minetest/irr/include/SViewFrustum.h
2024-03-26 21:39:02 +01:00

450 lines
13 KiB
C++

// Copyright (C) 2002-2012 Nikolaus Gebhardt
// This file is part of the "Irrlicht Engine".
// For conditions of distribution and use, see copyright notice in irrlicht.h
#pragma once
#include "plane3d.h"
#include "vector3d.h"
#include "line3d.h"
#include "aabbox3d.h"
#include "matrix4.h"
#include "IVideoDriver.h"
namespace irr
{
namespace scene
{
//! Defines the view frustum. That's the space visible by the camera.
/** The view frustum is enclosed by 6 planes. These six planes share
eight points. A bounding box around these eight points is also stored in
this structure.
*/
struct SViewFrustum
{
enum VFPLANES
{
//! Far plane of the frustum. That is the plane furthest away from the eye.
VF_FAR_PLANE = 0,
//! Near plane of the frustum. That is the plane nearest to the eye.
VF_NEAR_PLANE,
//! Left plane of the frustum.
VF_LEFT_PLANE,
//! Right plane of the frustum.
VF_RIGHT_PLANE,
//! Bottom plane of the frustum.
VF_BOTTOM_PLANE,
//! Top plane of the frustum.
VF_TOP_PLANE,
//! Amount of planes enclosing the view frustum. Should be 6.
VF_PLANE_COUNT
};
//! Default Constructor
SViewFrustum() :
BoundingRadius(0.f), FarNearDistance(0.f) {}
//! Copy Constructor
SViewFrustum(const SViewFrustum &other);
//! This constructor creates a view frustum based on a projection and/or view matrix.
//\param zClipFromZero: Clipping of z can be projected from 0 to w when true (D3D style) and from -w to w when false (OGL style).
SViewFrustum(const core::matrix4 &mat, bool zClipFromZero);
//! This constructor creates a view frustum based on a projection and/or view matrix.
//\param zClipFromZero: Clipping of z can be projected from 0 to w when true (D3D style) and from -w to w when false (OGL style).
inline void setFrom(const core::matrix4 &mat, bool zClipFromZero);
//! transforms the frustum by the matrix
/** \param mat: Matrix by which the view frustum is transformed.*/
void transform(const core::matrix4 &mat);
//! returns the point which is on the far left upper corner inside the the view frustum.
core::vector3df getFarLeftUp() const;
//! returns the point which is on the far left bottom corner inside the the view frustum.
core::vector3df getFarLeftDown() const;
//! returns the point which is on the far right top corner inside the the view frustum.
core::vector3df getFarRightUp() const;
//! returns the point which is on the far right bottom corner inside the the view frustum.
core::vector3df getFarRightDown() const;
//! returns the point which is on the near left upper corner inside the the view frustum.
core::vector3df getNearLeftUp() const;
//! returns the point which is on the near left bottom corner inside the the view frustum.
core::vector3df getNearLeftDown() const;
//! returns the point which is on the near right top corner inside the the view frustum.
core::vector3df getNearRightUp() const;
//! returns the point which is on the near right bottom corner inside the the view frustum.
core::vector3df getNearRightDown() const;
//! returns a bounding box enclosing the whole view frustum
const core::aabbox3d<f32> &getBoundingBox() const;
//! recalculates the bounding box and sphere based on the planes
inline void recalculateBoundingBox();
//! get the bounding sphere's radius (of an optimized sphere, not the AABB's)
float getBoundingRadius() const;
//! get the bounding sphere's radius (of an optimized sphere, not the AABB's)
core::vector3df getBoundingCenter() const;
//! the cam should tell the frustum the distance between far and near
void setFarNearDistance(float distance);
//! get the given state's matrix based on frustum E_TRANSFORMATION_STATE
core::matrix4 &getTransform(video::E_TRANSFORMATION_STATE state);
//! get the given state's matrix based on frustum E_TRANSFORMATION_STATE
const core::matrix4 &getTransform(video::E_TRANSFORMATION_STATE state) const;
//! clips a line to the view frustum.
