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directional shadow mapping - simple question


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#1 fread   Members   -  Reputation: 240

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Posted 18 June 2014 - 11:06 AM

Okay guys, I'm almost ready with the implementation of this technique, but I have one problem.

How to setup the projection (ortho) and view (??) matrix of directional light for a given scene bounds?

let's say my scene mins are (-100, 0, -100) and maxs are (100,50,100).

How should I setup the light matrices?

I've already done spot and point shadow mapping, but the directional one is still bothering me ;s thanks for any tips!



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#2 HappyCoder   Members   -  Reputation: 2880

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Posted 18 June 2014 - 01:49 PM

You can calculate the bounding box for your scene, then transform that into the light's coordinate space. Then calculate the bounding box of the transformed points. The top, bottom, left, right, front, and back of the bounding box will be your inputs to glOrtho.

 

This will work for small scenes, but once your scene becomes large enough you will have serious lightmap resolution problems. To fix that you can only lightmap a small portion of the scene around the player. In this case you would have fixed values for glOrtho and have the directional light follow a fixed offset from the player.

 

If you want to get really fancy you can implement perspective shadow maps. Although I would focus on getting the basic light map working first.



#3 WiredCat   Members   -  Reputation: 368

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Posted 19 June 2014 - 09:27 AM

heres an example in delphi (coz thats the simplest code i have) its a projection texture mapping, but when you change initialization to GL_DEPTH_COMPONENT you know something similar to:

 glGenTextures(1,&shadowMapTexture);
 glBindTexture(GL_TEXTURE_2D, shadowMapTexture);
  glTexImage2D(GL_TEXTURE_2D, 0, GL_DEPTH_COMPONENT, 512, 512, 0, GL_DEPTH_COMPONENT, GL_FLOAT, 0);

since you should only lookup for opengl calls its really no matter in what language this sample will be:

 

but before showing it to you :P

it uses an old gluLookAt function (you can eaisly glrotate gltranslate scene if you dont want to use this function)

 

this function is used for 2 cases first to draw scene from camera view and then from light view.

(with glulookat its easy to say that light is in pos x,y,z and its pointing in x2,y2,z2 direction or point.

combining znear and zfar too will give you a desired effect.

 

 

 

first of all you need to enable (in openglinitalization)

glEnable(GL_TEXTURE_2D);
glTexGendv(GL_S, GL_OBJECT_PLANE, SPlane);
glTexGendv(GL_T, GL_OBJECT_PLANE, TPlane);
glTexGendv(GL_R, GL_OBJECT_PLANE, RPlane);
glTexGendv(GL_Q, GL_OBJECT_PLANE, QPlane);

glTexGeni(GL_S, GL_TEXTURE_GEN_MODE, GL_OBJECT_LINEAR);
glTexGeni(GL_T, GL_TEXTURE_GEN_MODE, GL_OBJECT_LINEAR);
glTexGeni(GL_R, GL_TEXTURE_GEN_MODE, GL_OBJECT_LINEAR);
glTexGeni(GL_Q, GL_TEXTURE_GEN_MODE, GL_OBJECT_LINEAR);


glDisable(GL_TEXTURE_2D);

wheres



double *SPlane;
double *TPlane;
double *RPlane;
double *QPlane;


SPlane = new double[4];
SPlane[0] = 1.0;
SPlane[1] = 0.0;
SPlane[2] = 0.0;
SPlane[3] = 0.0;

TPlane = new double[4];
TPlane[0] = 0.0;
TPlane[1] = 1.0;
TPlane[2] = 0.0;
TPlane[3] = 0.0;

RPlane = new double[4];
RPlane[0] = 0.0;
RPlane[1] = 0.0;
RPlane[2] = 1.0;
RPlane[3] = 0.0;

QPlane = new double[4];
QPlane[0] = 0.0;
QPlane[1] = 0.0;
QPlane[2] = 0.0;
QPlane[3] = 1.0;

then you enable blending

draw your scene from eye view

then you change blending func

enable these glplane s t r q

set light viewmatrix

draw the same scene ut w/o textures

 

heres the code:

