ch17p1_alphablendfade.cpp

介绍在Alpha混合过程中实现渐进退色效果的程序及其源代码

/*
#############################################################################

  Ch17p1_AlphaBlendFade.cpp: a program that demonstrates the fire algorithm,
  without any annoying bells and/or whistles.
  
#############################################################################
*/

// include files ////////////////////////////////////////////////////////////
#define STRICT
#include <stdio.h>
#include <math.h>
#include <D3DX8.h>
#include "D3DApp.h"
#include "D3DFile.h"
#include "D3DFont.h"
#include "D3DUtil.h"
#include "DXUtil.h"
#include "D3DHelperFuncs.h"
#include "Ch17p1_resource.h"

// A structure for our custom vertex type. 
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: class CMyD3DApplication
// Desc: Application class. The base class (CD3DApplication) provides the 
//       generic functionality needed in all Direct3D samples. CMyD3DApplication 
//       adds functionality specific to this sample program.
//-----------------------------------------------------------------------------
class CMyD3DApplication : public CD3DApplication
{
  // Font for drawing text
  CD3DFont* m_pFont;
  CD3DFont* m_pFontSmall;

  // Scene
  LPDIRECT3DVERTEXBUFFER8 m_pVB;
  
  DWORD        m_dwNumVertices;
  
  // Transforms
  D3DXMATRIX  m_matPosition;
  D3DXMATRIX  m_matView;
  D3DXMATRIX  m_matProj;

  // original and scratch textures
  LPDIRECT3DTEXTURE8 m_pOrigTexture;
  
  // width and height of texture image
  int m_iTextureWidth, m_iTextureHeight;
  
  float m_fFadeTime;
  D3DXCOLOR m_FadeToColor;

protected:
  void ProcessFeedback();
  HRESULT OneTimeSceneInit();
  HRESULT InitDeviceObjects();
  HRESULT RestoreDeviceObjects();
  HRESULT InvalidateDeviceObjects();
  HRESULT DeleteDeviceObjects();
  HRESULT FinalCleanup();
  HRESULT Render();
  HRESULT FrameMove();
  HRESULT ConfirmDevice( D3DCAPS8* pCaps, DWORD dwBehavior, D3DFORMAT Format );
  LRESULT MsgProc( HWND hWnd, UINT uMsg, WPARAM wParam, LPARAM lParam );

public:
  CMyD3DApplication();
};

//-----------------------------------------------------------------------------
// Name: WinMain()
// Desc: Entry point to the program. Initializes everything, and goes into a
//       message-processing loop. Idle time is used to render the scene.
//-----------------------------------------------------------------------------
INT WINAPI WinMain( HINSTANCE hInst, HINSTANCE, LPSTR, INT )
{
  CMyD3DApplication d3dApp;
  if( FAILED( d3dApp.Create( hInst ) ) )
    return 0;

  return d3dApp.Run();
}

//-----------------------------------------------------------------------------
// Name: CMyD3DApplication()
// Desc: Application constructor. Sets attributes for the app.
//-----------------------------------------------------------------------------
CMyD3DApplication::CMyD3DApplication()
{
  m_strWindowTitle    = _T("Ch17p1_AlphaBlendFade");
  m_bUseDepthBuffer   = TRUE;

  m_pFont            = new CD3DFont( _T("Arial"), 12, D3DFONT_BOLD );
  m_pFontSmall       = new CD3DFont( _T("Arial"),  9, D3DFONT_BOLD );
  m_pVB              = NULL;
  m_dwNumVertices    = 6;
  m_pOrigTexture     = NULL;
  
  m_dwCreationWidth = 512;
  m_dwCreationHeight = 384;
  
}


//-----------------------------------------------------------------------------
// Name: OneTimeSceneInit()
// Desc: Called during initial app startup, this function performs all the
//       permanent initialization.
//-----------------------------------------------------------------------------
HRESULT CMyD3DApplication::OneTimeSceneInit()
{
  return S_OK;
}

//-----------------------------------------------------------------------------
// Name: FrameMove()
// Desc: Called once per frame, the call is the entry point for animating
//       the scene.
//-----------------------------------------------------------------------------
HRESULT CMyD3DApplication::FrameMove()
{
  FLOAT fSecsPerFrame = m_fElapsedTime;
  if (m_fFadeTime > 0.0f) {
    m_fFadeTime += m_fElapsedTime;
    if (m_fFadeTime > 7.0f) m_fFadeTime = 0.0f;
  }

  return S_OK;
}


void FadeQuadVerts(D3DXCOLOR FadeToColor, float fFadeTime, 
                   float fEffectTime, LPDIRECT3DVERTEXBUFFER8 pVB)
{
  HRESULT hr;
  CUSTOMVERTEX* pVertices;
  
