How do I fix my resize function - winapi

Question

This is all the code I have. The functions begining with zx are just so that when I'm done I can quickly put together a custom library based on those functions. The function I need help with is zxResizeGL which is used only on the WM_SIZE event atm.
#include <windows.h>
#include <gl/gl.h>
LRESULT CALLBACK WindowProc(HWND, UINT, WPARAM, LPARAM);
void EnableOpenGL(HWND hwnd, HDC*, HGLRC*);
void DisableOpenGL(HWND, HDC, HGLRC);
/* Necessary value we need access to */
EXTERN_C IMAGE_DOS_HEADER __ImageBase;
#define ZX_THIS_INSTANCE ((HINSTANCE)&__ImageBase)
/* We define 2 here so dev can retrieve the FPN b4 it is multiplied by 100 */
#define ZX__PERCENT( NUM, OF ) ( ( NUM ) / ( OF ) )
#define ZX_PERCENT( NUM, OF ) ( ZX__PERCENT( NUM, OF ) * 100 )
WNDCLASSEX zxGetOSWindowClassEX( void );
BOOL zxInitOSClasses( void );
HWND zxNewOSWindow( int w, int h, int x, int y, char const *text );
HDC hDC = NULL;
HGLRC hRC = NULL;
void zxResizeGL(int width, int height )
{
glViewport(0, 0, width, height);
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
glOrtho(0, width, 0, height, -1.0, 1.0);
glFlush();
glMatrixMode( GL_MODELVIEW );
glLoadIdentity();
}
int WINAPI WinMain(HINSTANCE hInstance,
HINSTANCE hPrevInstance,
LPSTR lpCmdLine,
int nCmdShow)
{
HWND hwnd;
MSG msg;
BOOL bQuit = FALSE;
float theta = 0,
width = 256,
height = width,
w = ZX__PERCENT( width - 20, width ),
h = w;
if ( !zxInitOSClasses() )
return 0;
hwnd = zxNewOSWindow( 480, 480, 0, 0, "OpenGL Sample" );
ShowWindow(hwnd, nCmdShow);
/* enable OpenGL for the window */
EnableOpenGL(hwnd, &hDC, &hRC);
/* program main loop */
while (!bQuit)
{
/* check for messages */
if (PeekMessage(&msg, NULL, 0, 0, PM_REMOVE))
{
/* handle or dispatch messages */
switch ( msg.message )
{
case WM_QUIT:
bQuit = TRUE;
break;
case WM_SIZE:
/* This is where I'm trying to peform the resize */
width = LOWORD( msg.lParam );
height = HIWORD( msg.lParam );
w = ZX__PERCENT( width - 20, width );
h = ZX__PERCENT( height - 20, height );
zxResizeGL( width, height );
break;
default:
TranslateMessage(&msg);
DispatchMessage(&msg);
}
}
else
{
/* OpenGL animation code goes here */
glClearColor(0.0f, 0.0f, 0.0f, 0.0f);
glClear(GL_COLOR_BUFFER_BIT);
glPushMatrix();
glRotatef(theta, 0.0f, 0.0f, 1.0f);
glBegin(GL_TRIANGLES);
glColor3f(1.0f, 0.0f, 0.0f); glVertex2f( 0.0f, h );
glColor3f(0.0f, 1.0f, 0.0f); glVertex2f( w, -h );
glColor3f(0.0f, 0.0f, 1.0f); glVertex2f( -w, -h );
glEnd();
glPopMatrix();
SwapBuffers(hDC);
theta += 1.0f;
Sleep (1);
}
}
/* shutdown OpenGL */
DisableOpenGL(hwnd, hDC, hRC);
/* destroy the window explicitly */
DestroyWindow(hwnd);
return msg.wParam;
}
The defines for the functions broken off from main code.
WNDCLASSEX zxGetOSWindowClassEX( void )
{
WNDCLASSEX wx = {0};
wx.cbSize = sizeof( WNDCLASSEX );
wx.style = CS_OWNDC;
wx.lpfnWndProc = WindowProc;
wx.hInstance = ZX_THIS_INSTANCE;
wx.hIcon = LoadIcon( NULL, IDI_APPLICATION );
wx.hCursor = LoadCursor( NULL, IDC_ARROW );
wx.hbrBackground = (HBRUSH)GetStockObject(BLACK_BRUSH);
wx.lpszClassName = "zxOSWindow";
wx.hIconSm = LoadIcon( NULL, IDI_APPLICATION );
return wx;
}
BOOL zxInitOSClasses( void )
{
WNDCLASSEX wx = zxGetOSWindowClassEX();
if ( !RegisterClassEx( &wx ) )
return 0;
return 1;
}
HWND zxNewOSWindow( int w, int h, int x, int y, char const *text )
{
WNDCLASSEX wx = zxGetOSWindowClassEX();
return CreateWindowEx(
0, wx.lpszClassName, text,
WS_OVERLAPPEDWINDOW,
x, y, w, h, NULL, NULL,
wx.hInstance, NULL );
}
LRESULT CALLBACK WindowProc(HWND hwnd, UINT uMsg, WPARAM wParam, LPARAM lParam)
{
switch (uMsg)
{
case WM_CLOSE:
PostQuitMessage(0);
break;
case WM_DESTROY:
return 0;
case WM_KEYDOWN:
{
switch (wParam)
{
case VK_ESCAPE:
PostQuitMessage(0);
break;
}
}
break;
default:
return DefWindowProc(hwnd, uMsg, wParam, lParam);
}
return 0;
}
void EnableOpenGL(HWND hwnd, HDC* hDC, HGLRC* hRC)
{
PIXELFORMATDESCRIPTOR pfd;
int iFormat;
/* get the device context (DC) */
*hDC = GetDC(hwnd);
/* set the pixel format for the DC */
ZeroMemory(&pfd, sizeof(pfd));
pfd.nSize = sizeof(pfd);
pfd.nVersion = 1;
pfd.dwFlags = PFD_DRAW_TO_WINDOW |
PFD_SUPPORT_OPENGL | PFD_DOUBLEBUFFER;
pfd.iPixelType = PFD_TYPE_RGBA;
pfd.cColorBits = 24;
pfd.cDepthBits = 16;
pfd.iLayerType = PFD_MAIN_PLANE;
iFormat = ChoosePixelFormat(*hDC, &pfd);
SetPixelFormat(*hDC, iFormat, &pfd);
/* create and enable the render context (RC) */
*hRC = wglCreateContext(*hDC);
wglMakeCurrent(*hDC, *hRC);
}
void DisableOpenGL (HWND hwnd, HDC hDC, HGLRC hRC)
{
wglMakeCurrent(NULL, NULL);
wglDeleteContext(hRC);
ReleaseDC(hwnd, hDC);
}

Answer 1

Microsoft says WM_SIZE messages are sent (not posted) and thus come in via WindowProc().
PeekMessage() can only retrieve posted messages.
Handle WM_SIZE in your WindowProc().

Answer 2

After having tried a break point I noticed I was not receiving the WM_SIZE event, will investigate alternate ways to perform resize. For now I will put the zxResizeGL in the drawing loop