mirror of
https://github.com/ptitSeb/Serious-Engine
synced 2024-11-22 18:30:27 +01:00
dbe524f0b2
except for EntitiesMP/Fish.es which I'm not sure about, and in Computer.cpp the weird "if (_iActiveMessage < _acmMessages.Count()==0)" construct whichs intention I didn't fully grasp, either.
595 lines
20 KiB
C++
595 lines
20 KiB
C++
/* Copyright (c) 2002-2012 Croteam Ltd.
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This program is free software; you can redistribute it and/or modify
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it under the terms of version 2 of the GNU General Public License as published by
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the Free Software Foundation
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License along
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with this program; if not, write to the Free Software Foundation, Inc.,
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51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. */
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#include "Engine/StdH.h"
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#include <Engine/Math/Projection.h>
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#include <Engine/Math/TextureMapping.h>
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#include <Engine/Math/OBBox.h>
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#include <Engine/Math/Geometry.inl>
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#include <Engine/Math/Clipping.inl>
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/////////////////////////////////////////////////////////////////////
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// CPerspectiveProjection3D
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// constructor
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CPerspectiveProjection3D::CPerspectiveProjection3D(void)
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{
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ppr_fMetersPerPixel = -1.0f; // never used by default
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ppr_fViewerDistance = -1.0f;
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}
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/*
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* Prepare for projecting.
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*/
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void CPerspectiveProjection3D::Prepare(void)
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{
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FLOATmatrix3D t3dObjectStretch; // matrix for object stretch
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FLOATmatrix3D t3dObjectRotation; // matrix for object angles
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// calc. matrices for viewer and object angles and stretch
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MakeRotationMatrixFast(
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t3dObjectRotation, pr_ObjectPlacement.pl_OrientationAngle);
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MakeInverseRotationMatrixFast(
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pr_ViewerRotationMatrix, pr_ViewerPlacement.pl_OrientationAngle);
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t3dObjectStretch.Diagonal(pr_ObjectStretch);
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pr_vViewerPosition = pr_ViewerPlacement.pl_PositionVector;
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BOOL bXInverted = pr_ObjectStretch(1)<0;
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BOOL bYInverted = pr_ObjectStretch(2)<0;
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BOOL bZInverted = pr_ObjectStretch(3)<0;
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pr_bInverted = (bXInverted != bYInverted) != bZInverted;
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// if the projection is mirrored
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if (pr_bMirror) {
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// reflect viewer
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ReflectPositionVectorByPlane(pr_plMirror, pr_vViewerPosition);
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ReflectRotationMatrixByPlane_rows(pr_plMirror, pr_ViewerRotationMatrix);
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// get mirror plane in view space
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pr_plMirrorView = pr_plMirror;
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pr_plMirrorView -= pr_vViewerPosition;
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pr_plMirrorView *= pr_ViewerRotationMatrix;
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// invert inversion
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pr_bInverted = !pr_bInverted;
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} else if (pr_bWarp) {
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// get mirror plane in view space
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pr_plMirrorView = pr_plMirror;
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}
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// if the object is face-forward
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if (pr_bFaceForward) {
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// if it turns only heading
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if (pr_bHalfFaceForward) {
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// get the y-axis vector of object rotation
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FLOAT3D vY(t3dObjectRotation(1,2), t3dObjectRotation(2,2), t3dObjectRotation(3,2));
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// find z axis of viewer
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FLOAT3D vViewerZ(
