VOID FrmRenderTextureToScreen_GLES( FLOAT32 sx, FLOAT32 sy, FLOAT32 w, FLOAT32 h,
UINT32 hTexture,
INT32 hShaderProgram, INT32 hScreenSizeLoc )
{
struct { GLint x, y, width, height; } viewport;
glGetIntegerv( GL_VIEWPORT, (GLint*)&viewport );
FLOAT32 fTextureWidth = w;
FLOAT32 fTextureHeight = h;
FLOAT32 fScreenWidth = (FLOAT32)viewport.width;
FLOAT32 fScreenHeight = (FLOAT32)viewport.height;
if( sx < 0.0f ) sx += fScreenWidth - fTextureWidth;
if( sy < 0.0f ) sy += fScreenHeight - fTextureHeight;
sx = FrmFloor( sx );
sy = FrmFloor( sy );
// Set the geoemtry
FRMVECTOR4 vQuad[] =
{
// Screenspace x Screenspace y tu tv
FRMVECTOR4( sx, sy, 0.0f, 1.0f ),
FRMVECTOR4( sx, sy+fTextureHeight, 0.0f, 0.0f ),
FRMVECTOR4( sx+fTextureWidth, sy+fTextureHeight, 1.0f, 0.0f ),
FRMVECTOR4( sx+fTextureWidth, sy, 1.0f, 1.0f ),
};
glVertexAttribPointer( 0, 4, GL_FLOAT, 0, 0, vQuad );
glEnableVertexAttribArray( 0 );
// Set the texture
glActiveTexture( GL_TEXTURE0 );
glBindTexture( GL_TEXTURE_2D, hTexture );
glBlendFunc( GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA );
glEnable( GL_BLEND );
glDisable( GL_DEPTH_TEST );
// Set the shader program
glUseProgram( hShaderProgram );
glUniform2f( hScreenSizeLoc, fScreenWidth, fScreenHeight );
// Draw the quad
glDrawArrays( GL_TRIANGLE_FAN, 0, 4 );
glEnable( GL_DEPTH_TEST );
glDisable( GL_BLEND );
}
//--------------------------------------------------------------------------------------
// 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 );
}
