y0) / (y1 - y0);rec.v = (z - z0) / (z1 - z0);rec.t = t;rec.normal = vec3(1, 0, 0);rec.mat_ptr = mp;rec.p = r.point_at_parameter(t);return true;
}class sphere : public hittable
{public:vec3 center;float radius;material *mat_ptr; /* NEW */sphere() {}sphere(vec3 cen, float r, material *m) : center(cen), radius(r), mat_ptr(m) {}; //new//如果命中了，命中记录保存到recvirtual bool hit(const ray &r, float t_min, float t_max, hit_record &rec) const{vec3 oc = r.origin() - center;float a = dot(r.direction(), r.direction());float b = dot(oc, r.direction());float c = dot(oc, oc) - radius * radius;float discriminant = b * b - a * c;if (discriminant > 0){float temp = (-b - sqrt(discriminant)) / a; //小实数根if (temp < t_max && temp > t_min){rec.t = temp;rec.p = r.point_at_parameter(rec.t);rec.normal = (rec.p - center) / radius;rec.mat_ptr = mat_ptr; /* NEW */vec3 outward_normal = (rec.p - center) / radius;get_sphere_uv(outward_normal, rec.u, rec.v);return true;}temp = (-b + sqrt(discriminant)) / a; //大实数根if (temp < t_max && temp > t_min){rec.t = temp;rec.p = r.point_at_parameter(rec.t);rec.normal = (rec.p - center) / radius;rec.mat_ptr = mat_ptr; /* NEW */vec3 outward_normal = (rec.p - center) / radius;get_sphere_uv(outward_normal, rec.u, rec.v);return true;}}return false;}bool bounding_box(float t0, float t1, aabb &box) const{box = aabb(center - vec3(radius, radius, radius), center + vec3(radius, radius, radius));return true;}
};class moving_sphere : public hittable
{public:vec3 center0, center1;float time0, time1;float radius;material *mat_ptr; /* NEW */vec3 center(float time) const{return center0 + ((time - time0) / (time1 - time0)) * (center1 - center0);}moving_sphere() {}moving_sphere(vec3 cen0, vec3 cen1, double t0, double t1, double r, material *m): center0(cen0), center1(cen1), time0(t0), time1(t1), radius(r), mat_ptr(m){};//如果命中了，命中记录保存到recvirtual bool hit(const ray &r, float t_min, float t_max, hit_record &rec) const{vec3 oc = r.origin() - center(r.time());float a = dot(r.direction(), r.direction());float b = dot(oc, r.direction());float c = dot(oc, oc) - radius * radius;float discriminant = b * b - a * c;if (discriminant > 0){float temp = (-b - sqrt(discriminant)) / a; //小实数根if (temp < t_max && temp > t_min){rec.t = temp;rec.p = r.point_at_parameter(rec.t);rec.normal = (rec.p - center(r.time())) / radius;rec.mat_ptr = mat_ptr; /* NEW */return true;}temp = (-b + sqrt(discriminant)) / a; //大实数根if (temp < t_max && temp > t_min){rec.t = temp;rec.p = r.point_at_parameter(rec.t);rec.normal = (rec.p - center(r.time())) / radius;rec.mat_ptr = mat_ptr; /* NEW */return true;}}return false;}bool bounding_box(float t0, float t1, aabb &box) const{aabb box0(center(t0) - vec3(radius, radius, radius), center(t0) + vec3(radius, radius, radius));aabb box1(center(t1) - vec3(radius, radius, radius), center(t1) + vec3(radius, radius, radius));box = surrounding_box(box0, box1);return true;}
};class hittable_list : public hittable
{public:hittable **list;int list_size;hittable_list() {}hittable_list(hittable **l, int n){list = l;list_size = n;}//如果命中了，命中记录保存到recvirtual bool hit(const ray &r, float t_min, float t_max, hit_record &rec) const{hit_record temp_rec;bool hit_anything = false;double closest_so_far = t_max; //记录目前最近的t值for (int i = 0; i < list_size; i++){if (list[i]->hit(r, t_min, closest_so_far, temp_rec)){hit_anything = true;closest_so_far = temp_rec.t;rec = temp_rec; //只记录打到的最近的球}}return hit_anything;}bool bounding_box(float t0, float t1, aabb &box) const{if (list_size < 1)return false;aabb temp_box;bool first_true = list[0]->bounding_box(t0, t1, temp_box);if (!first_true)return false;elsebox = temp_box;for (int i = 1; i < list_size; i++){if (list[i]->bounding_box(t0, t1, temp_box)){box = surrounding_box(box, temp_box);}elsereturn false;}return true;}
