[pax]

program MY_3D;
const 
	Steps=5;
 numpoints=8;
 numlines=12;

var 
 points :array[1..numpoints,1..5] of integer;
 lines :array[1..numlines, 1..2] of integer;

 distance,i        : integer;
 FPS_LastCount,FPS_Count,MS,MSL	: integer;
 cx, cy         	: integer;

 rx, ry, rz      : real;
 Srx,Crx,Sry,Cry,Srz,Crz 	: real;
 ox,tx,ty,tz      : real;
	Step,Direction,Faza:Integer;
	
Function ISgn(Val:Integer):Integer;
Begin
	if val=0 then ISgn:=1 else
 ISgn:=Val/Abs(Val);
End; 

Procedure UpdateCube;
var P1,P2:Integer;
Begin
	if Step>Steps then
 Begin
 	Direction:=-Direction;
 	if Direction>0 then Faza:=Faza+1;
 	If Faza>4 then Faza:=1;
 	Step:=0;
 end
	else
 Step:=Step+1;
	
	If Faza=1 then	Begin P1:=1;P2:=7;	End;
	
	If Faza=2 then	Begin P1:=2;P2:=8;	End;
	
	If Faza=3 then	Begin P1:=3;P2:=5;	End;
	
	If Faza=4 then	Begin P1:=4;P2:=6;	End;
 
 	points[P1,1]:=points[P1,1]+Direction*ISgn(points[P1,1]); 
 	points[P1,2]:=points[P1,2]+Direction*ISgn(points[P1,2]); 
 	points[P1,3]:=points[P1,3]+Direction*ISgn(points[P1,3]);
 	
 	points[P2,1]:=points[P2,1]+Direction*ISgn(points[P2,1]); 
 	points[P2,2]:=points[P2,2]+Direction*ISgn(points[P2,2]); 
 	points[P2,3]:=points[P2,3]+Direction*ISgn(points[P2,3]);
end;

Procedure Rotate3D;
begin
 Srx:=Sin(rx); Crx:=Cos(rx);
 Sry:=Sin(ry); Cry:=Cos(ry);
 Srz:=Sin(rz); Crz:=Cos(rz);
for i:=1 to numpoints do
 begin
  //X rotation
  ty := points[i,2] * Crx - points[i,3] * Srx;
  tz := points[i,2] * Srx + points[i,3] * Crx;
  //Y rotation
  tx := points[i,1] * Cry - tz * Sry;
  tz := points[i,1] * Sry + tz * Cry;
  //Z rotation
  ox := tx;
  tx := tx * Crz - ty * Srz;
  ty := ox * Srz + ty * Crz;
  //Calculate new x and y location with perspective
  points[i,4] := Trunc(512 * tx / (distance - tz))+cx; //x
  points[i,5] := Trunc(512 * ty / (distance - tz))+cy; //y
 end;
end; 

begin 
Direction:=1;
Faza:=1;
distance:=100;
cx:=GetWidth/2;
cy:=GetHeight/2;

 points[1,1]:=5; points[1,2]:=-5; points[1,3]:=-5;
 points[2,1]:=5; points[2,2]:=-5; points[2,3]:=5;
 points[3,1]:=5; points[3,2]:=5; points[3,3]:=5;
 points[4,1]:=5; points[4,2]:=5; points[4,3]:=-5;
 points[5,1]:=-5; points[5,2]:=-5; points[5,3]:=-5;
 points[6,1]:=-5; points[6,2]:=-5; points[6,3]:=5;
 points[7,1]:=-5; points[7,2]:=5; points[7,3]:=5;
 points[8,1]:=-5; points[8,2]:=5; points[8,3]:=-5;
 
 lines[1,1]:=1; lines[1,2]:=2;
 lines[2,1]:=2; lines[2,2]:=3;
 lines[3,1]:=3; lines[3,2]:=4;
 lines[4,1]:=4; lines[4,2]:=1;
 lines[5,1]:=2; lines[5,2]:=6;
 lines[6,1]:=3; lines[6,2]:=7;
 lines[7,1]:=4; lines[7,2]:=8;
 lines[8,1]:=1; lines[8,2]:=5;
 lines[9,1]:=5; lines[9,2]:=6;
 lines[10,1]:=6;	lines[10,2]:=7;
 lines[11,1]:=7;	lines[11,2]:=8;
 lines[12,1]:=8;	lines[12,2]:=5;

 while true do 
  begin 
  SetColor(255, 255, 255);
  FillRect(0, 0, GetWidth, GetHeight); 
  
  rx:=rx+ToRadians(1);
  ry:=2*rx;
  rz:=3*rx;
  
  UpdateCube;
  
  Rotate3D;
  
  SetColor(255, 0, 0); 
  //Draw3D;
  for i:=1 to numlines do
  begin
  DrawLine(points[lines[i,1],4], points[lines[i,1],5], points[lines[i,2],4], points[lines[i,2],5]); 
  end;
  
  MS:=GetSecond(GetCurrentTime);
  If MS<>MSL Then
  begin
  FPS_LastCount:=FPS_Count;
  FPS_Count:=0;
  MSL:=MS;
  end 
  Else
  FPS_Count:=FPS_Count+1;
  
  SetColor(0, 0, 255); 
  DrawText('FPS:'+IntegerToString(FPS_LastCount), 0, 0);
  
  Repaint;
  
  if GetKeyPressed = KE_KEY1 then distance:=distance-10;
  if GetKeyPressed = KE_KEY3 then distance:=distance+10;
  if GetKeyPressed = KE_KEY2 then cy:=cy-2;
  if GetKeyPressed = KE_KEY4 then cx:=cx-2;
  if GetKeyPressed = KE_KEY6 then cx:=cx+2;
  if GetKeyPressed = KE_KEY8 then cy:=cy+2;
 Delay(30); 

  end; 
end.