//-----------------------------------------------------------------------------
// File: Textures.cpp
//
// Desc: Better than just lights and materials, 3D objects look much more
//       convincing when texture-mapped. Textures can be thought of as a sort
//       of wallpaper, that is shrinkwrapped to fit a texture. Textures are
//       typically loaded from image files, and D3DX provides a utility to
//       function to do this for us. Like a vertex buffer, textures have
//       Lock() and Unlock() functions to access (read or write) the image
//       data. Textures have a width, height, miplevel, and pixel format. The
//       miplevel is for "mipmapped" textures, an advanced performance-
//       enhancing feature which uses lower resolutions of the texture for
//       objects in the distance where detail is less noticeable. The pixel
//       format determines how the colors are stored in a texel. The most
//       common formats are the 16-bit R5G6B5 format (5 bits of red, 6-bits of
//       green and 5 bits of blue) and the 32-bit A8R8G8B8 format (8 bits each
//       of alpha, red, green, and blue).
//
//       Textures are associated with geometry through texture coordinates.
//       Each vertex has one or more sets of texture coordinates, which are
//       named tu and tv and range from 0.0 to 1.0. Texture coordinates can be
//       supplied by the geometry, or can be automatically generated using
//       Direct3D texture coordinate generation (which is an advanced feature).
//
// Copyright (c) 2000-2001 Microsoft Corporation. All rights reserved.
//-----------------------------------------------------------------------------
#include <d3dx8.h>
#include <mmsystem.h>




//-----------------------------------------------------------------------------
// Global variables
//-----------------------------------------------------------------------------
LPDIRECT3D8             g_pD3D       = NULL; // Used to create the D3DDevice
LPDIRECT3DDEVICE8       g_pd3dDevice = NULL; // Our rendering device
LPDIRECT3DVERTEXBUFFER8 g_pVB        = NULL; // Buffer to hold vertices
LPDIRECT3DTEXTURE8      g_pTexture   = NULL; // Our texture

// A structure for our custom vertex type. We added texture coordinates
struct CUSTOMVERTEX
{
    D3DXVECTOR3 position; // The position
    D3DCOLOR    color;    // The color
    FLOAT       tu, tv;   // The texture coordinates
};

// Our custom FVF, which describes our custom vertex structure
#define D3DFVF_CUSTOMVERTEX (D3DFVF_XYZ|D3DFVF_DIFFUSE|D3DFVF_TEX1)




//-----------------------------------------------------------------------------
// Name: InitD3D()
// Desc: Initializes Direct3D
//-----------------------------------------------------------------------------
HRESULT InitD3D( HWND hWnd )
{
    // Create the D3D object.
    if( NULL == ( g_pD3D = Direct3DCreate8( D3D_SDK_VERSION ) ) )
        return E_FAIL;

    // Get the current desktop display mode, so we can set up a back
    // buffer of the same format
    D3DDISPLAYMODE d3ddm;
    if( FAILED( g_pD3D->GetAdapterDisplayMode( D3DADAPTER_DEFAULT, &d3ddm ) ) )
        return E_FAIL;

    // Set up the structure used to create the D3DDevice. Since we are now
    // using more complex geometry, we will create a device with a zbuffer.
    D3DPRESENT_PARAMETERS d3dpp;
    ZeroMemory( &d3dpp, sizeof(d3dpp) );
    d3dpp.Windowed = TRUE;
    d3dpp.SwapEffect = D3DSWAPEFFECT_DISCARD;
    d3dpp.BackBufferFormat = d3ddm.Format;
    d3dpp.EnableAutoDepthStencil = TRUE;
    d3dpp.AutoDepthStencilFormat = D3DFMT_D16;

    // Create the D3DDevice
    if( FAILED( g_pD3D->CreateDevice( D3DADAPTER_DEFAULT, D3DDEVTYPE_HAL, hWnd,
                                      D3DCREATE_SOFTWARE_VERTEXPROCESSING,
                                      &d3dpp, &g_pd3dDevice ) ) )
    {
        return E_FAIL;
    }

    // Turn off culling
    g_pd3dDevice->SetRenderState( D3DRS_CULLMODE, D3DCULL_NONE );

    // Turn off D3D lighting
    g_pd3dDevice->SetRenderState( D3DRS_LIGHTING, FALSE );

    // Turn on the zbuffer
    g_pd3dDevice->SetRenderState( D3DRS_ZENABLE, TRUE );

    return S_OK;
}




//-----------------------------------------------------------------------------
// Name: InitGeometry()
// Desc: Create the textures and vertex buffers
//-----------------------------------------------------------------------------
HRESULT InitGeometry()
{
    // Use D3DX to create a texture from a file based image
    if( FAILED( D3DXCreateTextureFromFile( g_pd3dDevice, "banana.bmp",
                                           &g_pTexture ) ) )
        return E_FAIL;