/** \return True if the line was clipped, false if not */
bool clipLine(core::line3d<f32> &line) const;
//! the position of the camera
core::vector3df cameraPosition;
//! all planes enclosing the view frustum.
core::plane3d<f32> planes[VF_PLANE_COUNT];
//! bounding box around the view frustum
core::aabbox3d<f32> boundingBox;
private:
//! Hold a copy of important transform matrices
enum E_TRANSFORMATION_STATE_FRUSTUM
{
ETS_VIEW = 0,
ETS_PROJECTION = 1,
ETS_COUNT_FRUSTUM
};
//! recalculates the bounding sphere based on the planes
inline void recalculateBoundingSphere();
//! Hold a copy of important transform matrices
core::matrix4 Matrices[ETS_COUNT_FRUSTUM];
float BoundingRadius;
float FarNearDistance;
core::vector3df BoundingCenter;
};
/*!
Copy constructor ViewFrustum
*/
inline SViewFrustum::SViewFrustum(const SViewFrustum &other)
{
cameraPosition = other.cameraPosition;
boundingBox = other.boundingBox;
u32 i;
for (i = 0; i < VF_PLANE_COUNT; ++i)
planes[i] = other.planes[i];
for (i = 0; i < ETS_COUNT_FRUSTUM; ++i)
Matrices[i] = other.Matrices[i];
BoundingRadius = other.BoundingRadius;
FarNearDistance = other.FarNearDistance;
BoundingCenter = other.BoundingCenter;
}
inline SViewFrustum::SViewFrustum(const core::matrix4 &mat, bool zClipFromZero)
{
setFrom(mat, zClipFromZero);
}
inline void SViewFrustum::transform(const core::matrix4 &mat)
{
for (u32 i = 0; i < VF_PLANE_COUNT; ++i)
mat.transformPlane(planes[i]);
mat.transformVect(cameraPosition);
recalculateBoundingBox();
}
inline core::vector3df SViewFrustum::getFarLeftUp() const
{
core::vector3df p;
planes[scene::SViewFrustum::VF_FAR_PLANE].getIntersectionWithPlanes(
planes[scene::SViewFrustum::VF_TOP_PLANE],
planes[scene::SViewFrustum::VF_LEFT_PLANE], p);
return p;
}
inline core::vector3df SViewFrustum::getFarLeftDown() const
{
core::vector3df p;
planes[scene::SViewFrustum::VF_FAR_PLANE].getIntersectionWithPlanes(
planes[scene::SViewFrustum::VF_BOTTOM_PLANE],
planes[scene::SViewFrustum::VF_LEFT_PLANE], p);
return p;
}
inline core::vector3df SViewFrustum::getFarRightUp() const
{
core::vector3df p;
planes[scene::SViewFrustum::VF_FAR_PLANE].getIntersectionWithPlanes(
planes[scene::SViewFrustum::VF_TOP_PLANE],
planes[scene::SViewFrustum::VF_RIGHT_PLANE], p);
return p;
}
inline core::vector3df SViewFrustum::getFarRightDown() const
{
core::vector3df p;
planes[scene::SViewFrustum::VF_FAR_PLANE].getIntersectionWithPlanes(
planes[scene::SViewFrustum::VF_BOTTOM_PLANE],
planes[scene::SViewFrustum::VF_RIGHT_PLANE], p);
return p;
}
inline core::vector3df SViewFrustum::getNearLeftUp() const
{
core::vector3df p;
planes[scene::SViewFrustum::VF_NEAR_PLANE].getIntersectionWithPlanes(
planes[scene::SViewFrustum::VF_TOP_PLANE],
planes[scene::SViewFrustum::VF_LEFT_PLANE], p);
return p;
}
inline core::vector3df SViewFrustum::getNearLeftDown() const
{
core::vector3df p;
planes[scene::SViewFrustum::VF_NEAR_PLANE].getIntersectionWithPlanes(
planes[scene::SViewFrustum::VF_BOTTOM_PLANE],
planes[scene::SViewFrustum::VF_LEFT_PLANE], p);
return p;
}
inline core::vector3df SViewFrustum::getNearRightUp() const
{
core::vector3df p;
planes[scene::SViewFrustum::VF_NEAR_PLANE].getIntersectionWithPlanes(