//------------------------------------------------------------------------
//
// Author      : Jan Horn
// Email       : jhorn@global.co.za
// Website     : http://www.sulaco.co.za
//               http://home.global.co.za/~jhorn
// Date        : 12 March 2002
// Version     : 1.0
// Description : A very basic game engine I put tegether in about 2 hours
//
//------------------------------------------------------------------------
program OpenGLApp;

uses
  Windows,
  Messages,
  OpenGL,
  SysUtils,
  Textures;

const
  WND_TITLE = 'Basic game engine by Jan Horn';
  FPS_TIMER = 1;                     // Timer to calculate FPS
  FPS_INTERVAL = 500;               // Calculate FPS every 1000 ms

type
  TCoord = Record
    X, Y, Z : glFLoat;
  end;
  TFace = Record
    V1, V2, V3, V4 : Integer;
    U, V : glFloat;
    TextureIndex : Integer;
  end;

var
  h_Wnd  : HWND;                     // Global window handle
  h_DC   : HDC;                      // Global device context
  h_RC   : HGLRC;                    // OpenGL rendering context
  keys : Array[0..255] of Boolean;   // Holds keystrokes
  FPSCount : Integer = 0;            // Counter for FPS
  ElapsedTime : Integer;             // Elapsed time between frames
  FrameTime : Integer;

  // Textures
  Texture : Array of glUint;

  // User variables
  TextureCount : Integer;
  VertexCount  : Integer;
  FaceCount    : Integer;
  Vertex : Array of TCoord;
  Face   : Array of TFace;

  X, Z : glFloat;
  HeadMovement, HeadMovAngle : glFloat;
  mpos : TPoint;
  Heading : glFloat;
  Tilt    : glFloat;

  MouseSpeed : Integer = 7;
  MoveSpeed  : glFloat = 0.03;
   Pmv : array[0..15] of single;
    ProjectedTex : glUint;
  WallTex : glUint;
  FloorTex : glUint;
  CubeDL : glUint;
  imopi : single = 3.14/ 180.0;


  MoveTexture : Boolean;
  RoomDL : glUint;
  FloorDL : glUint;
  sphereX, sphereY, sphereZ : glFloat;
  SPlane : array [0..3] of GLfloat = (1, 0, 0, 0);
  TPlane : array [0..3] of GLfloat = (0, 1, 0, 0);
  RPlane : array [0..3] of GLfloat = (0, 0, 1, 0);
  QPlane : array [0..3] of GLfloat = (0, 0, 0, 1);
  ax,ay,az : single;

{$R *.RES}

procedure glBindTexture(target: GLenum; texture: GLuint); stdcall; external opengl32;

{------------------------------------------------------------------}
{  Load the map info from the map.txt files                        }
{------------------------------------------------------------------}
procedure LoadMap;
var F : Textfile;
    Tex : Array of String;
    S : String;
    I, J : Integer;
begin
  AssignFile(F, 'map.txt');
  Reset(F);

  // Load the textures
  Readln(F, TextureCount);
  SetLength(Tex, TextureCount);
  SetLength(Texture, TextureCount);
  for I :=0 to TextureCount-1 do
  begin
    Readln(F, S);
    Tex[i] :=Copy(S, 1, Pos(' ', S)-1);
    S :=Copy(S, Pos(' ', S)+1, length(S));
    LoadTexture(S, Texture[i], FALSE);
  end;

  // Load the vertices
  Readln(F, VertexCount);
  SetLength(Vertex, VertexCount);
  for I :=0 to VertexCount-1 do
    Readln(F, Vertex[i].X, Vertex[i].Y, Vertex[i].Z);

  // Load the faces
  Readln(F, FaceCount);
  SetLength(Face, FaceCount);
  for I :=0 to FaceCount-1 do
  begin
    Readln(F, Face[i].V1, Face[i].V2, Face[i].V3, Face[i].V4, Face[i].U, Face[i].V, S);
    S :=Trim(Copy(S, 1, 12));

    for J :=0 to TextureCount-1 do
      if Tex[J] = S then
        Face[i].TextureIndex :=J;
  end;
  CloseFile(F);
end;


procedure drawscene();
var
i:integer;
begin

//  glRotate(Tilt, 1, 0, 0);
//  glRotate(Heading, 0, 1, 0);
//  glTranslatef(X, -0.5 + HeadMovement, Z);


