program SimpleLoadFromFile; {$mode objfpc}{$H+} uses {$IFDEF UNIX}{$IFDEF UseCThreads} cthreads, {$ENDIF}{$ENDIF} Classes, Windows, SysUtils, dglOpenGL, glBitmap, Helper; var oglWindow: TOpenGLWindow; running: Boolean = true; function WindowProc(hWnd: HWND; Msg: UINT; wParam: WPARAM; lParam: LPARAM): LRESULT; stdcall; var tex: TglBitmap2D; begin case Msg of WM_DESTROY: begin running := false; end; WM_KEYDOWN: begin if wParam = VK_RETURN then begin tex := TglBitmap2D.Create; // create empty texture try tex.GrabScreen(0, 0, 800, 600, tfRGB8ub3); // copy current framebuffer content to texture tex.SaveToFile(ExtractFilePath(ApplicationName) + 'screen.bmp', ftBMP); // save texture to file WriteLn('screen saved to screen.bmp'); finally FreeAndNil(tex); end; end; end; end; result := DefWindowProc(hWnd, Msg, wParam, lParam); end; procedure RenderLoop; begin glBegin(GL_TRIANGLES); glColor4f(1, 0, 0, 1); glVertex2f(400, 100); glColor4f(0, 1, 0, 1); glVertex2f(100, 500); glColor4f(0, 0, 1, 1); glVertex2f(700, 500); glEnd; end; begin oglWindow := CreateOpenGLWindow('GrapScreen (hit enter to grab screen)', 800, 600, @WindowProc); while running and ProgressMesages do begin RenderLoop; SwapBuffers(oglWindow.DC); end; DestroyOpenGLWindow(oglWindow); end.