223 lines
9.1 KiB
C++
223 lines
9.1 KiB
C++
#include "light/light.h"
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#include "primitive/triangle.h"
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#include "scene/scene.h"
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#include "shader/shader.h"
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#include <array>
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#include <cassert>
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#include <fstream>
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#include <iostream>
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#include <sstream>
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#include <string>
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const std::string WHITESPACE = " \n\r\t\f\v";
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std::string ltrim(const std::string &s) {
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size_t start = s.find_first_not_of(WHITESPACE);
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return (start == std::string::npos) ? "" : s.substr(start);
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}
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std::string rtrim(const std::string &s) {
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size_t end = s.find_last_not_of(WHITESPACE);
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return (end == std::string::npos) ? "" : s.substr(0, end + 1);
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}
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std::string trim(const std::string &s) { return rtrim(ltrim(s)); }
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void Scene::add(const std::shared_ptr<Light> &light) { this->lights_.push_back(light); }
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void Scene::add(const std::shared_ptr<Primitive> &primitive) {
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assert(primitive->shader() != nullptr);
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this->primitives_.push_back(primitive);
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}
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void Scene::addObj(char const *fileName, Vector3d const &scale, Vector3d const &translation,
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const std::shared_ptr<Shader> &shader, bool flipU, bool flipV) {
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std::vector<std::shared_ptr<Primitive>> triangles = loadObj(fileName, scale, translation, shader, flipU, flipV);
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this->primitives_.insert(this->primitives_.end(), std::make_move_iterator(triangles.begin()),
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std::make_move_iterator(triangles.end()));
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}
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std::vector<std::shared_ptr<Primitive>> Scene::loadObj(char const *fileName, Vector3d const &scale,
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Vector3d const &translation,
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const std::shared_ptr<Shader> &shader, bool flipU, bool flipV) {
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std::vector<std::shared_ptr<Primitive>> faces;
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std::vector<std::array<int, 3>> indices;
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// Open file from disk
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std::ifstream file;
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file.open(fileName);
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if (!file.is_open()) {
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std::cout << "(Scene): Could not open .obj file: " << fileName << std::endl;
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return std::vector<std::shared_ptr<Primitive>>();
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}
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// Print the file name
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std::cout << "(Scene): Loading \"" << fileName << "\"" << std::endl;
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// Actual model data
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std::vector<Vector3d> vData;
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std::vector<Vector3d> tangentData;
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std::vector<Vector3d> bitangentData;
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std::vector<Vector3d> normalData;
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std::vector<Vector3d> vnData;
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std::vector<Vector2d> vtData;
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// Read vertices, normals, textures, and faces from the file
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std::string line;
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while (getline(file, line)) {
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std::stringstream lineStream(trim(line));
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std::string type;
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lineStream >> type;
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// Vertices
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if (type == "v") {
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float x, y, z;
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lineStream >> x >> y >> z;
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vData.emplace_back(componentProduct(Vector3d(x, y, z), scale) + translation);
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tangentData.emplace_back();
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bitangentData.emplace_back();
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normalData.emplace_back();
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}
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// Texture coordinates
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if (type == "vt") {
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float u, v;
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lineStream >> u >> v;
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vtData.emplace_back(flipU ? 1.0f - u : u, flipV ? 1.0f - v : v);
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}
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// Normals
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if (type == "vn") {
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float a, b, c;
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lineStream >> a >> b >> c;
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vnData.emplace_back(normalized(componentQuotient(
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Vector3d(a, b, c),
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scale))); // Division needed for preventing stretched normals, normals' = (transform^-1)^T * normals
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}
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// Faces
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if (type == "f") {
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std::string vertex[3];
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std::array<int, 3> vertInd = {-1, -1, -1};
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std::array<int, 3> texInd = {-1, -1, -1};
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std::array<int, 3> normInd = {-1, -1, -1};
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lineStream >> vertex[0] >> vertex[1] >> vertex[2];
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// triangulate polygons, like quads (which must be given in triangle fan notation)
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while (!vertex[2].empty()) {
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auto triangle = std::make_shared<Triangle>(shader);
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for (int i = 0; i < 3; ++i) {
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std::stringstream vertexSteam(vertex[i]);
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std::string reference;
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// vertex index
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getline(vertexSteam, reference, '/');
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try {