};class flip_normals : public hittable {public:flip_normals(hittable *p) : ptr(p) {}virtual bool hit(const ray& r, float t_min, float t_max, hit_record& rec) const {if (ptr->hit(r, t_min, t_max, rec)) {rec.normal = -rec.normal;return true;}elsereturn false;}virtual bool bounding_box(float t0, float t1, aabb& box) const {return ptr->bounding_box(t0, t1, box);}hittable *ptr;
};class box : public hittable {public:box() {}box(const vec3& p0, const vec3& p1, material *ptr);virtual bool hit(const ray& r, float t0, float t1, hit_record& rec) const;virtual bool bounding_box(float t0, float t1, aabb& box) const {box = aabb(pmin, pmax);return true;}vec3 pmin, pmax;hittable *list_ptr;
};box::box(const vec3& p0, const vec3& p1, material *ptr) {pmin = p0;pmax = p1;hittable **list = new hittable*[6];list[0] = new xy_rect(p0.x(), p1.x(), p0.y(), p1.y(), p1.z(), ptr);list[1] = new flip_normals(new xy_rect(p0.x(), p1.x(), p0.y(), p1.y(), p0.z(), ptr));list[2] = new xz_rect(p0.x(), p1.x(), p0.z(), p1.z(), p1.y(), ptr);list[3] = new flip_normals(new xz_rect(p0.x(), p1.x(), p0.z(), p1.z(), p0.y(), ptr));list[4] = new yz_rect(p0.y(), p1.y(), p0.z(), p1.z(), p1.x(), ptr);list[5] = new flip_normals(new yz_rect(p0.y(), p1.y(), p0.z(), p1.z(), p0.x(), ptr));list_ptr = new hittable_list(list, 6);
}bool box::hit(const ray& r, float t0, float t1, hit_record& rec) const {return list_ptr->hit(r, t0, t1, rec);
}class translate : public hittable {public:translate(hittable *p, const vec3& displacement): ptr(p), offset(displacement) {}virtual bool hit(const ray& r, float t_min, float t_max, hit_record& rec) const;virtual bool bounding_box(float t0, float t1, aabb& box) const;hittable *ptr;vec3 offset;
};bool translate::hit(const ray& r, float t_min, float t_max, hit_record& rec) const {ray moved_r(r.origin() - offset, r.direction(), r.time());if (ptr->hit(moved_r, t_min, t_max, rec)) {rec.p += offset;return true;}elsereturn false;
}bool translate::bounding_box(float t0, float t1, aabb& box) const {if (ptr->bounding_box(t0, t1, box)) {box = aabb(box.min() + offset, box.max() + offset);return true;}elsereturn false;
}class rotate_y : public hittable {public:rotate_y(hittable *p, float angle);virtual bool hit(const ray& r, float t_min, float t_max, hit_record& rec) const;virtual bool bounding_box(float t0, float t1, aabb& box) const {box = bbox; return hasbox;}hittable *ptr;float sin_theta;float cos_theta;bool hasbox;aabb bbox;
};rotate_y::rotate_y(hittable *p, float angle) : ptr(p) {float radians = (M_PI / 180.) * angle;sin_theta = sin(radians);cos_theta = cos(radians);hasbox = ptr->bounding_box(0, 1, bbox);vec3 min(FLT_MAX, FLT_MAX, FLT_MAX);vec3 max(-FLT_MAX, -FLT_MAX, -FLT_MAX);for (int i = 0; i < 2; i++) {for (int j = 0; j < 2; j++) {for (int k = 0; k < 2; k++) {float x = i * bbox.max().x() + (1 - i)*bbox.min().x();float y = j * bbox.max().y() + (1 - j)*bbox.min().y();float z = k * bbox.max().z() + (1 - k)*bbox.min().z();float newx = cos_theta * x + sin_theta * z;float newz = -sin_theta * x + cos_theta * z;vec3 tester(newx, y, newz);for (int c = 0; c < 3; c++){if (tester[c] > max[c])max[c] = tester[c];if (tester[c] < min[c])min[c] = tester[c];}}}}bbox = aabb(min, max);
