update()

void fl::WaveSimulation1D_Real::update

(

)

Definition at line 90 of file wave_simulation_real.cpp.

                                   {
    int16_t *curr = (whichGrid == 0) ? grid1.get() : grid2.get();
    int16_t *next = (whichGrid == 0) ? grid2.get() : grid1.get();
 
    // Update boundaries with a Neumann (zero-gradient) condition:
    curr[0] = curr[1];
    curr[length + 1] = curr[length];
 
    // Compute dampening factor as an integer value: 2^(mDampenening)
    int32_t dampening_factor = 1 << mDampenening;
 
    int32_t mCourantSq32 = static_cast<int32_t>(mCourantSq);
    // Iterate over each inner cell.
    for (size_t i = 1; i < length + 1; i++) {
        // Compute the 1D Laplacian:
        // lap = curr[i+1] - 2 * curr[i] + curr[i-1]
        int32_t lap =
            (int32_t)curr[i + 1] - ((int32_t)curr[i] << 1) + curr[i - 1];
 
        // Multiply the Laplacian by the simulation speed using Q15 arithmetic:
        int32_t term = (mCourantSq32 * lap) >> 15;
 
        // Compute the new value:
        // f = -next[i] + 2 * curr[i] + term
        int32_t f = -(int32_t)next[i] + ((int32_t)curr[i] << 1) + term;
 
        // Apply damping:
        f = f - (f / dampening_factor);
 
        // Clamp the result to the Q15 range [-32768, 32767].
        if (f > 32767)
            f = 32767;
        else if (f < -32768)
            f = -32768;
 
        next[i] = (int16_t)f;
    }
 
    if (mHalfDuplex) {
        // Set the negative values to zero.
        for (size_t i = 1; i < length + 1; i++) {
            if (next[i] < 0) {
                next[i] = 0;
            }
        }
    }
 
    // Toggle the active grid.
    whichGrid ^= 1;
}

References grid1, grid2, length, mCourantSq, mDampenening, mHalfDuplex, and whichGrid.