; PROJECT : 3d_v2_Torus_PB_Version
; AUTHOR  : Paul Rene J?rgensen  & Kev Picone
; CREATED : 12/03/2022
; EDITED  : 14/03/2022
; ---------------------------------------------------------------------

;--------------------------------------------------------------------------------
	#include "BlitzWrapper.pba"
;--------------------------------------------------------------------------------


; 3d
;
;       Author : Paul Rene J?rgensen, <>
;  Last update : 20. February, 2001
;
; 9 Muls rotator, Mergesort, Gourad shader,
; Backface-culling, Vector based lightsource


Global numvertex,numpoly
Global width=640
Global height=480

BB_Graphics width,height,32,2
BB_AppTitle("Gourad shading")

BB_SetBuffer BB_BackBuffer()

Dim xpos(height,2)
Dim zpos(height,2)
Dim rpos(height,2)
Dim gpos(height,2)
Dim bpos(height,2)

Type tlightsource
   x,y,z
EndType

Type tvertex
   x,y,z
   xr,yr,zr
   nx,ny,nz
   nxr,nyr,nzr
   x2d,y2d
EndType

Type tpoly
   v0,v1,v2,v3
   order
EndType

Restore MyObject
	numvertex = Readdata()
	numpoly		=ReadData()

Dim zcenter(numpoly)
Dim zworking(numpoly)
Dim ordertable(numpoly)
Dim oworking(numpoly)

Restore coords
Dim vertex(numvertex) as tvertex
For n=0 To numvertex-1
  vertex(n)=New tvertex
  vertex(n).x = Readdata()
  vertex(n).y= Readdata()
  vertex(n).z= Readdata()
Next
Restore pnorms
For n=0 To numvertex-1
  vertex(n).nx = Readdata()
  vertex(n).ny = Readdata()
  vertex(n).nz = Readdata()
Next

Restore polys
Dim poly(numpoly) as tpoly
For n=0 To numpoly-1
  poly(n)=New tpoly
 ; BB_Read dum,dum
  dum = Readdata()
  dum = Readdata()
  poly(n).v0 = Readdata()
  poly(n).v1 = Readdata()
  poly(n).v2 = Readdata()
  poly(n).v3 = Readdata()
Next

Dim lightsource(2) as tlightsource
lightsource(0)=New tlightsource
lightsource(0).x=256
lightsource(0).y=256
lightsource(0).z=-256


x_angle=0
y_angle=0
z_angle=0

;setfps 31.7

global RenderMethod =0 

While Not BB_KeyDown(1)

	if enterKey()
		RenderMethod++
		if RenderMethod>2 then RenderMethod=0
		flushkeys
	endif

	select RenderMethod
			case 0
				Render_Method_Name$ ="fastDot inner loop"
			case 1
				Render_Method_Name$ ="gouraud strip inner loop"
			case 2
				Render_Method_Name$ ="gouraud triangle"
	endselect

  rotate_transform_vertices(x_angle,y_angle,z_angle)
  sort_polys()
  BB_Cls()
  draw_polys()
 ; draw_vertices()
  lfps=(1000/(BB_MilliSecs()-t))
  t=BB_MilliSecs()
  Text 10,10,"Current FPS : "+str$(lfps)
  Text 10,30,"Highest FPS : "+str$(hfps)
  Text 10,40,"Average FPS : "+str$(afps#)
  Text 10,50," Lowest FPS : "+str$(lfps)
  Text 10,60,"     Render : "+Render_Method_Name$
 
  Text 210,10,"  Points : "+str$(numvertex)
  Text 210,20,"Polygons : "+str$(numpoly)
 
  
  If hfps=0 Then hfps=lfps
  If lfps=0 Then lfps=lfps
  If afps#=0 Then afps#=lfps : afpscount=1
  If lfps>hfps Then hfps=lfps
  If lfps<lfps Then lfps=lfps
  afps#=((afps#*afpscount)+lfps)/(afpscount+1)
  afpscount=afpscount+1
  BB_Flip()
  x_angle=x_angle+1
  y_angle=y_angle+2
  z_angle=z_angle+4
  If x_angle>360 Then x_angle=x_angle-360
  If y_angle>360 Then y_angle=y_angle-360
  If z_angle>360 Then z_angle=z_angle-360


	if Spacekey() then end
	quittime=quittime+1
	If quittime> 25000 Then End
EndWhile



