update()

void fl::WaveSimulation2D_Real::update

(

)

Definition at line 226 of file wave_simulation_real.cpp.

                                   {
    int16_t *curr = (whichGrid == 0 ? grid1.data() : grid2.data());
    int16_t *next = (whichGrid == 0 ? grid2.data() : grid1.data());
 
    // Update horizontal boundaries.
    for (size_t j = 0; j < height + 2; ++j) {
        if (mXCylindrical) {
            curr[j * stride + 0] = curr[j * stride + width];
            curr[j * stride + (width + 1)] = curr[j * stride + 1];
        } else {
            curr[j * stride + 0] = curr[j * stride + 1];
            curr[j * stride + (width + 1)] = curr[j * stride + width];
        }
    }
 
    // Update vertical boundaries.
    for (size_t i = 0; i < width + 2; ++i) {
        curr[0 * stride + i] = curr[1 * stride + i];
        curr[(height + 1) * stride + i] = curr[height * stride + i];
    }
 
    // Compute the dampening factor as an integer: 2^(dampening).
    int32_t dampening_factor = 1 << mDampening; // e.g., 6 -> 64
    int32_t mCourantSq32 = static_cast<int32_t>(mCourantSq);
 
    // Update each inner cell.
    for (size_t j = 1; j <= height; ++j) {
        for (size_t i = 1; i <= width; ++i) {
            int index = j * stride + i;
            // Laplacian: sum of four neighbors minus 4 times the center.
            int32_t laplacian = (int32_t)curr[index + 1] + curr[index - 1] +
                                curr[index + stride] + curr[index - stride] -
                                ((int32_t)curr[index] << 2);
            // Compute the new value:
            // f = - next[index] + 2 * curr[index] + mCourantSq * laplacian
            // The multiplication is in Q15, so we shift right by 15.
            int32_t term = (mCourantSq32 * laplacian) >> 15;
            int32_t f =
                -(int32_t)next[index] + ((int32_t)curr[index] << 1) + term;
 
            // Apply damping:
            f = f - (f / dampening_factor);
 
            // Clamp f to the Q15 range.
            if (f > 32767)
                f = 32767;
            else if (f < -32768)
                f = -32768;
 
            next[index] = (int16_t)f;
        }
    }
 
    if (mHalfDuplex) {
        // Set negative values to zero.
        for (size_t j = 1; j <= height; ++j) {
            for (size_t i = 1; i <= width; ++i) {
                int index = j * stride + i;
                if (next[index] < 0) {
                    next[index] = 0;
                }
            }
        }
    }
 
    // Swap the roles of the grids.
    whichGrid ^= 1;
}

References grid1, grid2, height, mCourantSq, mDampening, mHalfDuplex, mXCylindrical, stride, whichGrid, and width.