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vertInd[i] = stoi(reference) - 1;
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triangle->setVertex(i, vData.at(vertInd[i]));
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} catch (...) {
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std::cout << "Error: vertex index invalid on line \"" << line << "\"" << std::endl;
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}
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// texture index
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if (getline(vertexSteam, reference, '/')) {
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if (!reference.empty()) {
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try {
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texInd[i] = stoi(reference) - 1;
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triangle->setSurface(i, vtData.at(texInd[i]));
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} catch (...) {
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std::cout << "Error: texture coordinate index invalid on line \"" << line << "\"" << std::endl;
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}
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}
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// normal index
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if (getline(vertexSteam, reference, '/')) {
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try {
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normInd[i] = stoi(reference) - 1;
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triangle->setNormal(i, vnData.at(normInd[i]));
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} catch (...) {
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std::cout << "Error: normal index invalid on line \"" << line << "\"" << std::endl;
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}
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}
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}
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}
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// calculate and accumulate tangent and bitangent vectors
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if (std::all_of(vertInd.begin(), vertInd.end(), [](int i) { return i > -1; }) &&
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std::all_of(texInd.begin(), texInd.end(), [](int i) { return i > -1; })) {
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for (int i = 0; i < 3; i++) {
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const Vector3d deltaPos1 = vData.at(vertInd[(i + 1) % 3]) - vData.at(vertInd[i]);
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const Vector3d deltaPos2 = vData.at(vertInd[(i + 2) % 3]) - vData.at(vertInd[i]);
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const Vector2d deltaUV1 = vtData.at(texInd[(i + 1) % 3]) - vtData.at(texInd[i]);
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const Vector2d deltaUV2 = vtData.at(texInd[(i + 2) % 3]) - vtData.at(texInd[i]);
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const float r = 1.0f / (deltaUV1.u * deltaUV2.v - deltaUV1.v * deltaUV2.u);
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tangentData[vertInd[i]] += (deltaPos1 * deltaUV2.v - deltaPos2 * deltaUV1.v) * r;
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bitangentData[vertInd[i]] += (deltaPos2 * deltaUV1.u - deltaPos1 * deltaUV2.u) * r;
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normalData[vertInd[i]] += crossProduct(tangentData[vertInd[i]], bitangentData[vertInd[i]]);
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}
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}
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faces.push_back(triangle);
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indices.push_back(vertInd);
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// get the next triangle
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if (lineStream.eof())
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break;
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vertex[1] = vertex[2];
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lineStream >> vertex[2];
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}
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}
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}
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// Close the file
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file.close();
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// set the normalized tangents and bitangents
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for (int i = 0; i < faces.size(); i++) {
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for (int j = 0; j < 3; j++) {
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Vector3d tangent = normalized(tangentData[indices[i][j]]);
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const Vector3d bitangent = normalized(bitangentData[indices[i][j]]);
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// try to use the normal from the obj file, if it doesn't exist, use the computed normal
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Vector3d normal = normalized(normalData[indices[i][j]]);
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if (vnData.size() > 0)
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normal = dynamic_cast<Triangle *>(faces[i].get())->getNormal(j);
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// gram-schmidt orthogonalization
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tangent = normalized(tangent - normal * dotProduct(normal, tangent));
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// check handedness of coordinate system
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if (dotProduct(crossProduct(normal, tangent), bitangent) < 0.0f)
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tangent *= -1.0f;
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dynamic_cast<Triangle *>(faces[i].get())->setTangent(j, tangent);
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dynamic_cast<Triangle *>(faces[i].get())->setBitangent(j, bitangent);
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dynamic_cast<Triangle *>(faces[i].get())->setNormal(j, normal);
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}
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}
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// Debug output
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std::cout << " -> " << vData.size() << " vertices parsed" << std::endl;
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std::cout << " -> " << vnData.size() << " normals parsed" << std::endl;
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std::cout << " -> " << vtData.size() << " uv-positions parsed" << std::endl;
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std::cout << " -> " << faces.size() << " primitives parsed" << std::endl;
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return faces;
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}
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Color Scene::traceRay(Ray &ray) const {
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if (this->findIntersection(ray) && ray.remainingBounces-- > 0) {
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// If the ray has hit an object, call the shader ...
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return ray.primitive->shader()->shade(*this, ray);
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} else if (this->environmentMap) {
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// ... otherwise look up the environment map ...
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float const phi = std::acos(ray.direction.y);
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float const rho = std::atan2(ray.direction.z, ray.direction.x) + float(PI);
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return this->environmentMap->color(rho / (2.0f * float(PI)), phi / float(PI));
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} else {
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// ... if all else fails, just return the background color
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return this->backgroundColor;
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}
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}
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