    // Create the vertex buffer.
    if( FAILED( g_pd3dDevice->CreateVertexBuffer( 50*2*sizeof(CUSTOMVERTEX),
                                                  0, D3DFVF_CUSTOMVERTEX,
                                                  D3DPOOL_DEFAULT, &g_pVB ) ) )
    {
        return E_FAIL;
    }

    // Fill the vertex buffer. We are setting the tu and tv texture
    // coordinates, which range from 0.0 to 1.0
    CUSTOMVERTEX* pVertices;
    if( FAILED( g_pVB->Lock( 0, 0, (BYTE**)&pVertices, 0 ) ) )
        return E_FAIL;
    for( DWORD i=0; i<50; i++ )
    {
        FLOAT theta = (2*D3DX_PI*i)/(50-1);

        pVertices[2*i+0].position = D3DXVECTOR3( sinf(theta),-1.0f, cosf(theta) );
        pVertices[2*i+0].color    = 0xffffffff;
        pVertices[2*i+0].tu       = ((FLOAT)i)/(50-1);
        pVertices[2*i+0].tv       = 1.0f;

        pVertices[2*i+1].position = D3DXVECTOR3( sinf(theta), 1.0f, cosf(theta) );
        pVertices[2*i+1].color    = 0xff808080;
        pVertices[2*i+1].tu       = ((FLOAT)i)/(50-1);
        pVertices[2*i+1].tv       = 0.0f;
    }
    g_pVB->Unlock();

    return S_OK;
}




//-----------------------------------------------------------------------------
// Name: Cleanup()
// Desc: Releases all previously initialized objects
//-----------------------------------------------------------------------------
VOID Cleanup()
{
    if( g_pTexture != NULL )
        g_pTexture->Release();

    if( g_pVB != NULL )
        g_pVB->Release();

    if( g_pd3dDevice != NULL )
        g_pd3dDevice->Release();

    if( g_pD3D != NULL )
        g_pD3D->Release();
}



//-----------------------------------------------------------------------------
// Name: SetupMatrices()
// Desc: Sets up the world, view, and projection transform matrices.
//-----------------------------------------------------------------------------
VOID SetupMatrices()
{
    // For our world matrix, we will just leave it as the identity
    D3DXMATRIX matWorld;
    D3DXMatrixIdentity( &matWorld );
    D3DXMatrixRotationX( &matWorld, timeGetTime()/1000.0f );
    g_pd3dDevice->SetTransform( D3DTS_WORLD, &matWorld );

    // Set up our view matrix. A view matrix can be defined given an eye point,
    // a point to lookat, and a direction for which way is up. Here, we set the
    // eye five units back along the z-axis and up three units, look at the
    // origin, and define "up" to be in the y-direction.
    D3DXMATRIX matView;
    D3DXMatrixLookAtLH( &matView, &D3DXVECTOR3( 0.0f, 3.0f,-5.0f ),
                                  &D3DXVECTOR3( 0.0f, 0.0f, 0.0f ),
                                  &D3DXVECTOR3( 0.0f, 1.0f, 0.0f ) );
    g_pd3dDevice->SetTransform( D3DTS_VIEW, &matView );

    // For the projection matrix, we set up a perspective transform (which
    // transforms geometry from 3D view space to 2D viewport space, with
    // a perspective divide making objects smaller in the distance). To build
    // a perpsective transform, we need the field of view (1/4 pi is common),
    // the aspect ratio, and the near and far clipping planes (which define at
    // what distances geometry should be no longer be rendered).
    D3DXMATRIX matProj;
    D3DXMatrixPerspectiveFovLH( &matProj, D3DX_PI/4, 1.0f, 1.0f, 100.0f );
    g_pd3dDevice->SetTransform( D3DTS_PROJECTION, &matProj );
}




//-----------------------------------------------------------------------------
// Name: Render()
// Desc: Draws the scene
//-----------------------------------------------------------------------------
VOID Render()
{
    // Clear the backbuffer and the zbuffer
    g_pd3dDevice->Clear( 0, NULL, D3DCLEAR_TARGET|D3DCLEAR_ZBUFFER,
                         D3DCOLOR_XRGB(0,0,255), 1.0f, 0 );

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

    // Setup the world, view, and projection matrices
    SetupMatrices();

