raytrace-retro/turbo-pascal/ray11.pas

program mmmmmmmmmmmmm;
{$X+}
uses Crt,Vga13h,RayTrace;

type
  TgaHeader = record { 18 bytes total }
    who_knows: array[1..12] of Byte;
    Width: Word;
    Height: Word;
    BitsPerPixel: Byte;
    who_knows2: Byte;
  end;

const
  DefaultHeader: TgaHeader = (
    who_knows: (0, 0, 2, 0, 0, 0, 0, 0, 0, 0, 0, 0);
    Width: 320;
    Height: 200;
    BitsPerPixel: 24;
    who_knows2: 32
  );

var
  tf: File of Byte;
  tff: File absolute tf;

procedure StartTga(s: String);
begin
  Assign(tf,s);
  Rewrite(tf);
  BlockWrite(tff,DefaultHeader,18);
end;

procedure EndTga;
begin
  Close(tf);
end;

procedure TgaDot(r,g,b: Integer);
begin
  if r > 255 then r := 255;
  if g > 255 then g := 255;
  if b > 255 then b := 255;
  if r < 0 then r := 0;
  if g < 0 then g := 0;
  if b < 0 then b := 0;
  Write(tf,Byte(b),Byte(g),Byte(r));
end;

{ r,g,b:0-255 }
function Rgb(r,g,b: Integer): Integer;
begin
  if r > 255 then r := 255;
  if g > 255 then g := 255;
  if b > 255 then b := 255;
  Rgb := (b shr 6) or ((g shr 3) and $1c) or (r and $e0);
end;

procedure RgbDot(x,y,r,g,b: Integer);
var
  r1,g1,b1,r2,g2,b2,c1,c2: Integer;
begin
  if r > 255 then r := 255;
  if g > 255 then g := 255;
  if b > 255 then b := 255;
  if r < 0 then r := 0;
  if g < 0 then g := 0;
  if b < 0 then b := 0;
  r1 := r and $e0; g1 := g and $e0; b1 := b and $c0;
  r2 := r1 + (r mod 32)+16;
  g2 := g1 + (g mod 32)+16;
  b2 := b1 + (b mod 64)+32;
  c1 := Rgb(r1,g1,b1); c2 := Rgb(r2,g2,b2);
  if (x mod 2) = (y mod 2) then PutPixel(x,y,c1) else PutPixel(x,y,c2);
end;

procedure SetUpRgb;
var
  Clrs: array[0..255,0..2] of Byte;
  i: Integer;
begin
  for i := 0 to 255 do begin
    Clrs[i,0] := (i and $e0) shr 2;
    Clrs[i,1] := (i and $1c) shl 1;
    Clrs[i,2] := (i and 3) shl 4;
    case Clrs[i,2] of
      15..31: Inc(Clrs[i,2],4);
      32..63: Inc(Clrs[i,2],8);
    end;
  end;
  SetColorBlock(0,256,Clrs);
end;

procedure Save(var u: Universe; st: String);
var
  x,y: Integer;
  c: LongInt;
  r,g,b: Integer;
begin
  StartTga(st);
  x := 0;
  for y := 0 to u.Height-1 do
    for x := 0 to u.Width-1 do begin
      c := u.TracePoint(x,y);
      r := (c and $ff0000) shr 16;
      g := (c and $ff00) shr 8;
      b := c and $ff;
      RgbDot(x,u.Height-1-y,r,g,b);
      TgaDot(r,g,b);
    end;
  EndTga;
end;

procedure Draw(var u: Universe);
var
  x,y: Integer;
  c: LongInt;
begin
  x := 0;
  while (x < u.Width) and (not KeyPressed) do begin
    for y := 0 to u.Height-1 do begin
      c := u.TracePoint(x,u.Height-1-y);
      if c <> 0 then
        RgbDot(x,y,(c and $ff0000) shr 16,(c and $ff00) shr 8,c and $ff);
    end;
    Inc(x);
  end;
end;

