xboxdemo.cpp

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

#include "stdafx.h"

//-----------------------------------------------------------------------------
// Global variables
//-----------------------------------------------------------------------------
LPDIRECT3D9             g_pD3D       = NULL; // Used to create the D3DDevice
LPDIRECT3DDEVICE9       g_pd3dDevice = NULL; // Our rendering device
LPDIRECT3DVERTEXBUFFER9 g_pVB        = NULL; // Buffer to hold vertices

// A structure for our custom vertex type
struct CUSTOMVERTEX
{
    FLOAT x, y, z; // The vertex position
    DWORD color;   // The vertex color
};

// Our custom FVF, which describes our custom vertex structure
#define D3DFVF_CUSTOMVERTEX (D3DFVF_XYZ|D3DFVF_DIFFUSE)

FLOAT fSecsPerTick;
LARGE_INTEGER qwTime, qwLastTime, qwElapsedTime, qwAppTime, qwElapsedAppTime;
FLOAT fTime, fElapsedTime, fAppTime, fElapsedAppTime;

VOID InitTime()
{
    // Get the frequency of the timer
	LARGE_INTEGER qwTicksPerSec;
    QueryPerformanceFrequency( &qwTicksPerSec );
    fSecsPerTick = 1.0f / (FLOAT)qwTicksPerSec.QuadPart;

    // Save the start time
    QueryPerformanceCounter( &qwTime );
    qwLastTime.QuadPart = qwTime.QuadPart;

    qwAppTime.QuadPart        = 0;
    qwElapsedTime.QuadPart    = 0;
    qwElapsedAppTime.QuadPart = 0;
}


//-----------------------------------------------------------------------------
// Name: InitD3D()
// Desc: Initializes Direct3D
//-----------------------------------------------------------------------------
HRESULT InitD3D()
{
    // Create the D3D object.
    if( NULL == ( g_pD3D = Direct3DCreate9( D3D_SDK_VERSION ) ) )
        return E_FAIL;

    // Set up the structure used to create the D3DDevice.
    D3DPRESENT_PARAMETERS d3dpp; 
    ZeroMemory( &d3dpp, sizeof(d3dpp) );
    d3dpp.BackBufferWidth        = 640;
    d3dpp.BackBufferHeight       = 480;
    d3dpp.BackBufferFormat       = D3DFMT_X8R8G8B8;
    d3dpp.BackBufferCount        = 1;
    d3dpp.EnableAutoDepthStencil = TRUE;
    d3dpp.AutoDepthStencilFormat = D3DFMT_D24S8;
    d3dpp.SwapEffect             = D3DSWAPEFFECT_DISCARD;
    d3dpp.PresentationInterval = D3DPRESENT_INTERVAL_ONE;

    // Create the Direct3D device.
    if( FAILED( g_pD3D->CreateDevice( 0, D3DDEVTYPE_HAL, NULL,
                                      D3DCREATE_HARDWARE_VERTEXPROCESSING,
                                      &d3dpp, &g_pd3dDevice ) ) )
        return E_FAIL;

    // Set the projection matrix
    D3DXMATRIX matProj;
    D3DXMatrixPerspectiveFovLH( &matProj, D3DX_PI/4, 4.0f/3.0f, 1.0f, 200.0f );
    g_pd3dDevice->SetTransform( D3DTS_PROJECTION, &matProj );

    // Set the view matrix
    D3DXVECTOR3 vEyePt    = D3DXVECTOR3( 0.0f, 0.0f,-7.0f );
    D3DXVECTOR3 vLookatPt = D3DXVECTOR3( 0.0f, 0.0f, 0.0f );
    D3DXVECTOR3 vUp       = D3DXVECTOR3( 0.0f, 1.0f, 0.0f );
    D3DXMATRIX  matView;
    D3DXMatrixLookAtLH( &matView, &vEyePt, &vLookatPt, &vUp );
    g_pd3dDevice->SetTransform( D3DTS_VIEW, &matView );

    return S_OK;
}




//-----------------------------------------------------------------------------
// Name: InitVB()
// Desc: Creates a vertex buffer and fills it with our vertices. The vertex
//       buffer is basically just a chunk of memory that holds vertices. After
//       creating it, we must Lock()/Unlock() it to fill it.
//-----------------------------------------------------------------------------
HRESULT InitVB()
{
    // Initialize three vertices for rendering a triangle
    CUSTOMVERTEX g_Vertices[] =
    {
        {  0.0f, -1.1547f, 0.0f, 0xffffff00 }, // x, y, z, color
        { -1.0f,  0.5777f, 0.0f, 0xff00ff00 },
        {  1.0f,  0.5777f, 0.0f, 0xffff0000 },
    };

