minetest/src/daynightratio.h

58 lines
1.3 KiB
C

// Luanti
// SPDX-License-Identifier: LGPL-2.1-or-later
// Copyright (C) 2010-2013 celeron55, Perttu Ahola <celeron55@gmail.com>
#pragma once
inline u32 time_to_daynight_ratio(float time_of_day, bool smooth)
{
float t = time_of_day;
if (t < 0.0f)
t += ((int)(-t) / 24000) * 24000.0f;
if (t >= 24000.0f)
t -= ((int)(t) / 24000) * 24000.0f;
if (t > 12000.0f)
t = 24000.0f - t;
const float values[9][2] = {
{4250.0f + 125.0f, 175.0f},
{4500.0f + 125.0f, 175.0f},
{4750.0f + 125.0f, 250.0f},
{5000.0f + 125.0f, 350.0f},
{5250.0f + 125.0f, 500.0f},
{5500.0f + 125.0f, 675.0f},
{5750.0f + 125.0f, 875.0f},
{6000.0f + 125.0f, 1000.0f},
{6250.0f + 125.0f, 1000.0f},
};
if (!smooth) {
float lastt = values[0][0];
for (u32 i = 1; i < 9; i++) {
float t0 = values[i][0];
float switch_t = (t0 + lastt) / 2.0f;
lastt = t0;
if (switch_t <= t)
continue;
return values[i][1];
}
return 1000;
}
if (t <= 4625.0f) // 4500 + 125
return values[0][1];
else if (t >= 6125.0f) // 6000 + 125
return 1000;
for (u32 i = 0; i < 9; i++) {
if (values[i][0] <= t)
continue;
float td0 = values[i][0] - values[i - 1][0];
float f = (t - values[i - 1][0]) / td0;
return f * values[i][1] + (1.0f - f) * values[i - 1][1];
}
return 1000;
}