added obb

This commit is contained in:
2026-05-07 05:04:35 +03:00
parent 6b637f6267
commit fbc35391c4
4 changed files with 407 additions and 41 deletions
+2
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@@ -0,0 +1,2 @@
<?xml version="1.0" encoding="UTF-8"?>
<module classpath="CIDR" type="CPP_MODULE" version="4" />
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//
// Created by Vladislav on 07.05.2026.
//
#pragma once
#include "omath/linear_algebra/vector3.hpp"
#include <array>
#include <type_traits>
namespace omath::primitives
{
// Oriented bounding box: a rectangular cuboid defined by a center, three
// orthonormal local axes, and the half-size along each of those axes.
template<class Type>
requires std::is_floating_point_v<Type>
struct Obb final
{
Vector3<Type> center;
Vector3<Type> axis_x;
Vector3<Type> axis_y;
Vector3<Type> axis_z;
Vector3<Type> half_extents;
[[nodiscard]]
constexpr std::array<Vector3<Type>, 8> vertices() const noexcept
{
const auto ex = axis_x * half_extents.x;
const auto ey = axis_y * half_extents.y;
const auto ez = axis_z * half_extents.z;
return {
center - ex - ey - ez, center + ex - ey - ez, center - ex + ey - ez, center + ex + ey - ez,
center - ex - ey + ez, center + ex - ey + ez, center - ex + ey + ez, center + ex + ey + ez,
};
}
};
} // namespace omath::primitives
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@@ -5,6 +5,7 @@
#pragma once
#include "omath/3d_primitives/aabb.hpp"
#include "omath/3d_primitives/obb.hpp"
#include "omath/linear_algebra/mat.hpp"
#include "omath/linear_algebra/triangle.hpp"
#include "omath/linear_algebra/vector3.hpp"
@@ -380,49 +381,9 @@ namespace omath::projection
[[nodiscard]] bool is_aabb_culled_by_frustum(const primitives::Aabb<NumericType>& aabb) const noexcept
{
const auto& m = get_view_projection_matrix();
// Gribb-Hartmann: extract 6 frustum planes from the view-projection matrix.
// Each plane is (a, b, c, d) such that ax + by + cz + d >= 0 means inside.
// For a 4x4 matrix with rows r0..r3:
// Left = r3 + r0
// Right = r3 - r0
// Bottom = r3 + r1
// Top = r3 - r1
// Near = r3 + r2 ([-1,1]) or r2 ([0,1])
// Far = r3 - r2
struct Plane final
{
NumericType a, b, c, d;
};
const auto extract_plane = [&m](const int sign, const int row) -> Plane
{
return {
m.at(3, 0) + static_cast<NumericType>(sign) * m.at(row, 0),
m.at(3, 1) + static_cast<NumericType>(sign) * m.at(row, 1),
m.at(3, 2) + static_cast<NumericType>(sign) * m.at(row, 2),
m.at(3, 3) + static_cast<NumericType>(sign) * m.at(row, 3),
};
};
std::array<Plane, 6> planes = {
extract_plane(1, 0), // left
extract_plane(-1, 0), // right
extract_plane(1, 1), // bottom
extract_plane(-1, 1), // top
extract_plane(-1, 2), // far
};
// Near plane depends on NDC depth range
if constexpr (depth_range == NDCDepthRange::ZERO_TO_ONE)
planes[5] = {m.at(2, 0), m.at(2, 1), m.at(2, 2), m.at(2, 3)};
else
planes[5] = extract_plane(1, 2);
// For each plane, find the AABB corner most in the direction of the plane normal
// (the "positive vertex"). If it's outside, the entire AABB is outside.
for (const auto& [a, b, c, d] : planes)
for (const auto& [a, b, c, d] : extract_frustum_planes())
{
const auto px = a >= NumericType{0} ? aabb.max.x : aabb.min.x;
const auto py = b >= NumericType{0} ? aabb.max.y : aabb.min.y;
@@ -435,6 +396,26 @@ namespace omath::projection
return false;
}
[[nodiscard]] bool is_obb_culled_by_frustum(const primitives::Obb<NumericType>& obb) const noexcept
{
// For each plane, project the OBB extents onto the plane normal to get the
// effective radius, then test the center's signed distance against it.
for (const auto& [a, b, c, d] : extract_frustum_planes())
{
const Vector3<NumericType> normal{a, b, c};
const auto center_distance = normal.dot(obb.center) + d;
const auto radius = obb.half_extents.x * std::abs(normal.dot(obb.axis_x))
+ obb.half_extents.y * std::abs(normal.dot(obb.axis_y))
+ obb.half_extents.z * std::abs(normal.dot(obb.axis_z));
if (center_distance + radius < NumericType{0})
return true;
}
return false;
}
[[nodiscard]] std::expected<Vector3<NumericType>, Error>
world_to_view_port(const Vector3<NumericType>& world_position,
const ViewPortClipping& clipping = ViewPortClipping::AUTO) const noexcept
@@ -517,6 +498,51 @@ namespace omath::projection
Vector3<NumericType> m_origin;
private:
struct FrustumPlane final
{
NumericType a, b, c, d;
};
// Gribb-Hartmann: extract 6 frustum planes from the view-projection matrix.
