OpenGL window always busy - c++

Question

I have a small framework which displays a texture in borderless screen window, but when I start it, the application is showing a busy mouse icon when I activate the OpenGL window, and I cannot seem to understand where it is coming from.
The following code is the complete solution (Visual Studio 2010) and should compile as is.
Unfortunately I don't even know where to start looking, thus I copied the complete code here.
BasicProject creates a random texture, and pipes that into the OpenGL window.
Can anyone see why the code is stuck into a busy window?
The OpenGL Callbacks are never reached, but I do not see why not.
BasicProject.cpp (entry point):
/** Sample Project for OpenGL-Display functionality
*
* Anton Roth, 2013
*/
#include "stdafx.h"
#include <conio.h>
#include <process.h>
#include <vector>
#include <Windows.h>
#include <cstdlib>
#include <ctime>
#include "OpenGL-Display.h"
void RunOpenGL(void* pParams);
bool applicationRunning = true;
HANDLE threadOGL;
int _tmain(int argc, _TCHAR* argv[]) {
OGD::OpenGLDisplay_Init(640, 480, 200, 200, 0, "First Display");
threadOGL = (HANDLE)_beginthread(RunOpenGL, 0, NULL);
while(!_kbhit()) {
Sleep(500);
}
applicationRunning = false;
WaitForSingleObject( threadOGL, 500 );
return 0;
}
void RunOpenGL(void* pParams) {
std::vector<char> texture;
texture.resize(640 * 480 * 3);
std::srand(time(0));
while(applicationRunning) {
for(int i = 0; i < 640 * 480 * 3; ++i) {
texture.at(i) = std::rand() % 255;
}
OGD::OpenGLDisplay_Wrapper(&texture.at(0), 640, 480, false, 24, 0);
int x, y;
OGD::OpenGLDisplay_MousePos(x, y, 0);
Sleep(300);
}
}
OpenGL-Display.h:
#ifndef __OPENGLDISPLAY
#define __OPENGLDISPLAY
#include <windows.h> // Header File For Windows
#include <stdio.h> // Header File For Standard Input/Output
#include <gl\gl.h> // Header File For The OpenGL32 Library
#include <gl\glu.h> // Header File For The GLu32 Library
#include <vector>
namespace OGD
{
class OpenGL_Display
{
public:
OpenGL_Display(int newId);
~OpenGL_Display();
void Init_Display(int width, int height, int posX, int posY, LPCSTR className);
void DrawNewImage(int width, int height, char* imageData, bool flip, int bpp);
void GetMouseCords(int& x, int& y);
int ID;
protected:
bool CreateGLWindow(char* title, int bits, int posX, int posY, LPCSTR className);
GLvoid ReSizeGLScene(GLsizei width, GLsizei height);
int LoadGLTextures();
int InitGL(GLvoid);
void UpdateGLBuffers(int width, int height, char* imageData, int bpp);
int DrawGLScene(bool flip);
GLvoid KillGLWindow(GLvoid);
HDC hDC; // Private GDI Device Context
static LRESULT CALLBACK WndProc(HWND, UINT, WPARAM, LPARAM); // Declaration For WndProc
HGLRC hRC; // Permanent Rendering Context
HWND hWnd; // Holds Our Window Handle
HINSTANCE hInstance; // Holds The Instance Of The Application
bool keys[256]; // Array Used For The Keyboard Routine
bool active; // Window Active Flag Set To TRUE By Default
bool fullscreen; // Fullscreen Flag Set To Fullscreen Mode By Default
bool g_bExitThread; // end thread
GLuint texture; // Bitmap image buffer
int g_iCounter; // Current buffer being grabbed to
bool g_GLdone; // Counter to make sure no unnecessary updates are made which cause CPU load
int xPos;
int yPos;
int xPos_right;
int yPos_right;
int width;
int height;
};
static std::vector<OGD::OpenGL_Display*> oglDisp;
void OpenGLDisplay_Wrapper(char* image, int width, int height, bool flip, int bpp, int ID);
void OpenGLDisplay_Init(int width, int height, int posX, int posY, int ID, LPCSTR className);
void OpenGLDisplay_MousePos(int&x, int&y, int ID);
};
#endif
OpenGL-Display.cpp:
/** Based on code by NeHe tutorials
Adapted to display live camera display with OpenGL
*/
#include "OpenGL-Display.h"
using namespace OGD;
OpenGL_Display::OpenGL_Display(int newId)
{
xPos = -1;
yPos = -1;
ID = newId;
width = 1;
height = 1;
}
OpenGL_Display::~OpenGL_Display()
{
KillGLWindow();
}
void OpenGL_Display::Init_Display(int newWidth, int newHeight, int posX, int posY, LPCSTR inputName)
{
width = newWidth;
height = newHeight;
className = inputName;
if (!CreateGLWindow((char*)className, 24, posX, posY, className))
{
throw;
}
}
LRESULT CALLBACK OpenGL_Display::WndProc( HWND hWnd, // Handle For This Window
UINT uMsg, // Message For This Window
WPARAM wParam, // Additional Message Information
LPARAM lParam) // Additional Message Information
{
switch (uMsg) // Check For Windows Messages
{
case WM_SYSCOMMAND: // Intercept System Commands
{
switch (wParam) // Check System Calls
{
case SC_SCREENSAVE: // Screensaver Trying To Start?
