289 lines
10 KiB
C++
289 lines
10 KiB
C++
#ifndef GRID3_HPP
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#define GRID3_HPP
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#include <unordered_map>
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#include "../vectorlogic/vec3.hpp"
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#include "../vectorlogic/vec4.hpp"
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#include "../timing_decorator.hpp"
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#include "../output/frame.hpp"
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#include "../noise/pnoise2.hpp"
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#include "../vecmat/mat4.hpp"
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#include <vector>
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#include <algorithm>
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#include "../basicdefines.hpp"
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struct Voxel {
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float active;
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//Vec3f position;
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Vec3ui8 color;
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};
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struct Camera {
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Ray3f posfor;
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Vec3f up;
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float fov;
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Camera(Vec3f pos, Vec3f viewdir, Vec3f up, float fov = 80) : posfor(Ray3f(pos, viewdir)), up(up), fov(fov) {}
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};
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class VoxelGrid {
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private:
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size_t width, height, depth;
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std::vector<Voxel> voxels;
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static Mat4f lookAt(Vec3f const& eye, Vec3f const& center, Vec3f const& up) {
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Vec3f const f = (center - eye).normalized();
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Vec3f const s = f.cross(up).normalized();
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Vec3f const u = s.cross(f);
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Mat4f Result = Mat4f::identity();
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Result(0, 0) = s.x;
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Result(1, 0) = s.y;
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Result(2, 0) = s.z;
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Result(3, 0) = -s.dot(eye);
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Result(0, 1) = u.x;
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Result(1, 1) = u.y;
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Result(2, 1) = u.z;
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Result(3, 1) = -u.dot(eye);
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Result(0, 2) = -f.x;
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Result(1, 2) = -f.y;
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Result(2, 2) = -f.z;
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Result(3, 2) = f.dot(eye);
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return Result;
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}
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static Mat4f perspective(float fovy, float aspect, float zNear, float zfar) {
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float const tanhalfF = tan(fovy / 2);
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Mat4f Result = 0;
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Result(0,0) = 1 / (aspect * tanhalfF);
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Result(1,1) = 1 / tanhalfF;
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Result(2,2) = zfar / (zNear - zfar);
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Result(2,3) = -1;
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Result(3,2) = -(zfar * zNear) / (zfar - zNear);
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return Result;
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}
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public:
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VoxelGrid(size_t w, size_t h, size_t d) : width(w), height(h), depth(d) {
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voxels.resize(w * h * d);
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}
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Voxel& get(size_t x, size_t y, size_t z) {
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return voxels[z * width * height + y * width + x];
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}
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const Voxel& get(size_t x, size_t y, size_t z) const {
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return voxels[z * width * height + y * width + x];
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}
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Voxel& get(const Vec3T& xyz) {
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return voxels[xyz.z*width*height+xyz.y*width+xyz.x];
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}
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void resize() {
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//TODO: proper resizing
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}
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void set(size_t x, size_t y, size_t z, float active, Vec3ui8 color) {
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//expand grid if needed.
