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This commit is contained in:
Nikita Edel 2026-03-11 20:02:11 +01:00
parent c0198bb8a7
commit 5d88fa9cf5
1 changed files with 18 additions and 4 deletions
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22
Minecraft.World/Util/Mth.cpp
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@ -10,13 +10,16 @@ const float Mth::RADDEG = 180.0f / PI;
float *Mth::_sin = NULL;
// 4jcraft for clarity
constexpr size_t SIN_TAB_CNT = 65536;
const float Mth::sinScale = 65536.0f / (float) (PI * 2);
// 4J - added - was in static constructor
void Mth::init()
{
_sin = new float[65536];
for (int i = 0; i < 65536; i++)
_sin = new float[SIN_TAB_CNT];
for (int i = 0; i < SIN_TAB_CNT; i++)
{
_sin[i] = (float) ::sin(i * PI * 2 / 65536.0f);
}
@ -24,16 +27,27 @@ void Mth::init()
float Mth::sin(float i)
{
if(_sin == NULL) init(); // 4J - added
return _sin[(int)fmodf(i * sinScale, 65536.0f) & 65535];
// 4jcraft changed, what ever this was, it was not safe
// fmodf returns between -65536 and 65536 (casted)
// last end is there to shift it into 0 to 65535
return _sin[(int32_t) fmodf(i * sinScale, (float) SIN_TAB_CNT) & (SIN_TAB_CNT - 1)];
}
float Mth::cos(float i)
{
if(_sin == NULL) init(); // 4J - added
return _sin[(int)fmodf(i * sinScale + 16384.0f, 65536.0f) & 65535];
// 4jcraft same thing as ::sin but shift by SIN_TAB_CNT / 4
// which is aquivalent to shift by pi / 2
// and again the same modulo logic to cramp and map it onto the computed table
return _sin[(int32_t) fmodf(i * sinScale + ((float) SIN_TAB_CNT / 4), (float)SIN_TAB_CNT) & (SIN_TAB_CNT - 1)];
}
float Mth::sqrt(float x)
{
return (float) ::sqrt(x);