Rename TerrainMesh to GeoData to drop inplace

1 files changed, 182 insertions, 158 deletions

diff --git a/game/geoData.cpp b/game/geoData.cpp
index 34a1030..d32bf8c 100644
--- a/game/geoData.cpp
+++ b/game/geoData.cpp
@@ -1,214 +1,238 @@
 #include "geoData.h"
-#include "gfx/image.h"
-#include <algorithm>
-#include <array>
-#include <cmath>
-#include <cstddef>
+#include <fstream>
 #include <glm/gtx/intersect.hpp>
-#include <initializer_list>
-#include <limits>
 #include <maths.h>
-#include <random>
-#include <ray.h>
-#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()
+GeoData
+GeoData::loadFromAsciiGrid(const std::filesystem::path & input)
 {
-	// 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 {ratio(sq(x - hpos.x), sq(hsize.x)) + ratio(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;
-			}
+	size_t ncols = 0, nrows = 0, xllcorner = 0, yllcorner = 0, cellsize = 0;
+	std::map<std::string_view, size_t *> properties {
+			{"ncols", &ncols},
+			{"nrows", &nrows},
+			{"xllcorner", &xllcorner},
+			{"yllcorner", &yllcorner},
+			{"cellsize", &cellsize},
+	};
+	std::ifstream f {input};
+	while (!properties.empty()) {
+		std::string property;
+		f >> property;
+		f >> *properties.at(property);
+		properties.erase(property);
+	}
+	std::vector<VertexHandle> vertices;
+	vertices.reserve(ncols * nrows);
+	GeoData mesh;
+	mesh.lowerExtent = {xllcorner, yllcorner, std::numeric_limits<float>::max()};
+	mesh.upperExtent
+			= {xllcorner + (cellsize * ncols), yllcorner + (cellsize * nrows), std::numeric_limits<float>::min()};
+	for (size_t row = 0; row < nrows; ++row) {
+		for (size_t col = 0; col < ncols; ++col) {
+			float height = 0;
+			f >> height;
+			mesh.upperExtent.z = std::max(mesh.upperExtent.z, height);
+			mesh.lowerExtent.z = std::min(mesh.lowerExtent.z, height);
+			vertices.push_back(mesh.add_vertex({xllcorner + (col * cellsize), yllcorner + (row * cellsize), height}));
 		}
 	}
-}
+	if (!f.good()) {
+		throw std::runtime_error("Couldn't read terrain file");
+	}
+	for (size_t row = 1; row < nrows; ++row) {
+		for (size_t col = 1; col < ncols; ++col) {
+			mesh.add_face({
+					vertices[ncols * (row - 1) + (col - 1)],
+					vertices[ncols * (row - 0) + (col - 0)],
+					vertices[ncols * (row - 0) + (col - 1)],
+			});
+			mesh.add_face({
+					vertices[ncols * (row - 1) + (col - 1)],
+					vertices[ncols * (row - 1) + (col - 0)],
+					vertices[ncols * (row - 0) + (col - 0)],
+			});
+		}
+	}
+	mesh.update_face_normals();
+	mesh.update_vertex_normals();
 
-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};
-	});
-}
+	return mesh;
+};
 
-GeoData::Quad
-GeoData::quad(glm::vec2 wcoord) const
+GeoData
+GeoData::createFlat(glm::vec2 lower, glm::vec2 upper, float h)
 {
-	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;
-			});
-}
+	GeoData mesh;
 
-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);
+	mesh.lowerExtent = lower ^ h;
+	mesh.upperExtent = upper ^ h;
+
+	const auto ll = mesh.add_vertex({lower.x, lower.y, h}), lu = mesh.add_vertex({lower.x, upper.y, h}),
+			   ul = mesh.add_vertex({upper.x, lower.y, h}), uu = mesh.add_vertex({upper.x, upper.y, h});
+
+	mesh.add_face(ll, uu, lu);
+	mesh.add_face(ll, ul, uu);
 
