viewgeom

//添加头文件和库CAD2010及其以上新增
(C) Copyright 1998-2006 by Autodesk, Inc.

Description:
 
worldDraw/viewportDraw() (showing use of getNumPixelsInUnitSquare)

This example demonstrates using viewportDraw(), getModelToEyeTransform(), doPerspective(), RegenType(), and polylineEye().
 
In a regular display of a pyramid made of six lines, you cannot easily determine which lines are on the back side of the pyramid. This example colors the pyramid edges blue if they're on the far side and yellow if they're on the front side, so that you get a sense of the visible and hidden edges of the pyramid.

This example could have been done with viewport's world coordinate polyline geometry. However, because the calculations on the vertices to figure out (per viewport) which edges were visible resulted in eye coordinates, this example uses polylineEye(), which accepts eye coordinates. The only drawback with eye coordinate line geometry is that it does not accept line types. For line types, use polyline() with world coordinate vertices.

Procedure:
1. Load viewgeom.arx.
2. Command: ASDKGEOM
3. Command: ZOOM Extents
4. Command: VPOINT 1,2,3

Note the blue lines are the back side edges.

The ObjectARX Developer's Guide and the source code explain what took place in more detail.

//数据可以是后台数据库，但是一定是保存了的数据库，不能是临时数据库
// (C) Copyright 1996-2006 by Autodesk, Inc. 
//
// Permission to use, copy, modify, and distribute this software in
// object code form for any purpose and without fee is hereby granted, 
// provided that the above copyright notice appears in all copies and 
// that both that copyright notice and the limited warranty and
// restricted rights notice below appear in all supporting 
// documentation.
//
// AUTODESK PROVIDES THIS PROGRAM "AS IS" AND WITH ALL FAULTS. 
// AUTODESK SPECIFICALLY DISCLAIMS ANY IMPLIED WARRANTY OF
// MERCHANTABILITY OR FITNESS FOR A PARTICULAR USE.  AUTODESK, INC. 
// DOES NOT WARRANT THAT THE OPERATION OF THE PROGRAM WILL BE
// UNINTERRUPTED OR ERROR FREE.
//
// Use, duplication, or disclosure by the U.S. Government is subject to 
// restrictions set forth in FAR 52.227-19 (Commercial Computer
// Software - Restricted Rights) and DFAR 252.227-7013(c)(1)(ii)
// (Rights in Technical Data and Computer Software), as applicable.
//
// viewgeom.cpp
//
// This example demonstrates using viewportDraw,
// getModelToEyeTransform, doPerspective, RegenType, and
// polylineEye.
//
// In a regular display of a pyramid made of 6 lines,
// you cannot easily determine which lines are on the
// back side of the pyramid.  This example colors the
// pyramid edges blue if they're on the far side and
// yellow if they're on the front side, so that you get
// a sense of the visible and hidden edges of the pyramid.
// This example could have been done with viewport's world
// coordinate polyline geometry, but since the calculations
// on the vertices to figure out (per viewport) which edges
// were visible resulted in eye coordinates, I chose to
// exemplify polylineEye() which accepts them.  The only
// drawback about eye coordinate line geometry is that it
// cannot currently be linetyped; to do that you use
// polyline() with world coordinate vertices.

#if defined(_DEBUG) && !defined(AC_FULL_DEBUG)
#error _DEBUG should not be defined except in internal Adesk debug builds
#endif

#include <string.h>
#include <stdlib.h>
#include <stdio.h>
#include <math.h>
#include "aced.h"
#include "dbsymtb.h"
#include "dbapserv.h"
#include "acgi.h"
#include "tchar.h"



// Helpful constants for setting attributes:

// COLOR
static const Adesk::UInt16 kColorByBlock   = 0;
static const Adesk::UInt16 kRed            = 1;
static const Adesk::UInt16 kYellow         = 2;
static const Adesk::UInt16 kGreen          = 3;
static const Adesk::UInt16 kCyan           = 4;
static const Adesk::UInt16 kBlue           = 5;
static const Adesk::UInt16 kMagenta        = 6;
static const Adesk::UInt16 kWhite          = 7;
static const Adesk::UInt16 kColorByLayer   = 256;
// LINETYPE
/*static const char* const no_linetype       = "Continuous";
static const char* const linetype_by_layer = "ByLayer";
static const char* const linetype_by_block = "ByBlock";
// LAYER
static const char* const layer_zero        = "0";
  */

class AsdkViewGeomSamp: public AcDbEntity
{
public:

    ACRX_DECLARE_MEMBERS(AsdkViewGeomSamp);

     AsdkViewGeomSamp(); 
protected:
    virtual Adesk::Boolean subWorldDraw(AcGiWorldDraw*);
    void subViewportDraw(AcGiViewportDraw*);
    Acad::ErrorStatus subTransformBy(const AcGeMatrix3d&);

private:

    Adesk::UInt32 mNumVerts;
    AcGePoint3d	  mVerts[4];
};

ACRX_DXF_DEFINE_MEMBERS(AsdkViewGeomSamp,\
    AcDbEntity,AcDb::kDHL_CURRENT, AcDb::kMReleaseCurrent, 
0,ASDKVIEWGEOMSAMP,AsdkViewGeom Sample);

// THE FOLLOWING CODE APPEARS IN THE SDK DOCUMENT.

AsdkViewGeomSamp::AsdkViewGeomSamp() : mNumVerts(4)
{
    mVerts[0] = AcGePoint3d(0.0, 0.0, 0.0);
    mVerts[1] = AcGePoint3d(1.0, 0.0, 0.0);
    mVerts[2] = AcGePoint3d(0.0, 1.0, 0.0);
    mVerts[3] = AcGePoint3d(0.0, 0.0, 1.0);
}


Acad::ErrorStatus
AsdkViewGeomSamp::subTransformBy(const AcGeMatrix3d &xfm)
{
    assertWriteEnabled();
    for (Adesk::UInt32 i = 0; i < mNumVerts; i++) {
        mVerts[i].transformBy(xfm);
    }
    return Acad::eOk;
}
 

Adesk::Boolean
AsdkViewGeomSamp::subWorldDraw(AcGiWorldDraw* pW)
{
    // Draw a pyramid.


    // If this is the REGULAR ACAD DISPLAY mode,
    //
    if (pW->regenType() == kAcGiStandardDisplay) {

        //  from each viewport's vantage point, figure out
        //  which sides of the pyramid are visible,
        //  then draw the visible ones yellow and the hidden
        //  ones blue.

        //  Set the extents of the pyramid here because 
        //  AcGiViewportGeometry's polylineEye() doesn't
        //  set extents.
        //
        for (Adesk::UInt32 i = 0; i < mNumVerts; i++) {
            AcGePoint3d pt[2];
            pt[0] = mVerts[i];
            pt[1] = mVerts[(i + 1) % mNumVerts];
            pW->geometry().setExtents(pt);
        }
        return Adesk::kFalse;  // Call viewport draws.
    }

    // Otherwise give HIDE, SHADE, RENDER, or Proxy Graphics
    // a pyramid with filled faces.
    //
    const Adesk::UInt32 faceListSize = 16;
    static Adesk::Int32 faceList[faceListSize] = {
        3, 0, 1, 2,
        3, 0, 2, 3,
        3, 0, 3, 1,
        3, 1, 2, 3
    };

    pW->geometry().shell(mNumVerts, mVerts, faceListSize,
        faceList);

    return Adesk::kTrue;  // Do NOT CALL viewportDraw.
}


void
AsdkViewGeomSamp::subViewportDraw(AcGiViewportDraw* pV)
{
    // For this viewport, draw a pyramid with yellow
    // visible lines and blue hidden lines.


    // Get this viewport's net transform.  This transform
    // includes this entity's block transforms and this
    // viewport's view transform; it does not include the
    // perspective transform if we're in perspective
    // mode -- that currently has to be applied separately
    // when in perspective mode.
    //
    AcGeMatrix3d modelToEyeMat;
    pV->viewport().getModelToEyeTransform(modelToEyeMat);

    // Get the pyramid's vertices.
    //
    AcGePoint3d A = mVerts[0];
    AcGePoint3d B = mVerts[1];
    AcGePoint3d C = mVerts[2];
    AcGePoint3d D = mVerts[3];

    // Convert them to the viewport's eye coordinates.
    //
    A.transformBy(modelToEyeMat);
    B.transformBy(modelToEyeMat);
    C.transformBy(modelToEyeMat);
    D.transformBy(modelToEyeMat);

    // Save the eye coordinates.
    //
    AcGePoint3d AEye = A;
    AcGePoint3d BEye = B;
    AcGePoint3d CEye = C;
    AcGePoint3d DEye = D;

    // Perform the perspective transform if necessary.
    //
    if (pV->viewport().isPerspective()) {
        pV->viewport().doPerspective(A);
        pV->viewport().doPerspective(B);
        pV->viewport().doPerspective(C);
        pV->viewport().doPerspective(D);
    }