    // Setup our texture. Using textures introduces the texture stage states,
    // which govern how textures get blended together (in the case of multiple
    // textures) and lighting information. In this case, we are modulating
    // (blending) our texture with the diffuse color of the vertices.
    g_pd3dDevice->SetTexture( 0, g_pTexture );
    g_pd3dDevice->SetTextureStageState( 0, D3DTSS_COLOROP,   D3DTOP_MODULATE );
    g_pd3dDevice->SetTextureStageState( 0, D3DTSS_COLORARG1, D3DTA_TEXTURE );
    g_pd3dDevice->SetTextureStageState( 0, D3DTSS_COLORARG2, D3DTA_DIFFUSE );
    g_pd3dDevice->SetTextureStageState( 0, D3DTSS_ALPHAOP,   D3DTOP_DISABLE );

#ifdef SHOW_HOW_TO_USE_TCI
    // Note: to use D3D texture coordinate generation, use the stage state
    // D3DTSS_TEXCOORDINDEX, as shown below. In this example, we are using
    // the position of the vertex in camera space to generate texture
    // coordinates. The tex coord index (TCI) parameters are passed into a
    // texture transform, which is a 4x4 matrix which transforms the x,y,z
    // TCI coordinates into tu, tv texture coordinates.

    // In this example, the texture matrix is setup to 
    // transform the texture from (-1,+1) position coordinates to (0,1) 
    // texture coordinate space:
    //    tu =  0.5*x + 0.5
    //    tv = -0.5*y + 0.5
    D3DXMATRIX mat;
    mat._11 = 0.25f; mat._12 = 0.00f; mat._13 = 0.00f; mat._14 = 0.00f;
    mat._21 = 0.00f; mat._22 =-0.25f; mat._23 = 0.00f; mat._24 = 0.00f;
    mat._31 = 0.00f; mat._32 = 0.00f; mat._33 = 1.00f; mat._34 = 0.00f;
    mat._41 = 0.50f; mat._42 = 0.50f; mat._43 = 0.00f; mat._44 = 1.00f;

    g_pd3dDevice->SetTransform( D3DTS_TEXTURE0, &mat );
    g_pd3dDevice->SetTextureStageState( 0, D3DTSS_TEXTURETRANSFORMFLAGS, D3DTTFF_COUNT2 );
    g_pd3dDevice->SetTextureStageState( 0, D3DTSS_TEXCOORDINDEX, D3DTSS_TCI_CAMERASPACEPOSITION );
#endif

    // Render the vertex buffer contents
    g_pd3dDevice->SetStreamSource( 0, g_pVB, sizeof(CUSTOMVERTEX) );
    g_pd3dDevice->SetVertexShader( D3DFVF_CUSTOMVERTEX );
    g_pd3dDevice->DrawPrimitive( D3DPT_TRIANGLESTRIP, 0, 2*50-2 );

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

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




//-----------------------------------------------------------------------------
// Name: MsgProc()
// Desc: The window's message handler
//-----------------------------------------------------------------------------
LRESULT WINAPI MsgProc( HWND hWnd, UINT msg, WPARAM wParam, LPARAM lParam )
{
    switch( msg )
    {
        case WM_DESTROY:
            PostQuitMessage( 0 );
            return 0;
    }

    return DefWindowProc( hWnd, msg, wParam, lParam );
}




//-----------------------------------------------------------------------------
// Name: WinMain()
// Desc: The application's entry point
//-----------------------------------------------------------------------------
INT WINAPI WinMain( HINSTANCE hInst, HINSTANCE, LPSTR, INT )
{
    // Register the window class
    WNDCLASSEX wc = { sizeof(WNDCLASSEX), CS_CLASSDC, MsgProc, 0L, 0L,
                      GetModuleHandle(NULL), NULL, NULL, NULL, NULL,
                      "D3D Tutorial", NULL };
    RegisterClassEx( &wc );

    // Create the application's window
    HWND hWnd = CreateWindow( "D3D Tutorial", "D3D Tutorial 05: Textures",
                              WS_OVERLAPPEDWINDOW, 100, 100, 300, 300,
                              GetDesktopWindow(), NULL, wc.hInstance, NULL );

    // Initialize Direct3D
    if( SUCCEEDED( InitD3D( hWnd ) ) )
    {
        // Create the scene geometry
        if( SUCCEEDED( InitGeometry() ) )
        {
            // Show the window
            ShowWindow( hWnd, SW_SHOWDEFAULT );
            UpdateWindow( hWnd );

            // Enter the message loop
            MSG msg;
            ZeroMemory( &msg, sizeof(msg) );
            while( msg.message!=WM_QUIT )
            {
                if( PeekMessage( &msg, NULL, 0U, 0U, PM_REMOVE ) )
                {
                    TranslateMessage( &msg );
                    DispatchMessage( &msg );
                }
                else
                    Render();
            }
        }
    }

    // Clean up everything and exit the app
    Cleanup();
    UnregisterClass( "D3D Tutorial", wc.hInstance );
    return 0;
}



