Simple Win32 Program         Petzold style Ogre program

Intention

I wanted to create an archetype program that would be able
to handle multiple key combinations. Say, the right shift key and the
the key character 'X'. My options available were OIS, MFC, or WxWindows.
MFC and WxWindows would be a lot overhead and dll version management for
what is a simple program. After unsuccseful attempts at making OIS work,
I decided that the Petzold style of program would minimize the windows
"portion" and show how ogre would need to interact. When finished, this program
would show the classic orgehead mesh, respond to a few key inputs and
adjust to camera position in response to the mouse or the keyboard.

Starting point

First this program was created with Microsoft Visual Studio 2003 and links to
the Eihort version 1.3.0 of OGRE. The easiest way to start off is to use the
wizard to create a simple windows application ogre32, which should give you the following files:

ogre32.cpp
ogre32.h
ogre32.ico
ogre32.ncb
ogre32.rc
ogre32.sln
ogre32.vcproj
ReadMe.txt
Resource.h
small.ico
stdafx.cpp
stdafx.h


Before modifying the code that the wizard created, you will need to
get the media files and scripts necessary to display the ogrehead.mesh
file. To do this you will need to create the directory 'media' under your
main project and copy the following files into this directory.
The png and jpg files can be found in the textures directory.
The Ogre.material file is a modified version of the Ogre.material
file that comes with the OGRE source code. The original one can be found
at .\ogrenew\Samples\Media\materials\scripts.

cursor.png
dirt01.jpg
GreenSkin.jpg
Ogre.material
ogreborder.png
ogreborderUp.png
ogrehead.mesh
spheremap.png
WeirdEye.png


You will need to create three configuration files:

{CODE(wrap="1"}ogre.cfg
Plugins.cfg
resources.cfg
{CODE}

ogre.cfg

Render System=Direct3D9 Rendering Subsystem

[Direct3D9 Rendering Subsystem]
Allow NVPerfHUD=No
FSAA=0
Floating-point mode=Fastest
Full Screen=No
Rendering Device=NVIDIA GeForce FX 5200
VSync=No
Video Mode=800 x 600 @ 32-bit colour

[OpenGL Rendering Subsystem]
Colour Depth=32
Display Frequency=60
FSAA=0
Full Screen=Yes
RTT Preferred Mode=FBO
VSync=No
Video Mode=1024 x 768


Note: If you hear your graphics card squealing when showing the Ogre head, turn Vsync to "yes" in ogre.cfg! Your graphics card will squeal when there are too many frames per second being rendered.

Plugins.cfg

# Defines plugins to load

# Define plugin folder
PluginFolder=.

# Define plugins
Plugin=RenderSystem_Direct3D9

resources.cfg

# Resource locations to be added to the default path
[General]
FileSystem=./media


You will need to edit the follow files:

stdafx.h
ogre32.cpp

stdafx.h

#pragma once

#define WIN32_LEAN_AND_MEAN
#include <windows.h>
// C RunTime Header Files
#include <stdlib.h>
#include <malloc.h>
#include <memory.h>
#include <tchar.h>
#include <Ogre.h>    //brings in almost everything

ogre32.cpp

The following is the original ogre32.cpp file
This will create a simple project that displays the ogrehead mesh file.

// ogre32.cpp : Defines the entry point for the application.
//

#include "stdafx.h"
#include "ogre32.h"
#define MAX_LOADSTRING 100

// Global Variables:
HINSTANCE hInst;            // current instance
TCHAR szTitle[MAX_LOADSTRING];        // The title bar text
TCHAR szWindowClass[MAX_LOADSTRING];    // the main window class name

using namespace Ogre; // <-- ultimate in lazy


The most important of the following variables is mRoot.
As the "Root class represents a starting point for the client application.
From here, the application can gain access to the fundamentals of the system ...
and Root must be created before any other Ogre operations are called.
Once an instance has been created, the same instance is accessible throughout the life of that
object by using Root::getSingleton (as a reference) or Root::getSingletonPtr (as a pointer). "
See http://www.ogre3d.org/docs/api/html/classOgre_1_1Root.html#_details for more details.

Please consult the wiki for more
detailed reasons on why we added each of
these variables.

