ch19p1_particleeventsequence.cpp

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

#include "Ch19p1_ParticleEventSequence.h"
#include <algorithm>

CParticleEventSequence::CParticleEventSequence()
{
  m_pd3dDevice = NULL;
  m_texParticle = NULL;
  m_Particles = NULL;
  Reset();
}

CParticleEventSequence::~CParticleEventSequence()
{
  Reset();
}

void CParticleEventSequence::Reset()
{
	m_iTotalParticleLives = 0;
	m_Loops = -1;

  m_iNumParticles = 100;
  m_fNumNewPartsExcess = 0.0f;
  m_vGravity = CMinMax<D3DXVECTOR3>(D3DXVECTOR3(0.0f, 0.0f, 0.0f),D3DXVECTOR3(0.0f, 0.0f, 0.0f));
  m_vEmitRadius = CMinMax<D3DXVECTOR3>(D3DXVECTOR3(0.0f, 0.0f, 0.0f),D3DXVECTOR3(0.0f, 0.0f, 0.0f));
  for (std::vector<CParticleEvent *>::iterator i = m_Events.begin(); i != m_Events.end(); i++) {
    // can't use safe delete here, because it will set i = NULL.
    if (*i) delete (*i);
  }
  m_Events.clear();

  SAFE_DELETE(m_Particles);
  SAFE_RELEASE(m_texParticle);
}

void CParticleEventSequence::SortEvents(void)
{
  // sort the events by the time they occur (initial = 1st, final = last)
  // a testament to the power of STL: one line to accomplish this.  Pretty sweet, huh?
  CParticleEvent_CompareFunc cf;
  std::sort(m_Events.begin(), m_Events.end(), cf);

#ifdef _DEBUG
  // spit out the list of events, for debugging purposes.
  OutputDebugString("\n\nSorted Events:");
  for (std::vector<CParticleEvent *>::iterator i = m_Events.begin(); i != m_Events.end(); i++) {
    char buf[256];
    _snprintf(buf, sizeof(buf), "\nTime: %0.2f Type: %20s Fade: %c",
      (*i)->GetActualTime(), typeid(*(*i)).name(), (*i)->IsFade() ? 'Y' : 'N');
    OutputDebugString(buf);
  }

#endif
}

void CParticleEventSequence::CreateFadeLists()
{
  // for each event,
  for (std::vector<CParticleEvent *>::iterator i = m_Events.begin(); i != m_Events.end(); i++) {
    // try to find the next fade event of the same type.
    for (std::vector<CParticleEvent *>::iterator j = i; j != m_Events.end(); j++) {
      if (j != i && typeid(**j) == typeid(**i) && (*j)->IsFade()) {
        // we've found a fade event further in the future.  make a note that
        // this event needs to be linked to this future fade event (so that we
        // can calculate the deltas later).
        (*i)->m_NextFadeEvent = (*j);
        break;
      }
    }
  }

}
void CParticleEventSequence::NailDownRandomTimes(void)
{
  for (std::vector<CParticleEvent *>::iterator i = m_Events.begin(); i != m_Events.end(); i++) {
    (*i)->SetActualTime((*i)->GetTimeRange().GetRandomNumInRange());
  }
}

HRESULT CParticleEventSequence::RestoreDeviceObjects(LPDIRECT3DDEVICE8 pDev)
{
  m_pd3dDevice = pDev;
  m_Particles = new CRecyclingArrayDyn<CParticle>(m_iNumParticles);
  
  SetTexture(m_strTexFilename.c_str()); // trick ourselves into loading the texture

  // restore device objects for each event in this sequence
  for (std::vector<CParticleEvent *>::iterator i = m_Events.begin(); i != m_Events.end(); i++) {
    (*i)->RestoreDeviceObjects(pDev);
  }

  return S_OK;
}

HRESULT CParticleEventSequence::InvalidateDeviceObjects()
{
  SAFE_DELETE(m_Particles);
  SAFE_RELEASE(m_texParticle);
  