    // From that view, figure out which faces are
    // facing the the viewport and which are not.
    //
    int which_faces;
    which_faces  = ((C - A).crossProduct(B - A)).z 
        > 0.0 ? 1 : 0;
    which_faces |= ((D - A).crossProduct(C - A)).z 
        > 0.0 ? 2 : 0;
    which_faces |= ((B - A).crossProduct(D - A)).z 
        > 0.0 ? 4 : 0;
    which_faces |= ((B - D).crossProduct(C - D)).z 
        > 0.0 ? 8 : 0;

    // Those edges that meet between two faces that are
    // facing away from the viewport will be hidden edges
    // so draw them blue; otherwise, they are visible
    // edges.  (This example is incomplete as the test is
    // indeterminate when the face is edge-on to the
    // screen -- neither facing away or toward the screen.)

    // Draw the 6 edges connecting the vertices using eye
    // coordinate geometry that can be back and front
    // clipped.

    AcGePoint3d verts[2];
    Adesk::UInt16 color;
    // AB
    color = which_faces & 0x5 ? kYellow : kBlue;
    pV->subEntityTraits().setColor(color);
    verts[0] = AEye;
    verts[1] = BEye;
    pV->geometry().polylineEye(2, verts);
    // AC
    color = which_faces & 0x3 ? kYellow : kBlue;
    pV->subEntityTraits().setColor(color);
    verts[0] = AEye;
    verts[1] = CEye;
    pV->geometry().polylineEye(2, verts);
    // AD
    color = which_faces & 0x6 ? kYellow : kBlue;
    pV->subEntityTraits().setColor(color);
    verts[0] = AEye;
    verts[1] = DEye;
    pV->geometry().polylineEye(2, verts);
    // CD
    color = which_faces & 0xa ? kYellow : kBlue;
    pV->subEntityTraits().setColor(color);
    verts[0] = CEye;
    verts[1] = DEye;
    pV->geometry().polylineEye(2, verts);
    // DB
    color = which_faces & 0xc ? kYellow : kBlue;
    pV->subEntityTraits().setColor(color);
    verts[0] = DEye;
    verts[1] = BEye;
    pV->geometry().polylineEye(2, verts);
    // BC
    color = which_faces & 0x9 ? kYellow : kBlue;
    pV->subEntityTraits().setColor(color);
    verts[0] = BEye;
    verts[1] = CEye;
    pV->geometry().polylineEye(2, verts);
}

// END CODE APPEARING IN SDK DOCUMENT.

void
addAsdkViewGeomSampObject()
{
    AsdkViewGeomSamp *pNewObj = new AsdkViewGeomSamp;

    AcDbBlockTable *pBlockTable;
    acdbHostApplicationServices()->workingDatabase()
        ->getSymbolTable(pBlockTable, AcDb::kForRead);

    AcDbBlockTableRecord *pBlock;
    pBlockTable->getAt(ACDB_MODEL_SPACE, pBlock,
        AcDb::kForWrite);

    AcDbObjectId objId;
    pBlock->appendAcDbEntity(objId, pNewObj);

    pBlockTable->close();
    pBlock->close();
    pNewObj->close();
}


void
initAsdkViewGeomSamp()
{
    AsdkViewGeomSamp::rxInit();
    acrxBuildClassHierarchy();

    acedRegCmds->addCommand(_T("ASDK_VIEWGEOM_SAMP"),
                            _T("ASDKGEOM"),
                            _T("GEOM"),
                            ACRX_CMD_TRANSPARENT,
                            addAsdkViewGeomSampObject);
}

extern "C" AcRx::AppRetCode
acrxEntryPoint(AcRx::AppMsgCode msg, void* appId) 
{
    switch(msg) {
	case AcRx::kInitAppMsg:
        acrxDynamicLinker->unlockApplication(appId);
		acrxDynamicLinker->registerAppMDIAware(appId);
	    initAsdkViewGeomSamp();
	    break;
	case AcRx::kUnloadAppMsg:
	    acedRegCmds->removeGroup(_T("ASDK_VIEWGEOM_SAMP"));
            deleteAcRxClass(AsdkViewGeomSamp::desc());
    }
    return AcRx::kRetOK;
}

//如果使用当前数据库，一定要保存文件否则会出错，
//当前数据库有自动保存操作，即使不操作，如果不保存，也会出错。