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if (x >= 0 || y >= 0 || z >= 0) {
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if (!(x < width)) {
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//until resizing added:
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return;
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width = x;
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resize();
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}
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else if (!(y < height)) {
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//until resizing added:
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return;
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height = y;
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resize();
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}
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else if (!(z < depth)) {
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//until resizing added:
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return;
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depth = z;
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resize();
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}
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Voxel& v = get(x, y, z);
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v.active = std::clamp(active, 0.0f, 1.0f);
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v.color = color;
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}
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}
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template<typename T>
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bool inGrid(Vec3<T> voxl) {
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return (voxl >= 0 && voxl.x < width && voxl.y < height && voxl.z < depth);
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}
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Vec3f perPixelRayDir(size_t x, size_t y, size_t imgWidth, size_t imgHeight, const Camera& cam) const {
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float normedX = (x + 0.5) / imgWidth * 2 - 1;
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float normedY = 1 - (y+0.5) / imgHeight * 2;
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float aspect = imgWidth / imgHeight;
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float fovRad = cam.fov * M_PI / 180;
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float scale = tan(fovRad * 0.5);
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Vec3f rayDirCam = Vec3f(normedX * aspect * scale, normedY * scale, -1).normalized();
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Vec3f eye = cam.posfor.origin;
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Vec3f center = eye + cam.posfor.direction;
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Mat4f viewMat = lookAt(eye, center, cam.up);
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Mat4f invViewMat = viewMat.inverse();
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Vec3f rayDirWorld = invViewMat.transformDirection(rayDirCam);
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return rayDirWorld.normalized();
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}
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bool rayCast(const Ray3f& ray, float maxDistance, Vec3f hitPos, Vec3f hitNormal, Vec3f& hitColor) {
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hitColor = Vec3f(0,0,0);
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Vec3f rayDir = ray.direction;
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Vec3f rayOrigin = ray.origin;
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Vec3T currentVoxel = rayOrigin.floorToT();
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Vec3i step;
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step.x = (rayDir.x > 0) ? 1 : -1;
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step.y = (rayDir.y > 0) ? 1 : -1;
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step.z = (rayDir.z > 0) ? 1 : -1;
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Vec3f tMax;
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Vec3f tDelta;
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//initialization
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tDelta.x = std::abs(1.0 / rayDir.x);
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tDelta.y = std::abs(1.0 / rayDir.y);
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tDelta.z = std::abs(1.0 / rayDir.z);
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tMax = mix(((rayOrigin - currentVoxel.toFloat()) / -rayDir).toFloat(), (((currentVoxel.toFloat() + 1) - rayOrigin) / rayDir).toFloat(), rayDir.mask([](float x, float value) { return x > 0; }, 0));
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if (!inGrid(rayOrigin)) {
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/*
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The initialization phase begins by identifying the voxel in which the ray origin, →
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u, is found. If the ray origin is outside the grid, we find the point in which the ray enters the grid and take the adjacent voxel. The integer
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variables X and Y are initialized to the starting voxel coordinates. In addition, the variables stepX and
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stepY are initialized to either 1 or -1 indicating whether X and Y are incremented or decremented as the
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ray crosses voxel boundaries (this is determined by the sign of the x and y components of →
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v).
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Next, we determine the value of t at which the ray crosses the first vertical voxel boundary and
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store it in variable tMaxX. We perform a similar computation in y and store the result in tMaxY. The
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minimum of these two values will indicate how much we can travel along the ray and still remain in the
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current voxel.
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*/
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Vec3f tBMin;
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Vec3f tBMax;
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tBMin.x = (0.0 - rayOrigin.x) / rayDir.x;
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tBMax.x = (width - rayOrigin.x) / rayDir.x;
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if (tBMin.x > tBMax.x) std::swap(tBMin.x, tBMax.x);
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tBMin.y = (0.0 - rayOrigin.y) / rayDir.y;
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tBMax.y = (height - rayOrigin.y) / rayDir.y;
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if (tBMin.y > tBMax.y) std::swap(tBMin.y, tBMax.y);
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tBMin.z = (0.0 - rayOrigin.z) / rayDir.z;
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tBMax.z = (depth - rayOrigin.z) / rayDir.z;
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if (tBMin.z > tBMax.z) std::swap(tBMin.z, tBMax.z);
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float tEntry = tBMin.maxComp();
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float tExit = tBMax.minComp();
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if (tEntry > tExit || tExit < 0.0) return false;
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if (tEntry < 0.0) tEntry = 0.0;
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if (tEntry > 0.0) {
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rayOrigin = rayOrigin + rayDir * tEntry;
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currentVoxel = rayOrigin.floorToT();
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tMax = mix(((currentVoxel.toFloat() + 1) - rayOrigin) / rayDir, (rayOrigin - currentVoxel) / -rayDir, rayDir.mask([](float x, float value) { return x > 0; }, 0) );
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}
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}
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float aalpha = 0.0;
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bool hit = false;
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float tDist = 0.0;
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/*
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Finally, we compute tDeltaX and tDeltaY. TDeltaX indicates how far along the ray we must move
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(in units of t) for the horizontal component of such a movement to equal the width of a voxel. Similarly,
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we store in tDeltaY the amount of movement along the ray which has a vertical component equal to the
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height of a voxel.