-	return wcoord || heightMid;
+	mesh.update_face_normals();
+	mesh.update_vertex_normals();
+
+	return mesh;
 }
 
-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)}
+OpenMesh::FaceHandle
+GeoData::findPoint(glm::vec2 p) const
 {
+	return findPoint(p, *faces_begin());
 }
 
-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}
+GeoData::PointFace::PointFace(const glm::vec2 p, const GeoData * mesh) : PointFace {p, mesh, *mesh->faces_begin()} { }
+
+GeoData::PointFace::PointFace(const glm::vec2 p, const GeoData * mesh, FaceHandle start) :
+	PointFace {p, mesh->findPoint(p, start)}
 {
 }
 
-std::pair<float, float>
-GeoData::RayTracer::byAxis(glm::vec2 p0, glm::vec2 p1, glm::vec2 d, glm::length_t axis)
+GeoData::FaceHandle
+GeoData::PointFace::face(const GeoData * mesh, FaceHandle start) const
 {
-	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]};
+	if (_face.is_valid()) {
+		assert(mesh->triangleContainsPoint(point, _face));
+		return _face;
 	}
 	else {
-		return {-1, (p0[axis] - std::floor(p0[axis])) * d[1 - axis]};
+		return (_face = mesh->findPoint(point, start));
 	}
 }
 
-glm::vec2
-GeoData::RayTracer::next()
+GeoData::FaceHandle
+GeoData::PointFace::face(const GeoData * mesh) const
 {
-	const glm::vec2 cur {p};
+	return face(mesh, *mesh->faces_begin());
+}
+
+namespace {
+	[[nodiscard]] constexpr inline bool
+	pointLeftOfLine(const glm::vec2 p, const glm::vec2 e1, const glm::vec2 e2)
+	{
+		return (e2.x - e1.x) * (p.y - e1.y) > (e2.y - e1.y) * (p.x - e1.x);
+	}
 
-	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];
+	static_assert(pointLeftOfLine({1, 2}, {1, 1}, {2, 2}));
+	static_assert(pointLeftOfLine({2, 1}, {2, 2}, {1, 1}));
+	static_assert(pointLeftOfLine({2, 2}, {1, 2}, {2, 1}));
+	static_assert(pointLeftOfLine({1, 1}, {2, 1}, {1, 2}));
 
-	return cur;
+	[[nodiscard]] constexpr inline bool
+	linesCross(const glm::vec2 a1, const glm::vec2 a2, const glm::vec2 b1, const glm::vec2 b2)
+	{
+		return pointLeftOfLine(a2, b1, b2) && pointLeftOfLine(a1, b2, b1) && pointLeftOfLine(b1, a1, a2)
+				&& pointLeftOfLine(b2, a2, a1);
+	}
+
+	static_assert(linesCross({1, 1}, {2, 2}, {1, 2}, {2, 1}));
 }
 
-std::optional<glm::vec3>
-GeoData::intersectRay(const Ray & ray) const
+OpenMesh::FaceHandle
+GeoData::findPoint(glm::vec2 p, OpenMesh::FaceHandle f) 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]);
+	ConstFaceVertexIter vertices;
+	while (f.is_valid() && !triangleContainsPoint(p, vertices = cfv_iter(f))) {
+		for (auto next = cfh_iter(f); next.is_valid(); ++next) {
+			f = opposite_face_handle(*next);
+			if (f.is_valid()) {
+				const auto e1 = point(to_vertex_handle(*next));
+				const auto e2 = point(to_vertex_handle(opposite_halfedge_handle(*next)));
+				if (pointLeftOfLine(p, e1, e2)) {
+					break;
 				}
 			}
-		}
-		catch (std::range_error &) {
-			const auto rel = n / !ray.direction;
-			if (rel.x > 0 && rel.y > 0) {
-				return {};
-			}
+			f.reset();
 		}
 	}
+	return f;
+}
 