  For I :=0 to FaceCount-1 do
  with face[i] do
  begin
    glBindTexture(GL_TEXTURE_2D, Texture[TextureIndex]);
    glBegin(GL_QUADS);
      glTexCoord(0, 0);  glVertex3fv(@Vertex[V1-1]);
      glTexCoord(U, 0);  glVertex3fv(@Vertex[V2-1]);
      glTexCoord(U, V);  glVertex3fv(@Vertex[V3-1]);
      glTexCoord(0, V);  glVertex3fv(@Vertex[V4-1]);
    glEnd();
  end;

end;



procedure drawscene2();
var
i:integer;
begin

//  glRotate(-Tilt, 1, 0, 0);
//  glRotate(-Heading, 0, 1, 0);

  For I :=0 to FaceCount-1 do
  with face[i] do
  begin

    glBegin(GL_QUADS);
      glTexCoord(0, 0);  glVertex3fv(@Vertex[V1-1]);
      glTexCoord(U, 0);  glVertex3fv(@Vertex[V2-1]);
      glTexCoord(U, V);  glVertex3fv(@Vertex[V3-1]);
      glTexCoord(0, V);  glVertex3fv(@Vertex[V4-1]);
    glEnd();
  end;



end;
{------------------------------------------------------------------}
{  Function to draw the actual scene                               }
{------------------------------------------------------------------}
procedure glDraw();
var I : Integer;
begin



 glEnable(GL_BLEND);
 glEnable(GL_TEXTURE_2D);

  glClear(GL_COLOR_BUFFER_BIT or GL_DEPTH_BUFFER_BIT);    // Clear The Screen And The Depth Buffer


glBlendFunc(GL_ONE, GL_ZERO);



glMatrixMode(GL_MODELVIEW);

glLoadIdentity();                                       // Reset The View

ax := 100000.0*(sin((Heading)*imopi)*cos((Tilt)*imopi));
az := 100000.0*(cos((Heading)*imopi)*cos((Tilt)*imopi));
ay := 100000.0*(sin((Tilt)*imopi));
gluLookAt(x,0.2,z,x+ax,
0.2-ay,z-az,0,1,0);

drawscene;


glcolor3f(1,1,1);
  glBlendFunc(GL_DST_COLOR, GL_ONE);
  glBindTexture(GL_TEXTURE_2D, ProjectedTex);




  glEnable(GL_TEXTURE_GEN_S);
  glEnable(GL_TEXTURE_GEN_T);
  glEnable(GL_TEXTURE_GEN_R);
  glEnable(GL_TEXTURE_GEN_Q);




  
  glMatrixMode(GL_TEXTURE);
  glLoadIdentity;
  glTranslatef(0.5, 0.5, 0);
  glScalef(0.5, 0.5, 1);
  gluPerspective(90, 4.0/3.0, 0.1, 100.0);

gluLookAt(2.218,0.3,0.96,
-2.58,0.3,2.87,
0,1,0);//light view matrix set


 glMatrixMode(GL_MODELVIEW);
  glPushMatrix();
drawscene2;
  glPopMatrix();



  glDisable(GL_TEXTURE_GEN_S);
  glDisable(GL_TEXTURE_GEN_T);
  glDisable(GL_TEXTURE_GEN_R);
  glDisable(GL_TEXTURE_GEN_Q);
  glMatrixMode(GL_TEXTURE);
  glLoadIdentity;



 glDisable(GL_TEXTURE_2D);
glDisable(GL_BLEND);

end;


{------------------------------------------------------------------}
{  Initialise OpenGL                                               }
{------------------------------------------------------------------}
procedure glInit();
begin
  glClearColor(0.0, 0.0, 0.0, 0.0); 	   // Black Background
  glShadeModel(GL_SMOOTH);                 // Enables Smooth Color Shading
  glClearDepth(1.0);                       // Depth Buffer Setup
  glEnable(GL_DEPTH_TEST);                 // Enable Depth Buffer
  glDepthFunc(GL_LEQUAL);		           // The Type Of Depth Test To Do

  glHint(GL_PERSPECTIVE_CORRECTION_HINT, GL_NICEST);   //Realy Nice perspective calculations

  glEnable(GL_TEXTURE_2D);                     // Enable Texture Mapping
  LoadMap;

  Heading :=180;
  X :=1.615;
  Z :=-2.52;



  glEnable(GL_TEXTURE_2D);                     // Enable Texture Mapping
  LoadTexture('biohazard.bmp', ProjectedTex,FALSE);    // Load the Texture
  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP);
  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP);

