From ba69d51cc372197ef55feb87a33ed03afd1b0ca3 Mon Sep 17 00:00:00 2001
From: Dan Goodliffe <dan@randomdan.homeip.net>
Date: Thu, 6 Mar 2025 02:41:09 +0000
Subject: Create AxisAlignedBoundingBox

Used to define the extents of GeoData mesh
---
 game/geoData.cpp | 21 ++++++++++-----------
 game/geoData.h   |  7 ++++---
 game/water.cpp   |  2 +-
 3 files changed, 15 insertions(+), 15 deletions(-)

(limited to 'game')

diff --git a/game/geoData.cpp b/game/geoData.cpp
index 4291a64..5cea4dd 100644
--- a/game/geoData.cpp
+++ b/game/geoData.cpp
@@ -35,16 +35,16 @@ GeoData::loadFromAsciiGrid(const std::filesystem::path & input)
 	std::vector<VertexHandle> vertices;
 	vertices.reserve(ncols * nrows);
 	GeoData mesh;
-	mesh.lowerExtent = {xllcorner, yllcorner, std::numeric_limits<GlobalDistance>::max()};
-	mesh.upperExtent = {xllcorner + (cellsize * (ncols - 1)), yllcorner + (cellsize * (nrows - 1)),
-			std::numeric_limits<GlobalDistance>::min()};
+	mesh.extents = {{xllcorner, yllcorner, std::numeric_limits<GlobalDistance>::max()},
+			{xllcorner + (cellsize * (ncols - 1)), yllcorner + (cellsize * (nrows - 1)),
+					std::numeric_limits<GlobalDistance>::min()}};
 	for (size_t row = 0; row < nrows; ++row) {
 		for (size_t col = 0; col < ncols; ++col) {
 			float heightf = 0;
 			f >> heightf;
 			const auto height = static_cast<GlobalDistance>(std::round(heightf * 1000.F));
-			mesh.upperExtent.z = std::max(mesh.upperExtent.z, height);
-			mesh.lowerExtent.z = std::min(mesh.lowerExtent.z, height);
+			mesh.extents.max.z = std::max(mesh.extents.max.z, height);
+			mesh.extents.min.z = std::min(mesh.extents.min.z, height);
 			vertices.push_back(mesh.add_vertex({xllcorner + (col * cellsize), yllcorner + (row * cellsize), height}));
 		}
 	}
@@ -78,8 +78,7 @@ GeoData::createFlat(GlobalPosition2D lower, GlobalPosition2D upper, GlobalDistan
 	assert((upper - lower) % GRID_SIZE == GlobalPosition2D {});
 	GeoData mesh;
 
-	mesh.lowerExtent = {lower, h};
-	mesh.upperExtent = {upper, h};
+	mesh.extents = {{lower, h}, {upper, h}};
 
 	std::vector<VertexHandle> vertices;
 	for (GlobalDistance row = lower.x; row <= upper.x; row += GRID_SIZE) {
@@ -120,7 +119,7 @@ GeoData::intersectRay(const Ray<GlobalPosition3D> & ray, FaceHandle face) const
 {
 	GeoData::IntersectionResult out;
 	walkUntil(PointFace {ray.start, face},
-			ray.start.xy() + (ray.direction.xy() * RelativePosition2D(upperExtent.xy() - lowerExtent.xy())),
+			ray.start.xy() + (ray.direction.xy() * ::difference(extents.max.xy(), extents.min.xy())),
 			[&out, &ray, this](const auto & step) {
 				BaryPosition bari {};
 				RelativeDistance dist {};
@@ -325,9 +324,9 @@ GeoData::setHeights(const std::span<const GlobalPosition3D> triangleStrip, const
 	if (triangleStrip.size() < 3) {
 		return {};
 	}
-	const auto stripMinMax = std::ranges::minmax(triangleStrip, {}, &GlobalPosition3D::z);
-	lowerExtent.z = std::min(upperExtent.z, stripMinMax.min.z);
-	upperExtent.z = std::max(upperExtent.z, stripMinMax.max.z);
+	for (const auto & vertex : triangleStrip) {
+		extents += vertex;
+	}
 
 	class SetHeights {
 	public:
diff --git a/game/geoData.h b/game/geoData.h
index b2a75bd..a504f9b 100644
--- a/game/geoData.h
+++ b/game/geoData.h
@@ -2,6 +2,7 @@
 
 #include "collections.h" // IWYU pragma: keep IterableCollection
 #include "geoDataMesh.h"
+#include "gfx/aabb.h"
 #include "surface.h"
 #include <filesystem>
 #include <glm/vec2.hpp>
@@ -57,10 +58,10 @@ public:
 
 	std::set<FaceHandle> setHeights(std::span<const GlobalPosition3D> triangleStrip, const SetHeightsOpts &);
 
-	[[nodiscard]] auto
+	[[nodiscard]] auto &
 	getExtents() const
 	{
-		return std::tie(lowerExtent, upperExtent);
+		return extents;
 	}
 
 	template<typename HandleT>
@@ -80,5 +81,5 @@ protected:
 	virtual void afterChange();
 
 private:
-	GlobalPosition3D lowerExtent {}, upperExtent {};
+	AxisAlignedBoundingBox extents;
 };
diff --git a/game/water.cpp b/game/water.cpp
index 94a8596..527e85a 100644
--- a/game/water.cpp
+++ b/game/water.cpp
@@ -82,7 +82,7 @@ Water::generateMeshes()
 						const auto pos = (p * TILE_SIZE) + GlobalPosition2D {x, y};
 						const auto v = vertexIndex.emplace(pos, vertices.size());
 						if (v.second) {
-							const auto cpos = glm::clamp(pos, std::get<0>(extents).xy(), std::get<1>(extents).xy());
+							const auto cpos = glm::clamp(pos, extents.min.xy(), extents.max.xy());
 							vertices.emplace_back(geoData->positionAt(cpos));
 						}
 						*out++ = static_cast<unsigned int>(v.first->second);
-- 
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