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Add interpolation helper

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This commit is contained in:
Miloslav Číž 2018-11-18 14:00:21 +01:00
parent 182ee3b65d
commit c3a70d6f7e
1 changed files with 20 additions and 1 deletions
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21
s3l.h
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@ -48,6 +48,25 @@ typedef struct
int16_t minorDiff; int16_t minorDiff;
} S3L_BresenhamState; } S3L_BresenhamState;
/**
Returns a value interpolated between the three triangle vertices based on
barycentric coordinates.
*/
static inline S3L_Unit S3L_interpolateBarycentric(
S3L_Unit value0, S3L_Unit value1, S3L_Unit value2,
S3L_Unit barycentric0, S3L_Unit barycentric1, S3L_Unit barycentric2)
{
return
(
(value0 * barycentric0) +
(value1 * barycentric1) +
(value2 * barycentric2)
) / S3L_FRACTIONS_PER_UNIT;
}
// general helper functions:
static inline int16_t S3L_abs(int16_t value) static inline int16_t S3L_abs(int16_t value)
{ {
return value >= 0 ? value : -1 * value; return value >= 0 ? value : -1 * value;
@ -68,7 +87,7 @@ static inline S3L_Unit S3L_wrap(S3L_Unit value, S3L_Unit mod)
return value >= 0 ? (value % mod) : (mod + (value % mod) - 1); return value >= 0 ? (value % mod) : (mod + (value % mod) - 1);
} }
static inline S3L_nonZero(S3L_Unit value) static inline S3L_Unit S3L_nonZero(S3L_Unit value)
{ {
return value != 0 ? value : 1; return value != 0 ? value : 1;
} }