die ne Klasse zur Kapselung eines PBuffers mitbringt

Man muß den PBuffer mit anderen Attributen erstellen, wenn man ihn nacher an eine Texture binden will

interface
uses WINDOWS,sysutils,OpenGL12;
type
TpBuffer= class
private
FDC : HDC;
FRC : HGLRC;
FWindowDC: HDC;
FWindowRC : HGLRC;
FHandle: HPBUFFERARB;
FWidth:Integer;
FHeight:Integer;
function LoadFunctions:Boolean;
public
TextureID:GLuint;
Constructor Create(const WindowDC:HDC;const WindowRC:HGLRC;const Width,Height:Integer);
Destructor Destroy; override;
property DC:HDC read FDC;
property RC:HGLRC read FRC;
procedure Bind;
procedure RenderMode(ON:Boolean);
end;
const
WGL_FRONT_LEFT_ARB = $2083;
WGL_TEXTURE_FORMAT_ARB = $2072;
WGL_TEXTURE_TARGET_ARB = $2073;
WGL_TEXTURE_2D_ARB = $207A;
WGL_TEXTURE_RGB_ARB = $2075;
WGL_TEXTURE_RGBA_ARB = $2076;
WGL_BIND_TO_TEXTURE_RGB_ARB = $2070;
WGL_BIND_TO_TEXTURE_RGBA_ARB = $2071;

var
//Funktionen für die einfache Verwendung als Textur
wglBindTexImageARB: function(hPbuffer: HPBUFFERARB; iBuffer: TGLint): Boolean; {$IFDEF Win32} stdcall; {$ENDIF} {$IFDEF LINUX} cdecl; {$ENDIF}
wglReleaseTexImageARB: function(hPbuffer: HPBUFFERARB; iBuffer: TGLint): Boolean; {$IFDEF Win32} stdcall; {$ENDIF} {$IFDEF LINUX} cdecl; {$ENDIF}
implementation
type
TPFB =array [0..18]of Integer ;
const
cPixelFormatBuffer:TPFB =
(WGL_SUPPORT_OPENGL_ARB, 1, // pbuffer will be used with gl
WGL_COLOR_BITS_ARB,32, // 32 bits for color buffer
WGL_DEPTH_BITS_ARB, 24, // 24 bits for depth buffer
WGL_DRAW_TO_PBUFFER_ARB, 1, // enable render to pbuffer
WGL_PIXEL_TYPE_ARB,WGL_TYPE_RGBA_ARB, //RGBA mode
WGL_ACCELERATION_ARB,WGL_FULL_ACCELERATION_ARB,// ?
WGL_BIND_TO_TEXTURE_RGBA_ARB, 1, // pbuffer will be used as a texture
WGL_TEXTURE_FORMAT_ARB,WGL_TEXTURE_RGBA_ARB, // ?
WGL_TEXTURE_TARGET_ARB,WGL_TEXTURE_2D_ARB, // ?
0 );// zero terminates the list

Constructor TpBuffer.Create(const WindowDC:HDC;const WindowRC:HGLRC;const Width,Height:Integer);
var
PFB:TPFB;//Das wunsch PixelFormat für das Buffer
Count:Integer;
pfbID:Integer; //Das PixelFormat welches wir erhalten haben
EmptyInt:Integer;
begin
if not LoadFunctions then Exception.Create('Für den pBuffer benötigte Funktionen konnten nicht geladen werden');
EmptyInt := 0;
FWidth := Width;
FHeight:= Height;
FWindowDC := WindowDC;
FWindowRC := WindowRC;

PFB := cPixelFormatBuffer;
Count := 0;
// choose a pixel format that meets our minimum requirements
wglChoosePixelFormatARB(Windowdc,@PFB, @EmptyInt, 1,@pfbID,@count);
if Count = 0 then raise Exception.Create('P-buffer: Unable to find an acceptable pixel format');
// allocate the pbuffer
FHandle := wglCreatePbufferARB(Windowdc, pfbID, width, height, @EmptyInt );
FDC := wglGetPbufferDCARB(FHandle);
FRC := wglCreateContext(FDC);
if FHandle = 0 then raise Exception.Create('P-buffer: Unable to create P-buffer');
// make a texture object for binding the pbuffer to

wglShareLists(windowRC, Frc);

glGenTextures(1, @TextureID);
glBindTexture(GL_TEXTURE_2D, TextureID);
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);

glTexEnvi(GL_TEXTURE_2D, GL_TEXTURE_ENV_MODE, GL_MODULATE);

{$IFDEF COPYMODE}
glCopyTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, 0, 0, Width, Height, 0);
{$ENDIF}

{Grund-Einstellungen}

wglMakeCurrent(Fdc, Frc);

glEnable(GL_TEXTURE_2D);
glViewport(0, 0, Width, Height); //Aktuelle Sicht dem Bild anpassen

wglMakeCurrent(WindowDC, WindowRC);
end;
Destructor TpBuffer.Destroy;
begin
//wglReleaseTexImageARB(FHandle, WGL_FRONT_LEFT_ARB);
wglDeleteContext(FRC);
wglReleasePbufferDCARB(FHandle, FDC);
wglDestroyPbufferARB(FHandle);
glDeleteTextures(1, @TextureID);
end;
procedure TpBuffer.Bind;
begin
glBindTexture(GL_TEXTURE_2D,TextureID);
wglBindTexImageARB(FHandle,WGL_FRONT_LEFT_ARB);
end;

procedure TpBuffer.RenderMode(On:Boolean);
begin
if On then
begin
wglMakeCurrent(FDC, FRC);
wglReleaseTexImageARB(FHandle,WGL_FRONT_LEFT_ARB);
end
else
begin
{$IFDEF COPYMODE}
glBindTexture(GL_TEXTURE_2D, TextureID);
//Bild nur übertragen(Nicht erstellen)
glCopyTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, 0, 0, FWidth, FHeight);
{$ENDIF}
wglMakeCurrent(Fwindowdc, Fwindowrc);

end;
end;

function TpBuffer.LoadFunctions:Boolean;
begin
result := false;
wglBindTexImageARB := wglGetProcAddress('wglBindTexImageARB');
wglReleaseTexImageARB := wglGetProcAddress('wglReleaseTexImageARB');
//Überprüfen ob es Funktionen gibt die nicht geladen werden konnten.
if @wglReleaseTexImageARB =nil then exit;
if @wglBindTexImageARB = nil then exit;
if @wglChoosePixelFormatARB = nil then exit;
if @wglCreatePbufferARB = nil then exit;
if @wglGetPbufferDCARB = nil then exit;
if @wglReleasePbufferDCARB = nil then exit;
if @wglDestroyPbufferARB = nil then exit;
if @wglQueryPbufferARB = nil then exit;
result := true;
end;

end.