Serious-Engine/Sources/Engine/Math/Projection_Perspective.cpp

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/* Copyright (c) 2002-2012 Croteam Ltd. All rights reserved. */
#include "Engine/StdH.h"
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#include <Engine/Math/Projection.h>
#include <Engine/Math/TextureMapping.h>
#include <Engine/Math/OBBox.h>
#include <Engine/Math/Geometry.inl>
#include <Engine/Math/Clipping.inl>
/////////////////////////////////////////////////////////////////////
// CPerspectiveProjection3D
// constructor
CPerspectiveProjection3D::CPerspectiveProjection3D(void)
{
ppr_fMetersPerPixel = -1.0f; // never used by default
ppr_fViewerDistance = -1.0f;
}
/*
* Prepare for projecting.
*/
void CPerspectiveProjection3D::Prepare(void)
{
FLOATmatrix3D t3dObjectStretch; // matrix for object stretch
FLOATmatrix3D t3dObjectRotation; // matrix for object angles
// calc. matrices for viewer and object angles and stretch
MakeRotationMatrixFast(
t3dObjectRotation, pr_ObjectPlacement.pl_OrientationAngle);
MakeInverseRotationMatrixFast(
pr_ViewerRotationMatrix, pr_ViewerPlacement.pl_OrientationAngle);
t3dObjectStretch.Diagonal(pr_ObjectStretch);
pr_vViewerPosition = pr_ViewerPlacement.pl_PositionVector;
BOOL bXInverted = pr_ObjectStretch(1)<0;
BOOL bYInverted = pr_ObjectStretch(2)<0;
BOOL bZInverted = pr_ObjectStretch(3)<0;
pr_bInverted = bXInverted!=bYInverted!=bZInverted;
// if the projection is mirrored
if (pr_bMirror) {
// reflect viewer
ReflectPositionVectorByPlane(pr_plMirror, pr_vViewerPosition);
ReflectRotationMatrixByPlane_rows(pr_plMirror, pr_ViewerRotationMatrix);
// get mirror plane in view space
pr_plMirrorView = pr_plMirror;
pr_plMirrorView -= pr_vViewerPosition;
pr_plMirrorView *= pr_ViewerRotationMatrix;
// invert inversion
pr_bInverted = !pr_bInverted;
} else if (pr_bWarp) {
// get mirror plane in view space
pr_plMirrorView = pr_plMirror;
}
// if the object is face-forward
if (pr_bFaceForward) {
// if it turns only heading
if (pr_bHalfFaceForward) {
// get the y-axis vector of object rotation
FLOAT3D vY(t3dObjectRotation(1,2), t3dObjectRotation(2,2), t3dObjectRotation(3,2));
// find z axis of viewer
FLOAT3D vViewerZ(
pr_ViewerRotationMatrix(3,1),
pr_ViewerRotationMatrix(3,2),
pr_ViewerRotationMatrix(3,3));
// calculate x and z axis vectors to make object head towards viewer
FLOAT3D vX = (-vViewerZ)*vY;
vX.Normalize();
FLOAT3D vZ = vY*vX;
// compose the rotation matrix back from those angles
t3dObjectRotation(1,1) = vX(1); t3dObjectRotation(1,2) = vY(1); t3dObjectRotation(1,3) = vZ(1);
t3dObjectRotation(2,1) = vX(2); t3dObjectRotation(2,2) = vY(2); t3dObjectRotation(2,3) = vZ(2);
