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Add smallpt as an example notebook (#235)
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‎.github/workflows/deploy-github-page.yml

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@@ -72,6 +72,7 @@ jobs:
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--XeusAddon.prefix=${{ env.PREFIX }} \
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--contents README.md \
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--contents notebooks/xeus-cpp-lite-demo.ipynb \
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--contents notebooks/smallpt.ipynb \
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--contents notebooks/images/marie.png \
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--contents notebooks/audio/audio.wav \
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--output-dir dist

‎CMakeLists.txt

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@@ -445,8 +445,9 @@ if(EMSCRIPTEN)
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# TODO: Remove the exported runtime methods
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# after the next xeus release.
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target_link_options(xcpp
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PUBLIC "SHELL: -s USE_SDL=2"
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PUBLIC "SHELL: -s EXPORTED_RUNTIME_METHODS='[\"FS\",\"PATH\",\"LDSO\",\"loadDynamicLibrary\",\"ERRNO_CODES\"]'"
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PUBLIC "SHELL: --preload-file ${SYSROOT_PATH}/include@/include"
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PUBLIC "SHELL: --preload-file ${SYSROOT_PATH}/@/"
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PUBLIC "SHELL: --post-js ${CMAKE_CURRENT_SOURCE_DIR}/wasm_patches/post.js"
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)
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# TODO: Emscripten supports preloading files just once before it generates

‎notebooks/smallpt.ipynb

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{
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"cells": [
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{
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"cell_type": "code",
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"execution_count": 1,
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"id": "72cd5c0c-3a52-43a5-a714-0baee1f7464c",
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"metadata": {
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"trusted": true,
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"vscode": {
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"languageId": "c++"
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}
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},
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"outputs": [],
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"source": [
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"// Adapted from smallpt, a Path Tracer by Kevin Beason, 2008\n",
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"#include <math.h>\n",
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"#include <stdlib.h>\n",
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"#include <vector>\n",
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"\n",
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"struct Vec {\n",
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" double x, y, z; // position, also color (r,g,b)\n",
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" Vec(double x_ = 0, double y_ = 0, double z_ = 0) {\n",
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" x = x_;\n",
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" y = y_;\n",
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" z = z_;\n",
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" }\n",
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" Vec operator+(const Vec &b) const { return Vec(x + b.x, y + b.y, z + b.z); }\n",
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" Vec operator-(const Vec &b) const { return Vec(x - b.x, y - b.y, z - b.z); }\n",
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" Vec operator*(double b) const { return Vec(x * b, y * b, z * b); }\n",
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" Vec mult(const Vec &b) const { return Vec(x * b.x, y * b.y, z * b.z); }\n",
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" Vec &norm() { return *this = *this * (1 / sqrt(x * x + y * y + z * z)); }\n",
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" double dot(const Vec &b) const { return x * b.x + y * b.y + z * b.z; }\n",
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" Vec operator%(Vec &b) { // cross\n",
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" return Vec(y * b.z - z * b.y, z * b.x - x * b.z, x * b.y - y * b.x);\n",
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" }\n",
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"};\n",
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"struct Ray {\n",
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" Vec o, d;\n",
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" Ray(Vec o_, Vec d_) : o(o_), d(d_) {}\n",
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"};\n",
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"enum Refl_t { DIFF, SPEC, REFR }; // material types, used in radiance()\n",
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"struct Sphere {\n",
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" double rad; // radius\n",
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" Vec p, e, c; // position, emission, color\n",
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" Refl_t refl; // reflection type (DIFFuse, SPECular, REFRactive)\n",
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" Sphere(double rad_, Vec p_, Vec e_, Vec c_, Refl_t refl_)\n",
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" : rad(rad_), p(p_), e(e_), c(c_), refl(refl_) {}\n",
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" double intersect(const Ray &r) const { // returns distance, 0 if nohit\n",
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" Vec op = p - r.o; // Solve t^2*d.d + 2*t*(o-p).d + (o-p).(o-p)-R^2 = 0\n",
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" double t, eps = 1e-4, b = op.dot(r.d), det = b * b - op.dot(op) + rad * rad;\n",
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" if (det < 0)\n",
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" return 0;\n",
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" else\n",
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" det = sqrt(det);\n",
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" return (t = b - det) > eps ? t : ((t = b + det) > eps ? t : 0);\n",
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" }\n",
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"};"
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]
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},
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{
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"cell_type": "code",
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"execution_count": 2,
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"id": "acc1ec30-5f0a-446f-a066-3dc3369ed39e",
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"metadata": {
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"trusted": true,
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"vscode": {
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"languageId": "c++"
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}
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},