  // calculate the new color value
  FadeToColor.a = FadeToColor.a * (fFadeTime / fEffectTime);
  if (FadeToColor.a > 1.0f) FadeToColor.a = 1.0f;

  if( FAILED( hr = pVB->Lock( 0, 6*sizeof(CUSTOMVERTEX), (BYTE**)&pVertices, 0 ) ) )
      return;

  pVertices[0].color    = (DWORD)FadeToColor;
  pVertices[1].color    = (DWORD)FadeToColor;
  pVertices[2].color    = (DWORD)FadeToColor;
  
  pVertices[3].color    = (DWORD)FadeToColor;
  pVertices[4].color    = (DWORD)FadeToColor;
  pVertices[5].color    = (DWORD)FadeToColor;
  
  if( FAILED( hr = pVB->Unlock() ) ) return;
}
//-----------------------------------------------------------------------------
// Name: Render()
// Desc: Called once per frame, the call is the entry point for 3d
//       rendering. This function sets up render states, clears the
//       viewport, and renders the scene.
//-----------------------------------------------------------------------------
HRESULT CMyD3DApplication::Render()
{
  // Set up an orthagonal projection matrix, so we can render the entire
  // texture.
  D3DXMATRIX mat;
  D3DXMatrixOrthoLH(&mat, (float)m_iTextureWidth, (float)m_iTextureHeight, 
    0.0, 100.0);
  m_pd3dDevice->SetTransform( D3DTS_PROJECTION, &mat );

  // this world matrix, combined with orthogonal projection, causes the 
  // texture to completely and exactly fill the rendering surface.
  D3DXMATRIX matWorld,matTrans,matScale;
  D3DXMatrixScaling(&matScale, (float)m_iTextureWidth/2.0f, (float)m_iTextureHeight/2.0f, 1.0);

  // move the quad left and up 0.5 units, so that the texels are perfectly
  // centered on the screen pixels.
  D3DXMatrixMultiply(&matWorld, &matScale, D3DXMatrixTranslation(&matTrans, -0.5f, -0.5f, 0));

  // our matrix is now finished.  Tell D3D to use it!
  m_pd3dDevice->SetTransform( D3DTS_WORLD, &matWorld );

  // Clear the backbuffer
  m_pd3dDevice->Clear( 0L, NULL, D3DCLEAR_TARGET|D3DCLEAR_ZBUFFER,
                       0x000000, 1.0f, 0L );

  // begin rendering the scene
  if( SUCCEEDED( m_pd3dDevice->BeginScene() ) )
  {
    m_pd3dDevice->SetRenderState(D3DRS_ALPHABLENDENABLE, FALSE);
  
    // set our texture active...
    m_pd3dDevice->SetTexture( 0, m_pOrigTexture );

    // set up our texture stages for a simple texture copy...
    m_pd3dDevice->SetTextureStageState( 0, D3DTSS_COLOROP,   D3DTOP_SELECTARG1 );
    m_pd3dDevice->SetTextureStageState( 0, D3DTSS_COLORARG1, D3DTA_TEXTURE );
    m_pd3dDevice->SetTextureStageState( 0, D3DTSS_COLORARG2, D3DTA_DIFFUSE );
    m_pd3dDevice->SetTextureStageState( 0, D3DTSS_ALPHAOP,   D3DTOP_SELECTARG1 );

    // draw our quad
    m_pd3dDevice->SetStreamSource( 0, m_pVB, sizeof(CUSTOMVERTEX) );
    m_pd3dDevice->SetVertexShader( D3DFVF_CUSTOMVERTEX );
    m_pd3dDevice->DrawPrimitive( D3DPT_TRIANGLELIST, 0, 2 );

    if (m_fFadeTime > 0.0f) {
      // set up texture stage states for blending the 2nd quad on top
      m_pd3dDevice->SetTextureStageState( 0, D3DTSS_COLORARG1, D3DTA_DIFFUSE );
      m_pd3dDevice->SetTextureStageState( 0, D3DTSS_ALPHAARG1, D3DTA_DIFFUSE );

      // put the correct colors into the quad's verts
      FadeQuadVerts(m_FadeToColor, m_fFadeTime, 5.0f, m_pVB);