case SC_MONITORPOWER: // Monitor Trying To Enter Powersave?
return 0; // Prevent From Happening
}
break; // Exit
}
case WM_CLOSE: // Did We Receive A Close Message?
{
PostQuitMessage(0); // Send A Quit Message
return 0; // Jump Back
}
case WM_SIZE: // Resize The OpenGL Window
{
oglDisp.at(0)->ReSizeGLScene(LOWORD(lParam),HIWORD(lParam)); // LoWord=Width, HiWord=Height
return 0; // Jump Back
}
}
// Pass All Unhandled Messages To DefWindowProc
return DefWindowProc(hWnd,uMsg,wParam,lParam);
}
bool OpenGL_Display::CreateGLWindow(char* title, int bits, int posX, int posY, LPCSTR className)
{
GLuint PixelFormat; // Holds The Results After Searching For A Match
WNDCLASS wc; // Windows Class Structure
DWORD dwExStyle; // Window Extended Style
DWORD dwStyle; // Window Style
RECT WindowRect; // Grabs Rectangle Upper Left / Lower Right Values
WindowRect.left=(long)0; // Set Left Value To 0
WindowRect.right=(long)width; // Set Right Value To Requested Width
WindowRect.top=(long)0; // Set Top Value To 0
WindowRect.bottom=(long)height; // Set Bottom Value To Requested Height
hInstance = GetModuleHandle(NULL); // Grab An Instance For Our Window
wc.style = CS_HREDRAW | CS_VREDRAW | CS_OWNDC; // Redraw On Size, And Own DC For Window.
wc.lpfnWndProc = WndProc; // WndProc Handles Messages
wc.cbClsExtra = 0; // No Extra Window Data
wc.cbWndExtra = 0; // No Extra Window Data
wc.hInstance = hInstance; // Set The Instance
wc.hIcon = LoadIcon(NULL, IDI_WINLOGO); // Load The Default Icon
wc.hCursor = LoadCursor(NULL, IDC_ARROW); // Load The Arrow Pointer
wc.hbrBackground = NULL; // No Background Required For GL
wc.lpszMenuName = NULL; // We Don't Want A Menu
wc.lpszClassName = className; // Set The Class Name
RegisterClass(&wc); // Return FALSE
dwExStyle=WS_EX_APPWINDOW | WS_EX_WINDOWEDGE; // Window Extended Style
dwStyle=WS_VISIBLE | WS_POPUP | WS_CLIPSIBLINGS | WS_CLIPCHILDREN;; // Windows Style
AdjustWindowRectEx(&WindowRect, dwStyle, FALSE, dwExStyle); // Adjust Window To True Requested Size
//HWND hwndC = GetConsoleWindow();
// Create The Window
hWnd=CreateWindowEx( dwExStyle, // Extended Style For The Window
className, // Class Name
title, // Window Title
//WS_OVERLAPPEDWINDOW,
dwStyle | // Defined Window Style
WS_CLIPSIBLINGS | // Required Window Style
WS_CLIPCHILDREN, // Required Window Style
posX, posY, // Window Position
WindowRect.right-WindowRect.left, // Calculate Window Width
WindowRect.bottom-WindowRect.top, // Calculate Window Height
NULL, // No Parent Window
NULL, // No Menu
hInstance, // Instance
NULL);
static PIXELFORMATDESCRIPTOR pfd= // pfd Tells Windows How We Want Things To Be
{
sizeof(PIXELFORMATDESCRIPTOR), // Size Of This Pixel Format Descriptor
1, // Version Number
PFD_DRAW_TO_WINDOW | // Format Must Support Window
PFD_SUPPORT_OPENGL | // Format Must Support OpenGL
PFD_DOUBLEBUFFER, // Must Support Double Buffering
PFD_TYPE_RGBA, // Request An RGBA Format
bits, // Select Our 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, // Accumulation Bits Ignored
