1 #ifndef INCLUDED_FIXED_POINT_H
2 #define INCLUDED_FIXED_POINT_H
7 /* Unterstes Byte als Nachkomma. 16 Bit Nutzlast! Sonst geht Multiplikation flöten. */
8 typedef struct { int32_t data
; } fixed_point
;
10 static inline fixed_point
fixed_point_add(fixed_point x
, fixed_point y
) { fixed_point r
= { x
.data
+ y
.data
}; return r
; }
11 static inline fixed_point
fixed_point_sub(fixed_point x
, fixed_point y
) { fixed_point r
= { x
.data
- y
.data
}; return r
; }
12 static inline fixed_point
fixed_point_mul(fixed_point x
, fixed_point y
) { fixed_point r
= { x
.data
* y
.data
/ 256 }; return r
; }
13 static inline fixed_point
fixed_point_div(fixed_point x
, fixed_point y
) { fixed_point r
= { (x
.data
* 256) / y
.data
}; return r
; }
15 static inline fixed_point
fixed_point_neg(fixed_point x
) { fixed_point r
= { -x
.data
}; return r
; }
16 static inline fixed_point
fixed_point_abs(fixed_point x
) { fixed_point r
= { x
.data
< 0 ? -x
.data
: x
.data
}; return r
; }
18 static inline bool fixed_point_lt(fixed_point x
, fixed_point y
) { return x
.data
< y
.data
; }
19 static inline bool fixed_point_gt(fixed_point x
, fixed_point y
) { return x
.data
> y
.data
; }
20 static inline bool fixed_point_le(fixed_point x
, fixed_point y
) { return x
.data
<= y
.data
; }
21 static inline bool fixed_point_ge(fixed_point x
, fixed_point y
) { return x
.data
>= y
.data
; }
22 static inline bool fixed_point_eq(fixed_point x
, fixed_point y
) { return x
.data
== y
.data
; }
23 static inline bool fixed_point_ne(fixed_point x
, fixed_point y
) { return x
.data
!= y
.data
; }
25 #define FIXED_POINT_I(x, y) { ((x) * 256) + ((y) * 256 / 1000) }
26 #define FIXED_INT_I(x) FIXED_POINT_I(x, 0)
28 static inline fixed_point
FIXED_POINT(int32_t x
, int32_t y
) {
29 fixed_point r
= FIXED_POINT_I(x
, y
);
33 static inline fixed_point
FIXED_INT(int32_t x
) { return FIXED_POINT(x
, 0); }
35 // sign bit is shifted in if x.data < 0, so this is x.data / 256 - (x.data < 0).
36 // This means 0.123 is cast to 1, which is what we want when we cast a model coordinate
37 // to a screen coordinate.
38 static inline int fixed_point_cast_int(fixed_point x
) { return x
.data
>> 8; }
40 static inline fixed_point
fixed_point_min(fixed_point x
, fixed_point y
) { return fixed_point_lt(x
, y
) ? x
: y
; }
41 static inline fixed_point
fixed_point_max(fixed_point x
, fixed_point y
) { return fixed_point_gt(x
, y
) ? x
: y
; }
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