ch17p2_solidfadetransition.cpp

游戏开发特殊技巧-special.effects.game.programming

#include "Ch17p2_SolidFadeTransition.h"

CSolidFadeTransition::CSolidFadeTransition(LPDIRECT3DDEVICE8 pDev, LPDIRECT3DTEXTURE8 pOrigTexture,
                                           D3DXCOLOR FadeToColor)
{
  m_pd3dDevice = pDev;
  m_FadeToColor = FadeToColor;
  m_fFadeTime = 0;
  m_pOrigImage = pOrigTexture;

  // create vertex buffer for one quad
  if (FAILED(CreateQuad(&m_pVB, D3DPOOL_MANAGED, 2, 0, pDev))) {
    throw("Error creating vertex buffer!");
  }

}

CSolidFadeTransition::~CSolidFadeTransition()
{
  SAFE_RELEASE(m_pVB);
}

void CSolidFadeTransition::DoTransition(float fTransTime)
{
  m_fFadeTime += fTransTime;
}


void CSolidFadeTransition::FadeQuadVerts()
{
  HRESULT hr;
  VERTEX_XYZ_DIFFUSE_TEX1* pVertices;
  D3DXCOLOR FadeToColor = m_FadeToColor;

  // calculate the new color value
  FadeToColor.a = FadeToColor.a * (m_fFadeTime / m_fDuration);
  if (FadeToColor.a > 1.0f) FadeToColor.a = 1.0f;

  if( FAILED( hr = m_pVB->Lock( 0, 6*sizeof(VERTEX_XYZ_DIFFUSE_TEX1), (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 = m_pVB->Unlock() ) ) return;
}

void CSolidFadeTransition::DoRender(D3DXMATRIX mFinalScale)
{
  m_pd3dDevice->SetRenderState(D3DRS_ALPHABLENDENABLE, FALSE);
  
  // set our texture active...
  m_pd3dDevice->SetTexture( 0, m_pOrigImage );

  // 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(VERTEX_XYZ_DIFFUSE_TEX1) );
  m_pd3dDevice->SetVertexShader( D3DFVF_XYZ_DIFFUSE_TEX1 );
  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_pd3dDevice->SetRenderState( D3DRS_ALPHABLENDENABLE, TRUE );
    m_pd3dDevice->SetRenderState( D3DRS_SRCBLEND, D3DBLEND_SRCALPHA );
    m_pd3dDevice->SetRenderState( D3DRS_DESTBLEND, D3DBLEND_INVSRCALPHA );

    m_pd3dDevice->SetStreamSource(0, m_pVB, sizeof(VERTEX_XYZ_DIFFUSE_TEX1));
    m_pd3dDevice->SetVertexShader(D3DFVF_XYZ_DIFFUSE_TEX1);
    m_pd3dDevice->DrawPrimitive(D3DPT_TRIANGLELIST, 0, 2);

    m_pd3dDevice->SetRenderState( D3DRS_ALPHABLENDENABLE, FALSE );
  }
}