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Add sin/cos

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Miloslav Číž 2018-11-20 14:44:14 +01:00
parent 4f14e1e1cb
commit e330136046
1 changed files with 38 additions and 0 deletions
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38
s3l.h
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@ -56,6 +56,23 @@ typedef int16_t S3L_Unit; /**< Units of measurement in 3D space. There is
#define S3L_FRACTIONS_PER_UNIT 1024 #define S3L_FRACTIONS_PER_UNIT 1024
#define S3L_SIN_TABLE_LENGTH 128
static const S3L_Unit S3L_sinTable[S3L_SIN_TABLE_LENGTH] =
{
0, 12, 25, 37, 50, 62, 75, 87, 100, 112, 125, 137, 150, 162, 175, 187, 199,
212, 224, 236, 248, 260, 273, 285, 297, 309, 321, 333, 344, 356, 368, 380,
391, 403, 414, 426, 437, 449, 460, 471, 482, 493, 504, 515, 526, 537, 547,
558, 568, 579, 589, 599, 609, 620, 629, 639, 649, 659, 668, 678, 687, 696,
706, 715, 724, 732, 741, 750, 758, 767, 775, 783, 791, 799, 807, 814, 822,
829, 837, 844, 851, 858, 865, 871, 878, 884, 890, 897, 903, 908, 914, 920,
925, 930, 936, 941, 946, 950, 955, 959, 964, 968, 972, 976, 979, 983, 986,
990, 993, 996, 999, 1001, 1004, 1006, 1008, 1010, 1012, 1014, 1016, 1017,
1019, 1020, 1021, 1022, 1022, 1023, 1023, 1023
};
#define S3L_SIN_TABLE_UNIT_STEP\
(S3L_FRACTIONS_PER_UNIT / (S3L_SIN_TABLE_LENGTH * 4))
typedef int16_t S3L_ScreenCoord; typedef int16_t S3L_ScreenCoord;
typedef uint16_t S3L_Index; typedef uint16_t S3L_Index;
@ -203,6 +220,27 @@ static inline S3L_Unit S3L_nonZero(S3L_Unit value)
return value != 0 ? value : 1; return value != 0 ? value : 1;
} }
static inline S3L_Unit S3L_sin(S3L_Unit x)
{
x = S3L_wrap(x / S3L_SIN_TABLE_UNIT_STEP,S3L_SIN_TABLE_LENGTH * 4);
if (x < S3L_SIN_TABLE_LENGTH)
x = x;
else if (x < S3L_SIN_TABLE_LENGTH * 2)
x = S3L_SIN_TABLE_LENGTH * 2 - x - 1;
else if (x < S3L_SIN_TABLE_LENGTH * 3)
x = x - S3L_SIN_TABLE_LENGTH * 2;
else
x = S3L_SIN_TABLE_LENGTH - (x - S3L_SIN_TABLE_LENGTH * 3) - 1;
return S3L_sinTable[x];
}
static inline S3L_Unit S3L_cos(S3L_Unit x)
{
return S3L_sin(x - S3L_FRACTIONS_PER_UNIT / 4);
}
/** /**
Interpolated between two values, v1 and v2, in the same ratio as t is to Interpolated between two values, v1 and v2, in the same ratio as t is to
tMax. Does NOT prevent zero division. tMax. Does NOT prevent zero division.