Function draw_polys()
  lockbuffer
    ThisRGB = point(0,0)
		
	  For n=0 To numpoly-1
	  index=ordertable(n)	
    v0=poly(index).v0
    v1=poly(index).v1
    v2=poly(index).v2

    x1=vertex(v0).x2d
    y1=vertex(v0).y2d
    nx=vertex(v0).nxr
    ny=vertex(v0).nyr
    nz=vertex(v0).nzr
    c1=((nx*lightsource(0).x)+(ny*lightsource(0).y)+(nz*lightsource(0).z))/256
    If c1<0 Then c1=0
    If c1>255 Then c1=255

    x2=vertex(v1).x2d
    y2=vertex(v1).y2d
    nx=vertex(v1).nxr
    ny=vertex(v1).nyr
    nz=vertex(v1).nzr
    c2=((nx*lightsource(0).x)+(ny*lightsource(0).y)+(nz*lightsource(0).z))/256
   ; If c2<0 Then c2=0
   ; If c2>255 Then c2=255
	c2=cliprange(c2,0,255)
		

    x3=vertex(v2).x2d
    y3=vertex(v2).y2d
    nx=vertex(v2).nxr
    ny=vertex(v2).nyr
    nz=vertex(v2).nzr
    c3=((nx*lightsource(0).x)+(ny*lightsource(0).y)+(nz*lightsource(0).z))/256
    If c3<0 Then c3=0
    If c3>255 Then c3=255
 
    ; Back-face culling
    If (x3-x1)*(y2-y1)-(x2-x1)*(y3-y1)>=0
    	Select RenderMethod
    			case 0
		     		 gpolygon(x1,y1,c1,c1,c1,x2,y2,c2,c2,c2,x3,y3,c3,c3,c3)
    			case 1
		     		 gpolygon1(x1,y1,c1,c1,c1,x2,y2,c2,c2,c2,x3,y3,c3,c3,c3)
    			case 2
		     		 gpolygon2(x1,y1,c1,c1,c1,x2,y2,c2,c2,c2,x3,y3,c3,c3,c3)
	  endselect
     ; Line vertex(v0).x2d,vertex(v0).y2d,vertex(v1).x2d,vertex(v1).y2d
;      Line vertex(v1)\x2d,vertex(v1)\y2d,vertex(v2)\x2d,vertex(v2)\y2d
;      Line vertex(v2)\x2d,vertex(v2)\y2d,vertex(v0)\x2d,vertex(v0)\y2d
    EndIf
  Next
  unlockbuffer
EndFunction 0


Function draw_vertices()
  BB_LockBuffer 0
  lRGB=(255 << 16)+(255 << 8)+255
  For n=0 To numvertex-1
    BB_WritePixel vertex(n).x2d,vertex(n).y2d,lRGB,0
  Next
  BB_UnlockBuffer 0
EndFunction 0



Function sort_polys()
  For n=0 To numpoly-1
    v0=poly(n).v0
    v1=poly(n).v1
    v2=poly(n).v2
    z1=vertex(v0).zr
    z2=vertex(v1).zr
    z3=vertex(v2).zr
    z=z1+z2+z3
    zcenter(n)=z
    ordertable(n)=n    
  Next
  mergesort(0,numpoly-1)
EndFunction 0

Function mergesort(lo,hi)
  ; Base case
  If lo=hi Then ExitFUNCTION 0

  ; Recurse
  length=hi-lo+1
  pivot=(lo+hi)/2
  mergesort(lo,pivot)
  mergesort(pivot+1,hi)