  // invalidate device objects for each event in this sequence
  for (std::vector<CParticleEvent *>::iterator i = m_Events.begin(); i != m_Events.end(); i++) {
    (*i)->InvalidateDeviceObjects();
  }

  return S_OK;
}

void CParticleEventSequence::SetTexture(const char *strTexFilename)
{
  m_strTexFilename = strTexFilename;
  if (m_pd3dDevice) {
    SAFE_RELEASE(m_texParticle);
    if (FAILED(D3DXCreateTextureFromFile(m_pd3dDevice, 
    m_strTexFilename.c_str(), &m_texParticle))) {
    m_texParticle = NULL;
    }
  }
}

void CParticleEventSequence::CreateNewParticle(D3DXVECTOR3 m_vPartSysPos)
{
	
  CParticle *part = m_Particles->New();

  part->m_fLifetime = m_Lifetime.GetRandomNumInRange();
  part->m_vPos = m_vPartSysPos + m_vEmitRadius.GetRandomNumInRange();

  // process any initial events
  for (std::vector<CParticleEvent *>::iterator i = m_Events.begin(); i != m_Events.end() && !(*i)->GetActualTime(); i++) {
    (*i)->DoItToIt(*part);
  }
  part->m_CurEvent = i;
	m_iTotalParticleLives++;
}

void CParticleEventSequence::RunEvents(CParticle &part)
{
  // apply any other events to this particle
  for (std::vector<CParticleEvent *>::iterator i = part.m_CurEvent; 
       i != m_Events.end() && (*i)->GetActualTime() <= part.m_fEventTimer; i++) {
    float oldeventtimer = part.m_fEventTimer;
    (*i)->DoItToIt(part);
    if (part.m_fEventTimer != oldeventtimer) {
      // event timer has changed, we need to recalc m_CurEvent.
      for (std::vector<CParticleEvent *>::iterator RecalcIter = m_Events.begin(); 
           RecalcIter != m_Events.end() && (*RecalcIter)->GetActualTime() < part.m_fEventTimer; 
           RecalcIter++);

      // set our main iterator to the recalculated iterator
      // the -1 just compensates for the i++ in the main for loop
      i = RecalcIter-1; 
    }
  }
  part.m_CurEvent = i;
}
void CParticleEventSequence::Update(float fElapsedTime, float fTimeDelta, D3DXVECTOR3 m_vPartSysPos)
{
  if (!m_Particles) return;
  // update existing particles
  {
    for (int q=0; q < m_Particles->GetTotalElements(); q++) {
      if (m_Particles->IsAlive(q)) {
        CParticle &part = m_Particles->GetAt(q);

        if (!part.Update(fTimeDelta)) {
          m_Particles->Delete(&part);
        }
        else {
          // apply gravity to this particle.
          part.m_vDir += fTimeDelta * m_vGravity.GetRandomNumInRange();
          // run all the particle's events
          RunEvents(part);
        }
      } // is alive
    } // next particle
  }

  float fEmitRateThisFrame = m_EmitRate.GetRandomNumInRange();
  int iNumNewParts = fEmitRateThisFrame * fTimeDelta;
  m_fNumNewPartsExcess += (float)(fEmitRateThisFrame * fTimeDelta)-iNumNewParts;
  
  if (m_fNumNewPartsExcess > 1.0f) {
    iNumNewParts += (int)m_fNumNewPartsExcess;
    m_fNumNewPartsExcess -= (int)m_fNumNewPartsExcess;
  }

	if (m_Loops > 0 && m_iTotalParticleLives+iNumNewParts > m_Loops * m_iNumParticles) {
		iNumNewParts = (m_Loops*m_iNumParticles)-m_iTotalParticleLives;
		if (iNumNewParts <= 0) {
			iNumNewParts = 0;
		}
	}
  for (int q=0; q < iNumNewParts && m_Particles->GetNumFreeElements(); q++) {
    try {
      CreateNewParticle(m_vPartSysPos);
    } catch(...) { q = iNumNewParts; }
  }
    
  
}

void CParticleEventSequence::Render(LPDIRECT3DVERTEXBUFFER8 pVB, int iVBSize)
{
  HRESULT hr;

