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#include "maths.h"
#include <cmath>
#include <glm/glm.hpp>
#include <glm/gtx/rotate_vector.hpp>
#include <glm/gtx/transform.hpp>
#include <initializer_list>
#include <stdexcept>
glm::mat4
flat_orientation(const glm::vec3 & diff)
{
static const auto oneeighty {glm::rotate(pi, up)};
const auto flatdiff {glm::normalize(glm::vec3 {diff.x, 0, diff.z})};
auto e {glm::orientation(flatdiff, north)};
// Handle if diff is exactly opposite to north
return (std::isnan(e[0][0])) ? oneeighty : e;
}
float
vector_yaw(const glm::vec3 & diff)
{
return std::atan2(diff.x, diff.z);
}
float
vector_pitch(const glm::vec3 & diff)
{
return std::atan(diff.y);
}
float
round_frac(const float & v, const float & frac)
{
return std::round(v / frac) * frac;
}
float
normalize(float ang)
{
while (ang > pi) {
ang -= two_pi;
}
while (ang <= -pi) {
ang += two_pi;
}
return ang;
}
Arc::Arc(const glm::vec3 & centre3, const glm::vec3 & e0p, const glm::vec3 & e1p) :
Arc([&]() -> Arc {
const auto diffa = e0p - centre3;
const auto diffb = e1p - centre3;
const auto anga = vector_yaw(diffa);
const auto angb = [&diffb, &anga]() {
const auto angb = vector_yaw(diffb);
return (angb < anga) ? angb + two_pi : angb;
}();
return {anga, angb};
}())
{
}
std::pair<glm::vec2, bool>
find_arc_centre(glm::vec2 as, float entrys, glm::vec2 bs, float entrye)
{
if (as == bs) {
return {as, false};
}
for (const auto lr : {1.F, -1.F}) { // left or right turn (maybe possible with removal of positve check below)
const auto perps = entrys + (half_pi * lr);
const auto perpe = entrye - (half_pi * lr);
const glm::vec2 ad {std::sin(perps), std::cos(perps)};
const glm::vec2 bd {std::sin(perpe), std::cos(perpe)};
const auto dx = bs.x - as.x;
const auto dy = bs.y - as.y;
const auto det = bd.x * ad.y - bd.y * ad.x;
if (det != 0) { // near parallel line will yield noisy results
const auto u = (dy * bd.x - dx * bd.y) / det;
const auto v = (dy * ad.x - dx * ad.y) / det;
if (u >= 0 && v >= 0) {
return {as + ad * u, lr < 0};
}
}
}
throw std::runtime_error("no intersection");
}
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