t3dObjectRotation(3,1) = vX(3); t3dObjectRotation(3,2) = vY(3); t3dObjectRotation(3,3) = vZ(3);
// first apply object stretch then object rotation and then viewer rotation
pr_mDirectionRotation = pr_ViewerRotationMatrix*t3dObjectRotation;
pr_RotationMatrix = pr_mDirectionRotation*t3dObjectStretch;
// if it is fully face forward
} else {
// apply object stretch and banking only
FLOATmatrix3D mBanking;
MakeRotationMatrixFast(
mBanking, ANGLE3D(0,0, pr_ObjectPlacement.pl_OrientationAngle(3)));
pr_mDirectionRotation = mBanking;
pr_RotationMatrix = mBanking*t3dObjectStretch;
}
} else {
// first apply object stretch then object rotation and then viewer rotation
pr_mDirectionRotation = pr_ViewerRotationMatrix*t3dObjectRotation;
pr_RotationMatrix = pr_mDirectionRotation*t3dObjectStretch;
}
// calc. offset of object from viewer
pr_TranslationVector = pr_ObjectPlacement.pl_PositionVector - pr_vViewerPosition;
// rotate offset only by viewer angles
pr_TranslationVector = pr_TranslationVector*pr_ViewerRotationMatrix;
// transform handle from object space to viewer space and add it to the offset
pr_TranslationVector -= pr_vObjectHandle*pr_RotationMatrix;
FLOAT2D vMin, vMax;
// if using a shadow projection
if (ppr_fMetersPerPixel>0) {
// caclulate factors
FLOAT fFactor = ppr_fViewerDistance/ppr_fMetersPerPixel;
ppr_PerspectiveRatios(1) = -fFactor;
ppr_PerspectiveRatios(2) = -fFactor;
pr_ScreenCenter = -pr_ScreenBBox.Min();
vMin = pr_ScreenBBox.Min();
vMax = pr_ScreenBBox.Max();
// if using normal projection
} else if (ppr_boxSubScreen.IsEmpty()) {
// calculate perspective constants
FLOAT2D v2dScreenSize = pr_ScreenBBox.Size();
pr_ScreenCenter = pr_ScreenBBox.Center();
/* calculate FOVHeight from FOVWidth by formula:
halfanglej = atan( tan(halfanglei)*jsize*aspect/isize ) */
ANGLE aHalfI = ppr_FOVWidth/2;
ANGLE aHalfJ = ATan(TanFast(aHalfI)*v2dScreenSize(2)*pr_AspectRatio/v2dScreenSize(1));
/* calc. perspective ratios by formulae:
xratio = isize/(2*tan(anglei/2))
yratio = jsize/(2*tan(anglej/2))
sign is negative since viewer is looking down the -z axis
*/
ppr_PerspectiveRatios(1) = -v2dScreenSize(1)/(2.0f*TanFast(aHalfI))*pr_fViewStretch;
ppr_PerspectiveRatios(2) = -v2dScreenSize(2)/(2.0f*TanFast(aHalfJ))*pr_fViewStretch;
vMin = pr_ScreenBBox.Min()-pr_ScreenCenter;
vMax = pr_ScreenBBox.Max()-pr_ScreenCenter;
// if using sub-drawport projection
} else {
// calculate perspective constants
FLOAT2D v2dScreenSize = pr_ScreenBBox.Size();
pr_ScreenCenter = pr_ScreenBBox.Center();
/* calculate FOVHeight from FOVWidth by formula:
halfanglej = atan( tan(halfanglei)*jsize*aspect/isize ) */
ANGLE aHalfI = ppr_FOVWidth/2;
ANGLE aHalfJ = ATan(TanFast(aHalfI)*v2dScreenSize(2)*pr_AspectRatio/v2dScreenSize(1));
/* calc. perspective ratios by formulae:
xratio = isize/(2*tan(anglei/2))
yratio = jsize/(2*tan(anglej/2))
sign is negative since viewer is looking down the -z axis
*/
ppr_PerspectiveRatios(1) = -v2dScreenSize(1)/(2.0f*TanFast(aHalfI))*pr_fViewStretch;
ppr_PerspectiveRatios(2) = -v2dScreenSize(2)/(2.0f*TanFast(aHalfJ))*pr_fViewStretch;
vMin = ppr_boxSubScreen.Min()-pr_ScreenCenter;
vMax = ppr_boxSubScreen.Max()-pr_ScreenCenter;
pr_ScreenCenter -= ppr_boxSubScreen.Min();
}
// find factors for left, right, up and down clipping
FLOAT fMinI = vMin(1); FLOAT fMinJ = vMin(2);
FLOAT fMaxI = vMax(1); FLOAT fMaxJ = vMax(2);
FLOAT fRatioX = ppr_PerspectiveRatios(1);
FLOAT fRatioY = ppr_PerspectiveRatios(2);
#define MySgn(x) ((x)>=0?1:-1)
FLOAT fDZ = -1.0f;
FLOAT fDXL = fDZ*fMinI/fRatioX;
FLOAT fDXR = fDZ*fMaxI/fRatioX;
FLOAT fDYU = -fDZ*fMinJ/fRatioY;
FLOAT fDYD = -fDZ*fMaxJ/fRatioY;
FLOAT fNLX = -fDZ;
FLOAT fNLZ = +fDXL;
FLOAT fOoNL = 1.0f/(FLOAT)sqrt(fNLX*fNLX+fNLZ*fNLZ);
fNLX*=fOoNL; fNLZ*=fOoNL;
FLOAT fNRX = +fDZ;
FLOAT fNRZ = -fDXR;
FLOAT fOoNR = 1.0f/(FLOAT)sqrt(fNRX*fNRX+fNRZ*fNRZ);
fNRX*=fOoNR; fNRZ*=fOoNR;
FLOAT fNDY = -fDZ;
FLOAT fNDZ = +fDYD;
FLOAT fOoND = 1.0f/(FLOAT)sqrt(fNDY*fNDY+fNDZ*fNDZ);
fNDY*=fOoND; fNDZ*=fOoND;
FLOAT fNUY = +fDZ;
FLOAT fNUZ = -fDYU;
FLOAT fOoNU = 1.0f/(FLOAT)sqrt(fNUY*fNUY+fNUZ*fNUZ);
fNUY*=fOoNU; fNUZ*=fOoNU;
// make clip planes
pr_plClipU = FLOATplane3D(FLOAT3D( 0,fNUY,fNUZ), 0.0f);
pr_plClipD = FLOATplane3D(FLOAT3D( 0,fNDY,fNDZ), 0.0f);
pr_plClipL = FLOATplane3D(FLOAT3D(fNLX, 0,fNLZ), 0.0f);
pr_plClipR = FLOATplane3D(FLOAT3D(fNRX, 0,fNRZ), 0.0f);
// mark as prepared
pr_Prepared = TRUE;
// calculate constant value used for calculating z-buffer k-value from vertex's z coordinate
pr_fDepthBufferFactor = -pr_NearClipDistance;
pr_fDepthBufferMul = pr_fDepthBufferFar-pr_fDepthBufferNear;
pr_fDepthBufferAdd = pr_fDepthBufferNear;
// calculate ratio for mip factor calculation
ppr_fMipRatio = pr_ScreenBBox.Size()(1)/(ppr_PerspectiveRatios(1)*640.0f);
}
/*
* Project 3D object point into 3D view space, before clipping.
*/
void CPerspectiveProjection3D::PreClip(const FLOAT3D &v3dObjectPoint,
FLOAT3D &v3dTransformedPoint) const
{
// check that the projection object is prepared for projecting
ASSERT(pr_Prepared);
// rotate and translate the point
v3dTransformedPoint = v3dObjectPoint*pr_RotationMatrix + pr_TranslationVector;
}
/*
* Project 3D object point into 3D view space, after clipping.