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"outputs": [],
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"source": [
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"std::vector<Sphere> spheres = {\n",
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" // Scene: radius, position, emission, color, material\n",
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" Sphere(1e5, Vec(1e5 + 1, 40.8, 81.6), Vec(), Vec(.75, .25, .25),\n",
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" DIFF), // Left\n",
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" Sphere(1e5, Vec(-1e5 + 99, 40.8, 81.6), Vec(), Vec(.25, .25, .75),\n",
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" DIFF), // Rght\n",
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" Sphere(1e5, Vec(50, 40.8, 1e5), Vec(), Vec(.75, .75, .75), DIFF), // Back\n",
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" Sphere(1e5, Vec(50, 40.8, -1e5 + 170), Vec(), Vec(), DIFF), // Frnt\n",
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" Sphere(1e5, Vec(50, 1e5, 81.6), Vec(), Vec(.75, .75, .75), DIFF), // Botm\n",
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" Sphere(1e5, Vec(50, -1e5 + 81.6, 81.6), Vec(), Vec(.75, .75, .75),\n",
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" DIFF), // Top\n",
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" Sphere(16.5, Vec(27, 16.5, 47), Vec(), Vec(1, 1, 1) * .999, SPEC), // Mirr\n",
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" Sphere(16.5, Vec(73, 16.5, 78), Vec(), Vec(1, 1, 1) * .999, REFR), // Glas\n",
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" Sphere(600, Vec(50, 681.6 - .27, 81.6), Vec(12, 12, 12), Vec(),\n",
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" DIFF) // Lite\n",
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"};\n",
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"\n",
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"inline double clamp(double x) { return x < 0 ? 0 : x > 1 ? 1 : x; }\n",
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"inline int toInt(double x) { return int(pow(clamp(x), 1 / 2.2) * 255 + .5); }\n",
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"inline bool intersect(const Ray &r, double &t, int &id) {\n",
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" double n = spheres.size(), d, inf = t = 1e20;\n",
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" for (int i = int(n); i--;)\n",
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" if ((d = spheres[i].intersect(r)) && d < t) {\n",
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" t = d;\n",
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" id = i;\n",
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" }\n",
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" return t < inf;\n",
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"}\n"
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]
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},
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{
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"cell_type": "code",
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"execution_count": 3,
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"id": "cf0fd047-c5da-4606-aeae-4358d2064f10",
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"metadata": {
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"trusted": true,
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"vscode": {
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"languageId": "c++"
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}
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},
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"outputs": [],
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"source": [
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"Vec radiance(const Ray &r, int depth, unsigned short *Xi) {\n",
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" double t; // distance to intersection\n",
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" int id = 0; // id of intersected object\n",
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" if (!intersect(r, t, id))\n",
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" return Vec(); // if miss, return black\n",
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" const Sphere &obj = spheres[id]; // the hit object\n",
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" Vec x = r.o + r.d * t, n = (x - obj.p).norm(),\n",
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" nl = n.dot(r.d) < 0 ? n : n * -1, f = obj.c;\n",
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" double p = f.x > f.y && f.x > f.z ? f.x : f.y > f.z ? f.y : f.z; // max refl\n",
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" if (++depth > 5) {\n",
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" if (erand48(Xi) < p) {\n",
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" f = f * (1 / p);\n",
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" } else {\n",
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" return obj.e; // R.R.\n",
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" }\n",
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" }\n",
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" if (obj.refl == DIFF) { // Ideal DIFFUSE reflection\n",
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" double r1 = 2 * M_PI * erand48(Xi), r2 = erand48(Xi), r2s = sqrt(r2);\n",
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" Vec w = nl, u = ((fabs(w.x) > .1 ? Vec(0, 1) : Vec(1)) % w).norm(),\n",
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" v = w % u;\n",
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" Vec d = (u * cos(r1) * r2s + v * sin(r1) * r2s + w * sqrt(1 - r2)).norm();\n",
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" return obj.e + f.mult(radiance(Ray(x, d), depth, Xi));\n",
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" } else if (obj.refl == SPEC) // Ideal SPECULAR reflection\n",
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" return obj.e +\n",
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" f.mult(radiance(Ray(x, r.d - n * 2 * n.dot(r.d)), depth, Xi));\n",
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" Ray reflRay(x, r.d - n * 2 * n.dot(r.d)); // Ideal dielectric REFRACTION\n",
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" bool into = n.dot(nl) > 0; // Ray from outside going in?\n",
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" double nc = 1, nt = 1.5, nnt = into ? nc / nt : nt / nc, ddn = r.d.dot(nl),\n",
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" cos2t;\n",
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" if ((cos2t = 1 - nnt * nnt * (1 - ddn * ddn)) <\n",
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" 0) // Total internal reflection\n",
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" return obj.e + f.mult(radiance(reflRay, depth, Xi));\n",
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" Vec tdir =\n",
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" (r.d * nnt - n * ((into ? 1 : -1) * (ddn * nnt + sqrt(cos2t)))).norm();\n",
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" double a = nt - nc, b = nt + nc, R0 = a * a / (b * b),\n",
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" c = 1 - (into ? -ddn : tdir.dot(n));\n",
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" double Re = R0 + (1 - R0) * c * c * c * c * c, Tr = 1 - Re, P = .25 + .5 * Re,\n",
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" RP = Re / P, TP = Tr / (1 - P);\n",
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" return obj.e +\n",
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" f.mult(depth > 2\n",
