MathHelper
MathHelper is a small collection of functions that act as small wrappers or cheaper versions of more complex operations.
Sin/Cos LUT
Sine and cosine are made faster by being read from a lookup table, which is computed on startup. It has 2^16 entries.
cpp
for (int i = 0; i < 65536; ++i)
table[i] = std::sin(i * M_PI * 2.0f / 65536);Sine
Sine is gotten by indexing into the LUT.
cpp
return SIN_TABLE[int(x * 10430.378f) & 0xFFFF]Cosine
Cosine is also gotten by indexing into the LUT, but shifted over
cpp
return SIN_TABLE[int(x * 10430.378f + 16384.0f) & 0xFFFF]The multiplier
The multiplier comes from the formula ( 2^16) / (PI * 2)(?).
MISSING
TODO: Add other MathHelper entries!