  ; Merge
  For i=0 To length-1
    zworking(i)=zcenter(lo+i)
    oworking(i)=ordertable(lo+i)
  Next
  m1=0
  m2=pivot-lo+1
  For i=0 To length-1
    If m2<=(hi-lo)
      If m1<=(pivot-lo)
        If zworking(m1)<zworking(m2)
          ordertable(i+lo)=oworking(m2)
          zcenter(i+lo)=zworking(m2)
          m2=m2+1
        Else
          ordertable(i+lo)=oworking(m1)
          zcenter(i+lo)=zworking(m1)
          m1=m1+1
        EndIf
      Else
        ordertable(i+lo)=oworking(m2)
        zcenter(i+lo)=zworking(m2)
        m2=m2+1
      EndIf
    Else
      ordertable(i+lo)=oworking(m1)
      zcenter(i+lo)=zworking(m1)
      m1=m1+1
    EndIf
  Next
EndFunction 0  // Assumed Integer return


Function rotate_transform_vertices(x_angle,y_angle,z_angle)
  ; 9 muls rotator
  c1#=Cos(x_angle)
  c2#=Cos(y_angle)
  c3#=Cos(z_angle)
  s1#=Sin(x_angle)
  s2#=Sin(y_angle)
  s3#=Sin(z_angle)
  xx#=c2#*c1#
  xy#=c2#*s1#
  xz#=s2#
  yx#=c3#*s1#+s3#*s2#*c1#
  yy#=-c3#*c1#+s3#*s2#*s1#
  yz#=-s3#*c2#
  zx#=s3#*s1#-c3#*s2#*c1#
  zy#=-s3#*c1#-c3#*s2#*s1#
  zz#=c3#*c2#
width2=width/2
height2=height/2
widthbyheight=(width/height)*256
  For n=0 To numvertex-1
    ; Vertices
    vertex(n).xr=xx#*vertex(n).x+xy#*vertex(n).y+xz#*vertex(n).z
    vertex(n).yr=yx#*vertex(n).x+yy#*vertex(n).y+yz#*vertex(n).z
    vertex(n).zr=zx#*vertex(n).x+zy#*vertex(n).y+zz#*vertex(n).z
    ; Vertice Normals
    vertex(n).nxr=xx#*vertex(n).nx+xy#*vertex(n).ny+xz#*vertex(n).nz
    vertex(n).nyr=yx#*vertex(n).nx+yy#*vertex(n).ny+yz#*vertex(n).nz
    vertex(n).nzr=zx#*vertex(n).nx+zy#*vertex(n).ny+zz#*vertex(n).nz
    ; 3d -> 2d transformation
    vertex(n).x2d=(widthbyheight*vertex(n).xr)/(vertex(n).zr+1024)+width2
    vertex(n).y2d=(256*vertex(n).yr)/(vertex(n).zr+1024)+height2
  Next
EndFunction 0


Function gpolygon(x1,y1,r1,g1,b1,x2,y2,r2,g2,b2,x3,y3,r3,g3,b3)
	
  For n=0 To height : xpos(n,0)=0 : xpos(n,1)=0 : Next
  drawedge(x1,y1,r1,g1,b1,x2,y2,r2,g2,b2)
  drawedge(x2,y2,r2,g2,b2,x3,y3,r3,g3,b3)
  drawedge(x3,y3,r3,g3,b3,x1,y1,r1,g1,b1)
  miny=y1
  If(miny>y2) Then miny=y2
  If(miny>y3) Then miny=y3
  maxy=y1
  If(maxy<y2) Then maxy=y2
  If(maxy<y3) Then maxy=y3
  minx=x1
  If(minx>x2) Then minx=x2
  If(minx>x3) Then minx=x3
  maxx=x1
  If(maxx<x2) Then maxx=x2
  If(maxx<x3) Then maxx=x3
  For y=miny To maxy
    horizontalline(xpos(y,0),xpos(y,1),y)
  Next
EndFunction 0





