Beispiel #1
0
//-----------------------------------------------------------------------------
// Purpose: 
//-----------------------------------------------------------------------------
int CSpriteTrail::DrawModel( int flags )
{
	VPROF_BUDGET( "CSpriteTrail::DrawModel", VPROF_BUDGETGROUP_PARTICLE_RENDERING );
	
	// Must have at least one point
	if ( m_nStepCount < 1 )
		return 1;

	//See if we should draw
	if ( !IsVisible() || ( m_bReadyToDraw == false ) )
		return 0;

	CEngineSprite *pSprite = Draw_SetSpriteTexture( GetModel(), m_flFrame, GetRenderMode() );
	if ( pSprite == NULL )
		return 0;

	// Specify all the segments.
	CMatRenderContextPtr pRenderContext( g_pMaterialSystem );
	CBeamSegDraw segDraw;
	segDraw.Start( pRenderContext, m_nStepCount + 1, pSprite->GetMaterial() );
	
	// Setup the first point, always emanating from the attachment point
	TrailPoint_t *pLast = GetTrailPoint( m_nStepCount-1 );
	TrailPoint_t currentPoint;
	currentPoint.m_flDieTime = gpGlobals->curtime + m_flLifeTime;
	ComputeScreenPosition( &currentPoint.m_vecScreenPos );
	currentPoint.m_flTexCoord = pLast->m_flTexCoord + currentPoint.m_vecScreenPos.DistTo(pLast->m_vecScreenPos) * m_flTextureRes;
	currentPoint.m_flWidthVariance = 0.0f;

#if SCREEN_SPACE_TRAILS
	VMatrix	viewMatrix;
	materials->GetMatrix( MATERIAL_VIEW, &viewMatrix );
	viewMatrix = viewMatrix.InverseTR();
#endif

	TrailPoint_t *pPrevPoint = NULL;
	float flTailAlphaDist = m_flMinFadeLength;
	for ( int i = 0; i <= m_nStepCount; ++i )
	{
		// This makes it so that we're always drawing to the current location
		TrailPoint_t *pPoint = (i != m_nStepCount) ? GetTrailPoint(i) : &currentPoint;

		float flLifePerc = (pPoint->m_flDieTime - gpGlobals->curtime) / m_flLifeTime;
		flLifePerc = clamp( flLifePerc, 0.0f, 1.0f );

		BeamSeg_t curSeg;
		curSeg.m_vColor.x = (float) m_clrRender->r / 255.0f;
		curSeg.m_vColor.y = (float) m_clrRender->g / 255.0f;
		curSeg.m_vColor.z = (float) m_clrRender->b / 255.0f;

		float flAlphaFade = flLifePerc;
		if ( flTailAlphaDist > 0.0f )
		{
			if ( pPrevPoint )
			{
				float flDist = pPoint->m_vecScreenPos.DistTo( pPrevPoint->m_vecScreenPos );
				flTailAlphaDist -= flDist;
			}

			if ( flTailAlphaDist > 0.0f )
			{
				float flTailFade = Lerp( (m_flMinFadeLength - flTailAlphaDist) / m_flMinFadeLength, 0.0f, 1.0f );
				if ( flTailFade < flAlphaFade )
				{
					flAlphaFade = flTailFade;
				}
			}
		}
		curSeg.m_flAlpha  = ( (float) GetRenderBrightness() / 255.0f ) * flAlphaFade;

#if SCREEN_SPACE_TRAILS
		curSeg.m_vPos = viewMatrix * pPoint->m_vecScreenPos;
#else
		curSeg.m_vPos = pPoint->m_vecScreenPos;
#endif

		if ( m_flEndWidth >= 0.0f )
		{
			curSeg.m_flWidth = Lerp( flLifePerc, m_flEndWidth.Get(), m_flStartWidth.Get() );
		}
		else
		{
			curSeg.m_flWidth = m_flStartWidth.Get();
		}
		curSeg.m_flWidth += pPoint->m_flWidthVariance;
		if ( curSeg.m_flWidth < 0.0f )
		{
			curSeg.m_flWidth = 0.0f;
		}

		curSeg.m_flTexCoord = pPoint->m_flTexCoord;

		segDraw.NextSeg( &curSeg );

		// See if we're done with this bad boy
		if ( pPoint->m_flDieTime <= gpGlobals->curtime )
		{
			// Push this back onto the top for use
			++m_nFirstStep;
			--i;
			--m_nStepCount;
		}

		pPrevPoint = pPoint;
	}

	segDraw.End();

	return 1;
}