mgcbezierrectangle3.cpp

《3D游戏引擎设计》的源码

// Magic Software, Inc.
// http://www.magic-software.com
// Copyright (c) 2000, All Rights Reserved
//
// Source code from Magic Software is supplied under the terms of a license
// agreement and may not be copied or disclosed except in accordance with the
// terms of that agreement.  The various license agreements may be found at
// the Magic Software web site.  This file is subject to the license
//
// RESTRICTED USE SOURCE CODE
// http://www.magic-software.com/License/restricted.pdf

#include "MgcBezierRectangle3.h"
#include "MgcTriMesh.h"

MgcImplementRTTI(MgcBezierRectangle3,MgcBezierRectangle);
MgcImplementStream(MgcBezierRectangle3);

// macros for initialization in the subdivision
#define XA(i) akCtrlPoint[m_auiIndex[i]]
#define CA(i) akCtrlColor[m_auiIndex[i]]
#define TA(i) akCtrlTexture[m_auiIndex[i]]

//----------------------------------------------------------------------------
MgcBezierRectangle3::MgcBezierRectangle3 (unsigned int* auiIndex)
    :
    MgcBezierRectangle(3,16,auiIndex)
{
}
//----------------------------------------------------------------------------
MgcBezierRectangle3::MgcBezierRectangle3 ()
{
}
//----------------------------------------------------------------------------
void MgcBezierRectangle3::InitializePoints (const MgcVector3* akCtrlPoint,
    BlockParameters& rkBP)
{
    // Xss[s][t]
    rkBP.m_aakXss[0][0] = 6.0*(XA( 0) - 2.0*XA( 1) + XA( 2));
    rkBP.m_aakXss[0][1] = 6.0*(XA(12) - 2.0*XA(13) + XA(14));
    rkBP.m_aakXss[1][0] = 6.0*(XA( 1) - 2.0*XA( 2) + XA( 3));
    rkBP.m_aakXss[1][1] = 6.0*(XA(13) - 2.0*XA(14) + XA(15));

    // Xtt[s][t]
    rkBP.m_aakXtt[0][0] = 6.0*(XA( 0) - 2.0*XA( 4) + XA( 8));
    rkBP.m_aakXtt[0][1] = 6.0*(XA( 4) - 2.0*XA( 8) + XA(12));
    rkBP.m_aakXtt[1][0] = 6.0*(XA( 3) - 2.0*XA( 7) + XA(11));
    rkBP.m_aakXtt[1][1] = 6.0*(XA( 7) - 2.0*XA(11) + XA(15));

    // Xsstt[s][t]
    rkBP.m_aakXsstt[0][0] = 36.0*(XA(0) + XA(2) + XA(8) + XA(10) -
        2.0*(XA(1) + XA(4) + XA(6) + XA(9)) + 4.0*XA(5));
    rkBP.m_aakXsstt[0][1] = 36.0*(XA(4) + XA(6) + XA(12) + XA(14) -
        2.0*(XA(5) + XA(8) + XA(10) + XA(13)) + 4.0*XA(9));
    rkBP.m_aakXsstt[1][0] = 36.0*(XA(1) + XA(3) + XA(9) + XA(11) -
        2.0*(XA(2) + XA(5) + XA(7) + XA(10)) + 4.0*XA(6));
    rkBP.m_aakXsstt[1][1] = 36.0*(XA(5) + XA(7) + XA(13) + XA(15) -
        2.0*(XA(6) + XA(9) + XA(11) + XA(14)) + 4.0*XA(10));
}
//----------------------------------------------------------------------------
void MgcBezierRectangle3::InitializeNormals (const MgcVector3* akCtrlPoint,
    BlockParameters& rkBP)
{
    // Xsst[s][t]
    rkBP.m_aakXsst[0][0] = 18.0*(XA(4) + XA(6) - XA(0) - XA(2) +
        2.0*(XA(1) - XA(5)));
    rkBP.m_aakXsst[0][1] = 18.0*(XA(5) + XA(7) - XA(1) - XA(3) +
        2.0*(XA(2) - XA(6)));
    rkBP.m_aakXsst[1][0] = 18.0*(XA(12) + XA(14) - XA(8) - XA(10) +
        2.0*(XA(9) - XA(13)));
    rkBP.m_aakXsst[1][1] = 18.0*(XA(13) + XA(15) - XA(9) - XA(11) +
        2.0*(XA(10) - XA(14)));