  // Set the render states for using point sprites
  m_pd3dDevice->SetRenderState(D3DRS_POINTSPRITEENABLE, true);
  m_pd3dDevice->SetRenderState(D3DRS_POINTSCALEENABLE,  true);
  m_pd3dDevice->SetRenderState(D3DRS_POINTSIZE_MIN, FtoDW(0.00f));
  m_pd3dDevice->SetRenderState(D3DRS_POINTSIZE_MAX, FtoDW(500.0f));
  m_pd3dDevice->SetRenderState(D3DRS_POINTSCALE_A,  FtoDW(0.00f));
  m_pd3dDevice->SetRenderState(D3DRS_POINTSCALE_B,  FtoDW(0.00f));
  m_pd3dDevice->SetRenderState(D3DRS_POINTSCALE_C,  FtoDW(1.00f));
  
  m_pd3dDevice->SetRenderState(D3DRS_SRCBLEND, GetSrcBlendMode());
  m_pd3dDevice->SetRenderState(D3DRS_DESTBLEND, GetDestBlendMode());

  // Set up the vertex buffer to be rendered
  m_pd3dDevice->SetStreamSource( 0, pVB, sizeof(VERTEX_PARTICLE) );
  m_pd3dDevice->SetVertexShader( D3DFVF_PARTICLE );

  m_pd3dDevice->SetTexture(0, m_texParticle);
  
  VERTEX_PARTICLE *pVertices;
  DWORD dwNumParticlesToRender = 0;

  // Lock the vertex buffer.  We fill the vertex buffer in small
  // chunks, using D3DLOCK_NOOVERWRITE.  When we are done filling
  // each chunk, we call DrawPrim, and lock the next chunk.  When
  // we run out of space in the vertex buffer, we start over at
  // the beginning, using D3DLOCK_DISCARD.

  int iCurStart = 0;

  if(FAILED(hr = pVB->Lock(iCurStart * sizeof(VERTEX_PARTICLE), iVBSize * sizeof(VERTEX_PARTICLE),
    (BYTE **) &pVertices, iCurStart ? D3DLOCK_NOOVERWRITE : D3DLOCK_DISCARD)))
  {
	  return;
  }

  // Render each particle
  for (int q=0; q < m_iNumParticles; q++) {
    
    // Render each particle a bunch of times to get a blurring effect
    if (m_Particles->IsAlive(q)) {
      CParticle &part = m_Particles->GetAt(q);
    
      pVertices->position = part.m_vPos;
      pVertices->pointsize = part.m_fSize;
      pVertices->color = (DWORD)part.m_Color;
      pVertices++;

      if( ++dwNumParticlesToRender == iVBSize ) {
        // Done filling this chunk of the vertex buffer.  Lets unlock and
        // draw this portion so we can begin filling the next chunk.

        pVB->Unlock();

        if(FAILED(hr = m_pd3dDevice->DrawPrimitive( 
          D3DPT_POINTLIST, iCurStart, dwNumParticlesToRender)))
	        return;

        // Lock the next chunk of the vertex buffer.  If we are at the 
        // end of the vertex buffer, DISCARD the vertex buffer and start
        // at the beginning.  Otherwise, specify NOOVERWRITE, so we can
        // continue filling the VB while the previous chunk is drawing.
        iCurStart = 0;

        if(FAILED(hr = pVB->Lock(0, iVBSize * sizeof(VERTEX_PARTICLE),
		      (BYTE **) &pVertices, D3DLOCK_DISCARD)))
          return;

        dwNumParticlesToRender = 0;
      }
    }
  }

  // Unlock the vertex buffer
  pVB->Unlock();

  // Render any remaining particles
  if( dwNumParticlesToRender )
  {
    if(FAILED(hr = m_pd3dDevice->DrawPrimitive( D3DPT_POINTLIST, iCurStart, dwNumParticlesToRender )))
		return;
  }

  // Reset render states
  m_pd3dDevice->SetRenderState( D3DRS_POINTSPRITEENABLE, FALSE );
  m_pd3dDevice->SetRenderState( D3DRS_POINTSCALEENABLE,  FALSE );


}