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pr_ViewerRotationMatrix(3,1),
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pr_ViewerRotationMatrix(3,2),
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pr_ViewerRotationMatrix(3,3));
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// calculate x and z axis vectors to make object head towards viewer
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FLOAT3D vX = (-vViewerZ)*vY;
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vX.Normalize();
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FLOAT3D vZ = vY*vX;
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// compose the rotation matrix back from those angles
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t3dObjectRotation(1,1) = vX(1); t3dObjectRotation(1,2) = vY(1); t3dObjectRotation(1,3) = vZ(1);
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t3dObjectRotation(2,1) = vX(2); t3dObjectRotation(2,2) = vY(2); t3dObjectRotation(2,3) = vZ(2);
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t3dObjectRotation(3,1) = vX(3); t3dObjectRotation(3,2) = vY(3); t3dObjectRotation(3,3) = vZ(3);
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// first apply object stretch then object rotation and then viewer rotation
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pr_mDirectionRotation = pr_ViewerRotationMatrix*t3dObjectRotation;
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pr_RotationMatrix = pr_mDirectionRotation*t3dObjectStretch;
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// if it is fully face forward
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} else {
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// apply object stretch and banking only
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FLOATmatrix3D mBanking;
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MakeRotationMatrixFast(
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mBanking, ANGLE3D(0,0, pr_ObjectPlacement.pl_OrientationAngle(3)));
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pr_mDirectionRotation = mBanking;
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pr_RotationMatrix = mBanking*t3dObjectStretch;
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}
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} else {
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// first apply object stretch then object rotation and then viewer rotation
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pr_mDirectionRotation = pr_ViewerRotationMatrix*t3dObjectRotation;
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pr_RotationMatrix = pr_mDirectionRotation*t3dObjectStretch;
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}
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// calc. offset of object from viewer
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pr_TranslationVector = pr_ObjectPlacement.pl_PositionVector - pr_vViewerPosition;
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// rotate offset only by viewer angles
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pr_TranslationVector = pr_TranslationVector*pr_ViewerRotationMatrix;
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// transform handle from object space to viewer space and add it to the offset
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pr_TranslationVector -= pr_vObjectHandle*pr_RotationMatrix;
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FLOAT2D vMin, vMax;
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// if using a shadow projection
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if (ppr_fMetersPerPixel>0) {
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// caclulate factors
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FLOAT fFactor = ppr_fViewerDistance/ppr_fMetersPerPixel;
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ppr_PerspectiveRatios(1) = -fFactor;
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ppr_PerspectiveRatios(2) = -fFactor;
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pr_ScreenCenter = -pr_ScreenBBox.Min();
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vMin = pr_ScreenBBox.Min();
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vMax = pr_ScreenBBox.Max();
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// if using normal projection
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} else if (ppr_boxSubScreen.IsEmpty()) {
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// calculate perspective constants
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FLOAT2D v2dScreenSize = pr_ScreenBBox.Size();
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pr_ScreenCenter = pr_ScreenBBox.Center();
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/* calculate FOVHeight from FOVWidth by formula:
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halfanglej = atan( tan(halfanglei)*jsize*aspect/isize ) */
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ANGLE aHalfI = ppr_FOVWidth/2;
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ANGLE aHalfJ = ATan(TanFast(aHalfI)*v2dScreenSize(2)*pr_AspectRatio/v2dScreenSize(1));
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/* calc. perspective ratios by formulae:
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xratio = isize/(2*tan(anglei/2))
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yratio = jsize/(2*tan(anglej/2))
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sign is negative since viewer is looking down the -z axis
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*/
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ppr_PerspectiveRatios(1) = -v2dScreenSize(1)/(2.0f*TanFast(aHalfI))*pr_fViewStretch;
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ppr_PerspectiveRatios(2) = -v2dScreenSize(2)/(2.0f*TanFast(aHalfJ))*pr_fViewStretch;
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vMin = pr_ScreenBBox.Min()-pr_ScreenCenter;