    // Xstt[s][t]
    rkBP.m_aakXstt[0][0] = 18.0*(XA(1) + XA(9) - XA(0) - XA(8) +
        2.0*(XA(4) - XA(5)));
    rkBP.m_aakXstt[0][1] = 18.0*(XA(5) + XA(13) - XA(4) - XA(12) +
        2.0*(XA(8) - XA(9)));
    rkBP.m_aakXstt[1][0] = 18.0*(XA(3) + XA(11) - XA(2) - XA(10) +
        2.0*(XA(6) - XA(7)));
    rkBP.m_aakXstt[1][1] = 18.0*(XA(7) + XA(15) - XA(6) - XA(14) +
        2.0*(XA(10) - XA(11)));

    // Xsss
    rkBP.m_akXsss[0] = 6.0*(XA(3) + 3.0*(XA(1) - XA(2)) - XA(0));
    rkBP.m_akXsss[1] = 6.0*(XA(15) + 3.0*(XA(13) - XA(14)) - XA(12));

    // Xttt
    rkBP.m_akXttt[0] = 6.0*(XA(12) + 3.0*(XA(4) - XA(8)) - XA(0));
    rkBP.m_akXttt[1] = 6.0*(XA(15) + 3.0*(XA(7) - XA(11)) - XA(3));

    // Xssstt
    rkBP.m_akXssstt[0] = 36.0*(XA(3) + XA(11) - XA(0) - XA(8) +
        2.0*(XA(4) - XA(7)) + 3.0*(XA(1) + XA(9) - XA(2) - XA(10)) +
        6.0*(XA(6) - XA(5)));
    rkBP.m_akXssstt[1] = 36.0*(XA(7) + XA(15) - XA(4) - XA(12) +
        2.0*(XA(8) - XA(11)) + 3.0*(XA(5) + XA(13) - XA(6) - XA(14)) +
        6.0*(XA(10) - XA(9)));

    // Xtttss
    rkBP.m_akXssttt[0] = 36.0*(XA(12) + XA(14) - XA(0) - XA(2) +
        2.0*(XA(1) - XA(13)) + 3.0*(XA(4) + XA(6) - XA(8) - XA(10)) +
        6.0*(XA(9) - XA(5)));
    rkBP.m_akXssttt[1] = 36.0*(XA(13) + XA(15) - XA(1) - XA(3) +
        2.0*(XA(2) - XA(14)) + 3.0*(XA(5) + XA(7) - XA(9) - XA(11)) +
        6.0*(XA(10) - XA(6)));
}
//----------------------------------------------------------------------------
void MgcBezierRectangle3::InitializeColors (const MgcColor* akCtrlColor,
    BlockParameters& rkBP)
{
    // Css[s][t]
    rkBP.m_aakCss[0][0] = 6.0*(CA( 0) - 2.0*CA( 1) + CA( 2));
    rkBP.m_aakCss[0][1] = 6.0*(CA(12) - 2.0*CA(13) + CA(14));
    rkBP.m_aakCss[1][0] = 6.0*(CA( 1) - 2.0*CA( 2) + CA( 3));
    rkBP.m_aakCss[1][1] = 6.0*(CA(13) - 2.0*CA(14) + CA(15));