Function gpolygon1(x1,y1,r1,g1,b1,x2,y2,r2,g2,b2,x3,y3,r3,g3,b3)
  For n=0 To height : xpos(n,0)=0 : xpos(n,1)=0 : Next
  drawedge(x1,y1,r1,g1,b1,x2,y2,r2,g2,b2)
  drawedge(x2,y2,r2,g2,b2,x3,y3,r3,g3,b3)
  drawedge(x3,y3,r3,g3,b3,x1,y1,r1,g1,b1)
  miny=y1
  If(miny>y2) Then miny=y2
  If(miny>y3) Then miny=y3
  maxy=y1
  If(maxy<y2) Then maxy=y2
  If(maxy<y3) Then maxy=y3
  minx=x1
  If(minx>x2) Then minx=x2
  If(minx>x3) Then minx=x3
  maxx=x1
  If(maxx<x2) Then maxx=x2
  If(maxx<x3) Then maxx=x3
  For y=miny To maxy
    x1=xpos(y,0)
    x2=xpos(y,1)
    r1=rpos(y,0)
    r2=rpos(y,1)
    g1=gpos(y,0)
    g2=gpos(y,1)
    b1=bpos(y,0)
    b2=bpos(y,1)
    
    gouraudstriph x1,rgb(r1,g1,b1) , x2, rgb(r2,b2,g2), y
    
  Next
EndFunction 



Function gpolygon2(x1,y1,r1,g1,b1,x2,y2,r2,g2,b2,x3,y3,r3,g3,b3)
	rgb1=rgb(r1,g1,b1)	
	rgb2=rgb(r2,g2,b2)	
	rgb3=rgb(r3,g3,b3)	
	gouraudtri x1,y1,rgb1,x2,y2,rgb2,x3,y3,rgb3
EndFunction 


Function horizontalline(x1,x2,y)
  If(x1<>x2) ;Then 
    r1=rpos(y,0)
    r2=rpos(y,1)
    g1=gpos(y,0)
    g2=gpos(y,1)
    b1=bpos(y,0)
    b2=bpos(y,1)
    If(x1>x2) ;Then
      temp=x1
      x1=x2
      x2=temp
      temp=r1
      r1=r2
      r2=temp
      temp=g1
      g1=g2
      g2=temp
      temp=b1
      b1=b2
      b2=temp
    EndIf
    rslope=((r2-r1) << 8)/(x2-x1)
    gslope=((g2-g1) << 8)/(x2-x1)
    bslope=((b2-b1) << 8)/(x2-x1)
    r=r1 << 8
    g=g1 << 8
    b=b1 << 8
    
    For x=x1 To x2
      rt=r >> 8
      gt=g >> 8
      bt=b >> 8
 ;     lRGB=(rt << 16)+(gt << 8)+bt
      ;BB_WritePixel x,y,lRGB,BB_BackBuffer()
;      Dotc x,y,lRGB
      fastdot x,y,RGB(rt,gt,bt)
      r=r+rslope
      g=g+gslope
      b=b+bslope
    Next
    
  EndIf
EndFunction 0


Function drawedge(x1,y1,r1,g1,b1,x2,y2,r2,g2,b2)
  side=0
  If(y1<>y2) ;Then
    If(y1>=y2) ;Then
      side=1
      temp=x1
      x1=x2
      x2=temp
      temp=y1
      y1=y2
      y2=temp
      temp=r1
      r1=r2
      r2=temp
      temp=g1
      g1=g2
      g2=temp
      temp=b1
      b1=b2
      b2=temp
    EndIf
    
    Scaler = (1 << 8)
    xslope=((x2-x1) << 8)/(y2-y1)
    rslope=((r2-r1) << 8)/(y2-y1)
    gslope=((g2-g1) << 8)/(y2-y1)
    bslope=((b2-b1) << 8)/(y2-y1)
    x=(x1 << 8)+xslope
    r=(r1 << 8)+rslope
    g=(g1 << 8)+gslope
    b=(b1 << 8)+bslope
    For y=y1+1 To y2
      xpos(y,side)=x >> 8
      rpos(y,side)=r >> 8
      gpos(y,side)=g >> 8
      bpos(y,side)=b >> 8
      x=x+xslope
      r=r+rslope
      g=g+gslope
      b=b+bslope
    Next
  EndIf
EndFunction 0


   //  Object Data removed..  Download full code bellow