}bool rotate_y::hit(const ray& r, float t_min, float t_max, hit_record& rec) const {vec3 origin = r.origin();vec3 direction = r.direction();origin[0] = cos_theta * r.origin()[0] - sin_theta * r.origin()[2];origin[2] = sin_theta * r.origin()[0] + cos_theta * r.origin()[2];direction[0] = cos_theta * r.direction()[0] - sin_theta * r.direction()[2];direction[2] = sin_theta * r.direction()[0] + cos_theta * r.direction()[2];ray rotated_r(origin, direction, r.time());if (ptr->hit(rotated_r, t_min, t_max, rec)) {vec3 p = rec.p;vec3 normal = rec.normal;p[0] = cos_theta * rec.p[0] + sin_theta * rec.p[2];    //命中点坐标需要旋转p[2] = -sin_theta * rec.p[0] + cos_theta * rec.p[2];normal[0] = cos_theta * rec.normal[0] + sin_theta * rec.normal[2];   //命中点法线也要旋转normal[2] = -sin_theta * rec.normal[0] + cos_theta * rec.normal[2];rec.p = p;rec.normal = normal;return true;}elsereturn false;
}class lambertian : public material
{public:texture *albedo; //反射率lambertian(texture *a) : albedo(a) {}virtual bool scatter(const ray &r_in, const hit_record &rec, vec3 &attenuation, ray &scattered) const{vec3 s_world = rec.p + rec.normal + random_in_unit_sphere();scattered = ray(rec.p, s_world - rec.p, r_in.time()); //scattered为散射光线attenuation = albedo->value(rec.u, rec.v, rec.p);     //注意这是各通道的反射率！//attenuation = vec3(1, 0, 0);     //注意这是各通道的反射率！return true;}
};class metal : public material
{public:vec3 albedo;float fuzz;metal(const vec3 &a, float f) : albedo(a){fuzz = f < 1 ? f : 1;}virtual bool scatter(const ray &r_in, const hit_record &rec, vec3 &attenuation, ray &scattered) const{vec3 v = unit_vector(r_in.direction());vec3 n = rec.normal;vec3 p = rec.p;vec3 r = reflect(v, n);vec3 offset = fuzz * random_in_unit_sphere();scattered = ray(p, r + offset);attenuation = albedo;return (dot(scattered.direction(), rec.normal) > 0);}
};class dielectric : public material
{public:dielectric(float ri) : ref_idx(ri) {} //n2/n1virtual bool scatter(const ray &r_in, const hit_record &rec, vec3 &attenuation, ray &scattered) const{vec3 outward_normal;vec3 reflected = reflect(r_in.direction(), rec.normal);float ni_over_nt;attenuation = vec3(1.0, 1.0, 1.0);vec3 refracted;float reflect_prob; //反射概率float cosine;if (dot(r_in.direction(), rec.normal) > 0) //从里到外，即入射向量在法向量另外一侧的情况{outward_normal = -rec.normal;   //对法向量取反ni_over_nt = ref_idx;cosine = ref_idx * dot(r_in.direction(), rec.normal) / r_in.direction().length();//不知道为什么这里要乘一个ref_idx}else    //从外到里，即入射向量在法向量同一侧{outward_normal = rec.normal;    //法向量不变ni_over_nt = 1.0 / ref_idx;cosine = -dot(r_in.direction(), rec.normal) / r_in.direction().length();}if (refract(r_in.direction(), outward_normal, ni_over_nt, refracted)){reflect_prob = schlick(cosine, ref_idx);}else    //若无折射，则全反射{reflect_prob = 1.0;}if (random_double() < reflect_prob){scattered = ray(rec.p, reflected);}else{scattered = ray(rec.p, refracted);}return true;}float ref_idx;
};//material.h
class diffuse_light : public material {public:texture *emit;diffuse_light(texture *a) : emit(a) {}virtual bool scatter(const ray& r_in, const hit_record& rec, vec3& attenuation, ray& scattered) const {return false;}virtual vec3 emitted(float u, float v, const vec3& p) const {return emit->value(u, v, p);}