*/
void CPerspectiveProjection3D::PostClip( const FLOAT3D &v3dTransformedPoint,
FLOAT3D &v3dViewPoint) const
{
// check that the projection object is prepared for projecting
ASSERT(pr_Prepared);
// divide X and Y with Z and add the center of screen
const FLOAT f1oTransZ = 1.0f / v3dTransformedPoint(3);
v3dViewPoint(1) = pr_ScreenCenter(1) + v3dTransformedPoint(1) * ppr_PerspectiveRatios(1) *f1oTransZ;
v3dViewPoint(2) = pr_ScreenCenter(2) - v3dTransformedPoint(2) * ppr_PerspectiveRatios(2) *f1oTransZ;
}
void CPerspectiveProjection3D::PostClip( const FLOAT3D &v3dTransformedPoint, FLOAT fTransformedR,
FLOAT3D &v3dViewPoint, FLOAT &fViewR) const
{
// check that the projection object is prepared for projecting
ASSERT(pr_Prepared);
// multiply X and Y coordinates with zoom factor and add the center of screen
v3dViewPoint(3) = 1.0f / v3dTransformedPoint(3);
v3dViewPoint(1) = pr_ScreenCenter(1) + v3dTransformedPoint(1) * ppr_PerspectiveRatios(1) * v3dViewPoint(3);
v3dViewPoint(2) = pr_ScreenCenter(2) - v3dTransformedPoint(2) * ppr_PerspectiveRatios(2) * v3dViewPoint(3);
fViewR = fTransformedR * ppr_PerspectiveRatios(1) * v3dViewPoint(3);
}
/* Test if a sphere in view space is inside view frustum. */
INDEX CPerspectiveProjection3D::TestSphereToFrustum( const FLOAT3D &vViewPoint, FLOAT fRadius) const
{
ASSERT( pr_Prepared && fRadius>=0);
const FLOAT fX = vViewPoint(1);
const FLOAT fY = vViewPoint(2);
const FLOAT fZ = vViewPoint(3);
INDEX iPass = +1;
// check to near
if( fZ-fRadius>-pr_NearClipDistance) {
return -1;
} else if( fZ+fRadius>-pr_NearClipDistance) {
iPass = 0;
}
// check to far
if( pr_FarClipDistance>0) {
if( fZ+fRadius<-pr_FarClipDistance) {
return -1;
} else if( fZ-fRadius<-pr_FarClipDistance) {
iPass = 0;
}
}
// check to left
FLOAT fL = fX*pr_plClipL(1) + fZ*pr_plClipL(3) - pr_plClipL.Distance();
if( fL<-fRadius) {
return -1;
} else if( fL<fRadius) {
iPass = 0;
}
// check to right
FLOAT fR = fX*pr_plClipR(1) + fZ*pr_plClipR(3) - pr_plClipR.Distance();
if( fR<-fRadius) {
return -1;
} else if( fR<fRadius) {
iPass = 0;
}
// check to up
FLOAT fU = fY*pr_plClipU(2) + fZ*pr_plClipU(3) - pr_plClipU.Distance();
if( fU<-fRadius) {
return -1;
} else if( fU<fRadius) {
iPass = 0;
}
// check to down
FLOAT fD = fY*pr_plClipD(2) + fZ*pr_plClipD(3) - pr_plClipD.Distance();
if( fD<-fRadius) {
return -1;
} else if( fD<fRadius) {
iPass = 0;
}
// all done
return iPass;
}
/* Test if an oriented box in view space is inside view frustum. */
INDEX CPerspectiveProjection3D::TestBoxToFrustum(const FLOATobbox3D &box) const
{
ASSERT( pr_Prepared);
INDEX iPass = 1;
INDEX iTest;
// check to near
iTest = (INDEX) box.TestAgainstPlane( FLOATplane3D(FLOAT3D(0,0,-1), pr_NearClipDistance));
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if( iTest<0) {
return -1;
} else if( iTest==0) {
iPass = 0;
}
// check to far
if( pr_FarClipDistance>0) {
iTest = (INDEX) box.TestAgainstPlane( FLOATplane3D(FLOAT3D(0,0,1), -pr_FarClipDistance));
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if( iTest<0) {
return -1;
} else if( iTest==0) {
iPass = 0;
}
}
// check to left
iTest = (INDEX) box.TestAgainstPlane(pr_plClipL);
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if( iTest<0) {
return -1;
} else if( iTest==0) {
iPass = 0;
}
// check to right
iTest = (INDEX) box.TestAgainstPlane(pr_plClipR);
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if( iTest<0) {
return -1;
} else if( iTest==0) {
iPass = 0;
}
// check to up
iTest = (INDEX) box.TestAgainstPlane(pr_plClipU);
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if( iTest<0) {
return -1;
} else if( iTest==0) {
iPass = 0;
}
// check to down
iTest = (INDEX) box.TestAgainstPlane(pr_plClipD);
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if( iTest<0) {
return -1;
} else if( iTest==0) {
iPass = 0;
}
// all done
return iPass;
}
/*
* Project 3D object point into 3D view space.