Root *mRoot             = 0;  // 
SceneManager *mSceneMgr = 0;  // 
Camera *mCamera         = 0;  // 
Viewport* mViewPort     = 0; 
RenderWindow* mRenderWindow=0; 

// Forward declarations of functions included in this code module:
ATOM                MyRegisterClass(HINSTANCE hInstance);
BOOL                InitInstance(HINSTANCE, int);
LRESULT CALLBACK    WndProc(HWND, UINT, WPARAM, LPARAM);
LRESULT CALLBACK    About(HWND, UINT, WPARAM, LPARAM);

int APIENTRY _tWinMain(HINSTANCE hInstance,
                     HINSTANCE hPrevInstance,
                     LPTSTR    lpCmdLine,
                     int       nCmdShow)
{
     // TODO: Place code here.
    MSG msg;
    HACCEL hAccelTable;
    HWND hWnd;
    // Initialize global strings
    LoadString(hInstance, IDS_APP_TITLE, szTitle, MAX_LOADSTRING);
    LoadString(hInstance, IDC_OGRE32, szWindowClass, MAX_LOADSTRING);
    MyRegisterClass(hInstance);

    
    hInst = hInstance; // Store instance handle in our global variable

    hWnd = CreateWindow(szWindowClass, szTitle, WS_OVERLAPPEDWINDOW,CW_USEDEFAULT, 0, CW_USEDEFAULT, 0, NULL, NULL, hInstance, NULL);

    if (!hWnd)
    {
        return FALSE;
    }


create the root ogre system

mRoot = new Root();


load the configuration file

ConfigFile cf;
    cf.load("resources.cfg");

    ConfigFile::SectionIterator seci = cf.getSectionIterator();

    String secName, typeName, archName;
    while (seci.hasMoreElements())
    {
        secName = seci.peekNextKey();
        ConfigFile::SettingsMultiMap *settings = seci.getNext();
        ConfigFile::SettingsMultiMap::iterator i;
        for (i = settings->begin(); i != settings->end(); ++i)
        {
            typeName = i->first;
            archName = i->second;
            ResourceGroupManager::getSingleton().addResourceLocation(
                archName, typeName, secName);
        }
    }


Load the directx rendering system we dont have
to Display the configuration dialog.

RenderSystemList *rsList = mRoot->getAvailableRenderers();
    int c=0;
    bool foundit = false;
    RenderSystem *selectedRenderSystem=0;
    while(c < (int) rsList->size())
    {
        selectedRenderSystem = rsList->at(c);
        String rname = selectedRenderSystem->getName();
        if(rname.compare("Direct3D9 Rendering Subsystem")==0)
        {
            foundit=true;
            break;
        }
        c++; // <-- oh how clever
    }
    if(!foundit) 
        return FALSE; //we didn't find it...

    //we found it, we might as well use it!
    mRoot->setRenderSystem(selectedRenderSystem);

    selectedRenderSystem->setConfigOption("Full Screen","No");  
    selectedRenderSystem->setConfigOption("Video Mode","800 x 600 @ 16-bit colour");

    //retrieve the config option map
    ConfigOptionMap comap = selectedRenderSystem->getConfigOptions();

    //and now we need to run through all of it
    ConfigOptionMap::const_iterator start = comap.begin();
    ConfigOptionMap::const_iterator end = comap.end();
    while(start != end)
    {
        String OptionName = start->first;
        String CurrentValue = start->second.currentValue;
        StringVector PossibleValues = start->second.possibleValues;
        int c=0;
        while (c < (int) PossibleValues.size())
        {
            String OneValue = PossibleValues.at(c);
            c++;
        }
    start++;
    }    
    //end boilerplate


this is the magic! here is where we take the window that has been previously
been created and attach ogre to it.

mRoot->initialise(false,"Some Window Title");
    NameValuePairList misc;
    misc["externalWindowHandle"] = StringConverter::toString( (size_t)hWnd);
    mRenderWindow = mRoot->createRenderWindow( "My sub render window", 800, 600, false, &misc );


create a scene manager

// choose sm
    mSceneMgr = mRoot->createSceneManager(ST_GENERIC, "mSceneMgr");
    mSceneMgr->setAmbientLight(ColourValue(0.5, 0.5, 0.5));


This is so we can have scripts work and the mesh is properly rendered.

ResourceGroupManager::getSingleton().initialiseAllResourceGroups();


Load a mesh that is located in the ./media directory.

Entity *ent1 = mSceneMgr->createEntity( "ogre", "ogrehead.mesh" );
        SceneNode *node1 = mSceneMgr->getRootSceneNode()->createChildSceneNode( "RobotNode" );
        node1->attachObject( ent1 );


Create a camera so we can look at his lovely mug.