};//发射一条射线，并采样该射线最终输出到屏幕的颜色值值
//vec3 color(const ray &r, hittable *world, int depth) {//  hit_record rec;
//  if (world->hit(r, 0.001, FLT_MAX, rec)) //射线命中物体
//  {//      ray scattered; //散射光线
//      vec3 attenuation; //其实是反射率！
//      if (depth < 66 && rec.mat_ptr->scatter(r, rec, attenuation, scattered))
//      {//          return attenuation * color(scattered, world, depth + 1);
//      }
//      else
//      {//          return vec3(0, 0, 0);
//      }
//  }
//  else
//  {//      vec3 unit_direction = unit_vector(r.direction());
//      float t = 0.5 * (unit_direction.y() + 1.0);
//      return (1.0 - t) * vec3(1.0, 1.0, 1.0) + t * vec3(0.5, 0.7, 1.0);
//  }
//}vec3 color(const ray& r, hittable *world, int depth) {hit_record rec;if (world->hit(r, 0.001, FLT_MAX, rec)) {ray scattered;vec3 attenuation;vec3 emitted = rec.mat_ptr->emitted(rec.u, rec.v, rec.p);if (depth < 50 && rec.mat_ptr->scatter(r, rec, attenuation, scattered))return emitted + attenuation * color(scattered, world, depth + 1);elsereturn emitted;}elsereturn vec3(0, 0, 0);
}class perlin {public:float noise(const vec3& p) const {int i = (int)floor(p.x()) & 255;int j = (int)floor(p.y()) & 255;int k = (int)floor(p.z()) & 255;// return ranfloat[perm_x[i] ^ perm_y[j] ^ perm_z[k]];return get_ranfloat(i, j, k);}float get_ranfloat(int x, int y, int z) const {return ranfloat[perm_x[x & 255] ^ perm_y[y & 255] ^ perm_z[z & 255]];}static float *ranfloat;static int *perm_x;static int *perm_y;static int *perm_z;
};static float* perlin_generate() {float * p = new float[256];for (int i = 0; i < 256; ++i)p[i] = random_double();return p;
}void permute(int *p, int n) {for (int i = n - 1; i > 0; i--) {int target = int(random_double()*(i + 1));int tmp = p[i];p[i] = p[target];p[target] = tmp;}return;
}static int* perlin_generate_perm() {int * p = new int[256];for (int i = 0; i < 256; i++)p[i] = i;permute(p, 256);return p;
}float *perlin::ranfloat = perlin_generate();
int *perlin::perm_x = perlin_generate_perm();
int *perlin::perm_y = perlin_generate_perm();
int *perlin::perm_z = perlin_generate_perm();class noise_texture : public texture {public:noise_texture() {}virtual vec3 value(float u, float v, const vec3& p) const {return vec3(1, 1, 1) * noise.noise(p);}perlin noise;
};//hittable *random_scene() {//  int n = 500;
//  texture *pertext = new noise_texture();
//  hittable **list = new hittable*[n + 1];
//  list[0] = new sphere(vec3(0, -1000, 0), 1000, new lambertian(new constant_texture(vec3(0.5, 0.5, 0.5))));
//  texture *checker = new checker_texture(new constant_texture(vec3(0.2, 0.3, 0.1)), new constant_texture(vec3(0.9, 0.9, 0.9)));
//  list[0] = new sphere(vec3(0, -1000, 0), 1000, new lambertian(checker));
//  int i = 1;
//  //list[0] = new sphere(vec3(0, -1000, 0), 1000, new lambertian(pertext));
//  //list[i++] = new sphere(vec3(5, 1, 0), 1.0, new lambertian(pertext));
//  for (int a = -11; a < 11; a++) {//      for (int b = -11; b < 11; b++) {//          float choose_mat = random_double();
//          vec3 center(a + 0.9*random_double(), 0.2, b + 0.9*random_double());
//          if ((center - vec3(4, 0.2, 0)).length() > 0.9) {//              if (choose_mat < 0.8) {  // diffuse
//                  if (b % 2 == 0) //动态模糊的球体
//                  {//                      auto center2 = center + vec3(0, random_double(), 0);
//                      list[i++] = new moving_sphere(center, center2, 0.0, 1.0, 0.2,