16, // 16Bit Z-Buffer (Depth Buffer)
0, // No Stencil Buffer
0, // No Auxiliary Buffer
PFD_MAIN_PLANE, // Main Drawing Layer
0, // Reserved
0, 0, 0 // Layer Masks Ignored
};
hDC=GetDC(hWnd);
PixelFormat=ChoosePixelFormat(hDC,&pfd);
SetPixelFormat(hDC,PixelFormat,&pfd);
hRC=wglCreateContext(hDC);
wglMakeCurrent(hDC,hRC);
ShowWindow(hWnd,SW_SHOW); // Show The Window
SetForegroundWindow(hWnd); // Slightly Higher Priority
SetFocus(hWnd); // Sets Keyboard Focus To The Window
ReSizeGLScene(width, height); // Set Up Our Perspective GL Screen
InitGL();
return TRUE; // Success
}
int OpenGL_Display::LoadGLTextures() // Load Bitmaps And Convert To Textures
{
// Load The Bitmap, Check For Errors, If Bitmap's Not Found Quit
glGenTextures(1, &texture); // Create The Texture
// Typical Texture Generation Using Data From The Bitmap
glBindTexture(GL_TEXTURE_2D, texture);
glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MIN_FILTER,GL_NEAREST); // Minimizing filter, in case display is smaller image size
glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MAG_FILTER,GL_NEAREST); // Magnifying filter, in case display is smaller image size
return 1; // Return The Status
}
GLvoid OpenGL_Display::ReSizeGLScene(GLsizei newWidth, GLsizei newHeight) // Resize And Initialize The GL Window
{
width = newWidth;
height = newHeight;
}
int OpenGL_Display::InitGL(GLvoid) // All Setup For OpenGL Goes Here
{
if (!LoadGLTextures()) // Jump To Texture Loading Routine
{
return FALSE; // If Texture Didn't Load Return FALSE
}
return TRUE; // Initialization Went OK
}
void OpenGL_Display::GetMouseCords(int& x, int& y) // All Setup For OpenGL Goes Here
{
x = xPos;
y = yPos;
}
void OpenGL_Display::UpdateGLBuffers(int width, int height, char* imageData, int bpp) {
glBindTexture(GL_TEXTURE_2D, texture);
switch(bpp) {
case 8: glTexImage2D(GL_TEXTURE_2D, 0, GL_INTENSITY, width, height, 0, GL_RED, GL_UNSIGNED_BYTE, imageData); break;
case 16: glTexImage2D(GL_TEXTURE_2D, 0, GL_INTENSITY, width, height, 0, GL_RED, GL_UNSIGNED_SHORT, imageData); break;
case 24: glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB8, width, height, 0, GL_RGB, GL_UNSIGNED_BYTE, imageData); break;
default: return;
}
GLenum mError = glGetError();
glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MIN_FILTER,GL_NEAREST);
glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MAG_FILTER,GL_NEAREST);
}
int OpenGL_Display::DrawGLScene(bool flip) // Here's Where We Do All The Drawing
{
if (height==0) // Prevent A Divide By Zero
{
height=1; // Making Height Equal One
}
glViewport(0,0,width,height); // Reset The Current Viewport
glMatrixMode(GL_PROJECTION); // Select The Projection Matrix
glLoadIdentity(); // Reset The Projection Matrix
// Calculate The Aspect Ratio Of The Window
gluPerspective(25.0f,1.0f,0.1f,100.0f);
glMatrixMode(GL_MODELVIEW); // Select The Modelview Matrix
glLoadIdentity(); // Reset The Modelview Matrix
glEnable(GL_TEXTURE_2D); // Enable Texture Mapping
glShadeModel(GL_SMOOTH); // Enable Smooth Shading
