Cube: C++Builder Version

/****************************************************************************\
*                                                                            *
*  Cube.cpp                                                                  *
*  CubeU.cpp                                                                 *
*                                                                            *
*  This program draws a cube in 3D world space and allows the user to move   *
*  and rotate the cube through keyboard controls. Each of the six cube faces *
*  is a different color.                                                     *
*                                                                            *
\****************************************************************************/
#include 
#pragma hdrstop
#include "CubeU.h"
//---------------------------------------------------------------------------
#pragma resource "*.dfm"
TForm1 *Form1;
//---------------------------------------------------------------------------
__fastcall TForm1::TForm1(TComponent* Owner)
   : TForm(Owner)
{
}
//---------------------------------------------------------------------------
void __fastcall TForm1::OnIdle(TObject *Sender, bool &Done)
{
   CheckForMovement();
   Done = False;
}
//---------------------------------------------------------------------------
void __fastcall TForm1::FormActivate(TObject *Sender)
{
   fg_realize(hPal);
   Invalidate();
}
//---------------------------------------------------------------------------
void __fastcall TForm1::FormCreate(TObject *Sender)
{
   hDC = GetDC(Form1->Handle);
   fg_setdc(hDC);
   hPal = fg_defpal();
   fg_realize(hPal);
   fg_vbinit();
   vbDepth = fg_colors();
   fg_vbdepth(vbDepth);
   hVB = fg_vballoc(vbWidth,vbHeight);
   fg_vbopen(hVB);
   fg_vbcolors();
   fg_setcolor(-1);
   fg_fillpage();
   fg_3Dviewport(0,vbWidth-1,0,vbHeight-1,0.5);
   fg_3Drenderstate(FG_ZCLIP);
   Application->OnActivate = OnActivate;
   Application->OnIdle = OnIdle;
}
//---------------------------------------------------------------------------
void __fastcall TForm1::FormPaint(TObject *Sender)
{
   fg_vbscale(0,vbWidth-1,0,vbHeight-1,0,cxClient-1,0,cyClient-1);
}
//---------------------------------------------------------------------------
void __fastcall TForm1::FormResize(TObject *Sender)
{
   cxClient = ClientWidth;
   cyClient = ClientHeight;
   Invalidate();
}
//---------------------------------------------------------------------------
void __fastcall TForm1::FormDestroy(TObject *Sender)
{
   fg_vbclose();
   fg_vbfree(hVB);
   fg_vbfin();
   DeleteObject(hPal);
   ReleaseDC(Form1->Handle,hDC);
}
/****************************************************************************\
*                                                                            *
*  CheckForMovement()                                                        *
*                                                                            *
*  The CheckForMovement() function checks for key presses that control the   *
*  cube's movement, and if required redraws the cube at its new position and *
*  orientation. It is called from the application's OnIdle event handler.    *
*                                                                            *
\****************************************************************************/
void __fastcall TForm1::CheckForMovement()
{
   static double xWorld = 0.0, yWorld = 0.0, zWorld = 100.0;
   static int xAngle = 0, yAngle = 0, zAngle = 0;
   static bool Redraw = True;
   bool ShiftKey;
   // check if either shift key is pressed
   ShiftKey = fg_kbtest(42) | fg_kbtest(54);
   // + and - move cube along the z axis (+ is toward viewer, - is
   // away from viewer)
   if (fg_kbtest(74))
   {
      zWorld += 3.0;
      Redraw = True;
   }
   else if (fg_kbtest(78))
   {
      zWorld -= 3.0;
      Redraw = True;
   }
   // left and right arrow keys move cube along x axis
   else if (fg_kbtest(75))
   {
      xWorld -= 3.0;
      Redraw = True;
   }
   else if (fg_kbtest(77))
   {
      xWorld += 3.0;
      Redraw = True;
   }
   // up and down arrow keys move cube along y axis
   else if (fg_kbtest(72))
   {
      yWorld += 3.0;
      Redraw = True;
   }
   else if (fg_kbtest(80))
   {
      yWorld -= 3.0;
      Redraw = True;
   }
   // x rotates counterclockwise around x axis, X rotates clockwise
   else if (fg_kbtest(45))
   {
      if (ShiftKey)
      {
         xAngle += 6;
         if (xAngle >= 360) xAngle -= 360;
      }
      else
      {
         xAngle -= 6;
         if (xAngle < 0) xAngle += 360;
      }
      Redraw = True;
   }
   // y rotates counterclockwise around y axis, Y rotates clockwise
   else if (fg_kbtest(21))
   {
      if (ShiftKey)
      {
         yAngle += 6;
         if (yAngle >= 360) yAngle -= 360;
      }
      else
      {
         yAngle -= 6;
         if (yAngle < 0) yAngle += 360;
      }
      Redraw = True;
   }
   // z rotates counterclockwise around z axis, Z rotates clockwise
   else if (fg_kbtest(44))
   {
      if (ShiftKey)
      {
         zAngle += 6;
         if (zAngle >= 360) zAngle -= 360;
      }
      else
      {
         zAngle -= 6;
         if (zAngle < 0) zAngle += 360;
      }
      Redraw = True;
   }
   // if the cube's position or rotation changed, redraw the cube
   if (Redraw)
   {
      // erase the previous frame from the virtual buffer
      fg_setcolor(-1);
      fg_fillpage();
      // define the cube's new position and rotation in 3D world space
      fg_3Dsetobject(xWorld,yWorld,zWorld,xAngle*10,yAngle*10,zAngle*10);
      // draw the cube
      DrawCube();
      // display what we just drew
      fg_vbscale(0,vbWidth-1,0,vbHeight-1,0,cxClient-1,0,cyClient-1);
      Redraw = False;
   }
}
/****************************************************************************\
*                                                                            *
*  DrawCube()                                                                *
*                                                                            *
*  Draws each of the six cube faces in 3D world space.                       *
*                                                                            *
\****************************************************************************/
void __fastcall TForm1::DrawCube()
{
   register int i;
   int r, g, b;
   static int Colors[] = {84,88,92,96,100,104};
   for (i = 0; i < 6; i++)
   {
      if (vbDepth > 8)
      {
         fg_getrgb(Colors[i],&r,&g,&b);
         fg_setcolorrgb(r,g,b);
      }
      else
      {
         fg_setcolor(Colors[i]);
      }
      fg_3Dpolygonobject((double *)Faces[i],4);
   }
}