*/
void CPerspectiveProjection3D::ProjectCoordinate(const FLOAT3D &v3dObjectPoint,
FLOAT3D &v3dViewPoint) const
{
// rotate and translate the point
v3dViewPoint = v3dObjectPoint*pr_RotationMatrix + pr_TranslationVector;
// divide X and Y with Z and add the center of screen
v3dViewPoint(1) = pr_ScreenCenter(1) +
v3dViewPoint(1) * ppr_PerspectiveRatios(1) / v3dViewPoint(3);
v3dViewPoint(2) = pr_ScreenCenter(2) +
v3dViewPoint(2) * ppr_PerspectiveRatios(2) / v3dViewPoint(3);
}
/*
* Get a distance of object point from the viewer.
*/
FLOAT CPerspectiveProjection3D::GetDistance(const FLOAT3D &v3dObjectPoint) const
{
// get just the z coordinate of the point in viewer space
return
v3dObjectPoint(1)*pr_RotationMatrix(3,1)+
v3dObjectPoint(2)*pr_RotationMatrix(3,2)+
v3dObjectPoint(3)*pr_RotationMatrix(3,3)+
pr_TranslationVector(3);
}
/*
* Project 3D object direction vector into 3D view space.
*/
void CPerspectiveProjection3D::ProjectDirection(const FLOAT3D &v3dObjectPoint,
FLOAT3D &v3dViewPoint) const
{
// rotate the direction
v3dViewPoint = v3dObjectPoint*pr_mDirectionRotation;
}
/*
* Project 3D object axis aligned bounding box into 3D view space.
*/
void CPerspectiveProjection3D::ProjectAABBox(const FLOATaabbox3D &boxObject,
FLOATaabbox3D &boxView) const
{
ASSERTALWAYS( "This is not yet implemented");
}
/*
* Project 3D object plane into 3D view space.
*/
void CPerspectiveProjection3D::Project(const FLOATplane3D &p3dObjectPlane,
FLOATplane3D &p3dTransformedPlane) const
{
// check that the projection object is prepared for projecting
ASSERT(pr_Prepared);
// rotate and translate the normal vector
p3dTransformedPlane = p3dObjectPlane*pr_mDirectionRotation + pr_TranslationVector;
}
/* Calculate plane gradient for a plane in 3D view space. */
void CPerspectiveProjection3D::MakeOoKGradient(const FLOATplane3D &plViewerPlane, CPlanarGradients &pgOoK) const
{
// check that the projection object is prepared for projecting
ASSERT(pr_Prepared);
// get perspective factors
FLOAT oorx = +1/ppr_PerspectiveRatios(1);
FLOAT oory = -1/ppr_PerspectiveRatios(2);
FLOAT ci = pr_ScreenCenter(1);
FLOAT cj = pr_ScreenCenter(2);
FLOAT f = pr_fDepthBufferFactor;
FLOAT fn = f;
// normalize control vectors
FLOAT nx = plViewerPlane(1)*fn;
FLOAT ny = plViewerPlane(2)*fn;
FLOAT nz = plViewerPlane(3)*fn;
FLOAT oond = 1/plViewerPlane.Distance();
// calculate gradients
FLOAT dookodi = nx*oond*oorx;
FLOAT dookodj = ny*oond*oory;
FLOAT ook00 = nz*oond-dookodi*ci-dookodj*cj;
// remember the gradients
pgOoK.pg_f00 = ook00;
pgOoK.pg_fDOverDI = dookodi;
pgOoK.pg_fDOverDJ = dookodj;
}
/*
* Clip a line.