planes[scene::SViewFrustum::VF_TOP_PLANE],
planes[scene::SViewFrustum::VF_RIGHT_PLANE], p);
return p;
}
inline core::vector3df SViewFrustum::getNearRightDown() const
{
core::vector3df p;
planes[scene::SViewFrustum::VF_NEAR_PLANE].getIntersectionWithPlanes(
planes[scene::SViewFrustum::VF_BOTTOM_PLANE],
planes[scene::SViewFrustum::VF_RIGHT_PLANE], p);
return p;
}
inline const core::aabbox3d<f32> &SViewFrustum::getBoundingBox() const
{
return boundingBox;
}
inline void SViewFrustum::recalculateBoundingBox()
{
boundingBox.reset(getNearLeftUp());
boundingBox.addInternalPoint(getNearRightUp());
boundingBox.addInternalPoint(getNearLeftDown());
boundingBox.addInternalPoint(getNearRightDown());
boundingBox.addInternalPoint(getFarRightUp());
boundingBox.addInternalPoint(getFarLeftDown());
boundingBox.addInternalPoint(getFarRightDown());
boundingBox.addInternalPoint(getFarLeftUp());
// Also recalculate the bounding sphere when the bbox changes
recalculateBoundingSphere();
}
inline float SViewFrustum::getBoundingRadius() const
{
return BoundingRadius;
}
inline core::vector3df SViewFrustum::getBoundingCenter() const
{
return BoundingCenter;
}
inline void SViewFrustum::setFarNearDistance(float distance)
{
FarNearDistance = distance;
}
//! This constructor creates a view frustum based on a projection
//! and/or view matrix.
inline void SViewFrustum::setFrom(const core::matrix4 &mat, bool zClipFromZero)
{
// left clipping plane
planes[VF_LEFT_PLANE].Normal.X = mat[3] + mat[0];
planes[VF_LEFT_PLANE].Normal.Y = mat[7] + mat[4];
planes[VF_LEFT_PLANE].Normal.Z = mat[11] + mat[8];
planes[VF_LEFT_PLANE].D = mat[15] + mat[12];
// right clipping plane
planes[VF_RIGHT_PLANE].Normal.X = mat[3] - mat[0];
planes[VF_RIGHT_PLANE].Normal.Y = mat[7] - mat[4];
planes[VF_RIGHT_PLANE].Normal.Z = mat[11] - mat[8];
planes[VF_RIGHT_PLANE].D = mat[15] - mat[12];
// top clipping plane
planes[VF_TOP_PLANE].Normal.X = mat[3] - mat[1];
planes[VF_TOP_PLANE].Normal.Y = mat[7] - mat[5];
planes[VF_TOP_PLANE].Normal.Z = mat[11] - mat[9];
planes[VF_TOP_PLANE].D = mat[15] - mat[13];
// bottom clipping plane
planes[VF_BOTTOM_PLANE].Normal.X = mat[3] + mat[1];
planes[VF_BOTTOM_PLANE].Normal.Y = mat[7] + mat[5];
planes[VF_BOTTOM_PLANE].Normal.Z = mat[11] + mat[9];
planes[VF_BOTTOM_PLANE].D = mat[15] + mat[13];
// far clipping plane
planes[VF_FAR_PLANE].Normal.X = mat[3] - mat[2];
planes[VF_FAR_PLANE].Normal.Y = mat[7] - mat[6];
planes[VF_FAR_PLANE].Normal.Z = mat[11] - mat[10];
planes[VF_FAR_PLANE].D = mat[15] - mat[14];
// near clipping plane
if (zClipFromZero) {
planes[VF_NEAR_PLANE].Normal.X = mat[2];
planes[VF_NEAR_PLANE].Normal.Y = mat[6];
planes[VF_NEAR_PLANE].Normal.Z = mat[10];
planes[VF_NEAR_PLANE].D = mat[14];
} else {
// near clipping plane
planes[VF_NEAR_PLANE].Normal.X = mat[3] + mat[2];
planes[VF_NEAR_PLANE].Normal.Y = mat[7] + mat[6];
planes[VF_NEAR_PLANE].Normal.Z = mat[11] + mat[10];
planes[VF_NEAR_PLANE].D = mat[15] + mat[14];
}
// normalize normals
u32 i;
for (i = 0; i != VF_PLANE_COUNT; ++i) {
const f32 len = -core::reciprocal_squareroot(
planes[i].Normal.getLengthSQ());
planes[i].Normal *= len;
planes[i].D *= len;
}
// make bounding box
recalculateBoundingBox();
}
/*!
