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Weather example UB fixes
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This commit is contained in:
Nikita Lisitsa 2026-08-07 13:50:09 +03:00
parent 6201361b8c
commit c41e3874ca
1 changed files with 14 additions and 10 deletions
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24
examples/weather.cpp
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@ -73,8 +73,8 @@ struct weather_app
const float heating = 323.f * (std::exp(cooling * dt) - 1.f) / dt;
const float water_heating_factor = 0.9f;
const float coriolis = 0.001f;
const float coriolis_bands = 6.f;
const float band_force = 0.00001f;
const float coriolis_bands = 24.f;
const float band_force = 0.00004f;
const float friction = 0.f;
const float slope_friction = 1.f;
const float slope_force = 0.001f;
@ -287,6 +287,9 @@ struct weather_app
// Velocity & temperature advection
for (int i = 0; i < N; ++i)
{
new_velocity_(i, 0) = velocity_(i, 0);
new_velocity_(i, N - 1) = velocity_(i, N - 1);
new_temperature_(i, 0) = temperature_(i, 0);
new_temperature_(i, N - 1) = temperature_(i, N - 1);
@ -295,6 +298,9 @@ struct weather_app
if (!periodic_x)
{
new_velocity_(0, i) = velocity_(0, i);
new_velocity_(N - 1, i) = velocity_(N - 1, i);
new_temperature_(0, i) = temperature_(0, i);
new_temperature_(N - 1, i) = temperature_(N - 1, i);
@ -316,7 +322,7 @@ struct weather_app
p[0] = math::clamp(p[0], {0.f, N - 1.f});
int ix = std::floor(p[0]);
int iy = std::min<int>(N - 1, std::floor(p[1]));
int iy = std::min<int>(N - 2, std::floor(p[1]));
if (!periodic_x)
ix = std::min(N - 1, ix);
@ -348,9 +354,7 @@ struct weather_app
std::swap(humidity_, new_humidity_);
// Apply velocity diffusion
for (int y = 0; y < N; ++y)
for (int x = 0; x < N; ++x)
new_velocity_(x, y) = velocity_(x, y);
std::copy(velocity_.begin(), velocity_.end(), new_velocity_.begin());
for (int y = 1; y < N - 1; ++y)
{
for (int x = xmin; x < xmax; ++x)
@ -402,13 +406,13 @@ struct weather_app
[[maybe_unused]] math::vector terrain_gradient
{
(std::max(0.f, terrain_(x + 1, y)) - std::max(0.f, terrain_(x - 1, y))) / 2.f,
(std::max(0.f, terrain_(x, y + 1)) - std::max(0.f, terrain_(x, y - 1))) / 2.f,
(std::max(0.f, terrain_(wrap(x + 1), y)) - std::max(0.f, terrain_(wrap(x - 1), y))) / 2.f,
(std::max(0.f, terrain_(wrap(x), y + 1)) - std::max(0.f, terrain_(wrap(x), y - 1))) / 2.f,
};
[[maybe_unused]] math::vector temperature_gradient
{
(temperature_(x + 1, y) - temperature_(x - 1, y)) / 2.f,
(temperature_(wrap(x + 1), y) - temperature_(wrap(x - 1), y)) / 2.f,
(temperature_(x, y + 1) - temperature_(x, y - 1)) / 2.f,
};
@ -746,7 +750,7 @@ struct weather_app
{
// color = gfx::blend(color, map_color(precipitation_(x, y), {1.f, 1.f, 1.f, -1.f}, {1.f, 1.f, 1.f, 1.f}));
float alpha = 2.f / (1.f + std::exp(- 0.1f * precipitation_(x, y))) - 1.f;
float alpha = 2.f / (1.f + std::exp(- 0.5f * precipitation_(x, y))) - 1.f;
gfx::color_4f cloud_color{1.f, 1.f, 1.f, alpha * 0.875f};