cleanup some of the hexagon code

demo/demo/hexboard/board.cpp

@@ -35,10 +35,17 @@ namespace demo::hexboard {
 		grass.data->name = "grass";
 		grass.data->colour = {0.0F, 1.0F, 0.0};
 
-		fggl::grid::IntHex islandPoint{3,3};
-		auto island = islandPoint.hexesInRange(2);
-		for ( auto& hex : island) {
-			m_board->setTerrain(hex, grass);
+		std::array<fggl::grid::IntHex, 4> islands {{
+													   {3, 3},
+													   {7, 7},
+													   {10, 10},
+													   {7, 3}
+												   }};
+		for (auto islandPoint : islands){
+			auto island = islandPoint.hexesInRange(2);
+			for (auto &hex : island) {
+				m_board->setTerrain(hex, grass);
+			}
 		}
 
 	}
@@ -59,12 +66,10 @@ namespace demo::hexboard {
 		// check if a button was pressed
 		auto& input = this->input();
 		{
-			fggl::math::vec2 screenPos(
-				input.mouse.axis(fggl::input::MouseAxis::X),
-				input.mouse.axis(fggl::input::MouseAxis::Y)
+			const fggl::math::vec2 screenPos(
+				fggl::math::rescale_ndc(input.mouse.axis(fggl::input::MouseAxis::X), 0, 1920),
+				fggl::math::rescale_ndc(input.mouse.axis(fggl::input::MouseAxis::Y), 0, 1080)
 			);
-			screenPos.x = fggl::math::rescale_ndc(screenPos.x, 0, 1920);
-			screenPos.y = fggl::math::rescale_ndc(screenPos.y, 0, 1080);
 			m_selections->hover = fggl::grid::round2( m_layout->toGrid(screenPos) );
 
 			if (input.mouse.pressed(fggl::input::MouseButton::LEFT)) {
@@ -74,29 +79,13 @@ namespace demo::hexboard {
 	}
 
 	void Scene::drawGrid(fggl::gfx::Paint& paint) {
-		const float hexRadius = 64.0F;
-		const auto gridWidth = (int)( (1920 - hexRadius) / (hexRadius * std::sqrt(3.0F)) );
-		const auto gridHeight = (int)( (1080 - hexRadius) / (hexRadius * (3.0F / 2.0F) ));
-
 		auto tiles = m_board->getAllTiles();
-
-		fggl::grid::IntHex hexPos{0, 0};
-		auto rowBasis = hexPos;
-		for(auto i=0; i<gridHeight; ++i) {
-			for (auto j=0; j<gridWidth; ++j) {
-
-				auto terrain = m_board->getTerrain(hexPos);
-				if ( terrain.has_value() ) {
-					const auto& value = terrain.value();
-					m_layout->paintHex(paint, hexPos, value.colour);
-				}
-
-				// next hexagon
-				hexPos = hexPos.neighbour(fggl::grid::HexDirPointy::RIGHT);
+		for ( const auto& tile : tiles ) {
+			auto terrain = m_board->getTerrain(tile);
+			if ( terrain.has_value() ) {
+				const auto& terrainData = terrain.value();
+				m_layout->paintHex(paint, tile, terrainData.colour);
 			}
-
-			rowBasis = i % 2 == 0 ? rowBasis.neighbour(fggl::grid::HexDirPointy::BOTTOM_RIGHT) : rowBasis.neighbour(fggl::grid::HexDirPointy::BOTTOM_LEFT);
-			hexPos = rowBasis;
 		}
 	}
 

include/fggl/grid/layout.hpp

@@ -38,14 +38,18 @@
 
 namespace fggl::grid {
 
-	const math::mat2 MAT_HEX_POINTY {
-		std::sqrt(3.0F), 0.0F,
-		std::sqrt(3.0F) / 2.0F, 3.0F/2.0F
+	// factor out the call to sqrt so the matrices can be constexpr
+	constexpr float M_SQRT_3 = 1.73205080757F;
+	constexpr float M_SQRT_3_OVER_2 = M_SQRT_3 / 2.0F;
+
+	constexpr math::mat2 MAT_HEX_POINTY{
+		M_SQRT_3, 0.0F,
+		M_SQRT_3_OVER_2, 3.F / 2.F
 	};
 
-	const math::mat2 MAT_HEX_FLAT {
-		3.F/2.F, std::sqrt(3.F)/2.F,
-		0.0F, std::sqrt(3.F)
+	constexpr math::mat2 MAT_HEX_FLAT{
+		3.F / 2.F, M_SQRT_3_OVER_2,
+		0.0F, M_SQRT_3
 	};
 
 	struct Orientation {
@@ -73,6 +77,11 @@ namespace fggl::grid {
 		Layout(Orientation orientation, math::vec2 size, math::vec2 origin) : m_orientation(orientation), m_size(size), m_origin(origin){}
 		Layout(Orientation orientation, float size) : m_orientation(orientation), m_size(size, size), m_origin() {}
 
+		inline void translate(float dx, float dy){
+			m_origin.x += dx;
+			m_origin.y += dy;
+		}
+
 		[[nodiscard]]
 		inline math::vec2 origin() const {
 			return m_origin;