*/
ULONG CPerspectiveProjection3D::ClipLine(FLOAT3D &v3dPoint0, FLOAT3D &v3dPoint1) const
{
// check that the projection object is prepared for projecting
ASSERT(pr_Prepared);
ULONG ulCode0 = LCFVERTEX0(LCF_UNCLIPPED);
ULONG ulCode1 = LCFVERTEX1(LCF_UNCLIPPED);
// clip the line by each plane at the time, skip if some removes entire line
if (ClipLineByNearPlane(v3dPoint0, v3dPoint1, pr_NearClipDistance, ulCode0, ulCode1, LCF_NEAR)
&& ((pr_FarClipDistance<0) ||
ClipLineByFarPlane(v3dPoint0, v3dPoint1, pr_FarClipDistance, ulCode0, ulCode1, LCF_FAR))
// if something remains
) {
// return the clip code for both vertices
return ulCode0 | ulCode1;
// if some of the planes removed entire line
} else {
// return the code that tells that entire line is removed
return LCF_EDGEREMOVED;
}
}
/*
* Get placement for a ray through a projected point.
*/
void CPerspectiveProjection3D::RayThroughPoint(const FLOAT3D &v3dViewPoint,
CPlacement3D &plRay) const
{
// check that the projection object is prepared for projecting
ASSERT(pr_Prepared);
/* Assume z coordinate of -1 and calculate x and y for that.
* These are in fact just the perspective formulae, solved for transformed point.
* The result is a direction in viewer space.
*/
FLOAT3D v3dDirection;
v3dDirection(1) = -(v3dViewPoint(1) - pr_ScreenCenter(1))/ppr_PerspectiveRatios(1);
v3dDirection(2) = -(v3dViewPoint(2) - pr_ScreenCenter(2))/ppr_PerspectiveRatios(2);
v3dDirection(3) = -1.0f;
// back-rotate the ray to absolute space
v3dDirection *= !pr_ViewerRotationMatrix;
// normalize the ray
v3dDirection.Normalize();
// now calculate the angles from the direction
DirectionVectorToAngles(v3dDirection, plRay.pl_OrientationAngle);
// position is same as viewer's
plRay.pl_PositionVector = pr_vViewerPosition;
}
/*
* Check if an object-space plane is visible.
*/
BOOL CPerspectiveProjection3D::IsObjectPlaneVisible(const FLOATplane3D &p3dObjectPlane) const
{
// check that the projection object is prepared for projecting
ASSERT(pr_Prepared);
/*
In perspective projection, plane is invisible if viewer is not in front of plane.
NOTES: 1) Could add a check for plane beeing inside view frustum.
*/
// if viewer is in front of plane, after plane is transformed into viewer space
// (viewer is at 0,0,0)
if ( (p3dObjectPlane*pr_mDirectionRotation + pr_TranslationVector).Distance() < 0.0f ) {
// plane might be visible (although it still might be out of the view frustum)
return TRUE;
// if viewer is on the plane or behind it
} else {
// plane is surely not visible
return FALSE;
}
}
/*
* Check if a viewer-space plane is visible.
*/
BOOL CPerspectiveProjection3D::IsViewerPlaneVisible(const FLOATplane3D &p3dViewerPlane) const
{
// check that the projection object is prepared for projecting
ASSERT(pr_Prepared);
/*
In perspective projection, plane is invisible if viewer is not in front of plane.
NOTES: 1) Could add a check for plane beeing inside view frustum.
*/
// if viewer is in front of plane (viewer is at 0,0,0)
if ( p3dViewerPlane.Distance() < -0.01f ) {
// plane might be visible (although it still might be out of the view frustum)
return TRUE;
// if viewer is on the plane or behind it
} else {
// plane is surely not visible
return FALSE;
}
}
/*
* Calculate a mip-factor for a given object.
*/
// by its distance from viewer
FLOAT CPerspectiveProjection3D::MipFactor(FLOAT fDistance) const
{
// check that the projection object is prepared for projecting
ASSERT(pr_Prepared);
// calculated using following formula: k = log2(1024*z/xratio);
return Log2( (FLOAT)Abs(1024.0f*fDistance*ppr_fMipRatio));
}
// general mip-factor for target object
FLOAT CPerspectiveProjection3D::MipFactor(void) const
{
// check that the projection object is prepared for projecting
ASSERT(pr_Prepared);
// calculated using following formula: k = log2(1024*z/xratio);
// the distance is, in fact, the z coordinate of the translation vector
return -pr_TranslationVector(3)*TanFast(ppr_FOVWidth/2.0f); // /Tan(90.0f/2.0f)=1;
}