/* 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));
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));
if( iTest<0) {
return -1;
} else if( iTest==0) {
iPass = 0;
}
}
// check to left
iTest = (INDEX) box.TestAgainstPlane(pr_plClipL);
if( iTest<0) {
return -1;
} else if( iTest==0) {
iPass = 0;
}
// check to right
iTest = (INDEX) box.TestAgainstPlane(pr_plClipR);
if( iTest<0) {
return -1;
} else if( iTest==0) {
iPass = 0;
}
// check to up
iTest = (INDEX) box.TestAgainstPlane(pr_plClipU);
if( iTest<0) {
return -1;
} else if( iTest==0) {
iPass = 0;
}
// check to down
iTest = (INDEX) box.TestAgainstPlane(pr_plClipD);
if( iTest<0) {
return -1;
} else if( iTest==0) {
iPass = 0;
}
// all done
return iPass;
}
// calculate plane from default mapping vectors
void CMappingVectors::ToPlane(FLOATplane3D &plPlane) const
{
plPlane = FLOATplane3D(mv_vV*mv_vU, mv_vO);
}
/*
* 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);
}
