Method update

cpp/2_Concepts_and_Techniques/particles/particleSystem.cpp:255–307

step the simulation

// step the simulation
void ParticleSystem::update(float deltaTime)
{
    assert(m_bInitialized);

    float *dPos;

    if (m_bUseOpenGL) {
        dPos = (float *)mapGLBufferObject(&m_cuda_posvbo_resource);
    }
    else {
        dPos = (float *)m_cudaPosVBO;
    }

    // update constants
    setParameters(&m_params);

    // integrate
    integrateSystem(dPos, m_dVel, deltaTime, m_numParticles);

    // calculate grid hash
    calcHash(m_dGridParticleHash, m_dGridParticleIndex, dPos, m_numParticles);

    // sort particles based on hash
    sortParticles(m_dGridParticleHash, m_dGridParticleIndex, m_numParticles);

    // reorder particle arrays into sorted order and
    // find start and end of each cell
    reorderDataAndFindCellStart(m_dCellStart,
                                m_dCellEnd,
                                m_dSortedPos,
                                m_dSortedVel,
                                m_dGridParticleHash,
                                m_dGridParticleIndex,
                                dPos,
                                m_dVel,
                                m_numParticles,
                                m_numGridCells);

    // process collisions
    collide(m_dVel,
            m_dSortedPos,
            m_dSortedVel,
            m_dGridParticleIndex,
            m_dCellStart,
            m_dCellEnd,
            m_numParticles,
            m_numGridCells);

    // note: do unmap at end here to avoid unnecessary graphics/CUDA context switch
    if (m_bUseOpenGL) {
        unmapGLBufferObject(m_cuda_posvbo_resource);
    }
}

void ParticleSystem::dumpGrid()
{