program Lesson11;
{$L build/drunkenlogo.pcx.o}

{$mode objfpc} 

uses
  ctypes, nds9; 

{$include inc/drunkenlogo.pcx.inc}

var
  points: array [0..63, 0..31, 0..2] of v16;    // The Array For The Points On The Grid Of Our "Wave"
  wiggle_count: integer = 0;    // Counter Used To Control How Fast Flag Waves

  xrot: cfloat;       // X Rotation ( NEW )
  yrot: cfloat;       // Y Rotation ( NEW )
  zrot: cfloat;       // Z Rotation ( NEW )
  hold: v16;          // Temporarily Holds A Floating Point Value

  texture: array [0..0] of integer;     // Storage For 3 Textures (only going to use 1 on the DS for this demo)

function sin(angle: cfloat): cfloat;
var
  s: cint32;
begin
  s := sinLerp(cint((angle * DEGREES_IN_CIRCLE) / 360.0));
  result := f32tofloat(s);
end;

function cos(angle: cfloat): cfloat;
var
  c: int32;
begin
  c := cosLerp(cint((angle * DEGREES_IN_CIRCLE) / 360.0));
  result := f32tofloat(c);
end;

function DrawGLScene(): boolean;                      // Here's Where We Do All The Drawing
var
  x, y: integer;
  float_x, float_y, float_xb, float_yb: t16;
begin

  glColor3b(255,255,255);    // set the vertex color
  
  glLoadIdentity();                 // Reset The View

  glTranslatef(0.0,0.0,-12.0);
    
  glRotatef(xrot,1.0,0.0,0.0);
  glRotatef(yrot,0.0,1.0,0.0);  
  glRotatef(zrot,0.0,0.0,1.0);

  glBindTexture(GL_TEXTURE_2D, texture[0]);

  glBegin(GL_QUADS);
  for x := 0 to 30 do
  begin
    for  y := 0 to 30 do
    begin
      float_x := inttot16(x) shl 2;
      float_y := inttot16(y) shl 2;
      float_xb := inttot16(x+1) shl 2;
      float_yb := inttot16(y+1) shl 2;

      glTexCoord2t16( float_x, float_y);
      glVertex3v16( points[x][y][0], points[x][y][1], points[x][y][2] );

      glTexCoord2t16( float_x, float_yb );
      glVertex3v16( points[x][y+1][0], points[x][y+1][1], points[x][y+1][2] );

      glTexCoord2t16( float_xb, float_yb );
      glVertex3v16( points[x+1][y+1][0], points[x+1][y+1][1], points[x+1][y+1][2] );

      glTexCoord2t16( float_xb, float_y );
      glVertex3v16( points[x+1][y][0], points[x+1][y][1], points[x+1][y][2] );
    end;
  end;
  glEnd();

  if ( wiggle_count = 2 ) then
  begin
    for y := 0 to 31 do
    begin
      hold := points[0][y][2];
      for x := 0 to 31 do
      begin
        points[x][y][2] := points[x+1][y][2];
      end;
      points[31][y][2]:=hold;
    end;
    wiggle_count := 0;
  end;

  inc(wiggle_count);

  xrot:=xrot+0.3;
  yrot:=yrot+0.2;
  zrot:=zrot+0.4;

  result := true;                     // Everything Went OK

end;


 
function LoadGLTextures(): boolean;                 // Load PCX files And Convert To Textures
var
  pcx: sImage;                //////////////(NEW) and different from nehe.
begin
  //load our texture
  loadPCX(pcuint8(drunkenlogo_pcx), @pcx);

  image8to16(@pcx);

  glGenTextures(1, @texture[0]);
  glBindTexture(0, texture[0]);
  glTexImage2D(0, 0, GL_RGB, TEXTURE_SIZE_128 , TEXTURE_SIZE_128, 0, TEXGEN_TEXCOORD, pcx.image.data8);

  result := true;
end;

procedure InitGL();
var
  x, y:integer;
begin
  // Setup the Main screen for 3D 
  videoSetMode(MODE_0_3D);
  vramSetBankA(VRAM_A_TEXTURE);                        //NEW  must set up some memory for textures
  
  // initialize the geometry engine
  glInit();
  
  // enable textures
  glEnable(GL_TEXTURE_2D);
  
  // Set our viewport to be the same size as the screen
  glViewPort(0,0,255,191);
  
  // enable antialiasing
  glEnable(GL_ANTIALIAS);
  
  // setup the rear plane
  glClearColor(0,0,0,31); // BG must be opaque for AA to work
  glClearPolyID(63); // BG must have a unique polygon ID for AA to work
  glClearDepth($7FFF);
  
  LoadGLTextures();
  
  glMatrixMode(GL_PROJECTION);
  glLoadIdentity();
  gluPerspective(70, 256.0 / 192.0, 0.1, 100);
  
  //need to set up some material properties since DS does not have them set by default
  glMaterialf(GL_AMBIENT, RGB15(31,31,31));
  glMaterialf(GL_DIFFUSE, RGB15(31,31,31));
  glMaterialf(GL_SPECULAR, BIT(15) or RGB15(16,16,16));
  glMaterialf(GL_EMISSION, RGB15(31,31,31));
  
  //ds uses a table for shinyness..this generates a half-ass one
  glMaterialShinyness();
  
  //ds specific, several attributes can be set here 
  glPolyFmt(POLY_ALPHA(31) or POLY_CULL_NONE );
  

  for x:=0 to 31 do
  begin
    for y:=0 to 31 do
    begin
      points[x][y][0] := (inttov16(x) div 4);
      points[x][y][1] := (inttov16(y) div 4);
      points[x][y][2] := sinLerp(x * (DEGREES_IN_CIRCLE div 32));
    end;
  end;
end;

var
  pressed: integer;

begin 
  InitGL();
  
  glMatrixMode(GL_MODELVIEW);

  while true do
  begin 
    DrawGLScene();
    
    // flush to screen  
    glFlush(0);
    
    // wait for the screen to refresh
    swiWaitForVBlank();

    scanKeys();
    pressed := keysDown();
    if (pressed and KEY_START) <> 0 then break;
  end;
end.