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vMax = pr_ScreenBBox.Max()-pr_ScreenCenter;
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// if using sub-drawport projection
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} else {
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// calculate perspective constants
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FLOAT2D v2dScreenSize = pr_ScreenBBox.Size();
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pr_ScreenCenter = pr_ScreenBBox.Center();
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/* calculate FOVHeight from FOVWidth by formula:
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halfanglej = atan( tan(halfanglei)*jsize*aspect/isize ) */
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ANGLE aHalfI = ppr_FOVWidth/2;
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ANGLE aHalfJ = ATan(TanFast(aHalfI)*v2dScreenSize(2)*pr_AspectRatio/v2dScreenSize(1));
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/* calc. perspective ratios by formulae:
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xratio = isize/(2*tan(anglei/2))
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yratio = jsize/(2*tan(anglej/2))
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sign is negative since viewer is looking down the -z axis
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*/
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ppr_PerspectiveRatios(1) = -v2dScreenSize(1)/(2.0f*TanFast(aHalfI))*pr_fViewStretch;
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ppr_PerspectiveRatios(2) = -v2dScreenSize(2)/(2.0f*TanFast(aHalfJ))*pr_fViewStretch;
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vMin = ppr_boxSubScreen.Min()-pr_ScreenCenter;
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vMax = ppr_boxSubScreen.Max()-pr_ScreenCenter;
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pr_ScreenCenter -= ppr_boxSubScreen.Min();
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}
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// find factors for left, right, up and down clipping
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FLOAT fMinI = vMin(1); FLOAT fMinJ = vMin(2);
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FLOAT fMaxI = vMax(1); FLOAT fMaxJ = vMax(2);
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FLOAT fRatioX = ppr_PerspectiveRatios(1);
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FLOAT fRatioY = ppr_PerspectiveRatios(2);
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#define MySgn(x) ((x)>=0?1:-1)
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FLOAT fDZ = -1.0f;
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FLOAT fDXL = fDZ*fMinI/fRatioX;
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FLOAT fDXR = fDZ*fMaxI/fRatioX;
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FLOAT fDYU = -fDZ*fMinJ/fRatioY;
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FLOAT fDYD = -fDZ*fMaxJ/fRatioY;
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FLOAT fNLX = -fDZ;
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FLOAT fNLZ = +fDXL;
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FLOAT fOoNL = 1.0f/(FLOAT)sqrt(fNLX*fNLX+fNLZ*fNLZ);
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fNLX*=fOoNL; fNLZ*=fOoNL;
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FLOAT fNRX = +fDZ;
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FLOAT fNRZ = -fDXR;
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FLOAT fOoNR = 1.0f/(FLOAT)sqrt(fNRX*fNRX+fNRZ*fNRZ);
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fNRX*=fOoNR; fNRZ*=fOoNR;
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FLOAT fNDY = -fDZ;
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FLOAT fNDZ = +fDYD;
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FLOAT fOoND = 1.0f/(FLOAT)sqrt(fNDY*fNDY+fNDZ*fNDZ);
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fNDY*=fOoND; fNDZ*=fOoND;
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FLOAT fNUY = +fDZ;
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FLOAT fNUZ = -fDYU;
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FLOAT fOoNU = 1.0f/(FLOAT)sqrt(fNUY*fNUY+fNUZ*fNUZ);
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fNUY*=fOoNU; fNUZ*=fOoNU;
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// make clip planes
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pr_plClipU = FLOATplane3D(FLOAT3D( 0,fNUY,fNUZ), 0.0f);
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pr_plClipD = FLOATplane3D(FLOAT3D( 0,fNDY,fNDZ), 0.0f);
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pr_plClipL = FLOATplane3D(FLOAT3D(fNLX, 0,fNLZ), 0.0f);
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pr_plClipR = FLOATplane3D(FLOAT3D(fNRX, 0,fNRZ), 0.0f);
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// mark as prepared
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pr_Prepared = TRUE;
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// calculate constant value used for calculating z-buffer k-value from vertex's z coordinate
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pr_fDepthBufferFactor = -pr_NearClipDistance;
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pr_fDepthBufferMul = pr_fDepthBufferFar-pr_fDepthBufferNear;
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pr_fDepthBufferAdd = pr_fDepthBufferNear;
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// calculate ratio for mip factor calculation
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ppr_fMipRatio = pr_ScreenBBox.Size()(1)/(ppr_PerspectiveRatios(1)*640.0f);
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}
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/*
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* Project 3D object point into 3D view space, before clipping.
