void WaveParticleManager::SpawnCircularWave(int numberOfParticles, glm::vec2 position, float amplitude, float speed, float radius)
{
float dispersionAngle = 2.0f * 3.14159f / numberOfParticles;
float initializationTime = (radius / speed);
for (int i = 0; i < numberOfParticles; ++i)
{
WaveParticle* waveParticle = GetNextParticle();
WaveParticle* waveParticle2 = GetNextParticle();
float dispersionAngle = 2.0f * 3.14159f / numberOfParticles;
waveParticle->Initialize(glm::rotate(glm::vec2(1.f, 0.f), i * dispersionAngle), position, amplitude, speed, initializationTime, radius, dispersionAngle);
waveParticle2->Initialize(glm::rotate(glm::vec2(1.f, 0.f), i * dispersionAngle), position, -amplitude, speed, 0.f , radius, dispersionAngle);
}
}
//--------------------------------------------------------------------------------------
// Name: EmitParticles()
// Desc:
//--------------------------------------------------------------------------------------
VOID CParticleEmitter::EmitParticles( PARTICLE* pParticles, FLOAT32 fElapsedTime,
FLOAT32 fCurrentTime, FRMCOLOR Colors[NUM_COLORS],
FLOAT32 fTimePerColor,
EmitParticleShader *epShader,
GLuint *srcBuffer, GLuint *pVAOs, GLuint *dstBuffer,
FRM_VERTEX_ELEMENT* pVertexLayout,
UINT32 nVertexSize, BOOL bUseTransformFeedback, GLuint Query )
{
// Determine the color of the particles to be emitted
FLOAT32 t = ( fCurrentTime / fTimePerColor ) - FrmFloor( fCurrentTime / fTimePerColor );
UINT32 nColorIndex = (INT32)FrmFloor( fCurrentTime / fTimePerColor ) % NUM_COLORS;
FRMCOLOR vColor1 = Colors[ nColorIndex ];
FRMCOLOR vColor2 = Colors[(nColorIndex+1) % NUM_COLORS ];
FRMCOLOR vColor = FrmLerp( t, vColor1, vColor2 );
m_fLeftOverParticles += m_fEmissionRate * fElapsedTime;
if( !bUseTransformFeedback )
{
// Create the needed number of particles based upon our emission rate.
for( INT32 i = 0; i < (INT32)NUM_PARTICLES; i++ )
{
// Get the next particle
PARTICLE* pParticle = GetNextParticle( pParticles );
if( FrmRand() < m_fLeftOverParticles / NUM_PARTICLES )
{
FLOAT32 fAngle = m_fEmitterSpread * ( FrmRand() - 0.5f );
FRMMATRIX4X4 matRotate = FrmMatrixRotate( FrmRadians(fAngle), 0.0f, 0.0f, -1.0f );
FRMVECTOR3 vVelocity = FrmVector3TransformCoord( m_vVelocity, matRotate );
pParticle->m_vPosition = m_vPosition + FrmSphrand( m_fEmitterRadius );
pParticle->m_vVelocity = vVelocity * ApplyVariance( 1.0f, m_fSpeedVariance );
pParticle->m_vColor = FRMVECTOR4( vColor.r/255.0f, vColor.g/255.0f, vColor.b/255.0f, vColor.a/255.0f );
pParticle->m_vColor.a = ApplyVariance( m_fInitialOpacity, m_fOpacityVariance );
pParticle->m_fStartTime = fCurrentTime;
pParticle->m_fLifeSpan = ApplyVariance( m_fInitialLifeSpan, m_fLifeSpanVariance );
pParticle->m_fInitialSize = ApplyVariance( m_fInitialSize, m_fInitialSizeVariance );
pParticle->m_fSizeIncreaseRate = ApplyVariance( m_fSizeIncreaseRate, m_fSizeIncreaseRateVarience );
}
}
}
else
{
// Using transform feedback to do particle emission
// Set up the shader
glUseProgram( epShader->ShaderID );
glUniform3fv( epShader->slotvPosition, 1, (FLOAT32 *)&m_vPosition );
glUniform3fv( epShader->slotvVelocity, 1, (FLOAT32 *)&m_vVelocity );
glUniform1f( epShader->slotfEmitterSpread, m_fEmitterSpread );
glUniform1f( epShader->slotfEmitterRadius, m_fEmitterRadius );
glUniform1f( epShader->slotfSpeedVariance, m_fSpeedVariance );
glUniform1f( epShader->slotfInitialOpacity, m_fInitialOpacity );
glUniform1f( epShader->slotfOpacityVariance, m_fOpacityVariance );
glUniform1f( epShader->slotfInitialLifeSpan, m_fInitialLifeSpan );
glUniform1f( epShader->slotfLifeSpanVariance, m_fLifeSpanVariance );
glUniform1f( epShader->slotfInitialSize, m_fInitialSize );
glUniform1f( epShader->slotfInitialSizeVariance, m_fInitialSizeVariance );
glUniform1f( epShader->slotfSizeIncreaseRate, m_fSizeIncreaseRate );
glUniform1f( epShader->slotfSizeIncreaseRateVariance, m_fSizeIncreaseRateVarience );
glUniform1f( epShader->slotfTime, fCurrentTime );
glUniform4f( epShader->slotvColor, vColor.r/255.0f, vColor.g/255.0f, vColor.b/255.0f, vColor.a/255.0f );
glUniform1f( epShader->slotfEmissionRate, m_fLeftOverParticles/NUM_PARTICLES );
glEnable( GL_RASTERIZER_DISCARD );
glBindVertexArray(pVAOs[0]);
// set source buffer
glBindBuffer( GL_ARRAY_BUFFER, *srcBuffer );
FrmSetVertexLayout( pVertexLayout, nVertexSize, 0 );
glBindBuffer( GL_ARRAY_BUFFER, 0 );
glBindVertexArray(0);
// set destination buffer
glBindBufferBase( GL_TRANSFORM_FEEDBACK_BUFFER, 0, *dstBuffer );
glBindVertexArray(pVAOs[0]);
glBeginQuery(GL_TRANSFORM_FEEDBACK_PRIMITIVES_WRITTEN, Query);
// Perfom transform feedback
glBeginTransformFeedback( GL_POINTS );
glDrawArrays( GL_POINTS, 0, NUM_PARTICLES );
glEndTransformFeedback();
glEndQuery(GL_TRANSFORM_FEEDBACK_PRIMITIVES_WRITTEN);
glDisable( GL_RASTERIZER_DISCARD );
glBindVertexArray(0);
glBindBufferBase( GL_TRANSFORM_FEEDBACK_BUFFER, 0, 0 );
}
m_fLeftOverParticles -= FrmFloor( m_fLeftOverParticles );
}