    // Ctt[s][t]
    rkBP.m_aakCtt[0][0] = 6.0*(CA( 0) - 2.0*CA( 4) + CA( 8));
    rkBP.m_aakCtt[0][1] = 6.0*(CA( 4) - 2.0*CA( 8) + CA(12));
    rkBP.m_aakCtt[1][0] = 6.0*(CA( 3) - 2.0*CA( 7) + CA(11));
    rkBP.m_aakCtt[1][1] = 6.0*(CA( 7) - 2.0*CA(11) + CA(15));

    // Csstt[s][t]
    rkBP.m_aakCsstt[0][0] = 36.0*(CA(0) + CA(2) + CA(8) + CA(10) -
        2.0*(CA(1) + CA(4) + CA(6) + CA(9)) + 4.0*CA(5));
    rkBP.m_aakCsstt[0][1] = 36.0*(CA(4) + CA(6) + CA(12) + CA(14) -
        2.0*(CA(5) + CA(8) + CA(10) + CA(13)) + 4.0*CA(9));
    rkBP.m_aakCsstt[1][0] = 36.0*(CA(1) + CA(3) + CA(9) + CA(11) -
        2.0*(CA(2) + CA(5) + CA(7) + CA(10)) + 4.0*CA(6));
    rkBP.m_aakCsstt[1][1] = 36.0*(CA(5) + CA(7) + CA(13) + CA(15) -
        2.0*(CA(6) + CA(9) + CA(11) + CA(14)) + 4.0*CA(10));
}
//----------------------------------------------------------------------------
void MgcBezierRectangle3::InitializeTextures (const MgcVector2* akCtrlTexture,
    BlockParameters& rkBP)
{
    // Tss[s][t]
    rkBP.m_aakTss[0][0] = 6.0*(TA( 0) - 2.0*TA( 1) + TA( 2));
    rkBP.m_aakTss[0][1] = 6.0*(TA(12) - 2.0*TA(13) + TA(14));
    rkBP.m_aakTss[1][0] = 6.0*(TA( 1) - 2.0*TA( 2) + TA( 3));
    rkBP.m_aakTss[1][1] = 6.0*(TA(13) - 2.0*TA(14) + TA(15));

    // Ttt[s][t]
    rkBP.m_aakTtt[0][0] = 6.0*(TA( 0) - 2.0*TA( 4) + TA( 8));
    rkBP.m_aakTtt[0][1] = 6.0*(TA( 4) - 2.0*TA( 8) + TA(12));
    rkBP.m_aakTtt[1][0] = 6.0*(TA( 3) - 2.0*TA( 7) + TA(11));
    rkBP.m_aakTtt[1][1] = 6.0*(TA( 7) - 2.0*TA(11) + TA(15));

    // Tsstt[s][t]
    rkBP.m_aakTsstt[0][0] = 36.0*(TA(0) + TA(2) + TA(8) + TA(10) -
        2.0*(TA(1) + TA(4) + TA(6) + TA(9)) + 4.0*TA(5));
    rkBP.m_aakTsstt[0][1] = 36.0*(TA(4) + TA(6) + TA(12) + TA(14) -
        2.0*(TA(5) + TA(8) + TA(10) + TA(13)) + 4.0*TA(9));
    rkBP.m_aakTsstt[1][0] = 36.0*(TA(1) + TA(3) + TA(9) + TA(11) -
        2.0*(TA(2) + TA(5) + TA(7) + TA(10)) + 4.0*TA(6));
    rkBP.m_aakTsstt[1][1] = 36.0*(TA(5) + TA(7) + TA(13) + TA(15) -
        2.0*(TA(6) + TA(9) + TA(11) + TA(14)) + 4.0*TA(10));
}
//----------------------------------------------------------------------------
void MgcBezierRectangle3::Tessellate (unsigned int uiLevel,
    const MgcVector3* akCtrlPoint, const MgcColor* akCtrlColor,
    const MgcVector2* akCtrlTexture, MgcTriMesh* pkMesh,
    unsigned int& ruiVertexStart, unsigned int& ruiTriangleStart)
{
    GenerateConnectivity(uiLevel,pkMesh,ruiTriangleStart);

