• Home
  • Line#
  • Scopes#
  • Navigate#
  • Raw
  • Download
1 /**************************************************************************
2  *
3  * Copyright 2008 VMware, Inc.
4  * All Rights Reserved.
5  *
6  * Permission is hereby granted, free of charge, to any person obtaining a
7  * copy of this software and associated documentation files (the
8  * "Software"), to deal in the Software without restriction, including
9  * without limitation the rights to use, copy, modify, merge, publish,
10  * distribute, sub license, and/or sell copies of the Software, and to
11  * permit persons to whom the Software is furnished to do so, subject to
12  * the following conditions:
13  *
14  * The above copyright notice and this permission notice (including the
15  * next paragraph) shall be included in all copies or substantial portions
16  * of the Software.
17  *
18  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
19  * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
20  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.
21  * IN NO EVENT SHALL VMWARE AND/OR ITS SUPPLIERS BE LIABLE FOR
22  * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
23  * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
24  * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
25  *
26  **************************************************************************/
27 
28 
29 /**
30  * Math utilities and approximations for common math functions.
31  * Reduced precision is usually acceptable in shaders...
32  *
33  * "fast" is used in the names of functions which are low-precision,
34  * or at least lower-precision than the normal C lib functions.
35  */
36 
37 
38 #ifndef U_MATH_H
39 #define U_MATH_H
40 
41 
42 #include "c99_math.h"
43 #include <assert.h>
44 #include <float.h>
45 #include <stdarg.h>
46 
47 #include "bitscan.h"
48 #include "u_endian.h" /* for UTIL_ARCH_BIG_ENDIAN */
49 
50 #ifdef __cplusplus
51 extern "C" {
52 #endif
53 
54 
55 #ifndef M_SQRT2
56 #define M_SQRT2 1.41421356237309504880
57 #endif
58 
59 
60 /**
61  * Initialize math module.  This should be called before using any
62  * other functions in this module.
63  */
64 extern void
65 util_init_math(void);
66 
67 
68 union fi {
69    float f;
70    int32_t i;
71    uint32_t ui;
72 };
73 
74 
75 union di {
76    double d;
77    int64_t i;
78    uint64_t ui;
79 };
80 
81 
82 /**
83  * Extract the IEEE float32 exponent.
84  */
85 static inline signed
util_get_float32_exponent(float x)86 util_get_float32_exponent(float x)
87 {
88    union fi f;
89 
90    f.f = x;
91 
92    return ((f.ui >> 23) & 0xff) - 127;
93 }
94 
95 
96 #define LOG2_TABLE_SIZE_LOG2 8
97 #define LOG2_TABLE_SCALE (1 << LOG2_TABLE_SIZE_LOG2)
98 #define LOG2_TABLE_SIZE (LOG2_TABLE_SCALE + 1)
99 extern float log2_table[LOG2_TABLE_SIZE];
100 
101 
102 /**
103  * Fast approximation to log2(x).
104  */
105 static inline float
util_fast_log2(float x)106 util_fast_log2(float x)
107 {
108    union fi num;
109    float epart, mpart;
110    num.f = x;
111    epart = (float)(((num.i & 0x7f800000) >> 23) - 127);
112    /* mpart = log2_table[mantissa*LOG2_TABLE_SCALE + 0.5] */
113    mpart = log2_table[((num.i & 0x007fffff) + (1 << (22 - LOG2_TABLE_SIZE_LOG2))) >> (23 - LOG2_TABLE_SIZE_LOG2)];
114    return epart + mpart;
115 }
116 
117 
118 /**
119  * Floor(x), returned as int.
120  */
121 static inline int
util_ifloor(float f)122 util_ifloor(float f)
123 {
124 #if defined(USE_X86_ASM) && defined(__GNUC__) && defined(__i386__)
125    /*
126     * IEEE floor for computers that round to nearest or even.
127     * 'f' must be between -4194304 and 4194303.
128     * This floor operation is done by "(iround(f + .5) + iround(f - .5)) >> 1",
129     * but uses some IEEE specific tricks for better speed.
130     * Contributed by Josh Vanderhoof
131     */
132    int ai, bi;
133    double af, bf;
134    af = (3 << 22) + 0.5 + (double)f;
135    bf = (3 << 22) + 0.5 - (double)f;
136    /* GCC generates an extra fstp/fld without this. */
137    __asm__ ("fstps %0" : "=m" (ai) : "t" (af) : "st");
138    __asm__ ("fstps %0" : "=m" (bi) : "t" (bf) : "st");
139    return (ai - bi) >> 1;
140 #else
141    int ai, bi;
142    double af, bf;
143    union fi u;
144    af = (3 << 22) + 0.5 + (double) f;
145    bf = (3 << 22) + 0.5 - (double) f;
146    u.f = (float) af;  ai = u.i;
147    u.f = (float) bf;  bi = u.i;
148    return (ai - bi) >> 1;
149 #endif
150 }
151 
152 
153 /**
154  * Round float to nearest int.
