(****************************************
 *    NDS NeHe Lesson 08          *
 *    Author: Ethos         *
 ****************************************)

program Lesson08;
{$L build/drunkenlogo.pcx.o}

{$mode objfpc}

uses
  ctypes, nds9;

{$include inc/drunkenlogo.pcx.inc}

var
  light: boolean;       // Lighting ON/OFF ( NEW )
  lp: boolean;          // L Pressed? ( NEW )

  xrot: cfloat;       // X Rotation
  yrot: cfloat;       // Y Rotation
  xspeed: cfloat;       // X Rotation Speed
  yspeed: cfloat;       // Y Rotation Speed
  z: cfloat = -5.0;     // Depth Into The Screen

  texture: array [0..2] of integer;     // Storage For 3 Textures (only going to use 1 on the DS for this demo)

const
  LightAmbient: array [0..3] of cfloat =    ( 0.5, 0.5, 0.5, 1.0 );
  LightDiffuse: array [0..3] of cfloat =    ( 1.0, 1.0, 1.0, 1.0 );
  LightPosition: array [0..3] of cfloat =   ( 0.0, 0.0, 2.0, 1.0 );

function DrawGLScene(): boolean;                      // Here's Where We Do All The Drawing
begin
  glLoadIdentity();                 // Reset The View
  glTranslatef(0.0,0.0,z);

  glRotatef(xrot,1.0,0.0,0.0);
  glRotatef(yrot,0.0,1.0,0.0);
  
  glPolyFmt(POLY_ALPHA(31) or POLY_CULL_NONE  or POLY_FORMAT_LIGHT0);

  glBindTexture(GL_TEXTURE_2D, texture[0]);  //no filters to swtich between
  
  glBegin(GL_QUADS);
    // Front Face
    glNormal3f( 0.0, 0.0, 1.0);
    glTexCoord2f(0.0, 0.0); glVertex3f(-1.0, -1.0,  1.0);
    glTexCoord2f(1.0, 0.0); glVertex3f( 1.0, -1.0,  1.0);
    glTexCoord2f(1.0, 1.0); glVertex3f( 1.0,  1.0,  1.0);
    glTexCoord2f(0.0, 1.0); glVertex3f(-1.0,  1.0,  1.0);
    // Back Face
    glNormal3f( 0.0, 0.0,-1.0);
    glTexCoord2f(1.0, 0.0); glVertex3f(-1.0, -1.0, -1.0);
    glTexCoord2f(1.0, 1.0); glVertex3f(-1.0,  1.0, -1.0);
    glTexCoord2f(0.0, 1.0); glVertex3f( 1.0,  1.0, -1.0);
    glTexCoord2f(0.0, 0.0); glVertex3f( 1.0, -1.0, -1.0);
    // Top Face
    glNormal3f( 0.0, 1.0, 0.0);
    glTexCoord2f(0.0, 1.0); glVertex3f(-1.0,  1.0, -1.0);
    glTexCoord2f(0.0, 0.0); glVertex3f(-1.0,  1.0,  1.0);
    glTexCoord2f(1.0, 0.0); glVertex3f( 1.0,  1.0,  1.0);
    glTexCoord2f(1.0, 1.0); glVertex3f( 1.0,  1.0, -1.0);
  // Bottom Face
    glNormal3f( 0.0,-1.0, 0.0);
    glTexCoord2f(1.0, 1.0); glVertex3f(-1.0, -1.0, -1.0);
    glTexCoord2f(0.0, 1.0); glVertex3f( 1.0, -1.0, -1.0);
    glTexCoord2f(0.0, 0.0); glVertex3f( 1.0, -1.0,  1.0);
    glTexCoord2f(1.0, 0.0); glVertex3f(-1.0, -1.0,  1.0);
    // Right face
    glNormal3f( 1.0, 0.0, 0.0);
    glTexCoord2f(1.0, 0.0); glVertex3f( 1.0, -1.0, -1.0);
    glTexCoord2f(1.0, 1.0); glVertex3f( 1.0,  1.0, -1.0);
    glTexCoord2f(0.0, 1.0); glVertex3f( 1.0,  1.0,  1.0);
    glTexCoord2f(0.0, 0.0); glVertex3f( 1.0, -1.0,  1.0);
  glEnd();

  glPolyFmt(POLY_ALPHA(15) or POLY_CULL_BACK  or POLY_FORMAT_LIGHT0);
  
  glBegin(GL_QUADS);
  
  // Left Face
    glNormal3f(-1.0, 0.0, 0.0);
    glTexCoord2f(0.0, 0.0); glVertex3f(-1.0, -1.0, -1.0);
    glTexCoord2f(1.0, 0.0); glVertex3f(-1.0, -1.0,  1.0);
    glTexCoord2f(1.0, 1.0); glVertex3f(-1.0,  1.0,  1.0);
    glTexCoord2f(0.0, 1.0); glVertex3f(-1.0,  1.0, -1.0);
  glEnd();

  xrot := xrot+xspeed;
  yrot := yrot+yspeed;

  result := true;     
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);

  imageDestroy(@pcx);

  result := true;
end;

var
  pressed: integer;
  held: 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);
  
  glEnable(GL_BLEND);
  
  // 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);
  
  // Set our viewport to be the same size as the screen
  glViewPort(0,0,255,191);
  
  LoadGLTextures();
  
  glMatrixMode(GL_PROJECTION);
  glLoadIdentity();
  gluPerspective(70, 256.0 / 192.0, 0.1, 100);
  
  //set up a directional ligth arguments are light number (0-3), light color, 
  //and an x,y,z vector that points in the direction of the light
  glLight(0, RGB15(31,31,31) , 0, floattov10(-1.0), 0);
  
  
  glColor3f(1,1,1);
  
  glMatrixMode(GL_MODELVIEW);
  
  //need to set up some material properties since DS does not have them set by default
  
  glMaterialf(GL_AMBIENT, RGB15(16,16,16));
  glMaterialf(GL_DIFFUSE, RGB15(16,16,16));
  glMaterialf(GL_SPECULAR, BIT(15) or RGB15(8,8,8));
  glMaterialf(GL_EMISSION, RGB15(16,16,16));
  
  //ds uses a table for shinyness..this generates a half-ass one
  glMaterialShinyness();
  
  // Set the current matrix to be the model matrix
  glMatrixMode(GL_MODELVIEW);
  while true do
  begin
    //these little button functions are pretty handy
    scanKeys();
    held := keysHeld();
    pressed := keysDown();
        
    if (held and KEY_R)     <> 0 then z := z - 0.02;
    if (held and KEY_L)     <> 0 then z := z + 0.02;
    if (held and KEY_LEFT)  <> 0 then xspeed := xspeed - 0.01;
    if (held and KEY_RIGHT) <> 0 then xspeed := xspeed + 0.01;
    if (held and KEY_UP)    <> 0 then yspeed := yspeed + 0.01;
    if (held and KEY_DOWN)  <> 0 then yspeed := yspeed - 0.01;

    DrawGLScene();

    // flush to screen  
    glFlush(0);
    
    // wait for the screen to refresh
    swiWaitForVBlank();
  
    if (pressed and KEY_START) then break;
  end;
  
end.