From c2421c3ac2018faf5d47205ee979acec181d9672 Mon Sep 17 00:00:00 2001
From: Dan Goodliffe <dan@randomdan.homeip.net>
Date: Sun, 2 Jan 2022 18:04:00 +0000
Subject: Separate geographic data (GeoData) from its visual representation(s)
 (Terrain)

---
 game/geoData.cpp | 106 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 106 insertions(+)
 create mode 100644 game/geoData.cpp

(limited to 'game/geoData.cpp')

diff --git a/game/geoData.cpp b/game/geoData.cpp
new file mode 100644
index 0000000..55c69a1
--- /dev/null
+++ b/game/geoData.cpp
@@ -0,0 +1,106 @@
+#include "geoData.h"
+#include "gfx/image.h"
+#include <algorithm>
+#include <cstddef>
+#include <maths.h>
+#include <random>
+#include <stb/stb_image.h>
+#include <stdexcept>
+
+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};
+	});
+}
+
+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;
+}
-- 
cgit v1.2.3