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" ? (erand48(Xi) < P ? // Russian roulette\n",
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" radiance(reflRay, depth, Xi) * RP\n",
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" : radiance(Ray(x, tdir), depth, Xi) * TP)\n",
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" : radiance(reflRay, depth, Xi) * Re +\n",
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" radiance(Ray(x, tdir), depth, Xi) * Tr);\n",
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"}"
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]
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},
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{
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"cell_type": "code",
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"execution_count": 4,
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"id": "70a01b15-3b76-4008-b674-0cc05b0342dd",
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"metadata": {
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"trusted": true,
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"vscode": {
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"languageId": "c++"
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}
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},
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"outputs": [],
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"source": [
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"#include <SDL2/SDL.h>\n",
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"#include <string>\n",
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"#include <fstream>\n",
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"#include <sstream>\n",
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"#include <iostream>\n",
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"#include \"nlohmann/json.hpp\"\n",
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"#include \"xeus/xbase64.hpp\"\n",
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"#include \"xcpp/xdisplay.hpp\"\n",
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"\n",
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"namespace nl = nlohmann;\n",
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"\n",
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"namespace im\n",
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"{\n",
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" struct image\n",
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" { \n",
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" inline image(const std::string& filename)\n",
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" {\n",
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" std::ifstream fin(filename, std::ios::binary); \n",
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" m_buffer << fin.rdbuf();\n",
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" }\n",
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" \n",
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" std::stringstream m_buffer;\n",
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" };\n",
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" \n",
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" nl::json mime_bundle_repr(const image& i)\n",
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" {\n",
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" auto bundle = nl::json::object();\n",
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" bundle[\"image/bmp\"] = xeus::base64encode(i.m_buffer.str());\n",
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" return bundle;\n",
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" }\n",
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"}\n",
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"\n",
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"// Function to save SDL surface as BMP persistently\n",
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"void save_bmp_to_filesystem(SDL_Surface* surface, const std::string& filename)\n",
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"{\n",
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" if (surface)\n",
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" {\n",
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" if (SDL_SaveBMP(surface, filename.c_str()) == 0)\n",
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" {\n",
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" std::cout << \"[DEBUG] Surface saved to \" << filename << std::endl;\n",
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" }\n",
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" else\n",
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" {\n",
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" std::cerr << \"[ERROR] Failed to save BMP to \" << filename << \": \" << SDL_GetError() << std::endl;\n",
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" }\n",
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" }\n",
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" else\n",
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" {\n",
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" std::cerr << \"[ERROR] Surface is null, cannot save BMP.\" << std::endl;\n",
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" }\n",
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"}\n",
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"\n",
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"// Function to encode an SDL surface and render it in Jupyter\n",
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"void render_sdl_surface_to_jupyter(SDL_Surface* surface, const std::string& filename)\n",
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"{\n",
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"\n",
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" if (!surface)\n",
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" {\n",
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" std::cerr << \"[ERROR] Surface is null\" << std::endl;\n",
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" return;\n",
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" }\n",
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"\n",
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" std::cout << \"[DEBUG] Surface created successfully\" << std::endl;\n",
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"\n",
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" im::image output(filename);\n",
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" xcpp::display(output);\n",
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" \n",
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" // Cleanup\n",
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" SDL_FreeSurface(surface);\n",
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" std::cout << \"[DEBUG] Surface freed\" << std::endl;\n",
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" remove(filename.c_str());\n",
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"}"
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]
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},
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{
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"cell_type": "code",
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"execution_count": null,
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"id": "2fd6e42b-6e84-46e5-9197-0e0c2e054ad1",
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"metadata": {
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"trusted": true,
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"vscode": {