// Each plane is (a, b, c, d) such that ax + by + cz + d >= 0 means inside.
// For a 4x4 matrix with rows r0..r3:
// Left = r3 + r0
// Right = r3 - r0
// Bottom = r3 + r1
// Top = r3 - r1
// Near = r3 + r2 ([-1,1]) or r2 ([0,1])
// Far = r3 - r2
[[nodiscard]] std::array<FrustumPlane, 6> extract_frustum_planes() const noexcept
{
const auto& m = get_view_projection_matrix();
const auto extract_plane = [&m](const int sign, const int row) -> FrustumPlane
{
return {
m.at(3, 0) + static_cast<NumericType>(sign) * m.at(row, 0),
m.at(3, 1) + static_cast<NumericType>(sign) * m.at(row, 1),
m.at(3, 2) + static_cast<NumericType>(sign) * m.at(row, 2),
m.at(3, 3) + static_cast<NumericType>(sign) * m.at(row, 3),
};
};
std::array<FrustumPlane, 6> planes = {
extract_plane(1, 0), // left
extract_plane(-1, 0), // right
extract_plane(1, 1), // bottom
extract_plane(-1, 1), // top
extract_plane(-1, 2), // far
};
// Near plane depends on NDC depth range
if constexpr (depth_range == NDCDepthRange::ZERO_TO_ONE)
planes[5] = {m.at(2, 0), m.at(2, 1), m.at(2, 2), m.at(2, 3)};
else
planes[5] = extract_plane(1, 2);
return planes;
}
template<class Type>
[[nodiscard]] constexpr static bool is_ndc_out_of_bounds(const Type& ndc) noexcept
{
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//
// Created by Vladislav on 07.05.2026.
//
#include <cmath>
#include <gtest/gtest.h>
#include <numbers>
#include <omath/3d_primitives/obb.hpp>
#include <omath/engines/opengl_engine/camera.hpp>
#include <omath/engines/source_engine/camera.hpp>
#include <omath/engines/unity_engine/camera.hpp>
#include <omath/projection/camera.hpp>
using ObbF = omath::primitives::Obb<float>;
using ObbD = omath::primitives::Obb<double>;
using Vec3F = omath::Vector3<float>;
using Vec3D = omath::Vector3<double>;
namespace
{
constexpr ObbF axis_aligned_obb(const Vec3F& center, const Vec3F& half_extents) noexcept
{
return ObbF{center, {1.f, 0.f, 0.f}, {0.f, 1.f, 0.f}, {0.f, 0.f, 1.f}, half_extents};
}
ObbF rotated_around_z(const Vec3F& center, const Vec3F& half_extents, const float radians) noexcept
{
const auto c = std::cos(radians);
const auto s = std::sin(radians);
return ObbF{center, {c, s, 0.f}, {-s, c, 0.f}, {0.f, 0.f, 1.f}, half_extents};
}
ObbF rotated_around_y(const Vec3F& center, const Vec3F& half_extents, const float radians) noexcept
{
const auto c = std::cos(radians);
const auto s = std::sin(radians);
return ObbF{center, {c, 0.f, -s}, {0.f, 1.f, 0.f}, {s, 0.f, c}, half_extents};
}
} // namespace
// --- struct-level tests ---
TEST(ObbTests, VerticesOfAxisAlignedUnitBox)
{
constexpr auto box = axis_aligned_obb({0.f, 0.f, 0.f}, {1.f, 1.f, 1.f});
const auto v = box.vertices();
EXPECT_EQ(v[0], (Vec3F{-1.f, -1.f, -1.f}));
EXPECT_EQ(v[1], (Vec3F{1.f, -1.f, -1.f}));
EXPECT_EQ(v[2], (Vec3F{-1.f, 1.f, -1.f}));
EXPECT_EQ(v[3], (Vec3F{1.f, 1.f, -1.f}));
EXPECT_EQ(v[4], (Vec3F{-1.f, -1.f, 1.f}));
EXPECT_EQ(v[5], (Vec3F{1.f, -1.f, 1.f}));
EXPECT_EQ(v[6], (Vec3F{-1.f, 1.f, 1.f}));
EXPECT_EQ(v[7], (Vec3F{1.f, 1.f, 1.f}));
}
TEST(ObbTests, VerticesOfTranslatedBox)
{
constexpr auto box = axis_aligned_obb({10.f, 20.f, 30.f}, {1.f, 2.f, 3.f});
const auto v = box.vertices();
EXPECT_EQ(v[0], (Vec3F{9.f, 18.f, 27.f}));
EXPECT_EQ(v[7], (Vec3F{11.f, 22.f, 33.f}));
}
TEST(ObbTests, VerticesOfRotatedBox)
{
constexpr auto pi = std::numbers::pi_v<float>;
const auto box = rotated_around_z({0.f, 0.f, 0.f}, {1.f, 1.f, 1.f}, pi / 2.f);
const auto v = box.vertices();
// After 90° rotation around Z, local +X maps to world +Y, local +Y maps to world -X.
