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#include "geoData.h"
#include "gfx/image.h"
#include <algorithm>
#include <array>
#include <cmath>
#include <cstddef>
#include <glm/gtx/intersect.hpp>
#include <initializer_list>
#include <limits>
#include <maths.h>
#include <random>
#include <ray.hpp>
#include <stb/stb_image.h>
#include <stdexcept>
#include <util.h>
GeoData::GeoData(Limits l, float s) :
limit {std::move(l)}, size {(limit.second - limit.first) + 1}, scale {s}, nodes {[this]() {
return (static_cast<std::size_t>(size.x * size.y));
}()}
{
}
void
GeoData::generateRandom()
{
// We acknowledge this is terrible :)
// Add hills
std::mt19937 gen(std::random_device {}());
std::uniform_int_distribution<> rxpos(limit.first.x + 2, limit.second.x - 2),
rypos(limit.first.y + 2, limit.second.y - 2);
std::uniform_int_distribution<> rsize(10, 30);
std::uniform_real_distribution<float> rheight(1, 3);
for (int h = 0; h < 500;) {
const glm::ivec2 hpos {rxpos(gen), rypos(gen)};
const glm::ivec2 hsize {rsize(gen), rsize(gen)};
if (const auto lim1 = hpos - hsize; lim1.x > limit.first.x && lim1.y > limit.first.y) {
if (const auto lim2 = hpos + hsize; lim2.x < limit.second.x && lim2.y < limit.second.y) {
const auto height = rheight(gen);
const glm::ivec2 hsizesqrd {hsize.x * hsize.x, hsize.y * hsize.y};
for (auto y = lim1.y; y < lim2.y; y += 1) {
for (auto x = lim1.x; x < lim2.x; x += 1) {
const auto dist {hpos - glm::ivec2 {x, y}};
const glm::ivec2 distsqrd {dist.x * dist.x, dist.y * dist.y};
const auto out {rdiv(sq(x - hpos.x), sq(hsize.x)) + rdiv(sq(y - hpos.y), sq(hsize.y))};
if (out <= 1.0F) {
auto & node {nodes[at({x, y})]};
const auto m {1.F / (7.F * out - 8.F) + 1.F};
node.height += height * m;
}
}
}
h += 1;
}
}
}
}
void
GeoData::loadFromImages(const std::filesystem::path & fileName, float scale_)
{
const Image map {fileName.c_str(), STBI_grey};
size = {map.width, map.height};
limit = {{0, 0}, size - glm::uvec2 {1, 1}};
const auto points {size.x * size.y};
scale = scale_;
nodes.resize(points);
std::transform(map.data.data(), map.data.data() + points, nodes.begin(), [](auto d) {
return Node {(d * 0.1F) - 1.5F};
});
}
GeoData::Quad
GeoData::quad(glm::vec2 wcoord) const
{
constexpr static const std::array<glm::vec2, 4> corners {{{0, 0}, {0, 1}, {1, 0}, {1, 1}}};
return transform_array(transform_array(corners,
[coord = (wcoord / scale)](const auto c) {
return glm::vec2 {std::floor(coord.x), std::floor(coord.y)} + c;
}),
[this](const auto c) {
return (c * scale) || nodes[at(c)].height;
});
}
glm::vec3
GeoData::positionAt(const glm::vec2 wcoord) const
{
const auto point {quad(wcoord)};
const glm::vec2 frac = (wcoord - !point.front()) / scale;
auto edge = [&point, &frac](auto offset) {
return point[offset].z + ((point[offset + 2].z - point[offset].z) * frac.x);
};
const auto heightFloor = edge(0U), heightCeil = edge(1U),
heightMid = heightFloor + ((heightCeil - heightFloor) * frac.y);
return wcoord || heightMid;
}
GeoData::RayTracer::RayTracer(glm::vec2 p0, glm::vec2 p1) : RayTracer {p0, p1, glm::abs(p1)} { }
GeoData::RayTracer::RayTracer(glm::vec2 p0, glm::vec2 p1, glm::vec2 d) :
RayTracer {p0, d, byAxis(p0, p1, d, 0), byAxis(p0, p1, d, 1)}
{
}
GeoData::RayTracer::RayTracer(
glm::vec2 p0, glm::vec2 d_, std::pair<float, float> xdata, std::pair<float, float> ydata) :
p {glm::floor(p0)},
d {d_}, error {xdata.second - ydata.second}, inc {xdata.first, ydata.first}
{
}
std::pair<float, float>
GeoData::RayTracer::byAxis(glm::vec2 p0, glm::vec2 p1, glm::vec2 d, glm::length_t axis)
{
using Limits = std::numeric_limits<typename glm::vec2::value_type>;
static_assert(Limits::has_infinity);
if (d[axis] == 0) {
return {0, Limits::infinity()};
}
else if (p1[axis] > 0) {
return {1, (std::floor(p0[axis]) + 1.F - p0[axis]) * d[1 - axis]};
}
else {
return {-1, (p0[axis] - std::floor(p0[axis])) * d[1 - axis]};
}
}
glm::vec2
GeoData::RayTracer::next()
{
glm::vec2 cur {p};
static constexpr const glm::vec2 m {1, -1};
const int axis = (error > 0) ? 1 : 0;
p[axis] += inc[axis];
error += d[1 - axis] * m[axis];
return cur;
}
std::optional<glm::vec3>
GeoData::intersectRay(const Ray & ray) const
{
if (glm::length(!ray.direction) <= 0) {
return {};
}
RayTracer rt {ray.start / scale, ray.direction};
while (true) {
const auto n {rt.next() * scale};
try {
const auto point = quad(n);
for (auto offset : {0U, 1U}) {
glm::vec2 bary;
float distance;
if (glm::intersectRayTriangle(ray.start, ray.direction, point[offset], point[offset + 1],
point[offset + 2], bary, distance)) {
return point[offset] + ((point[offset + 1] - point[offset]) * bary[0])
+ ((point[offset + 2] - point[offset]) * bary[1]);
}
}
}
catch (std::range_error &) {
const auto rel = n / !ray.direction;
if (rel.x > 0 && rel.y > 0) {
return {};
}
}
}
return {};
}
unsigned int
GeoData::at(glm::ivec2 coord) const
{
if (coord.x < limit.first.x || coord.x > limit.second.x || coord.y < limit.first.y || coord.y > limit.second.y) {
throw std::range_error {"Coordinates outside GeoData limits"};
}
const glm::uvec2 offset = coord - limit.first;
return offset.x + (offset.y * size.x);
}
unsigned int
GeoData::at(int x, int y) const
{
return at({x, y});
}
GeoData::Limits
GeoData::getLimit() const
{
return limit;
}
float
GeoData::getScale() const
{
return scale;
}
glm::uvec2
GeoData::getSize() const
{
return size;
}
std::span<const GeoData::Node>
GeoData::getNodes() const
{
return nodes;
}
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