    // number of vertices in the subdivision
    unsigned int uiQuantity = GetVerticesPerRectanglePatch(uiLevel);

    // indices of four corners of patch, I[s][t]
    unsigned int uiTwoPowL = (1 << uiLevel);
    BlockParameters kBP;
    kBP.m_uiI00 = 0;
    kBP.m_uiI01 = uiTwoPowL*(uiTwoPowL + 1);
    kBP.m_uiI10 = uiTwoPowL;
    kBP.m_uiI11 = kBP.m_uiI01 + uiTwoPowL;

    // vertices for subdivision
    MgcVector3* akX = pkMesh->Vertices() + ruiVertexStart;
    akX[kBP.m_uiI00] = XA( 0);
    akX[kBP.m_uiI01] = XA(12);
    akX[kBP.m_uiI10] = XA( 3);
    akX[kBP.m_uiI11] = XA(15);

    // derivatives for subdivision (for normal vectors)
    MgcVector3* akXs;
    MgcVector3* akXt;
    if ( pkMesh->Normals() )
    {
        akXs = new MgcVector3[uiQuantity];
        akXs[kBP.m_uiI00] = 3.0*(XA( 1) - XA( 0));
        akXs[kBP.m_uiI01] = 3.0*(XA(13) - XA(12));
        akXs[kBP.m_uiI10] = 3.0*(XA( 3) - XA( 2));
        akXs[kBP.m_uiI11] = 3.0*(XA(15) - XA(14));

        akXt = new MgcVector3[uiQuantity];
        akXt[kBP.m_uiI00] = 3.0*(XA( 4) - XA( 0));
        akXt[kBP.m_uiI01] = 3.0*(XA(12) - XA( 8));
        akXt[kBP.m_uiI10] = 3.0*(XA( 7) - XA( 3));
        akXt[kBP.m_uiI11] = 3.0*(XA(15) - XA(11));
    }
    else
    {
        akXs = 0;
        akXt = 0;
    }

    // colors for subdivision
    MgcColor* akColor;
    if ( pkMesh->Colors() )
    {
        akColor = pkMesh->Colors() + ruiVertexStart;
        akColor[kBP.m_uiI00] = CA( 0);
        akColor[kBP.m_uiI01] = CA(12);
        akColor[kBP.m_uiI10] = CA( 3);
        akColor[kBP.m_uiI11] = CA(15);
    }
    else
    {
        akColor = 0;
    }

    // textures for subdivision
    MgcVector2* akTexture;
    if ( pkMesh->Textures() )
    {
        akTexture = pkMesh->Textures() + ruiVertexStart;
        akTexture[kBP.m_uiI00] = TA( 0);
        akTexture[kBP.m_uiI01] = TA(12);
        akTexture[kBP.m_uiI10] = TA( 3);
        akTexture[kBP.m_uiI11] = TA(15);
    }
    else
    {
        akTexture = 0;
    }

    // recursive subdivision
    if ( uiLevel > 0 )
    {
        InitializePoints(akCtrlPoint,kBP);

        if ( akXs )
            InitializeNormals(akCtrlPoint,kBP);

        if ( akCtrlColor )
            InitializeColors(akCtrlColor,kBP);

        if ( akCtrlTexture )
            InitializeTextures(akCtrlTexture,kBP);

        Subdivide(--uiLevel,0.25,akX,akXs,akXt,akColor,akTexture,kBP);
    }

    // calculate unit-length normals from derivative vectors
    if ( pkMesh->Normals() )
    {
        MgcVector3* akNormal = pkMesh->Normals() + ruiVertexStart;
        for (unsigned int uiI = 0; uiI < uiQuantity; uiI++)
            akNormal[uiI] = akXs[uiI].UnitCross(akXt[uiI]);