    // Create the vertex buffer. Here we are allocating enough memory
    // (from the default pool) to hold all our 3 custom vertices. We also
    // specify the FVF, so the vertex buffer knows what data it contains.
    if( FAILED( g_pd3dDevice->CreateVertexBuffer( 3*sizeof(CUSTOMVERTEX),
                                                  D3DUSAGE_WRITEONLY, 
                                                  D3DFVF_CUSTOMVERTEX,
                                                  D3DPOOL_MANAGED, &g_pVB, NULL ) ) )
        return E_FAIL;

    // Now we fill the vertex buffer. To do this, we need to Lock() the VB to
    // gain access to the vertices. This mechanism is required because the
    // vertex buffer may still be in use by the GPU. This can happen if the
    // CPU gets ahead of the GPU. The GPU could still be rendering the previous
    // frame.

    CUSTOMVERTEX* pVertices;
    if( FAILED( g_pVB->Lock( 0, 0, (void**)&pVertices, 0 ) ) )
        return E_FAIL;
    memcpy( pVertices, g_Vertices, 3*sizeof(CUSTOMVERTEX) );
    g_pVB->Unlock();

    return S_OK;
}


VOID UpdateTime()
{
    
    QueryPerformanceCounter( &qwTime );
    qwElapsedTime.QuadPart = qwTime.QuadPart - qwLastTime.QuadPart;
    qwLastTime.QuadPart    = qwTime.QuadPart;
    qwElapsedAppTime.QuadPart = qwElapsedTime.QuadPart;
    qwAppTime.QuadPart    += qwElapsedAppTime.QuadPart;

    // Store the current time values as floating point
    fTime           = fSecsPerTick * ((FLOAT)(qwTime.QuadPart));
    fElapsedTime    = fSecsPerTick * ((FLOAT)(qwElapsedTime.QuadPart));
    fAppTime        = fSecsPerTick * ((FLOAT)(qwAppTime.QuadPart));
    fElapsedAppTime = fSecsPerTick * ((FLOAT)(qwElapsedAppTime.QuadPart));
}

//-----------------------------------------------------------------------------
// Name: Update()
// Desc: Updates the world for the next frame
//-----------------------------------------------------------------------------
VOID Update()
{

    D3DXMATRIX matRotate;
    D3DXMATRIX matWorld;
    g_pd3dDevice->GetTransform( D3DTS_WORLD, &matWorld );
    FLOAT fZRotate = -fElapsedTime*D3DX_PI*0.5f;
    D3DXMatrixRotationYawPitchRoll( &matRotate, 0.0f, 0.0f, fZRotate );
    D3DXMatrixMultiply( &matWorld, &matWorld, &matRotate );
    g_pd3dDevice->SetTransform( D3DTS_WORLD, &matWorld );
    
}


//-----------------------------------------------------------------------------
// Name: Render()
// Desc: Draws the scene
//-----------------------------------------------------------------------------
VOID Render()
{
    // Clear the backbuffer to a blue color
    g_pd3dDevice->Clear( 0L, NULL, D3DCLEAR_TARGET|D3DCLEAR_ZBUFFER|D3DCLEAR_STENCIL, 
                         D3DCOLOR_XRGB(0,0,255), 1.0f, 0L );

    // Begin the scene
    g_pd3dDevice->BeginScene();

    // Draw the triangles in the vertex buffer. This is broken into a few
    // steps. We are passing the vertices down a "stream", so first we need
    // to specify the source of that stream, which is our vertex buffer. Then
    // we need to let D3D know what vertex shader to use. Full, custom vertex
    // shaders are an advanced topic, but in many cases the vertex shader is
    // just the FVF, so that D3D knows what type of vertices we are dealing
    // with. Finally, we call DrawPrimitive() which does the actual rendering
    // of our geometry (in this case, just one triangle).
	g_pd3dDevice->SetRenderState( D3DRS_LIGHTING, FALSE);
    g_pd3dDevice->SetStreamSource( 0, g_pVB, 0, sizeof(CUSTOMVERTEX) );
    g_pd3dDevice->SetFVF( D3DFVF_CUSTOMVERTEX );
    g_pd3dDevice->DrawPrimitive( D3DPT_TRIANGLELIST, 0, 1 );

    // End the scene
    g_pd3dDevice->EndScene();
}




//-----------------------------------------------------------------------------
// Name: main()
// Desc: The application's entry point
//-----------------------------------------------------------------------------
void __cdecl main()
{
    // Initialize Direct3D
    if( FAILED( InitD3D() ) )
        return;

    // Initialize the vertex buffer
    InitVB();

    InitTime();

    while( TRUE )
    {
        // What time is it?
        UpdateTime();
        // Update the world
        Update();   
        // Render the scene
        Render();

        // Present the backbuffer contents to the display
        g_pd3dDevice->Present( NULL, NULL, NULL, NULL );

    }
}