Function FL_TEST_FILE

tests/fl/math/wave/wave_simulation_real.cpp:13–210

#include "test.h"

FL_TEST_FILE(FL_FILEPATH) {

using namespace fl;

FL_TEST_CASE("WaveSimulation2D_Real clamps speed to CFL bound [0, 0.5]") {
    // 2D CFL bound for the 5-point stencil is C^2 <= 0.5. Pre-fix the
    // setter accepted up to ~1.0, which is unstable and could overflow.
    WaveSimulation2D_Real sim(8, 8, 0.16f, 6.0f);
    sim.setSpeed(10.0f);
    // Q15(0.5) = 16383 -> back to float -> 16383/32767 ~= 0.49999.
    FL_CHECK_CLOSE(sim.getSpeed(), 0.5f, 0.001f);

    sim.setSpeed(-2.0f);
    // Q15(0.0) = 0 -> 0.0f exactly.
    FL_CHECK_CLOSE(sim.getSpeed(), 0.0f, 0.001f);

    sim.setSpeed(0.16f);
    FL_CHECK_CLOSE(sim.getSpeed(), 0.16f, 0.001f);
}

FL_TEST_CASE("WaveSimulation1D_Real clamps speed to CFL bound [0, 1.0]") {
    // 1D CFL bound for the 5-point stencil is C^2 <= 1.0.
    WaveSimulation1D_Real sim(16, 0.16f, 6);
    sim.setSpeed(10.0f);
    FL_CHECK_CLOSE(sim.getSpeed(), 1.0f, 0.001f);

    sim.setSpeed(-2.0f);
    FL_CHECK_CLOSE(sim.getSpeed(), 0.0f, 0.001f);

    sim.setSpeed(0.42f);
    FL_CHECK_CLOSE(sim.getSpeed(), 0.42f, 0.001f);
}

FL_TEST_CASE("WaveSimulation2D_Real survives saturated checkerboard at max CFL") {
    // Worst case for the inner-loop Q15 multiply: speed at the CFL bound
    // (0.5) and every cell saturated alternating between +1.0 and -1.0
    // (Q15 values ~+/-32767). The laplacian magnitude approaches 262,140,
    // which times Q15(0.5)=16383 is ~4.3e9 - well past i32 max. Pre-fix
    // this overflowed; post-fix the i64 promote keeps the math correct
    // and the clamp keeps the result in i16 range.
    const u32 W = 16;
    const u32 H = 16;
    WaveSimulation2D_Real sim(W, H, 0.5f, 6.0f);
    sim.setHalfDuplex(false);  // keep negative values for the test

    for (u32 y = 0; y < H; ++y) {
        for (u32 x = 0; x < W; ++x) {
            const float v = ((x + y) & 1) ? -1.0f : 1.0f;
            sim.setf(x, y, v);
        }
    }
    sim.update();

    // Every cell must remain in valid Q15 range (the clamp at the end of
    // update() guarantees this; if the i32 multiply overflowed, the
    // clamp would still execute but on a wrong-sign value).
    bool any_nonzero = false;
    for (u32 y = 0; y < H; ++y) {