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*/
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while (inGrid(currentVoxel) && tDist < maxDistance) {
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Voxel& voxel = get(currentVoxel);
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if (voxel.active > EPSILON) {
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Vec3f voxelColor(static_cast<float>(voxel.color.x / 255.0), static_cast<float>(voxel.color.y / 255.0), static_cast<float>(voxel.color.z / 255.0));
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float contribution = voxel.active * (1.0 - aalpha);
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hitColor = hitColor + voxelColor * contribution;
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aalpha += contribution;
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hitPos = rayOrigin + rayDir * tDist;
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if (tMax.x <= tMax.y && tMax.x <= tMax.z) {
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hitNormal = Vec3f(-step.x, 0.0, 0.0);
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} else if (tMax.y <= tMax.x && tMax.y <= tMax.z) {
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hitNormal = Vec3f(0.0, -step.y, 0.0);
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} else {
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hitNormal = Vec3f(0.0, 0.0, -step.z);
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}
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}
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if (aalpha > EPSILON) {
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hit = true;
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}
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if (tMax.x < tMax.y) {
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if (tMax.x < tMax.z) {
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tDist = tMax.x;
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tMax.x += tDelta.x;
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currentVoxel.x += step.x;
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} else {
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tDist = tMax.z;
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tMax.z += tDelta.z;
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currentVoxel.z += step.z;
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}
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} else {
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if (tMax.y < tMax.z) {
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tDist = tMax.y;
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tMax.y += tDelta.y;
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currentVoxel.y += step.y;
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} else {
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tDist = tMax.z;
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tMax.z += tDelta.z;
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currentVoxel.z += step.z;
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}
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}
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}
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if (aalpha > EPSILON) {
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std::cout << "hit at: " << currentVoxel << " with value of " << aalpha << std::endl;
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}
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return hit;
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}
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size_t getWidth() const {
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return width;
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}
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size_t getHeight() const {
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return height;
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}
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size_t getDepth() const {
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return depth;
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}
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void renderOut(std::vector<uint8_t>& output, size_t& outwidth, size_t& outheight, const Camera& cam) {
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output.resize(outwidth * outheight * 3);
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Vec3f backgroundColor(0.1f, 0.1f, 0.1f);
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float maxDistance = std::sqrt(width*width + height*height + depth*depth) * 2.0f;
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for (size_t y = 0; y < outheight; y++) {
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for (size_t x = 0; x < outwidth; x++) {
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Vec3f rayDir = perPixelRayDir(x, y, outwidth, outheight, cam);
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Ray3f ray(cam.posfor.origin, rayDir);
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Vec3f hitPos;
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Vec3f hitNorm;
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Vec3f hitColor;
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bool hit = rayCast(ray, maxDistance, hitPos, hitNorm, hitColor);
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Vec3f finalColor;
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if (!hit) {
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finalColor = backgroundColor;
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} else {
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finalColor = hitColor;
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}
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finalColor = finalColor.clamp(0, 1);
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size_t pixelIndex = (y * outwidth + x) * 3;
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output[pixelIndex + 0] = static_cast<uint8_t>(finalColor.x * 255);
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output[pixelIndex + 1] = static_cast<uint8_t>(finalColor.y * 255);
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output[pixelIndex + 2] = static_cast<uint8_t>(finalColor.z * 255);
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}
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}
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}
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};
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#endif
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