130 lines
5.1 KiB
C++
130 lines
5.1 KiB
C++
//
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// Created by Иван Ильин on 14.01.2021.
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//
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#include "Camera.h"
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#include "utils/Log.h"
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#include "Consts.h"
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#include <cmath>
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std::vector<std::shared_ptr<Triangle>> Camera::project(std::shared_ptr<Mesh> mesh) {
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if(!_ready) {
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Log::log("Camera::project(): cannot project _tris without camera initialization ( Camera::init() ) ");
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return _triangles;
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}
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if(!mesh->isVisible()) {
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return this->_triangles;
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}
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// Model transform matrix: translate _tris in the origin of body.
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Matrix4x4 M = mesh->model();
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Matrix4x4 V = Matrix4x4::View(left(), up(), lookAt(), position());
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// We don't want to waste time re-allocating memory every time
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std::vector<Triangle> clippedTriangles, tempBuffer;
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for(auto& t : mesh->triangles()) {
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Triangle MTriangle = t * M;
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double dot = MTriangle.norm().dot((Vec3D(MTriangle[0]) - position()).normalized());
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if(dot > 0) {
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continue;
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}
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Triangle VMTriangle = MTriangle * V;
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// It needs to be cleared because it's reused through iterations. Usually it doesn't free memory.
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clippedTriangles.clear();
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tempBuffer.clear();
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// In the beginning we need to to translate triangle from world coordinate to our camera system:
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// After that we apply clipping for all planes from _clipPlanes
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clippedTriangles.emplace_back(VMTriangle);
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for(auto& plane : _clipPlanes) {
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while(!clippedTriangles.empty()) {
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std::vector<Triangle> clipResult = plane.clip(clippedTriangles.back());
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clippedTriangles.pop_back();
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for(auto & i : clipResult) {
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tempBuffer.emplace_back(i);
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}
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}
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clippedTriangles.swap(tempBuffer);
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}
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for(auto& clipped : clippedTriangles) {
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sf::Color color = clipped.color();
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sf::Color ambientColor = sf::Color((sf::Uint8)(color.r * (0.3 * std::abs(dot) + 0.7)),
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(sf::Uint8)(color.g * (0.3 * std::abs(dot) + 0.7)),
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(sf::Uint8)(color.b * (0.3 * std::abs(dot) + 0.7)),
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(sf::Uint8)color.a);
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// Finally its time to project our clipped colored drawTriangle from 3D -> 2D
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// and transform it's coordinate to screen space (in pixels):
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Triangle clippedProjected = clipped * _SP;
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Triangle clippedProjectedNormalized = Triangle(clippedProjected[0] / clippedProjected[0].w(),
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clippedProjected[1] / clippedProjected[1].w(),
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clippedProjected[2] / clippedProjected[2].w(),
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ambientColor);
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_triangles.emplace_back(std::make_shared<Triangle>(clippedProjectedNormalized));
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}
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}
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return this->_triangles;
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}
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void Camera::init(int width, int height, double fov, double ZNear, double ZFar) {
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// We need to init camera only after creation or changing width, height, fov, ZNear or ZFar.
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// Because here we calculate matrix that does not change during the motion of _objects or camera
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_aspect = (double)width / (double)height;
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Matrix4x4 P = Matrix4x4::Projection(fov, _aspect, ZNear, ZFar);
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Matrix4x4 S = Matrix4x4::ScreenSpace(width, height);
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_SP = S * P; // screen-space-projections matrix
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// This is planes for clipping _tris.
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// Motivation: we are not interest in _tris that we cannot see.
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_clipPlanes.emplace_back(Plane(Vec3D{0, 0, 1}, Vec3D{0, 0, ZNear})); // near plane
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_clipPlanes.emplace_back(Plane(Vec3D{0, 0, -1}, Vec3D{0, 0, ZFar})); // far plane
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double thetta1 = Consts::PI*fov*0.5/180.0;
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double thetta2 = atan(_aspect * tan(thetta1));
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_clipPlanes.emplace_back(Plane(Vec3D{-cos(thetta2), 0, sin(thetta2)}, Vec3D{0, 0, 0})); // left plane
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_clipPlanes.emplace_back(Plane(Vec3D{cos(thetta2), 0, sin(thetta2)}, Vec3D{0, 0, 0})); // right plane
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_clipPlanes.emplace_back(Plane(Vec3D{0, cos(thetta1), sin(thetta1)}, Vec3D{0, 0, 0})); // down plane
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_clipPlanes.emplace_back(Plane(Vec3D{0, -cos(thetta1), sin(thetta1)}, Vec3D{0, 0, 0})); // up plane
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_ready = true;
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Log::log("Camera::init(): camera successfully initialized.");
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}
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std::vector<std::shared_ptr<Triangle>> Camera::sorted() {
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// Sort _tris from _back to front
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// This is some replacement for Z-buffer
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std::sort(_triangles.begin(), _triangles.end(), [](std::shared_ptr<Triangle> &t1, std::shared_ptr<Triangle> &t2) {
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std::vector<double> v_z1({(*t1)[0].z(), (*t1)[1].z(), (*t1)[2].z()});
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std::vector<double> v_z2({(*t2)[0].z(), (*t2)[1].z(), (*t2)[2].z()});
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std::sort(v_z1.begin(), v_z1.end());
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std::sort(v_z2.begin(), v_z2.end());
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double z1 = v_z1[0] + v_z1[1] + v_z1[2];
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double z2 = v_z2[0] + v_z2[1] + v_z2[2];
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return z1 > z2;
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});
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return _triangles;
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}
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void Camera::clear() {
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// Cleaning all _tris and recalculation of View matrix
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_triangles.clear();
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}
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