//                          new lambertian(new constant_texture(vec3(random_double()*random_double(),
//                              random_double()*random_double(),
//                              random_double()*random_double()))
//                          )
//                      );
//                  }
//                  else
//                  {//                      list[i++] = new sphere(center, 0.2,
//                          new lambertian(new constant_texture(vec3(random_double()*random_double(),
//                              random_double()*random_double(),
//                              random_double()*random_double()))
//                          )
//                      );
//                  }
//              }
//              else if (choose_mat < 0.95) { // metal
//                  list[i++] = new sphere(center, 0.2,
//                      new metal(vec3(0.5*(1 + random_double()),
//                          0.5*(1 + random_double()),
//                          0.5*(1 + random_double())),
//                          0.5*random_double()));
//              }
//              else {  // glass
//                  list[i++] = new sphere(center, 0.2, new dielectric(1.5));
//              }
//          }
//      }
//  }
//
//  int nx, ny, nn;
//  unsigned char *earthmapjpg = stbi_load("F://earthmap.jpg", &nx, &ny, &nn, 0);
//  material *earthmapJpg = new lambertian(new image_texture(earthmapjpg, nx, ny));
//  unsigned char *Cristiano = stbi_load("F://Cristiano.jpg", &nx, &ny, &nn, 0);
//  material *CristianoJpg = new lambertian(new image_texture(Cristiano, nx, ny));
//  unsigned char *earthmappng = stbi_load("F://earthmap.png", &nx, &ny, &nn, 0);
//  material *earthmapPng = new lambertian(new image_texture(earthmappng, nx, ny));
//
//  list[i++] = new sphere(vec3(5, 1, 0), 1.0, earthmapJpg);
//  list[i++] = new sphere(vec3(0, 1, 0), 1.0, CristianoJpg);
//  list[i++] = new sphere(vec3(-5, 1, 0), 1.0, earthmapPng);
//  list[i++] = new sphere(vec3(5, 0.35, 4), 0.35, new dielectric(1.2));
//  list[i++] = new sphere(vec3(0, 0.4, 3), 0.4, new lambertian(new constant_texture(vec3(0.0, 1.0, 1.0))));
//  list[i++] = new sphere(vec3(-6, 0.5, 2), 0.5, new metal(vec3(0.8, 0.8, 0.8), 0.1));
//
//  //return new hittable_list(list, i);
//  return new bvh_node(list, i, 0.0, 1.0);
//}hittable *random_scene1() {texture *pertext = new noise_texture();hittable **list = new hittable*[4];int i = 0;list[i++] = new sphere(vec3(0, -1000, 0), 1000, new lambertian(new constant_texture(vec3(0.7, 0.5, 0.3))));int nx, ny, nn;unsigned char *Cristiano = stbi_load("F://Cristiano.jpg", &nx, &ny, &nn, 0);material *CristianoJpg = new lambertian(new image_texture(Cristiano, nx, ny));//list[i++] = new sphere(vec3(0, 2, 0), 2, new lambertian(pertext));list[i++] = new sphere(vec3(0, 2, 0), 2, CristianoJpg);list[i++] = new sphere(vec3(0, 6, 0), 1, new diffuse_light(new constant_texture(vec3(4, 4, 4))));list[i++] = new xy_rect(3, 5, 1, 3, -2, new diffuse_light(new constant_texture(vec3(4, 4, 4))));//return new hittable_list(list, i);return new bvh_node(list, i, 0.0, 1.0);