// The eight vertices are still the same eight points (a cube is symmetric), but their
// ordering changes. Check that the corner set as a whole is still |coord| == 1.
for (const auto& corner : v)
{
EXPECT_NEAR(std::abs(corner.x), 1.f, 1e-5f);
EXPECT_NEAR(std::abs(corner.y), 1.f, 1e-5f);
EXPECT_NEAR(std::abs(corner.z), 1.f, 1e-5f);
}
}
TEST(ObbTests, DoublePrecisionInstantiation)
{
constexpr ObbD box{{0.0, 0.0, 0.0}, {1.0, 0.0, 0.0}, {0.0, 1.0, 0.0}, {0.0, 0.0, 1.0}, {2.0, 3.0, 4.0}};
const auto v = box.vertices();
EXPECT_DOUBLE_EQ(v[0].x, -2.0);
EXPECT_DOUBLE_EQ(v[0].y, -3.0);
EXPECT_DOUBLE_EQ(v[0].z, -4.0);
EXPECT_DOUBLE_EQ(v[7].x, 2.0);
EXPECT_DOUBLE_EQ(v[7].y, 3.0);
EXPECT_DOUBLE_EQ(v[7].z, 4.0);
}
// --- frustum culling tests (Source Engine: +X forward, +Y left, +Z up) ---
TEST(ObbTests, AxisAlignedInFrontNotCulled)
{
constexpr auto fov = omath::projection::FieldOfView::from_degrees(90.f);
const auto cam = omath::source_engine::Camera({0, 0, 0}, omath::source_engine::ViewAngles{}, {1920.f, 1080.f}, fov,
0.01f, 1000.f);
const auto obb = axis_aligned_obb({100.f, 0.f, 0.f}, {10.f, 1.f, 1.f});
EXPECT_FALSE(cam.is_obb_culled_by_frustum(obb));
}
TEST(ObbTests, AxisAlignedBehindCameraCulled)
{
constexpr auto fov = omath::projection::FieldOfView::from_degrees(90.f);
const auto cam = omath::source_engine::Camera({0, 0, 0}, omath::source_engine::ViewAngles{}, {1920.f, 1080.f}, fov,
0.01f, 1000.f);
const auto obb = axis_aligned_obb({-150.f, 0.f, 0.f}, {50.f, 1.f, 1.f});
EXPECT_TRUE(cam.is_obb_culled_by_frustum(obb));
}
TEST(ObbTests, AxisAlignedBeyondFarPlaneCulled)
{
constexpr auto fov = omath::projection::FieldOfView::from_degrees(90.f);
const auto cam = omath::source_engine::Camera({0, 0, 0}, omath::source_engine::ViewAngles{}, {1920.f, 1080.f}, fov,
0.01f, 1000.f);
const auto obb = axis_aligned_obb({1750.f, 0.f, 0.f}, {250.f, 1.f, 1.f});
EXPECT_TRUE(cam.is_obb_culled_by_frustum(obb));
}
TEST(ObbTests, AxisAlignedFarLeftCulled)
{
constexpr auto fov = omath::projection::FieldOfView::from_degrees(90.f);
const auto cam = omath::source_engine::Camera({0, 0, 0}, omath::source_engine::ViewAngles{}, {1920.f, 1080.f}, fov,
0.01f, 1000.f);
const auto obb = axis_aligned_obb({100.f, 4500.f, 0.f}, {10.f, 500.f, 1.f});
EXPECT_TRUE(cam.is_obb_culled_by_frustum(obb));
}
TEST(ObbTests, AxisAlignedFarRightCulled)
{
constexpr auto fov = omath::projection::FieldOfView::from_degrees(90.f);
const auto cam = omath::source_engine::Camera({0, 0, 0}, omath::source_engine::ViewAngles{}, {1920.f, 1080.f}, fov,
0.01f, 1000.f);
const auto obb = axis_aligned_obb({100.f, -4500.f, 0.f}, {10.f, 500.f, 1.f});
EXPECT_TRUE(cam.is_obb_culled_by_frustum(obb));
}
TEST(ObbTests, AxisAlignedAboveCulled)
{
constexpr auto fov = omath::projection::FieldOfView::from_degrees(90.f);
const auto cam = omath::source_engine::Camera({0, 0, 0}, omath::source_engine::ViewAngles{}, {1920.f, 1080.f}, fov,