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*/
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void CPerspectiveProjection3D::PreClip(const FLOAT3D &v3dObjectPoint,
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FLOAT3D &v3dTransformedPoint) const
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{
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// check that the projection object is prepared for projecting
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ASSERT(pr_Prepared);
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// rotate and translate the point
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v3dTransformedPoint = v3dObjectPoint*pr_RotationMatrix + pr_TranslationVector;
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}
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/*
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* Project 3D object point into 3D view space, after clipping.
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*/
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void CPerspectiveProjection3D::PostClip( const FLOAT3D &v3dTransformedPoint,
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FLOAT3D &v3dViewPoint) const
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{
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// check that the projection object is prepared for projecting
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ASSERT(pr_Prepared);
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// divide X and Y with Z and add the center of screen
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const FLOAT f1oTransZ = 1.0f / v3dTransformedPoint(3);
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v3dViewPoint(1) = pr_ScreenCenter(1) + v3dTransformedPoint(1) * ppr_PerspectiveRatios(1) *f1oTransZ;
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v3dViewPoint(2) = pr_ScreenCenter(2) - v3dTransformedPoint(2) * ppr_PerspectiveRatios(2) *f1oTransZ;
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}
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void CPerspectiveProjection3D::PostClip( const FLOAT3D &v3dTransformedPoint, FLOAT fTransformedR,
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FLOAT3D &v3dViewPoint, FLOAT &fViewR) const
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{
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// check that the projection object is prepared for projecting
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ASSERT(pr_Prepared);
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// multiply X and Y coordinates with zoom factor and add the center of screen
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v3dViewPoint(3) = 1.0f / v3dTransformedPoint(3);
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v3dViewPoint(1) = pr_ScreenCenter(1) + v3dTransformedPoint(1) * ppr_PerspectiveRatios(1) * v3dViewPoint(3);
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v3dViewPoint(2) = pr_ScreenCenter(2) - v3dTransformedPoint(2) * ppr_PerspectiveRatios(2) * v3dViewPoint(3);
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fViewR = fTransformedR * ppr_PerspectiveRatios(1) * v3dViewPoint(3);
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}
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/* Test if a sphere in view space is inside view frustum. */
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INDEX CPerspectiveProjection3D::TestSphereToFrustum( const FLOAT3D &vViewPoint, FLOAT fRadius) const
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{
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ASSERT( pr_Prepared && fRadius>=0);
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const FLOAT fX = vViewPoint(1);
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const FLOAT fY = vViewPoint(2);
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const FLOAT fZ = vViewPoint(3);
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INDEX iPass = +1;
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// check to near
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if( fZ-fRadius>-pr_NearClipDistance) {
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return -1;
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} else if( fZ+fRadius>-pr_NearClipDistance) {
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iPass = 0;
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}
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// check to far
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if( pr_FarClipDistance>0) {
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if( fZ+fRadius<-pr_FarClipDistance) {
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return -1;
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} else if( fZ-fRadius<-pr_FarClipDistance) {
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iPass = 0;
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}
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}
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// check to left
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FLOAT fL = fX*pr_plClipL(1) + fZ*pr_plClipL(3) - pr_plClipL.Distance();
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if( fL<-fRadius) {
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return -1;
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} else if( fL<fRadius) {
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iPass = 0;
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}
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// check to right
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FLOAT fR = fX*pr_plClipR(1) + fZ*pr_plClipR(3) - pr_plClipR.Distance();
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if( fR<-fRadius) {
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return -1;
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} else if( fR<fRadius) {
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iPass = 0;
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}
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// check to up
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FLOAT fU = fY*pr_plClipU(2) + fZ*pr_plClipU(3) - pr_plClipU.Distance();
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if( fU<-fRadius) {
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return -1;
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} else if( fU<fRadius) {
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iPass = 0;
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}
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// check to down
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FLOAT fD = fY*pr_plClipD(2) + fZ*pr_plClipD(3) - pr_plClipD.Distance();
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if( fD<-fRadius) {
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return -1;
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} else if( fD<fRadius) {
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iPass = 0;
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}
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// all done
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return iPass;
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}
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/* Test if an oriented box in view space is inside view frustum. */
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INDEX CPerspectiveProjection3D::TestBoxToFrustum(const FLOATobbox3D &box) const
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{
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ASSERT( pr_Prepared);
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INDEX iPass = 1;
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INDEX iTest;
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// check to near
