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raytracetransform.cppgeometry.hteapot.geo
//[header] // A simple program to demonstrate how to ray-trace a polygon mesh //[/header] //[compile] // Download the raytracetransform.cpp, geometry.h and teapot.geo file to a folder. // Open a shell/terminal, and run the following command where the files are saved: // // c++ -o raytracetransform raytracetransform.cpp -std=c++11 -O3 // // Run with: ./raytracetransform. Open the file ./out.0000.png in Photoshop or any program // reading PPM files. //[/compile] //[ignore] // Copyright (C) 2012 www.scratchapixel.com // // This program is free software: you can redistribute it and/or modify // it under the terms of the GNU General Public License as published by // the Free Software Foundation, either version 3 of the License, or // (at your option) any later version. // // This program is distributed in the hope that it will be useful, // but WITHOUT ANY WARRANTY; without even the implied warranty of // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the // GNU General Public License for more details. // // You should have received a copy of the GNU General Public License // along with this program. If not, see <http://www.gnu.org/licenses/>. //[/ignore] #include <cstdio> #include <cstdlib> #include <memory> #include <vector> #include <utility> #include <cstdint> #include <iostream> #include <fstream> #include <cmath> #include <sstream> #include <chrono> #include "geometry.h" static const float kInfinity = std::numeric_limits<float>::max(); static const float kEpsilon = 1e-8; static const Vec3f kDefaultBackgroundColor = Vec3f(0.235294, 0.67451, 0.843137); template <> const Matrix44f Matrix44f::kIdentity = Matrix44f(); inline float clamp(const float &lo, const float &hi, const float &v) { return std::max(lo, std::min(hi, v)); } inline float deg2rad(const float &deg) { return deg * M_PI / 180; } struct Options { uint32_t width = 640; uint32_t height = 480; float fov = 90; Vec3f backgroundColor = kDefaultBackgroundColor; Matrix44f cameraToWorld; }; class Object { public: // [comment] // Setting up the object-to-world and world-to-object matrix // [/comment] Object(const Matrix44f &o2w) : objectToWorld(o2w), worldToObject(o2w.inverse()) {} virtual ~Object() {} virtual bool intersect(const Vec3f &, const Vec3f &, float &, uint32_t &, Vec2f &) const = 0; virtual void getSurfaceProperties(const Vec3f &, const Vec3f &, const uint32_t &, const Vec2f &, Vec3f &, Vec2f &) const = 0; Matrix44f objectToWorld, worldToObject; }; bool rayTriangleIntersect( const Vec3f &orig, const Vec3f &dir, const Vec3f &v0, const Vec3f &v1, const Vec3f &v2, float &t, float &u, float &v) { Vec3f v0v1 = v1 - v0; Vec3f v0v2 = v2 - v0; Vec3f pvec = dir.crossProduct(v0v2); float det = v0v1.dotProduct(pvec); // ray and triangle are parallel if det is close to 0 if (fabs(det) < kEpsilon) return false; float invDet = 1 / det; Vec3f tvec = orig - v0; u = tvec.dotProduct(pvec) * invDet; if (u < 0 || u > 1) return false; Vec3f qvec = tvec.crossProduct(v0v1); v = dir.dotProduct(qvec) * invDet; if (v < 0 || u + v > 1) return false; t = v0v2.dotProduct(qvec) * invDet; return true; } class TriangleMesh : public Object { public: // Build a triangle mesh from a face index array and a vertex index array TriangleMesh( const Matrix44f &o2w, const