0.01f, 1000.f);
const auto obb = axis_aligned_obb({100.f, 0.f, 5500.f}, {10.f, 1.f, 500.f});
EXPECT_TRUE(cam.is_obb_culled_by_frustum(obb));
}
TEST(ObbTests, AxisAlignedBelowCulled)
{
constexpr auto fov = omath::projection::FieldOfView::from_degrees(90.f);
const auto cam = omath::source_engine::Camera({0, 0, 0}, omath::source_engine::ViewAngles{}, {1920.f, 1080.f}, fov,
0.01f, 1000.f);
const auto obb = axis_aligned_obb({100.f, 0.f, -5500.f}, {10.f, 1.f, 500.f});
EXPECT_TRUE(cam.is_obb_culled_by_frustum(obb));
}
TEST(ObbTests, MatchesAabbForAxisAlignedBox)
{
// For axis-aligned OBBs, the result must agree with is_aabb_culled_by_frustum.
constexpr auto fov = omath::projection::FieldOfView::from_degrees(90.f);
const auto cam = omath::source_engine::Camera({0, 0, 0}, omath::source_engine::ViewAngles{}, {1920.f, 1080.f}, fov,
0.01f, 1000.f);
const struct
{
Vec3F center;
Vec3F half;
} cases[] = {
{{100.f, 0.f, 0.f}, {10.f, 1.f, 1.f}}, // in front
{{-150.f, 0.f, 0.f}, {50.f, 1.f, 1.f}}, // behind
{{1750.f, 0.f, 0.f}, {250.f, 1.f, 1.f}}, // beyond far
{{100.f, 4500.f, 0.f}, {10.f, 500.f, 1.f}}, // far left
{{0.f, 0.f, 0.f}, {500.f, 500.f, 500.f}}, // encloses camera
{{275.f, 0.f, 0.f}, {225.f, 1.f, 1.f}}, // straddles near
};
for (const auto& [center, half]: cases)
{
const omath::primitives::Aabb<float> aabb{center - half, center + half};
const auto obb = axis_aligned_obb(center, half);
EXPECT_EQ(cam.is_obb_culled_by_frustum(obb), cam.is_aabb_culled_by_frustum(aabb))
<< "mismatch for center (" << center.x << "," << center.y << "," << center.z << ")";
}
}
TEST(ObbTests, RotationCanPullBoxIntoFrustum)
{
// Tall thin column sitting just outside the +Y frustum boundary at X=50.
// Axis-aligned: every corner has Y≈100 at X≈50, all outside the +Y plane → culled.
// Rotated 90° around world Y: the 50-unit extent now points along world +X, so the rod
// sweeps forward to X≈100 where the +Y plane is far more permissive — front end inside,
// box no longer fully outside → not culled.
constexpr auto fov = omath::projection::FieldOfView::from_degrees(90.f);
const auto cam = omath::source_engine::Camera({0, 0, 0}, omath::source_engine::ViewAngles{}, {1920.f, 1080.f}, fov,
0.01f, 1000.f);
const Vec3F center{50.f, 100.f, 0.f};
const Vec3F half{1.f, 1.f, 50.f};
const auto axis_aligned = axis_aligned_obb(center, half);
EXPECT_TRUE(cam.is_obb_culled_by_frustum(axis_aligned));
const auto rotated = rotated_around_y(center, half, std::numbers::pi_v<float> / 2.f);
EXPECT_FALSE(cam.is_obb_culled_by_frustum(rotated));
}
TEST(ObbTests, RotationCanPushBoxOutOfFrustum)
{
// Long forward-pointing rod whose front end pokes into the frustum near the +Y boundary.
// Axis-aligned (long along X): the front end at X≈100 has Y=129 just inside the +Y plane,
// so part of the rod is visible → not culled.