  LoadTexture('brick27.bmp', WallTex,FALSE);    // Load the Texture
  LoadTexture('Wood004.bmp', FloorTex,FALSE);    // Load the Texture


glTexGenfv(GL_S, GL_OBJECT_PLANE, @SPlane);
glTexGenfv(GL_T, GL_OBJECT_PLANE, @TPlane);
glTexGenfv(GL_R, GL_OBJECT_PLANE, @RPlane);
glTexGenfv(GL_Q, GL_OBJECT_PLANE, @QPlane);

glTexGeni(GL_S, GL_TEXTURE_GEN_MODE, GL_OBJECT_LINEAR);
glTexGeni(GL_T, GL_TEXTURE_GEN_MODE, GL_OBJECT_LINEAR);
glTexGeni(GL_R, GL_TEXTURE_GEN_MODE, GL_OBJECT_LINEAR);
glTexGeni(GL_Q, GL_TEXTURE_GEN_MODE, GL_OBJECT_LINEAR);


  
  glDisable(GL_TEXTURE_2D);
end;


{------------------------------------------------------------------}
{  Handle window resize                                            }
{------------------------------------------------------------------}
procedure glResizeWnd(Width, Height : Integer);
begin
  if (Height = 0) then                // prevent divide by zero exception
    Height := 1;
  glViewport(0, 0, Width, Height);    // Set the viewport for the OpenGL window
  glMatrixMode(GL_PROJECTION);        // Change Matrix Mode to Projection
  glLoadIdentity();                   // Reset View
  gluPerspective(90.0, Width/Height, 0.1, 100.0);  // Do the perspective calculations. Last value = max clipping depth

  glMatrixMode(GL_MODELVIEW);         // Return to the modelview matrix
  glLoadIdentity();                   // Reset View
end;


{------------------------------------------------------------------}
{  Processes all the keystrokes                                    }
{------------------------------------------------------------------}
procedure ProcessKeys;
begin
  if Keys[VK_DOWN] then
  begin
    X := X - sin(Heading*pi/180)*FrameTime/600;   // FrameTime/600=movement speed
    Z := Z + cos(Heading*pi/180)*FrameTime/600;   // FrameTime/600=movement speed
    HeadMovAngle :=HeadMovAngle + 5;
    HeadMovement :=0.025*sin(HeadMovAngle*pi/180);
  end;
  if Keys[VK_UP] then
  begin
    X := X + sin(Heading*pi/180)*FrameTime/600;
    Z := Z - cos(Heading*pi/180)*FrameTime/600;
    HeadMovAngle :=HeadMovAngle - 5;
    HeadMovement :=0.025*sin(HeadMovAngle*pi/180);
  end;
  if Keys[VK_RIGHT] then
  begin
    X := X + sin((Heading+90)*pi/180)*FrameTime/900;  // FrameTime/900=movement speed
    Z := Z - cos((Heading+90)*pi/180)*FrameTime/900;  // straffing = 50% slower
  end;
  if Keys[VK_LEFT] then
  begin
    X := X - sin((Heading+90)*pi/180)*FrameTime/900;
    Z := Z + cos((Heading+90)*pi/180)*FrameTime/900;
  end;
end;


{------------------------------------------------------------------}
{  Determines the application’s response to the messages received  }
{------------------------------------------------------------------}
function WndProc(hWnd: HWND; Msg: UINT;  wParam: WPARAM;  lParam: LPARAM): LRESULT; stdcall;
begin
  case (Msg) of
    WM_CREATE:
      begin
        // Insert stuff you want executed when the program starts
      end;
    WM_CLOSE:
      begin
        PostQuitMessage(0);
        Result := 0
      end;
    WM_KEYDOWN:       // Set the pressed key (wparam) to equal true so we can check if its pressed
      begin
        keys[wParam] := True;
        Result := 0;
      end;
    WM_KEYUP:         // Set the released key (wparam) to equal false so we can check if its pressed
      begin
        keys[wParam] := False;
        Result := 0;
      end;
    WM_SIZE:          // Resize the window with the new width and height
      begin
        glResizeWnd(LOWORD(lParam),HIWORD(lParam));
        Result := 0;
      end;
    WM_TIMER :                     // Add code here for all timers to be used.
      begin
        if wParam = FPS_TIMER then
        begin
          FPSCount :=Round(FPSCount * 1000/FPS_INTERVAL);   // calculate to get per Second incase intercal is less or greater than 1 second
          SetWindowText(h_Wnd, PChar(WND_TITLE + '   [' + intToStr(FPSCount) + ' FPS]' + '    '+floattostr(x)+ '   ' + floattostr(z)));
          FPSCount := 0;
          Result := 0;
        end;
      end;
    else
      Result := DefWindowProc(hWnd, Msg, wParam, lParam);    // Default result if nothing happens
  end;
end;