View Frustum depends on Projection & View Matrix
*/
inline core::matrix4 &SViewFrustum::getTransform(video::E_TRANSFORMATION_STATE state)
{
u32 index = 0;
switch (state) {
case video::ETS_PROJECTION:
index = SViewFrustum::ETS_PROJECTION;
break;
case video::ETS_VIEW:
index = SViewFrustum::ETS_VIEW;
break;
default:
break;
}
return Matrices[index];
}
/*!
View Frustum depends on Projection & View Matrix
*/
inline const core::matrix4 &SViewFrustum::getTransform(video::E_TRANSFORMATION_STATE state) const
{
u32 index = 0;
switch (state) {
case video::ETS_PROJECTION:
index = SViewFrustum::ETS_PROJECTION;
break;
case video::ETS_VIEW:
index = SViewFrustum::ETS_VIEW;
break;
default:
break;
}
return Matrices[index];
}
//! Clips a line to the frustum
inline bool SViewFrustum::clipLine(core::line3d<f32> &line) const
{
bool wasClipped = false;
for (u32 i = 0; i < VF_PLANE_COUNT; ++i) {
if (planes[i].classifyPointRelation(line.start) == core::ISREL3D_FRONT) {
line.start = line.start.getInterpolated(line.end,
1.f - planes[i].getKnownIntersectionWithLine(line.start, line.end));
wasClipped = true;
}
if (planes[i].classifyPointRelation(line.end) == core::ISREL3D_FRONT) {
line.end = line.start.getInterpolated(line.end,
1.f - planes[i].getKnownIntersectionWithLine(line.start, line.end));
wasClipped = true;
}
}
return wasClipped;
}
inline void SViewFrustum::recalculateBoundingSphere()
{
// Find the center
const float shortlen = (getNearLeftUp() - getNearRightUp()).getLength();
const float longlen = (getFarLeftUp() - getFarRightUp()).getLength();
const float farlen = FarNearDistance;
const float fartocenter = (farlen + (shortlen - longlen) * (shortlen + longlen) / (4 * farlen)) / 2;
const float neartocenter = farlen - fartocenter;
BoundingCenter = cameraPosition + -planes[VF_NEAR_PLANE].Normal * neartocenter;
// Find the radius
core::vector3df dir[8];
dir[0] = getFarLeftUp() - BoundingCenter;
dir[1] = getFarRightUp() - BoundingCenter;
dir[2] = getFarLeftDown() - BoundingCenter;
dir[3] = getFarRightDown() - BoundingCenter;
dir[4] = getNearRightDown() - BoundingCenter;
dir[5] = getNearLeftDown() - BoundingCenter;
dir[6] = getNearRightUp() - BoundingCenter;
dir[7] = getNearLeftUp() - BoundingCenter;
u32 i = 0;
float diam[8] = {0.f};
for (i = 0; i < 8; ++i)
diam[i] = dir[i].getLengthSQ();
float longest = 0;
for (i = 0; i < 8; ++i) {
if (diam[i] > longest)
longest = diam[i];
}
BoundingRadius = sqrtf(longest);
}
} // end namespace scene
} // end namespace irr