Merge branch 'culling'

1 files changed, 40 insertions, 3 deletions

diff --git a/gfx/frustum.cpp b/gfx/frustum.cpp
index 9e046f6..faa676d 100644
--- a/gfx/frustum.cpp
+++ b/gfx/frustum.cpp
@@ -3,10 +3,10 @@
 #include <collections.h>
 #include <glm/ext/matrix_transform.hpp>
 
-static constexpr auto PLANES = std::array {0, 1, 2} * std::array {1.F, -1.F};
+static constexpr auto PLANES = std::array {0, 1, 2} * std::array {-1.F, 1.F};
 
-Frustum::Frustum(const glm::mat4 & view, const glm::mat4 & projection) :
-	view {view}, projection {projection}, viewProjection {}, inverseViewProjection {}, planes {}
+Frustum::Frustum(const GlobalPosition3D & pos, const glm::mat4 & view, const glm::mat4 & projection) :
+	position {pos}, view {view}, projection {projection}, viewProjection {}, inverseViewProjection {}, planes {}
 {
 	updateCache();
 }
@@ -18,6 +18,43 @@ Frustum::updateView(const glm::mat4 & newView)
 	updateCache();
 }
 
+bool
+Frustum::contains(const BoundingBox & aabb) const
+{
+	return boundByPlanes(aabb, FACES);
+}
+
+bool
+Frustum::shadedBy(const BoundingBox & aabb) const
+{
+	return boundByPlanes(aabb, FACES - 1);
+}
+
+bool
+Frustum::boundByPlanes(const BoundingBox & aabb, size_t nplanes) const
+{
+	static constexpr auto EXTENT_CORNER_IDXS = [] {
+		using Extent = GlobalPosition3D BoundingBox::*;
+		constexpr auto EXTENTS = std::array {&BoundingBox::min, &BoundingBox::max};
+		std::array<glm::vec<3, Extent>, 2ZU * 2ZU * 2ZU> out {};
+		std::ranges::copy(std::views::cartesian_product(EXTENTS, EXTENTS, EXTENTS)
+						| std::views::transform(
+								std::make_from_tuple<glm::vec<3, Extent>, std::tuple<Extent, Extent, Extent>>),
+				out.begin());
+		return out;
+	}();
+
+	const std::array<RelativePosition4D, 8> corners
+			= EXTENT_CORNER_IDXS * [relativeAabb = aabb - position](auto idxs) -> glm::vec4 {
+		return {(relativeAabb.*(idxs.x)).x, (relativeAabb.*(idxs.y)).y, (relativeAabb.*(idxs.z)).z, 1.F};
+	};
+	return std::ranges::none_of(std::span(planes).subspan(0, nplanes), [&corners](const auto & frustumPlane) {
+		return (std::ranges::all_of(corners, [&frustumPlane](const auto & corner) {
+			return glm::dot(frustumPlane, corner) < 0.F;
+		}));
+	});
+}
+
 void
 Frustum::updateCache()
 {