-	return {};
+glm::vec3
+GeoData::positionAt(const PointFace & p) const
+{
+	glm::vec3 out {};
+	Triangle<3> t {this, fv_range(p.face(this))};
+	glm::intersectLineTriangle(p.point ^ 0.F, up, t[0], t[1], t[2], out);
+	return p.point ^ out[0];
 }
 
-unsigned int
-GeoData::at(glm::ivec2 coord) const
+[[nodiscard]] std::optional<glm::vec3>
+GeoData::intersectRay(const Ray & ray) 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);
+	return intersectRay(ray, findPoint(ray.start));
 }
 
-unsigned int
-GeoData::at(int x, int y) const
+[[nodiscard]] std::optional<glm::vec3>
+GeoData::intersectRay(const Ray & ray, FaceHandle face) const
 {
-	return at({x, y});
+	std::optional<glm::vec3> out;
+	walkUntil(PointFace {ray.start, face}, ray.start + (ray.direction * 10000.F), [&out, &ray, this](FaceHandle face) {
+		glm::vec2 bari {};
+		float dist {};
+		Triangle<3> t {this, fv_range(face)};
+		if (glm::intersectRayTriangle(ray.start, ray.direction, t[0], t[1], t[2], bari, dist)) {
+			out = t * bari;
+			return true;
+		}
+		return false;
+	});
+	return out;
 }
 
-GeoData::Limits
-GeoData::getLimit() const
+void
+GeoData::walk(const PointFace & from, const glm::vec2 to, const std::function<void(FaceHandle)> & op) const
 {
-	return limit;
+	walkUntil(from, to, [&op](const auto & fh) {
+		op(fh);
+		return false;
+	});
 }
 
-float
-GeoData::getScale() const
+void
+GeoData::walkUntil(const PointFace & from, const glm::vec2 to, const std::function<bool(FaceHandle)> & op) const
+{
+	assert(from.face(this).is_valid()); // TODO replace with a boundary search
+	auto f = from.face(this);
+	FaceHandle previousFace;
+	while (f.is_valid() && !op(f)) {
+		for (auto next = cfh_iter(f); next.is_valid(); ++next) {
+			f = opposite_face_handle(*next);
+			if (f.is_valid() && f != previousFace) {
+				const auto e1 = point(to_vertex_handle(*next));
+				const auto e2 = point(to_vertex_handle(opposite_halfedge_handle(*next)));
+				if (linesCross(from.point, to, e1, e2)) {
+					previousFace = f;
+					break;
+				}
+			}
+			f.reset();
+		}
+	}
+}
+
+bool
+GeoData::triangleContainsPoint(const glm::vec2 p, const glm::vec2 a, const glm::vec2 b, const glm::vec2 c)
 {
-	return scale;
+	const auto det = (b.x - a.x) * (c.y - a.y) - (b.y - a.y) * (c.x - a.x);
+
+	return det * ((b.x - a.x) * (p.y - a.y) - (b.y - a.y) * (p.x - a.x)) >= 0
+			&& det * ((c.x - b.x) * (p.y - b.y) - (c.y - b.y) * (p.x - b.x)) >= 0
+			&& det * ((a.x - c.x) * (p.y - c.y) - (a.y - c.y) * (p.x - c.x)) >= 0;
 }
 
-glm::uvec2
-GeoData::getSize() const
+bool
+GeoData::triangleContainsPoint(const glm::vec2 p, FaceHandle face) const
 {
-	return size;
+	return triangleContainsPoint(p, cfv_iter(face));
 }
 
-std::span<const GeoData::Node>
-GeoData::getNodes() const
+bool
+GeoData::triangleContainsPoint(const glm::vec2 p, ConstFaceVertexIter vertices) const
 {
-	return nodes;
+	return triangleContainsPoint(p, point(*vertices++), point(*vertices++), point(*vertices++));
 }