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"languageId": "c++"
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}
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},
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"outputs": [],
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"source": [
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"int main() {\n",
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" // Debug: Initialization\n",
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" std::cout << \"[DEBUG] Initializing SDL\" << std::endl;\n",
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"\n",
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" if (SDL_Init(SDL_INIT_EVENTS) != 0) {\n",
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" std::cerr << \"[ERROR] SDL_Init failed: \" << SDL_GetError() << std::endl;\n",
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" return 1;\n",
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" }\n",
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" std::cout << \"[DEBUG] SDL initialized successfully\" << std::endl;\n",
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"\n",
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" // Define width, height, and samples\n",
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" int w = 320, h = 240, samps = 16; // # samples\n",
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" std::cout << \"[DEBUG] Dimensions: \" << w << \"x\" << h << \", Samples: \" << samps << std::endl;\n",
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"\n",
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" // Create an off-screen surface\n",
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" SDL_Surface* surface = SDL_CreateRGBSurfaceWithFormat(0, w, h, 32, SDL_PIXELFORMAT_RGBA32);\n",
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" if (!surface) {\n",
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" std::cerr << \"[ERROR] Failed to create SDL surface: \" << SDL_GetError() << std::endl;\n",
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" SDL_Quit();\n",
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" return 1;\n",
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" }\n",
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" std::cout << \"[DEBUG] SDL surface created successfully\" << std::endl;\n",
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"\n",
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" // Prepare the camera and pixel buffer\n",
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" Ray cam(Vec(50, 52, 295.6), Vec(0, -0.042612, -1).norm()); // cam pos, dir\n",
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" Vec cx = Vec(w * .5135 / h), cy = (cx % cam.d).norm() * .5135, r,\n",
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" *c = new Vec[w * h];\n",
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"\n",
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" std::cout << \"[DEBUG] The image should be on your screen soon\" << std::endl;\n",
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" // Render the scene\n",
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" for (int y = 0; y < h; y++) { // Loop over image rows\n",
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" unsigned short x, Xi[3] = {0, 0, static_cast<unsigned short>(y * y * y)};\n",
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" for (x = 0; x < w; x++) { // Loop cols\n",
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" int sy, i = (h - y - 1) * w + x;\n",
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" for (sy = 0; sy < 2; sy++) { // 2x2 subpixel rows\n",
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" int sx;\n",
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" for (sx = 0; sx < 2; sx++, r = Vec()) { // 2x2 subpixel cols\n",
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" for (int s = 0; s < samps; s++) { // Subpixel sampling\n",
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" double r1 = 2 * erand48(Xi),\n",
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" dx = r1 < 1 ? sqrt(r1) - 1 : 1 - sqrt(2 - r1);\n",
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" double r2 = 2 * erand48(Xi),\n",
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" dy = r2 < 1 ? sqrt(r2) - 1 : 1 - sqrt(2 - r2);\n",
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" Vec d = cx * (((sx + .5 + dx) / 2 + x) / w - .5) +\n",
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" cy * (((sy + .5 + dy) / 2 + y) / h - .5) + cam.d;\n",
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" r = r + radiance(Ray(cam.o + d * 140, d.norm()), 0, Xi) * (1. / samps);\n",
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" }\n",
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" c[i] = c[i] + Vec(clamp(r.x), clamp(r.y), clamp(r.z)) * .25;\n",
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" }\n",
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" }\n",
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" }\n",
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" }\n",
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"\n",
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" // Map the pixel buffer to the SDL surface\n",
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" uint8_t* pixels = (uint8_t*)surface->pixels;\n",
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" for (int i = 0; i < w * h; i++) {\n",
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" uint32_t* pixel_ptr = (uint32_t*)pixels + i;\n",
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" *pixel_ptr = SDL_MapRGBA(surface->format, \n",
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" toInt(c[i].x), // Red\n",
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" toInt(c[i].y), // Green\n",
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" toInt(c[i].z), // Blue\n",
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" 255); // Alpha\n",
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" }\n",
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" std::cout << \"[DEBUG] Mapped pixel buffer to surface\" << std::endl;\n",
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"\n",
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" // Save the BMP to the filesystem\n",
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" const std::string bmp_filename = \"render.bmp\";\n",
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" save_bmp_to_filesystem(surface, bmp_filename);\n",
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"\n",
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" // Render the surface to Jupyter\n",
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" render_sdl_surface_to_jupyter(surface, bmp_filename);\n",
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"\n",
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" // Cleanup\n",
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" delete[] c;\n",
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" SDL_Quit();\n",
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" std::cout << \"[DEBUG] Exiting main\" << std::endl;\n",
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"\n",
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" return 0;\n",
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"}\n",
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"\n",
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"main();"
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]
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}
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],
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