{---------------------------------------------------------------------}
{  Properly destroys the window created at startup (no memory leaks)  }
{---------------------------------------------------------------------}
procedure glKillWnd(Fullscreen : Boolean);
begin
  if Fullscreen then             // Change back to non fullscreen
  begin
    ChangeDisplaySettings(devmode(nil^), 0);
    ShowCursor(True);
  end;

  // Makes current rendering context not current, and releases the device
  // context that is used by the rendering context.
  if (not wglMakeCurrent(h_DC, 0)) then
    MessageBox(0, 'Release of DC and RC failed!', 'Error', MB_OK or MB_ICONERROR);

  // Attempts to delete the rendering context
  if (not wglDeleteContext(h_RC)) then
  begin
    MessageBox(0, 'Release of rendering context failed!', 'Error', MB_OK or MB_ICONERROR);
    h_RC := 0;
  end;

  // Attemps to release the device context
  if ((h_DC > 0) and (ReleaseDC(h_Wnd, h_DC) = 0)) then
  begin
    MessageBox(0, 'Release of device context failed!', 'Error', MB_OK or MB_ICONERROR);
    h_DC := 0;
  end;

  // Attempts to destroy the window
  if ((h_Wnd <> 0) and (not DestroyWindow(h_Wnd))) then
  begin
    MessageBox(0, 'Unable to destroy window!', 'Error', MB_OK or MB_ICONERROR);
    h_Wnd := 0;
  end;

  // Attempts to unregister the window class
  if (not UnRegisterClass('OpenGL', hInstance)) then
  begin
    MessageBox(0, 'Unable to unregister window class!', 'Error', MB_OK or MB_ICONERROR);
    hInstance := 0;
  end;
end;


{--------------------------------------------------------------------}
{  Creates the window and attaches a OpenGL rendering context to it  }
{--------------------------------------------------------------------}
function glCreateWnd(Width, Height : Integer; Fullscreen : Boolean; PixelDepth : Integer) : Boolean;
var
  wndClass : TWndClass;         // Window class
  dwStyle : DWORD;              // Window styles
  dwExStyle : DWORD;            // Extended window styles
  dmScreenSettings : DEVMODE;   // Screen settings (fullscreen, etc...)
  PixelFormat : GLuint;         // Settings for the OpenGL rendering
  h_Instance : HINST;           // Current instance
  pfd : TPIXELFORMATDESCRIPTOR;  // Settings for the OpenGL window
begin
  h_Instance := GetModuleHandle(nil);       //Grab An Instance For Our Window
  ZeroMemory(@wndClass, SizeOf(wndClass));  // Clear the window class structure

  with wndClass do                    // Set up the window class
  begin
    style         := CS_HREDRAW or    // Redraws entire window if length changes
                     CS_VREDRAW or    // Redraws entire window if height changes
                     CS_OWNDC;        // Unique device context for the window
    lpfnWndProc   := @WndProc;        // Set the window procedure to our func WndProc
    hInstance     := h_Instance;
    hCursor       := LoadCursor(0, IDC_ARROW);
    lpszClassName := 'OpenGL';
  end;

  if (RegisterClass(wndClass) = 0) then  // Attemp to register the window class
  begin
    MessageBox(0, 'Failed to register the window class!', 'Error', MB_OK or MB_ICONERROR);
    Result := False;
    Exit
  end;

  // Change to fullscreen if so desired
  if Fullscreen then
  begin
    ZeroMemory(@dmScreenSettings, SizeOf(dmScreenSettings));
    with dmScreenSettings do begin              // Set parameters for the screen setting
      dmSize       := SizeOf(dmScreenSettings);
      dmPelsWidth  := Width;                    // Window width
      dmPelsHeight := Height;                   // Window height
      dmBitsPerPel := PixelDepth;               // Window color depth
      dmFields     := DM_PELSWIDTH or DM_PELSHEIGHT or DM_BITSPERPEL;
    end;