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iTest = (INDEX) box.TestAgainstPlane( FLOATplane3D(FLOAT3D(0,0,-1), pr_NearClipDistance));
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if( iTest<0) {
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return -1;
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} else if( iTest==0) {
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iPass = 0;
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}
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// check to far
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if( pr_FarClipDistance>0) {
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iTest = (INDEX) box.TestAgainstPlane( FLOATplane3D(FLOAT3D(0,0,1), -pr_FarClipDistance));
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if( iTest<0) {
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return -1;
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} else if( iTest==0) {
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iPass = 0;
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}
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}
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// check to left
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iTest = (INDEX) box.TestAgainstPlane(pr_plClipL);
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if( iTest<0) {
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return -1;
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} else if( iTest==0) {
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iPass = 0;
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}
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// check to right
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iTest = (INDEX) box.TestAgainstPlane(pr_plClipR);
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if( iTest<0) {
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return -1;
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} else if( iTest==0) {
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iPass = 0;
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}
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// check to up
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iTest = (INDEX) box.TestAgainstPlane(pr_plClipU);
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if( iTest<0) {
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return -1;
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} else if( iTest==0) {
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iPass = 0;
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}
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// check to down
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iTest = (INDEX) box.TestAgainstPlane(pr_plClipD);
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if( iTest<0) {
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return -1;
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} else if( iTest==0) {
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iPass = 0;
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}
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// all done
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return iPass;
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}
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/*
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* Project 3D object point into 3D view space.
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*/
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void CPerspectiveProjection3D::ProjectCoordinate(const FLOAT3D &v3dObjectPoint,
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FLOAT3D &v3dViewPoint) const
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{
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// rotate and translate the point
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v3dViewPoint = v3dObjectPoint*pr_RotationMatrix + pr_TranslationVector;
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// divide X and Y with Z and add the center of screen
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v3dViewPoint(1) = pr_ScreenCenter(1) +
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v3dViewPoint(1) * ppr_PerspectiveRatios(1) / v3dViewPoint(3);
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v3dViewPoint(2) = pr_ScreenCenter(2) +
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v3dViewPoint(2) * ppr_PerspectiveRatios(2) / v3dViewPoint(3);
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}
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/*
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* Get a distance of object point from the viewer.
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*/
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FLOAT CPerspectiveProjection3D::GetDistance(const FLOAT3D &v3dObjectPoint) const
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{
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// get just the z coordinate of the point in viewer space
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return
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v3dObjectPoint(1)*pr_RotationMatrix(3,1)+
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v3dObjectPoint(2)*pr_RotationMatrix(3,2)+
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v3dObjectPoint(3)*pr_RotationMatrix(3,3)+
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pr_TranslationVector(3);
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}
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/*
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* Project 3D object direction vector into 3D view space.
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*/
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void CPerspectiveProjection3D::ProjectDirection(const FLOAT3D &v3dObjectPoint,
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FLOAT3D &v3dViewPoint) const
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{
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// rotate the direction
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v3dViewPoint = v3dObjectPoint*pr_mDirectionRotation;
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}
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/*
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* Project 3D object axis aligned bounding box into 3D view space.
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*/
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void CPerspectiveProjection3D::ProjectAABBox(const FLOATaabbox3D &boxObject,
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FLOATaabbox3D &boxView) const
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{
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ASSERTALWAYS( "This is not yet implemented");
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}
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/*
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* Project 3D object plane into 3D view space.
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*/
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void CPerspectiveProjection3D::Project(const FLOATplane3D &p3dObjectPlane,
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FLOATplane3D &p3dTransformedPlane) const
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{
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// check that the projection object is prepared for projecting
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ASSERT(pr_Prepared);
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// rotate and translate the normal vector
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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;
|
|
}
|