Unit1.cpp

//---------------------------------------------------------------------------
#include <vcl.h>
#pragma hdrstop

#include "Unit1.h"
//---------------------------------------------------------------------------
#pragma package(smart_init)
#pragma resource "*.dfm"
TForm1 *Form1;
HDC hOpenGLDC;
//---------------------------------------------------------------------------
__fastcall TForm1::TForm1(TComponent* Owner)
	: TForm(Owner)
{
    nRedColor = 0;
}
//---------------------------------------------------------------------------
void __fastcall TForm1::FormCreate(TObject *Sender)
{
    if(!InitializeOpenGL())
	{
		Application->MessageBox(_T("Failed initialize OpenGL"), _T("Error"));
		Application->Terminate();
		return;
	}
	Application->OnIdle = ApplicationIdle;
}
//---------------------------------------------------------------------------
void __fastcall TForm1::FormClose(TObject *Sender, TCloseAction &Action)
{
    DestroyOpenGL();
}
//---------------------------------------------------------------------------
void __fastcall TForm1::FormPaint(TObject *Sender)
{
	RenderScene();
}
//---------------------------------------------------------------------------
void __fastcall TForm1::WMEraseBkgnd(Winapi::Messages::TWMEraseBkgnd &Message)
{
     // Option A: Simply prevent flicker (do nothing, return true)
	Message.Result = 1;
    // Option B: Custom background drawing
    // HDC dc = Message.DC;
    // // Perform GDI drawing here using dc...
    // Message.Result = 1; // Tell Windows we handled it
}
//---------------------------------------------------------------------------
void __fastcall TForm1::ApplicationIdle(TObject *Sender, bool &bFlag)
{
	nRedColor++;
	Invalidate();
}
//---------------------------------------------------------------------------
BOOL TForm1::InitializeOpenGL()
{
    HGLRC hrc;
	hOpenGLDC = GetDC(Handle);
	PIXELFORMATDESCRIPTOR pfd =
	{
		sizeof(PIXELFORMATDESCRIPTOR), // size of this pfd
		1, // version number
		PFD_DRAW_TO_WINDOW | // support window
		PFD_SUPPORT_OPENGL | // support OpenGL
		PFD_DOUBLEBUFFER, // double buffered
		PFD_TYPE_RGBA, // RGBA type
		24, // 24-bit color depth
		0, 0, 0, 0, 0, 0, // color bits ignored
		0, // no alpha buffer
		0, // shift bit ignored
		0, // no accumulation buffer
		0, 0, 0, 0, // accum bits ignored
		32, // 32-bit z-buffer
		0, // no stencil buffer
		0, // no auxiliary buffer
		PFD_MAIN_PLANE, // main layer
		0, // reserved
		0, 0, 0 // layer masks ignored
	};
	int pixelformat = ChoosePixelFormat(hOpenGLDC, &pfd);
	if (pixelformat == 0)
	{
		return FALSE;
	}
	if (SetPixelFormat(hOpenGLDC, pixelformat, &pfd) == FALSE)
	{
		return FALSE;
	}
	hrc = wglCreateContext(hOpenGLDC);
	if (hrc == NULL) return FALSE;
	return wglMakeCurrent(hOpenGLDC, hrc);
}
//---------------------------------------------------------------------------
void TForm1::DestroyOpenGL()
{
    HGLRC hrc;
	hrc = wglGetCurrentContext();
	wglMakeCurrent(NULL, NULL);
	if (hrc != NULL)
		wglDeleteContext(hrc);
	ReleaseDC(Handle, hOpenGLDC);
	DeleteDC(hOpenGLDC);
}
//---------------------------------------------------------------------------
void TForm1::RenderScene()
{
    float fltRedColor = static_cast<float>(nRedColor) / 255.0f;
	glClearColor(fltRedColor, 0, 0, 0);
	glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
	glClearDepth(1.0f);
	SwapBuffers(hOpenGLDC);
}