}hittable *random_scene() {//cam.SetCamParams(vec3(278, 278, -800), vec3(278, 278, 0), vec3(0, 1, 0), 40, float(nx) / float(ny), 0.0, 10.0, 0.0, 1.0);hittable **list = new hittable*[8];int i = 0;material *red = new lambertian(new constant_texture(vec3(0.65, 0.05, 0.05)));material *white = new lambertian(new constant_texture(vec3(0.73, 0.73, 0.73)));material *green = new lambertian(new constant_texture(vec3(0.12, 0.45, 0.15)));material *light = new diffuse_light(new constant_texture(vec3(15, 15, 15)));list[i++] = new flip_normals(new yz_rect(0, 555, 0, 555, 555, green));list[i++] = new yz_rect(0, 555, 0, 555, 0, red);list[i++] = new xz_rect(213, 343, 227, 332, 554, light);list[i++] = new flip_normals(new xz_rect(0, 555, 0, 555, 555, white));list[i++] = new xz_rect(0, 555, 0, 555, 0, white);list[i++] = new flip_normals(new xy_rect(0, 555, 0, 555, 555, white));//list[i++] = new box(vec3(130, 0, 65), vec3(295, 165, 230), white);//list[i++] = new box(vec3(265, 0, 295), vec3(430, 330, 460), white);hittable *box1 = new box(vec3(0, 0, 0), vec3(165, 165, 165), white);hittable *box2 = new box(vec3(0, 0, 0), vec3(165, 330, 165), white);list[i++] = new translate(new rotate_y(box1, -18), vec3(130, 0, 65));list[i++] = new translate(new rotate_y(box2, 15), vec3(265, 0, 295));//int nn;//unsigned char *Cristiano = stbi_load("F://Cristiano.jpg", &nx, &ny, &nn, 0);//material *CristianoJpg = new lambertian(new image_texture(Cristiano, nx, ny));list[i++] = new sphere(vec3(0, 2, 0), 2, new lambertian(pertext));//list[i++] = new sphere(vec3(200, 130, 330), 130, CristianoJpg);return new bvh_node(list, i, 0.0, 1.0);
}hittable *world;void RayTracingInOneThread(int k)
{float R = cos(M_PI / 4);// list[0] = new sphere(vec3(-R, 0, -1), R, new lambertian(vec3(0, 0, 1)));// list[1] = new sphere(vec3(R, 0, -1), R, new lambertian(vec3(1, 0, 0)));// world = new hittable_list(list, 2);// list[0] = new sphere(vec3(0, 0, -1), 0.5, new lambertian(vec3(0.8, 0.3, 0.3)));// list[1] = new sphere(vec3(0, -100.5, -1), 100, new lambertian(vec3(0.1/2, 0.2/2, 0.5/2)));// list[2] = new sphere(vec3(1, 0, -1), 0.5, new metal(vec3(0.8, 0.6, 0.2), 0.3));    // list[3] = new sphere(vec3(-1, 0, -1), 0.5, new dielectric(1.5));// world = new hittable_list(list, 4); // camera cam(vec3(-2, 2, 1), vec3(-0.5, 0, -1), vec3(0, 1, 0), gFov, float(nx) / float(ny));camera cam(lookfrom, lookat, vec3(0, 1, 0), 40, float(nx) / float(ny), aperture, dist_to_focus, 0, 1.0);for (int j = ny - k; j >= 0; j -= numThread){for (int i = 0; i < nx; i++){RecordProgressAndTime();vec3 col(0, 0, 0);for (int s = 0; s < ns; s++){float u = float(i + random_double()) / float(nx);float v = float(j + random_double()) / float(ny);ray r = cam.get_ray(u, v);col += color(r, world, 0);}col /= float(ns);col = vec3(sqrt(col[0]), sqrt(col[1]), sqrt(col[2]));int ir = int(255.99 * col[0]);int ig = int(255.99 * col[1]);int ib = int(255.99 * col[2]);DrawPixel(i, j, ir, ig, ib);numPixelRendered++;}}
}void RayTracing()
{nx = 600;ny = 400;ns = 500;// hittable *world = random_scene();world = random_scene();numPixelTotal = nx * ny;while (true){while (!gRayTracingBegin){//wait until begin}// curTime = GetCurrentTimeMs();gFrameFinished = false;if (!framebufferInited){framebuffer = new int[display_w * display_h];lastFrameBuffer = new int[display_w * display_h];for (int i = 0; i < display_h * display_w; i++){lastFrameBuffer[i] = 0;}framebufferInited = true;}numPixelRendered = 0;ofstream outFile("output_" + to_string(nx) + "x" + to_string(ny) + ".ppm");outFile << "P3\n"<< nx << " " << ny << "\n255\n";vector<thread> threads;for (int k = 0; k < numThread; k++){threads.push_back(thread(RayTracingInOneThread, k));}for (auto &thread : threads){thread.join();}gFrameFinished = true;Framebuffer2File(nx, ny, ns, framebuffer, outFile, progressDone);for (int i = 0; i < display_h*display_w; i++){lastFrameBuffer[i] = framebuffer[i];}gRayTracingBegin = false;}return;