procedure Qwik(var u: Universe);
var
  x,y: Integer;
  c: LongInt;
  r,g,b: Byte;
begin
  x := 0;
  while (x < (u.Width div 2)) and (not KeyPressed) do begin
    for y := 0 to (u.Height div 2)-1 do begin
      c := u.TracePoint(x*2,u.Height-1-(y*2));
      if c <> 0 then begin
        r := (c and $ff0000) shr 16;
        g := (c and $ff00) shr 8;
        b := c and $ff;
        RgbDot(x*2,y*2,r,g,b); RgbDot(x*2+1,y*2,r,g,b);
        RgbDot(x*2+1,y*2+1,r,g,b); RgbDot(x*2,y*2+1,r,g,b);
      end;
    end;
    Inc(x);
  end;
end;

procedure Zoom(var u: Universe);
var
  x,y,i,j: Integer;
  c: LongInt;
  r,g,b: Byte;
begin
  x := 0;
  while (x < (u.Width div 4)) and (not KeyPressed) do begin
    for y := 0 to (u.Height div 4)-1 do begin
      c := u.TracePoint(x*4,u.Height-1-(y*4));
      if c <> 0 then begin
        r := (c and $ff0000) shr 16;
        g := (c and $ff00) shr 8;
        b := c and $ff;
        for i := 0 to 3 do
          for j := 0 to 3 do
            RgbDot(x*4+i,y*4+j,r,g,b);
      end;
    end;
    Inc(x);
  end;
end;

procedure Beep;
begin
  Sound(220);        { Beep }
  Delay(200);        { For 200 ms }
  NoSound;           { Relief! }
end;

type
  pplane = object(Plane)
    function GetColor(aray: Ray; time: Real): LongInt; virtual;
  end;
  BlankSphere = object(Sphere)
    function GetColor(aray: Ray; time: Real): LongInt; virtual;
  end;

const
  AmbientInt = 10;
  PointInt = 100;
  LightX = 15;
  LightY = 5;
  LightZ = 100;
  CoeffReflect = 0.85;

function pplane.GetColor(aray: Ray; time: Real): LongInt;
var
  costheta,d,x,y,z,I: Real;
  N,L: Ray;
  c: Integer;
begin
  SurfNormal(aray,time,N);
  d := Sqrt(Sqr(n.dx)+Sqr(n.dy)+Sqr(n.dz));
  if d <> 0 then begin
    n.dx := n.dx / d;
    n.dy := n.dy / d;
    n.dz := n.dz / d;
  end;
  x := LightX - (time * aray.dx + aray.ox);
  y := LightY - (time * aray.dy + aray.oy);
  z := LightZ - (time * aray.dz + aray.oz);
  d := Sqrt(Sqr(x)+Sqr(y)+Sqr(z));
  if d <> 0 then begin
    x := x / d;
    y := y / d;
    z := z / d;
  end;
  costheta :=
    (n.dx*x+n.dx*y+n.dx*z+
     n.dy*x+n.dy*y+n.dy*z+
     n.dz*x+n.dz*y+n.dz*z);
  if costheta < 0 then costheta := 0;
  I := (CoeffReflect * AmbientInt) +
    ((CoeffReflect * PointInt) / (d + 0.001)) * costheta;
  c := Round(I*15);
  GetColor := GetRgb(c,c,c);
end;

function BlankSphere.GetColor(aray: Ray; time: Real): LongInt;
begin
  GetColor := $ffffff;
end;

procedure TraceIt;
var
  u: Universe;
  p,p2,p3: Pplane;
  s: BlankSphere;
begin
  u.Init(320,200);
  s.Init(LightX,LightY,LightZ,1); {15,5,100}
  p.Init(0,-8,0, 0.25,1,0);
  p2.Init(0,0,150, 0,0,-1);
  p3.Init(-20,0,0, 1,0,0);
  u.Insert(@p);
  u.Insert(@p2);
  u.Insert(@p3);
  u.Insert(@s);
  Zoom(u);
  Beep;
  u.Done;
end;

begin
  Set13h;
  SetUpRgb;
  TraceIt;
  ReadKey;
  BiosMode(3);
end.