    // Try to change screen mode to fullscreen
    if (ChangeDisplaySettings(dmScreenSettings, CDS_FULLSCREEN) = DISP_CHANGE_FAILED) then
    begin
      MessageBox(0, 'Unable to switch to fullscreen!', 'Error', MB_OK or MB_ICONERROR);
      Fullscreen := False;
    end;
  end;

  // If we are still in fullscreen then
  if (Fullscreen) then
  begin
    dwStyle := WS_POPUP or                // Creates a popup window
               WS_CLIPCHILDREN            // Doesn't draw within child windows
               or WS_CLIPSIBLINGS;        // Doesn't draw within sibling windows
    dwExStyle := WS_EX_APPWINDOW;         // Top level window
    ShowCursor(False);                    // Turn of the cursor (gets in the way)
  end
  else
  begin
    dwStyle := WS_OVERLAPPEDWINDOW or     // Creates an overlapping window
               WS_CLIPCHILDREN or         // Doesn't draw within child windows
               WS_CLIPSIBLINGS;           // Doesn't draw within sibling windows
    dwExStyle := WS_EX_APPWINDOW or       // Top level window
                 WS_EX_WINDOWEDGE;        // Border with a raised edge
    ShowCursor(False);                    // Turn of the cursor (gets in the way)
  end;

  // Attempt to create the actual window
  h_Wnd := CreateWindowEx(dwExStyle,      // Extended window styles
                          'OpenGL',       // Class name
                          WND_TITLE,      // Window title (caption)
                          dwStyle,        // Window styles
                          0, 0,           // Window position
                          Width, Height,  // Size of window
                          0,              // No parent window
                          0,              // No menu
                          h_Instance,     // Instance
                          nil);           // Pass nothing to WM_CREATE
  if h_Wnd = 0 then
  begin
    glKillWnd(Fullscreen);                // Undo all the settings we've changed
    MessageBox(0, 'Unable to create window!', 'Error', MB_OK or MB_ICONERROR);
    Result := False;
    Exit;
  end;

  // Try to get a device context
  h_DC := GetDC(h_Wnd);
  if (h_DC = 0) then
  begin
    glKillWnd(Fullscreen);
    MessageBox(0, 'Unable to get a device context!', 'Error', MB_OK or MB_ICONERROR);
    Result := False;
    Exit;
  end;

  // Settings for the OpenGL window
  with pfd do
  begin
    nSize           := SizeOf(TPIXELFORMATDESCRIPTOR); // Size Of This Pixel Format Descriptor
    nVersion        := 1;                    // The version of this data structure
    dwFlags         := PFD_DRAW_TO_WINDOW    // Buffer supports drawing to window
                       or PFD_SUPPORT_OPENGL // Buffer supports OpenGL drawing
                       or PFD_DOUBLEBUFFER;  // Supports double buffering
    iPixelType      := PFD_TYPE_RGBA;        // RGBA color format
    cColorBits      := PixelDepth;           // OpenGL color depth
    cRedBits        := 0;                    // Number of red bitplanes
    cRedShift       := 0;                    // Shift count for red bitplanes
    cGreenBits      := 0;                    // Number of green bitplanes
    cGreenShift     := 0;                    // Shift count for green bitplanes
    cBlueBits       := 0;                    // Number of blue bitplanes
    cBlueShift      := 0;                    // Shift count for blue bitplanes
    cAlphaBits      := 0;                    // Not supported
    cAlphaShift     := 0;                    // Not supported
    cAccumBits      := 0;                    // No accumulation buffer
    cAccumRedBits   := 0;                    // Number of red bits in a-buffer
    cAccumGreenBits := 0;                    // Number of green bits in a-buffer
    cAccumBlueBits  := 0;                    // Number of blue bits in a-buffer
    cAccumAlphaBits := 0;                    // Number of alpha bits in a-buffer
    cDepthBits      := 16;                   // Specifies the depth of the depth buffer
    cStencilBits    := 0;                    // Turn off stencil buffer
    cAuxBuffers     := 0;                    // Not supported
    iLayerType      := PFD_MAIN_PLANE;       // Ignored
    bReserved       := 0;                    // Number of overlay and underlay planes
    dwLayerMask     := 0;                    // Ignored
    dwVisibleMask   := 0;                    // Transparent color of underlay plane
    dwDamageMask    := 0;                     // Ignored
  end;

