Frustum¶
#include <Imath/ImathFrustum.h>
The Frustum class template represents a 3D viewing frustum, with
predefined typedefs of type float and double.
Example:
#include <Imath/ImathFrustum.h>
void
frustum_example()
{
float near = 1.7f;
float far = 567.0f;
float left = -3.5f;
float right = 2.0f;
float top = 0.9f;
float bottom = -1.3f;
Imath::Frustumf frustum (near, far, left, right, top, bottom, false);
Imath::M44f m = frustum.projectionMatrix();
Imath::V3f p (1.0f, 1.0f, 1.0f);
Imath::V2f s = frustum.projectPointToScreen (p);
assert (s.equalWithAbsError (Imath::V2f (-0.345455f, -1.36364f), 0.0001f));
}
-
template<class
T>
classImath::Frustum¶ Template class
Frustum<T>The frustum is always located with the eye point at the origin facing down -Z. This makes the Frustum class compatable with OpenGL (or anything that assumes a camera looks down -Z, hence with a right-handed coordinate system) but not with RenderMan which assumes the camera looks down +Z. Additional functions are provided for conversion from and from various camera coordinate spaces.
nearPlane/farPlane: near/far are keywords used by Microsoft’s compiler, so we use nearPlane/farPlane instead to avoid issues.
Constructors and Assignment
-
inline constexpr
Frustum() noexcept¶ Initialize with default values: near=0.1, far=1000.0, left=-1.0, right=1.0, top=1.0, bottom=-1.0, ortho=false.
-
inline constexpr
Frustum(T nearPlane, T farPlane, T left, T right, T top, T bottom, bool ortho = false) noexcept¶ Initialize to specific values.
-
inline constexpr
Frustum(T nearPlane, T farPlane, T fovx, T fovy, T aspect) noexcept¶ Initialize with fov and aspect.
-
virtual
~Frustum() noexcept¶ Destructor.
Comparison
Query
-
inline constexpr bool
orthographic() const noexcept¶ Return true if the frustum is orthographic, false if perspective.
-
inline constexpr T
aspectExc() const¶ Return the aspect ratio.
Throw an exception if the aspect ratio is undefined.
-
inline constexpr Matrix44<T>
projectionMatrix() const noexcept¶ Return the project matrix that the frustum defines.
-
inline constexpr Matrix44<T>
projectionMatrixExc() const¶ Return the project matrix that the frustum defines.
Throw an exception if the frustum is degenerate.
-
inline constexpr bool
degenerate() const noexcept¶ Return true if the frustum is degenerate.
Set Value
-
inline void
set(T nearPlane, T farPlane, T left, T right, T top, T bottom, bool ortho = false) noexcept¶ Set functions change the entire state of the Frustum.
-
inline void
set(T nearPlane, T farPlane, T fovx, T fovy, T aspect) noexcept¶ Set functions change the entire state of the Frustum using field of view and aspect ratio.
-
inline void
setExc(T nearPlane, T farPlane, T fovx, T fovy, T aspect)¶ Set functions change the entire state of the Frustum using field of view and aspect ratio.
Throw an exception if
fovxand/orfovyare invalid.
-
inline void
modifyNearAndFar(T nearPlane, T farPlane) noexcept¶ Set the near and far clipping planes.
-
inline void
setOrthographic(bool) noexcept¶ Set the ortographic state.
-
void
planes(Plane3<T> p[6]) const noexcept¶ Set the planes in p to be the six bounding planes of the frustum, in the following order: top, right, bottom, left, near, far.
Note that the planes have normals that point out of the frustum.
-
void
planes(Plane3<T> p[6], const Matrix44<T> &M) const noexcept¶ Set the planes in p to be the six bounding planes of the frustum, in the following order: top, right, bottom, left, near, far.
Note that the planes have normals that point out of the frustum. Apply the given matrix to transform the frustum before setting the planes.
Utility Methods
-
inline constexpr Line3<T>
projectScreenToRay(const Vec2<T>&) const noexcept¶ Project a point in screen spaced to 3d ray.
-
constexpr Vec2<T>
projectPointToScreen(const Vec3<T>&) const noexcept¶ Project a 3D point into screen coordinates.
-
constexpr Vec2<T>
projectPointToScreenExc(const Vec3<T>&) const¶ Project a 3D point into screen coordinates.
Throw an exception if the point cannot be projected.
-
constexpr T
ZToDepth(long zval, long min, long max) const noexcept¶ Map a z value to its depth in the frustum.
-
constexpr T
ZToDepthExc(long zval, long min, long max) const¶ Map a z value to its depth in the frustum.
-
constexpr T
normalizedZToDepth(T zval) const noexcept¶ Map a normalized z value to its depth in the frustum.
-
constexpr T
normalizedZToDepthExc(T zval) const¶ Map a normalized z value to its depth in the frustum.
Throw an exception on error.
-
constexpr long
DepthToZExc(T depth, long zmin, long zmax) const¶ Map depth to z value. Throw an exception on error.
-
inline constexpr