// --------------------
    // Create the camera
    mCamera = mSceneMgr->createCamera("PlayerCam");
    // Position it at 500 in Z direction
    mCamera->setPosition(Ogre::Vector3(0,0,500));
    // Look back along -Z
    mCamera->lookAt(Ogre::Vector3(0,0,-300));
    mCamera->setNearClipDistance(5);
    // Set the viewport
    mViewPort = mRenderWindow->addViewport(mCamera);
    mViewPort->setBackgroundColour(Ogre::ColourValue(0.0f, 0.0f, 0.0f, 1.0f)); 

    ShowWindow(hWnd, nCmdShow);
    UpdateWindow(hWnd);

    
    hAccelTable = LoadAccelerators(hInstance, (LPCTSTR)IDC_OGRE32);

    // Main message loop:
    while (GetMessage(&msg, NULL, 0, 0)) 
    {       
                //placing renderOneFrame seems to allow for a clean shutdown.
                //thanks to user lakin for that hint.
        if (mRoot->renderOneFrame()) 
        {
            TranslateMessage(&msg);
            DispatchMessage(&msg);
        }
    }

    return (int) msg.wParam;
}

ATOM MyRegisterClass(HINSTANCE hInstance)
{
    WNDCLASSEX wcex;

    wcex.cbSize = sizeof(WNDCLASSEX); 

    wcex.style            = CS_HREDRAW | CS_VREDRAW;
    wcex.lpfnWndProc    = (WNDPROC)WndProc;
    wcex.cbClsExtra        = 0;
    wcex.cbWndExtra        = 0;
    wcex.hInstance        = hInstance;
    wcex.hIcon            = LoadIcon(hInstance, (LPCTSTR)IDI_OGRE32);
    wcex.hCursor        = LoadCursor(NULL, IDC_ARROW);
    wcex.hbrBackground    = (HBRUSH)(COLOR_WINDOW+1);
    wcex.lpszMenuName    = NULL;
    wcex.lpszClassName    = szWindowClass;
    wcex.hIconSm        = LoadIcon(wcex.hInstance, (LPCTSTR)IDI_SMALL);

    return RegisterClassEx(&wcex);
}

BOOL InitInstance(HINSTANCE hInstance, int nCmdShow)
{
   HWND hWnd;

   hInst = hInstance; // Store instance handle in our global variable

   hWnd = CreateWindow(szWindowClass, szTitle, WS_OVERLAPPEDWINDOW,
      CW_USEDEFAULT, 0, CW_USEDEFAULT, 0, NULL, NULL, hInstance, NULL);

   if (!hWnd)
   {
      return FALSE;
   }

   ShowWindow(hWnd, nCmdShow);
   UpdateWindow(hWnd);

   return TRUE;
}

LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
{
    int wmId, wmEvent;
    PAINTSTRUCT ps;
    HDC hdc;

    switch (message) 
    {
    case WM_COMMAND:
        wmId    = LOWORD(wParam); 
        wmEvent = HIWORD(wParam); 
        // Parse the menu selections:
        switch (wmId)
        {
        case IDM_EXIT:

I was told to do this. This may or may not be necessary.

mRoot->detachRenderTarget(mRenderWindow);
            DestroyWindow(hWnd);
            break;
        default:
            return DefWindowProc(hWnd, message, wParam, lParam);
        }
        break;
    case WM_PAINT:
        hdc = BeginPaint(hWnd, &ps);
        // TODO: Add any drawing code here...

        EndPaint(hWnd, &ps);
        break;
    case WM_DESTROY:
 
        PostQuitMessage(0);
        break;


Returning 1 will cause the screen not flicker when the
window is being resized.

case WM_ERASEBKGND:
      return 1;


Handle resizing the window.
one of the things this program does not do
is display full screen. This should be relatively
simple to implement. Also the section is
direct translation of the WxWindows code that
was posted to forum.

case WM_SIZE:
        if (mCamera) 
        { 
            RECT rect; 
            GetClientRect(hWnd,&rect); 

            // notify "render window" instance 
            mRenderWindow->windowMovedOrResized(); 

            // Adjust camera's aspect ratio, too 
            if ((rect.bottom - rect.top) != 0 && mCamera != 0) 
                mCamera->setAspectRatio((Ogre::Real)mRenderWindow->getWidth() / (Ogre::Real)mRenderWindow->getHeight()); 
            mCamera->yaw(Radian(0));
            Root::getSingletonPtr()->renderOneFrame(); 
        }

        break;
    default:
        return DefWindowProc(hWnd, message, wParam, lParam);
    }
    return 0;
}

#endif

Alias: Simple_Win32_Program