  // Attempts to find the pixel format supported by a device context that is the best match to a given pixel format specification.
  PixelFormat := ChoosePixelFormat(h_DC, @pfd);
  if (PixelFormat = 0) then
  begin
    glKillWnd(Fullscreen);
    MessageBox(0, 'Unable to find a suitable pixel format', 'Error', MB_OK or MB_ICONERROR);
    Result := False;
    Exit;
  end;

  // Sets the specified device context's pixel format to the format specified by the PixelFormat.
  if (not SetPixelFormat(h_DC, PixelFormat, @pfd)) then
  begin
    glKillWnd(Fullscreen);
    MessageBox(0, 'Unable to set the pixel format', 'Error', MB_OK or MB_ICONERROR);
    Result := False;
    Exit;
  end;

  // Create a OpenGL rendering context
  h_RC := wglCreateContext(h_DC);
  if (h_RC = 0) then
  begin
    glKillWnd(Fullscreen);
    MessageBox(0, 'Unable to create an OpenGL rendering context', 'Error', MB_OK or MB_ICONERROR);
    Result := False;
    Exit;
  end;

  // Makes the specified OpenGL rendering context the calling thread's current rendering context
  if (not wglMakeCurrent(h_DC, h_RC)) then
  begin
    glKillWnd(Fullscreen);
    MessageBox(0, 'Unable to activate OpenGL rendering context', 'Error', MB_OK or MB_ICONERROR);
    Result := False;
    Exit;
  end;

  // Initializes the timer used to calculate the FPS
  SetTimer(h_Wnd, FPS_TIMER, FPS_INTERVAL, nil);

  // Settings to ensure that the window is the topmost window
  ShowWindow(h_Wnd, SW_SHOW);
  SetForegroundWindow(h_Wnd);
  SetFocus(h_Wnd);

  // Ensure the OpenGL window is resized properly
  glResizeWnd(Width, Height);
  glInit();

  Result := True;
end;


{--------------------------------------------------------------------}
{  Main message loop for the application                             }
{--------------------------------------------------------------------}
function WinMain(hInstance : HINST; hPrevInstance : HINST;
                 lpCmdLine : PChar; nCmdShow : Integer) : Integer; stdcall;
var
  msg : TMsg;
  finished : Boolean;
  DemoStart, LastTime : DWord;
begin
  finished := False;

  // Perform application initialization:
  if not glCreateWnd(800, 600, FALSE, 32) then
  begin
    Result := 0;
    Exit;
  end;

  DemoStart := GetTickCount();            // Get Time when demo started
  SetCursorPos(400,300);

  // Main message loop:
  while not finished do
  begin
    if (PeekMessage(msg, 0, 0, 0, PM_REMOVE)) then // Check if there is a message for this window
    begin
      if (msg.message = WM_QUIT) then     // If WM_QUIT message received then we are done
        finished := True
      else
      begin                               // Else translate and dispatch the message to this window
  	TranslateMessage(msg);
        DispatchMessage(msg);
      end;
    end
    else
    begin
      Inc(FPSCount);                      // Increment FPS Counter

      FrameTime := GetTickCount() - ElapsedTime - DemoStart;
      LastTime :=ElapsedTime;
      ElapsedTime :=GetTickCount() - DemoStart;     // Calculate Elapsed Time
      ElapsedTime :=(LastTime + ElapsedTime) DIV 2; // Average it out for smoother movement

      // use mouse coordinates to calculate heading and tilt and reset mouse.
      if GetForegroundWindow = h_Wnd then
      begin
        GetCursorPos(mpos);
        SetCursorPos(400,300);
        Heading := Heading + (mpos.x - 400)/100 * MouseSpeed;
        Tilt := Tilt - (300 - mpos.y)/100 * MouseSpeed;
        if Tilt > 60 then Tilt :=60;
        if Tilt < -60 then Tilt :=-60;
      end;

      glDraw();                           // Draw the scene
      SwapBuffers(h_DC);                  // Display the scene

      if (keys[VK_ESCAPE]) then           // If user pressed ESC then set finised TRUE
        finished := True
      else
        ProcessKeys;                      // Check for any other key Pressed
    end;
  end;
  glKillWnd(FALSE);
  Result := msg.wParam;
end;


begin
  WinMain( hInstance, hPrevInst, CmdLine, CmdShow );
end.

and heres a result (see that middle and last picture) projected texture -> example above, and when you changed texture to a depth texture you got (last) a shadow (first image is my old notebook bugged graphics card)

 

Untsitled.jpg






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