// Rotated 90° around Z: the rod's long axis now points along world Y, so all corners
// shift to Y∈[80,180] at X≈50 — every corner is outside the +Y plane → culled.
constexpr auto fov = omath::projection::FieldOfView::from_degrees(90.f);
const auto cam = omath::source_engine::Camera({0, 0, 0}, omath::source_engine::ViewAngles{}, {1920.f, 1080.f}, fov,
0.01f, 1000.f);
const Vec3F center{50.f, 130.f, 0.f};
const Vec3F half{50.f, 1.f, 1.f};
const auto axis_aligned = axis_aligned_obb(center, half);
EXPECT_FALSE(cam.is_obb_culled_by_frustum(axis_aligned));
const auto rotated = rotated_around_z(center, half, std::numbers::pi_v<float> / 2.f);
EXPECT_TRUE(cam.is_obb_culled_by_frustum(rotated));
}
TEST(ObbTests, RotatedBoxStraddlingFrustumNotCulled)
{
constexpr auto fov = omath::projection::FieldOfView::from_degrees(90.f);
const auto cam = omath::source_engine::Camera({0, 0, 0}, omath::source_engine::ViewAngles{}, {1920.f, 1080.f}, fov,
0.01f, 1000.f);
// Box centred in front, rotated 30° — clearly straddles into the frustum.
const auto obb = rotated_around_z({200.f, 0.f, 0.f}, {50.f, 50.f, 50.f},
std::numbers::pi_v<float> / 6.f);
EXPECT_FALSE(cam.is_obb_culled_by_frustum(obb));
}
TEST(ObbTests, OpenGlEngineRotatedInFrontNotCulled)
{
// OpenGL: -Z forward, COLUMN_MAJOR, NEGATIVE_ONE_TO_ONE
constexpr auto fov = omath::projection::FieldOfView::from_degrees(90.f);
const auto cam = omath::opengl_engine::Camera({0, 0, 0}, {}, {1920.f, 1080.f}, fov, 0.01f, 1000.f);
const auto obb = rotated_around_z({0.f, 0.f, -100.f}, {5.f, 5.f, 5.f},
std::numbers::pi_v<float> / 4.f);
EXPECT_FALSE(cam.is_obb_culled_by_frustum(obb));
}
TEST(ObbTests, OpenGlEngineBehindCulled)
{
constexpr auto fov = omath::projection::FieldOfView::from_degrees(90.f);
const auto cam = omath::opengl_engine::Camera({0, 0, 0}, {}, {1920.f, 1080.f}, fov, 0.01f, 1000.f);
const auto obb = axis_aligned_obb({0.f, 0.f, 100.f}, {5.f, 5.f, 5.f});
EXPECT_TRUE(cam.is_obb_culled_by_frustum(obb));
}
TEST(ObbTests, UnityEngineBeyondFarCulled)
{
constexpr auto fov = omath::projection::FieldOfView::from_degrees(60.f);
const auto cam = omath::unity_engine::Camera({0, 0, 0}, {}, {1280.f, 720.f}, fov, 0.03f, 500.f);
const auto obb = rotated_around_z({0.f, 0.f, 700.f}, {5.f, 5.f, 5.f},
std::numbers::pi_v<float> / 4.f);
EXPECT_TRUE(cam.is_obb_culled_by_frustum(obb));
}
TEST(ObbTests, DegenerateZeroVolumeInsideNotCulled)
{
constexpr auto fov = omath::projection::FieldOfView::from_degrees(90.f);
const auto cam = omath::source_engine::Camera({0, 0, 0}, omath::source_engine::ViewAngles{}, {1920.f, 1080.f}, fov,
0.01f, 1000.f);
// Zero-extent OBB — collapses to a point, but still must not be culled if the centre is inside.
const auto obb = axis_aligned_obb({100.f, 0.f, 0.f}, {0.f, 0.f, 0.f});
EXPECT_FALSE(cam.is_obb_culled_by_frustum(obb));
}
TEST(ObbTests, EnclosingCameraNotCulled)
{
constexpr auto fov = omath::projection::FieldOfView::from_degrees(90.f);
const auto cam = omath::source_engine::Camera({0, 0, 0}, omath::source_engine::ViewAngles{}, {1920.f, 1080.f}, fov,
0.01f, 1000.f);
// Huge rotated box that fully encloses the camera origin.
const auto obb = rotated_around_z({0.f, 0.f, 0.f}, {500.f, 500.f, 500.f},
std::numbers::pi_v<float> / 5.f);
EXPECT_FALSE(cam.is_obb_culled_by_frustum(obb));
}