}int main(int, char **)
{totTime = 0;
#ifdef __APPLE__glfwWindowHint(GLFW_OPENGL_FORWARD_COMPAT, GL_TRUE);
#endifthread t(RayTracing);// Setup windowglfwSetErrorCallback(glfw_error_callback);if (!glfwInit())return 1;GLFWwindow *window = glfwCreateWindow(1800, 900, "Ray Tracing", NULL, NULL);if (window == NULL)return 1;glfwMakeContextCurrent(window);glfwSwapInterval(1); // Enable vsync// Setup Dear ImGui contextIMGUI_CHECKVERSION();ImGui::CreateContext();ImGuiIO &io = ImGui::GetIO();(void)io;// Setup Dear ImGui styleImGui::StyleColorsDark();// Setup Platform/Renderer bindingsImGui_ImplGlfw_InitForOpenGL(window, true);ImGui_ImplOpenGL2_Init();// Our statebool show_demo_window = true;bool show_another_window = false;// Main loopwhile (!glfwWindowShouldClose(window)){glfwPollEvents();// Start the Dear ImGui frameImGui_ImplOpenGL2_NewFrame();ImGui_ImplGlfw_NewFrame();ImGui::NewFrame();// 1. Show the big demo window (Most of the sample code is in ImGui::ShowDemoWindow()! You can browse its code to learn more about Dear ImGui!).if (show_demo_window)ImGui::ShowDemoWindow(&show_demo_window);// 2. Show a simple window that we create ourselves. We use a Begin/End pair to created a named window.{static float f = 0.0f;static int counter = 0;ImGui::Begin("Ray Tracing"); // Create a window called "Hello, world!" and append into it.if (ImGui::Button("Start")) // Buttons return true when clicked (most widgets return true when edited/activated){gRayTracingBegin = true;}ImGui::ProgressBar(progressDone, ImVec2(0.0f, 0.0f));// ImGui::SameLine(0.0f, ImGui::GetStyle().ItemInnerSpacing.x);ImGui::InputInt(" speed", &speedFactor);// ImGui::SameLine();ImGui::Text("Thread Num: %d ", numThread);ImGui::Text("Image Size:  %d x %d ", nx, ny);ImGui::Text("Camera fov:  %d ", gFov);ImGui::Text("Camera aperture: %.3f ", (float)aperture);ImGui::Text("Camera dist to focus: %.3f ", (float)dist_to_focus);// ImGui::Text("Progress Bar");ImGui::Text("Total time %.3f s", (float)totTime / 1000);ImGui::Text("timeRemaining time %.3f s", timeRemaining);ImGui::End();}// 3. Show another simple window.if (show_another_window){ImGui::Begin("Another Window", &show_another_window); // Pass a pointer to our bool variable (the window will have a closing button that will clear the bool when clicked)ImGui::Text("Hello from another window!");if (ImGui::Button("Close Me"))show_another_window = false;ImGui::End();}ImGui::Render();glfwGetFramebufferSize(window, &display_w, &display_h);glViewport(0, 0, display_w, display_h);glClearColor(0.0f, 0.0f, 0.00f, 1.00f);glClear(GL_COLOR_BUFFER_BIT);if (framebufferInited){if (gFrameFinished){DrawFrame(framebuffer);}else{// DrawFrame(lastFrameBuffer);DrawFrame(framebuffer);}// DrawFrame(framebuffer);}ImGui_ImplOpenGL2_RenderDrawData(ImGui::GetDrawData());glfwMakeContextCurrent(window);glfwSwapBuffers(window);}// CleanupImGui_ImplOpenGL2_Shutdown();ImGui_ImplGlfw_Shutdown();ImGui::DestroyContext();glfwDestroyWindow(window);glfwTerminate();return 0;
}

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【光线追踪系列十三】Cornell Box场景搭建

一、长方体

二、平移

三、旋转

四、旋转与平移

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