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updated formulas

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Orange
2026-04-23 19:48:55 +03:00
parent 42a8a5a763
commit b3ba9eaadf
3 changed files with 72 additions and 38 deletions
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28
source/engines/unreal_engine/formulas.cpp
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@@ -38,28 +38,16 @@ namespace omath::unreal_engine
Mat4X4 calc_perspective_projection_matrix(const float field_of_view, const float aspect_ratio, const float near,
const float far, const NDCDepthRange ndc_depth_range) noexcept
{
// UE stores horizontal FOV in FMinimalViewInfo — mirror engine's
// FMinimalViewInfo::CalculateProjectionMatrixGivenViewRectangle:
// XAxisMultiplier = 1 / tan(hfov/2)
// YAxisMultiplier = aspect / tan(hfov/2)
const float inv_tan_half_hfov = 1.f / std::tan(angles::degrees_to_radians(field_of_view) / 2.f);
const float x_axis = inv_tan_half_hfov;
const float y_axis = inv_tan_half_hfov * aspect_ratio;
// UE stores horizontal FOV in FMinimalViewInfo — use the left-handed
// horizontal-FOV builder directly.
if (ndc_depth_range == NDCDepthRange::ZERO_TO_ONE)
return {
{x_axis, 0, 0, 0},
{0, y_axis, 0, 0},
{0, 0, far / (far - near), -(near * far) / (far - near)},
{0, 0, 1, 0},
};
return mat_perspective_left_handed_horizontal_fov<
float, MatStoreType::ROW_MAJOR, NDCDepthRange::ZERO_TO_ONE>(
field_of_view, aspect_ratio, near, far);
if (ndc_depth_range == NDCDepthRange::NEGATIVE_ONE_TO_ONE)
return {
{x_axis, 0, 0, 0},
{0, y_axis, 0, 0},
{0, 0, (far + near) / (far - near), -(2.f * far * near) / (far - near)},
{0, 0, 1, 0},
};
return mat_perspective_left_handed_horizontal_fov<
float, MatStoreType::ROW_MAJOR, NDCDepthRange::NEGATIVE_ONE_TO_ONE>(
field_of_view, aspect_ratio, near, far);
std::unreachable();
}
} // namespace omath::unreal_engine