glClearColor(0.0f, 0.0f, 0.0f, 0.5f); // Black Background
glClearDepth(1.0f); // Depth Buffer Setup
glDisable(GL_DEPTH_TEST); // Enables Depth Testing
glDepthFunc(GL_LEQUAL); // The Type Of Depth Testing To Do
glHint(GL_PERSPECTIVE_CORRECTION_HINT, GL_NICEST); // Really Nice Perspective Calculations
GLenum mError = glGetError();
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); // Clear The Screen And The Depth Buffer
glLoadIdentity(); // Reset The View
glTranslatef(0.0f,0.0f,-5.0f);
mError = glGetError();
glBindTexture(GL_TEXTURE_2D, texture);
mError = glGetError();
glColor4f(1.0, 1.0, 1.0, 1.0);
mError = glGetError();
if(flip)
{
glBegin(GL_QUADS);
// Front Face
glTexCoord2f(0.0f, 0.0f); glVertex3f(-1.0f, -1.0f, 0.5f);
glTexCoord2f(1.0f, 0.0f); glVertex3f( 1.0f, -1.0f, 0.5f);
glTexCoord2f(1.0f, 1.0f); glVertex3f( 1.0f, 1.0f, 0.5f);
glTexCoord2f(0.0f, 1.0f); glVertex3f(-1.0f, 1.0f, 0.5f);
glEnd();
mError = glGetError();
}
else
{
glBegin(GL_QUADS);
// Front Face
glTexCoord2f(0.0f, 1.0f); glVertex3f(-1.0f, -1.0f, 0.5f);
glTexCoord2f(1.0f, 1.0f); glVertex3f( 1.0f, -1.0f, 0.5f);
glTexCoord2f(1.0f, 0.0f); glVertex3f( 1.0f, 1.0f, 0.5f);
glTexCoord2f(0.0f, 0.0f); glVertex3f(-1.0f, 1.0f, 0.5f);
glEnd();
mError = glGetError();
}
mError = glGetError();
return TRUE; // Keep Going
}
GLvoid OpenGL_Display::KillGLWindow(GLvoid) // Properly Kill The Window
{
if (fullscreen) // Are We In Fullscreen Mode?
{
ChangeDisplaySettings(NULL,0); // If So Switch Back To The Desktop
ShowCursor(TRUE); // Show Mouse Pointer
}
if (hRC) // Do We Have A Rendering Context?
{
wglMakeCurrent(NULL,NULL);
wglDeleteContext(hRC);
hRC=NULL; // Set RC To NULL
}
ReleaseDC(hWnd,hDC);
DestroyWindow(hWnd);
UnregisterClass("OpenGL_Display",hInstance);
}
void OpenGL_Display::DrawNewImage(int width, int height, char* imageData, bool flip, int bpp)
{
BOOL returnVal = wglMakeCurrent(hDC, hRC);
UpdateGLBuffers(width, height, imageData, bpp);
DrawGLScene(flip);
SwapBuffers(hDC);
wglMakeCurrent(NULL, NULL);
}
void OGD::OpenGLDisplay_Init(int width, int height, int posX, int posY, int ID, LPCSTR className)
{
for(unsigned int i = 0; i < oglDisp.size(); ++i) {
if(oglDisp.at(i)->ID == ID) {
return;
}
}
oglDisp.push_back(new OGD::OpenGL_Display(ID));
oglDisp.at(oglDisp.size()-1)->Init_Display(width, height, posX, posY, className); //by default this ID is latest
wglMakeCurrent(NULL, NULL);
GLenum mError = glGetError();
}
void OGD::OpenGLDisplay_Wrapper(char* image, int width, int height, bool flip, int bpp, int ID)
{
for(unsigned int i = 0; i < oglDisp.size(); ++i) {
if(oglDisp.at(i)->ID == ID) {
oglDisp.at(i)->DrawNewImage(width, height, image, flip, bpp);
return;
}
}
}

Answer 1

Even though your window is OpenGL-based, you should create a message loop and repeatedly call GetMessage, TranslateMessage and DispatchMessage. Handle WM_PAINT even though it doesn't need to draw anything. If you don't do this, Windows will think your application doesn't respond, and shows the busy cursor (or worse, shows the 'Application not responding' dialogue.)