Ray Tracing in One Weekend Part1

官方教程：Ray Tracing in One Weekend

参考：【Ray Tracing in One Weekend 超详解】 光线追踪1-1 之美 - 灰信网（软件开发博客聚合） (freesion.com)

任务2 Output an Image及任务3 The vec3 Class

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#include <iostream> #include<fstream> #include<string> #include "v3d.h" using namespace std;   void build_1_1() {     int nx = 200;     int ny = 100;       ofstream file("graph1-1.ppm");//如果window系统可以在ps中打开ppm文件，需要从cout变换输出流为ppm     if (file.is_open())     {         file << "P3\n" << nx << " " << ny << "\n255\n";//这个不能丢，一定要输出到对应的输出流中         for (int j = ny - 1; j >= 0; j--)         {             for (int i = 0; i < nx; i++)             {                 float r = float(i) / float(nx);                 float g = float(j) / float(ny);                 float b = 0;                 int ir = int(255.99 * r);                 int ig = int(255.99 * g);                 int ib = int(255.99 * b);                 string res = to_string(ir) + " " + to_string(ig) + " " + to_string(ib);                 file << res << endl;             }         }         file.close();     } }   void write_color(std::ostream& out, color pixel_color) {     // Write the translated [0,255] value of each color component.     out << static_cast<int>(255.999 * pixel_color.x()) << ' '         << static_cast<int>(255.999 * pixel_color.y()) << ' '         << static_cast<int>(255.999 * pixel_color.z()) << '\n'; }   int main() {     //build_1_1();     const int image_width = 256;     const int image_height = 256;       // Render     ofstream file("graph1-1.ppm");     file << "P3\n" << image_width << ' ' << image_height << "\n255\n";       for (int j = image_height - 1; j >= 0; --j) {         std::cerr << "\rScanlines remaining: " << j << ' ' << std::flush;         for (int i = 0; i < image_width; ++i) {             color pixel_color(double(i) / (image_width - 1), double(j) / (image_height - 1), 0.25);             write_color(file, pixel_color);         }     }       std::cerr << "\nDone.\n"; }