uint32_t nfaces, const std::unique_ptr<uint32_t []> &faceIndex, const std::unique_ptr<uint32_t []> &vertsIndex, const std::unique_ptr<Vec3f []> &verts, std::unique_ptr<Vec3f []> &normals, std::unique_ptr<Vec2f []> &st) : Object(o2w), numTris(0) { uint32_t k = 0, maxVertIndex = 0; // find out how many triangles we need to create for this mesh for (uint32_t i = 0; i < nfaces; ++i) { numTris += faceIndex[i] - 2; for (uint32_t j = 0; j < faceIndex[i]; ++j) if (vertsIndex[k + j] > maxVertIndex) maxVertIndex = vertsIndex[k + j]; k += faceIndex[i]; } maxVertIndex += 1; // allocate memory to store the position of the mesh vertices P = std::unique_ptr<Vec3f []>(new Vec3f[maxVertIndex]); for (uint32_t i = 0; i < maxVertIndex; ++i) { // [comment] // Transforming vertices to world space // [/comment] objectToWorld.multVecMatrix(verts[i], P[i]); } // allocate memory to store triangle indices trisIndex = std::unique_ptr<uint32_t []>(new uint32_t [numTris * 3]); uint32_t l = 0; // [comment] // Generate the triangle index array // Keep in mind that there is generally 1 vertex attribute for each vertex of each face. // So for example if you have 2 quads, you only have 6 vertices but you have 2 * 4 // vertex attributes (that is 8 normals, 8 texture coordinates, etc.). So the easiest // lazziest method in our triangle mesh, is to create a new array for each supported // vertex attribute (st, normals, etc.) whose size is equal to the number of triangles // multiplied by 3, and then set the value of the vertex attribute at each vertex // of each triangle using the input array (normals[], st[], etc.) // [/comment] N = std::unique_ptr<Vec3f []>(new Vec3f[numTris * 3]); texCoordinates = std::unique_ptr<Vec2f []>(new Vec2f[numTris * 3]); // [comment] // Computing the transpose of the object-to-world inverse matrix // [/comment] Matrix44f transformNormals = worldToObject.transpose(); // generate the triangle index array and set normals and st coordinates for (uint32_t i = 0, k = 0; i < nfaces; ++i) { // for each face for (uint32_t j = 0; j < faceIndex[i] - 2; ++j) { // for each triangle in the face trisIndex[l] = vertsIndex[k]; trisIndex[l + 1] = vertsIndex[k + j + 1]; trisIndex[l + 2] = vertsIndex[k + j + 2]; // [comment] // Transforming normals // [/comment] transformNormals.multDirMatrix(normals[k], N[l]); transformNormals.multDirMatrix(normals[k + j + 1], N[l + 1]); transformNormals.multDirMatrix(normals[k + j + 2], N[l + 2]); N[l].normalize(); N[l + 1].normalize(); N[l + 2].normalize(); texCoordinates[l] = st[k]; texCoordinates[l + 1] = st[k + j + 1]; texCoordinates[l + 2] = st[k + j + 2]; l += 3; } k += faceIndex[i]; } } // Test if the ray interesests this triangle mesh bool intersect(const Vec3f &orig, const Vec3f &dir, float &tNear, uint32_t &triIndex, Vec2f &uv) const { uint32_t j = 0; bool isect = false; for (uint32_t i = 0; i < numTris; ++i) { const Vec3f &v0 = P[trisIndex[j]]; const Vec3f &v1 = P[trisIndex[j + 1]]; const Vec3f &v2 = P[trisIndex[j + 2]]; float t = kInfinity, u, v; if (rayTriangleIntersect(orig, dir, v0, v1, v2, t, u, v) && t < tNear) { tNear = t; uv.x = u; uv.y = v; triIndex = i; isect = true; } j += 3; } return isect; } void getSurfaceProperties( const Vec3f &hitPoint, const Vec3f &viewDirection, const uint32_t &triIndex, const Vec2f &uv, Vec3f &hitNormal, Vec2f &hitTextureCoordinates) const { // face normal const Vec3f &v0 = P[trisIndex[triIndex * 3]]; const Vec3f &v1 = P[trisIndex[triIndex * 3 + 1]]; const Vec3f &v2 = P[trisIndex[triIndex * 3 + 2]]; hitNormal = (v1 - v0).crossProduct(v2 - v0); hitNormal.normalize(); // texture coordinates const Vec2f &st0 = texCoordinates[triIndex * 3]; const Vec2f &st1 = texCoordinates[triIndex * 3 + 1]; const Vec2f &st2 = texCoordinates[triIndex * 3 + 2]; hitTextureCoordinates = (1 - uv.x - uv.y) * st0 + uv.x * st1 + uv.y * st2; // vertex normal #if 0 const Vec3f &n0 = N[triIndex * 3]; const Vec3f &n1 = N[triIndex * 3 + 1]; const Vec3f &n2 = N[triIndex * 3 + 2]; hitNormal = (1 - uv.x - uv.y) * n0 + uv.x * n1 + uv.y * n2; // doesn't need to be normalized as the N's are normalized but just for safety hitNormal.normalize(); #endif } // member variables uint32_t numTris; // number of triangles std::unique_ptr<Vec3f []> P; // triangles vertex position std::unique_ptr<uint32_t []> trisIndex; // vertex index array std::unique_ptr<Vec3f []> N; // triangles vertex normals std::unique_ptr<Vec2f []> texCoordinates; // triangles texture coordinates }; TriangleMesh* loadPolyMeshFromFile(const char *file, const Matrix44f &o2w) { std::ifstream ifs; try { ifs.open(file); if (ifs.fail()) throw; std::stringstream ss; ss << ifs.rdbuf(); uint32_t numFaces; ss >> numFaces; std::unique_ptr<uint32_t []> faceIndex(new uint32_t[numFaces]); uint32_t vertsIndexArraySize = 0; // reading face index array for (uint32_t i = 0; i < numFaces; ++i) { ss >> faceIndex[i]; vertsIndexArraySize += faceIndex[i]; } std::unique_ptr<uint32_t []> vertsIndex(new uint32_t[vertsIndexArraySize]); uint32_t vertsArraySize = 0; // reading vertex index array for (uint32_t i = 0; i < vertsIndexArraySize; ++i) { ss >> vertsIndex[i]; if (vertsIndex[i] > vertsArraySize) vertsArraySize = vertsIndex[i]; } vertsArraySize += 1; // reading vertices std::unique_ptr<Vec3f []> verts(new Vec3f[vertsArraySize]); for (uint32_t i = 0; i < vertsArraySize; ++i) { ss >> verts[i].x >> verts[i].y >> verts[i].z; } // reading normals std::unique_ptr<Vec3f []> normals(new Vec3f[vertsIndexArraySize]); for (uint32_t i = 0; i < vertsIndexArraySize; ++i) { ss >> normals[i].x >> normals[i].y >> normals[i].z; } // reading st coordinates std::unique_ptr<Vec2f []> st(new Vec2f[vertsIndexArraySize]); for (uint32_t i = 0; i < vertsIndexArraySize; ++i) { ss >> st[i].x >> st[i].y; } return new TriangleMesh(o2w, numFaces, faceIndex, vertsIndex, verts, normals, st); } catch (...) { ifs.close(); } ifs.close(); return nullptr; } bool trace( const Vec3f &orig, const Vec3f &dir, const std::vector<std::unique_ptr<Object>> &objects, float &tNear, uint32_t &index, Vec2f &uv, Object **hitObject) { *hitObject = nullptr; for (uint32_t k = 0; k < objects.size(); ++k) { float tNearTriangle = kInfinity; uint32_t indexTriangle; Vec2f uvTriangle; if (objects[k]->intersect(orig, dir, tNearTriangle, indexTriangle, uvTriangle) && tNearTriangle < tNear) { *hitObject = objects[k].get(); tNear = tNearTriangle; index = indexTriangle; uv = uvTriangle; } } return (*hitObject != nullptr); } Vec3f castRay( const Vec3f &orig, const Vec3f &dir, const std::vector<std::unique_ptr<Object>> &objects, const Options &options) { Vec3f hitColor = options.backgroundColor; float tnear = kInfinity; Vec2f uv; uint32_t index = 0; Object *hitObject = nullptr; if (trace(orig, dir, objects, tnear, index, uv, &hitObject)) { Vec3f hitPoint = orig + dir * tnear; Vec3f hitNormal; Vec2f hitTexCoordinates; hitObject->getSurfaceProperties(hitPoint, dir, index, uv, hitNormal, hitTexCoordinates); float NdotView = std::max(0.f, hitNormal.dotProduct(-dir)); const int M = 4; float checker = (fmod(hitTexCoordinates.x * M, 1.0) > 0.5) ^ (fmod(hitTexCoordinates.y * M, 1.0) < 0.5); float c = 0.3 * (1 - checker) + 0.7 * checker; hitColor = c * NdotView; //Vec3f(uv.x, uv.y, 0); // Vec3f(hitTexCoordinates.x, hitTexCoordinates.y, 0); } return hitColor; } // [comment] // The main render function. This where we iterate over all pixels in the image, generate // primary rays and cast these rays into the scene. The content of the framebuffer is // saved to a file. // [/comment] void render( const Options &options, const std::vector<std::unique_ptr<Object>> &objects, const uint32_t &frame) { std::unique_ptr<Vec3f []> framebuffer(new Vec3f[options.width * options.height]); Vec3f *pix = framebuffer.get(); float scale = tan(deg2rad(options.fov * 0.5)); float imageAspectRatio = options.width / (float)options.height; Vec3f orig; options.cameraToWorld.multVecMatrix(Vec3f(0), orig); auto timeStart = std::chrono::high_resolution_clock::now(); for (uint32_t j = 0; j < options.height; ++j) { for (uint32_t i = 0; i < options.width; ++i) { // generate primary ray direction float x = (2 * (i + 0.5) / (float)options.width - 1) * imageAspectRatio * scale; float y = (1 - 2 * (j + 0.5) / (float)options.height) * scale; Vec3f dir; options.cameraToWorld.multDirMatrix(Vec3f(x, y, -1), dir); dir.normalize(); *(pix++) = castRay(orig, dir, objects, options); } fprintf(stderr, "\r%3d%c", uint32_t(j / (float)options.height * 100), '%'); } auto timeEnd = std::chrono::high_resolution_clock::now(); auto passedTime = std::chrono::duration<double, std::milli>(timeEnd - timeStart).count(); fprintf(stderr, "\rDone: %.2f (sec)\n", passedTime / 1000); // save framebuffer to file char buff[256]; sprintf(buff, "out.%04d.ppm", frame); std::ofstream ofs; ofs.open(buff); ofs << "P6\n" << options.width << " " << options.height << "\n255\n"; for (uint32_t i = 0; i < options.height * options.width; ++i) { char r = (char)(255 * clamp(0, 1, framebuffer[i].x)); char g = (char)(255 * clamp(0, 1, framebuffer[i].y)); char b = (char)(255 * clamp(0, 1, framebuffer[i].z)); ofs << r << g << b; } ofs.close(); } // [comment] // In the main function of the program, we create the scene (create objects and lights) // as well as set the options for the render (image widht and height, maximum recursion // depth, field-of-view, etc.). We then call the render function(). // [/comment] int main(int argc, char **argv) { // setting up options Options options; options.cameraToWorld = Matrix44f(0.931056, 0, 0.364877, 0, 0.177666, 0.873446, -0.45335, 0, -0.3187, 0.48692, 0.813227, 0, -41.229214, 81.862351, 112.456908, 1); options.fov = 18; // loading gemetry std::vector<std::unique_ptr<Object>> objects; Matrix44f objectToWorld = Matrix44f(1.624241, 0, 2.522269, 0, 0, 3, 0, 0, -2.522269, 0, 1.624241, 0, 0, 0, 0, 1); // Matrix44f::kIdentity; TriangleMesh *mesh = loadPolyMeshFromFile("./teapot.geo", objectToWorld); if (mesh != nullptr) objects.push_back(std::unique_ptr<Object>(mesh)); // finally, render render(options, objects, 0); return 0; }