155  */
156 static inline int
util_iround(float f)157 util_iround(float f)
158 {
159 #if defined(PIPE_CC_GCC) && defined(PIPE_ARCH_X86)
160    int r;
161    __asm__ ("fistpl %0" : "=m" (r) : "t" (f) : "st");
162    return r;
163 #elif defined(PIPE_CC_MSVC) && defined(PIPE_ARCH_X86)
164    int r;
165    _asm {
166       fld f
167       fistp r
168    }
169    return r;
170 #else
171    if (f >= 0.0f)
172       return (int) (f + 0.5f);
173    else
174       return (int) (f - 0.5f);
175 #endif
176 }
177 
178 
179 /**
180  * Approximate floating point comparison
181  */
182 static inline bool
util_is_approx(float a,float b,float tol)183 util_is_approx(float a, float b, float tol)
184 {
185    return fabsf(b - a) <= tol;
186 }
187 
188 
189 /**
190  * util_is_X_inf_or_nan = test if x is NaN or +/- Inf
191  * util_is_X_nan        = test if x is NaN
192  * util_X_inf_sign      = return +1 for +Inf, -1 for -Inf, or 0 for not Inf
193  *
194  * NaN can be checked with x != x, however this fails with the fast math flag
195  **/
196 
197 
198 /**
199  * Single-float
200  */
201 static inline bool
util_is_inf_or_nan(float x)202 util_is_inf_or_nan(float x)
203 {
204    union fi tmp;
205    tmp.f = x;
206    return (tmp.ui & 0x7f800000) == 0x7f800000;
207 }
208 
209 
210 static inline bool
util_is_nan(float x)211 util_is_nan(float x)
212 {
213    union fi tmp;
214    tmp.f = x;
215    return (tmp.ui & 0x7fffffff) > 0x7f800000;
216 }
217 
218 
219 static inline int
util_inf_sign(float x)220 util_inf_sign(float x)
221 {
222    union fi tmp;
223    tmp.f = x;
224    if ((tmp.ui & 0x7fffffff) != 0x7f800000) {
225       return 0;
226    }
227 
228    return (x < 0) ? -1 : 1;
229 }
230 
231 
232 /**
233  * Double-float
234  */
235 static inline bool
util_is_double_inf_or_nan(double x)236 util_is_double_inf_or_nan(double x)
237 {
238    union di tmp;
239    tmp.d = x;
240    return (tmp.ui & 0x7ff0000000000000ULL) == 0x7ff0000000000000ULL;
241 }
242 
243 
244 static inline bool
util_is_double_nan(double x)245 util_is_double_nan(double x)
246 {
247    union di tmp;
248    tmp.d = x;
249    return (tmp.ui & 0x7fffffffffffffffULL) > 0x7ff0000000000000ULL;
250 }
251 
252 
253 static inline int
util_double_inf_sign(double x)254 util_double_inf_sign(double x)
255 {
256    union di tmp;
257    tmp.d = x;
258    if ((tmp.ui & 0x7fffffffffffffffULL) != 0x7ff0000000000000ULL) {
259       return 0;
260    }
261 
262    return (x < 0) ? -1 : 1;
263 }
264 
265 
266 /**
267  * Half-float
268  */
269 static inline bool
util_is_half_inf_or_nan(int16_t x)270 util_is_half_inf_or_nan(int16_t x)
271 {
272    return (x & 0x7c00) == 0x7c00;
273 }
274 
275 
276 static inline bool
util_is_half_nan(int16_t x)277 util_is_half_nan(int16_t x)
278 {
279    return (x & 0x7fff) > 0x7c00;
280 }
281 
282 
283 static inline int
util_half_inf_sign(int16_t x)284 util_half_inf_sign(int16_t x)
285 {
286    if ((x & 0x7fff) != 0x7c00) {
287       return 0;
288    }
289 
290    return (x < 0) ? -1 : 1;
291 }
292 
293 
294 /**
295  * Return float bits.
296  */
297 static inline unsigned
fui(float f)298 fui( float f )
299 {
300    union fi fi;
301    fi.f = f;
302    return fi.ui;
303 }
304 
305 static inline float
uif(uint32_t ui)306 uif(uint32_t ui)
307 {
308    union fi fi;
309    fi.ui = ui;
310    return fi.f;
311 }
312 
313 
314 /**
315  * Convert uint8_t to float in [0, 1].
316  */
317 static inline float
ubyte_to_float(uint8_t ub)318 ubyte_to_float(uint8_t ub)
319 {
320    return (float) ub * (1.0f / 255.0f);
321 }
322 
323 
324 /**
325  * Convert float in [0,1] to uint8_t in [0,255] with clamping.
326  */
327 static inline uint8_t
float_to_ubyte(float f)328 float_to_ubyte(float f)
329 {
330    /* return 0 for NaN too */
331    if (!(f > 0.0f)) {
332       return (uint8_t) 0;
333    }
334    else if (f >= 1.0f) {
335       return (uint8_t) 255;
336    }
337    else {
338       union fi tmp;
339       tmp.f = f;
340       tmp.f = tmp.f * (255.0f/256.0f) + 32768.0f;
341       return (uint8_t) tmp.i;
342    }
343 }
344 
345 /**
346  * Convert uint16_t to float in [0, 1].
347  */
348 static inline float
ushort_to_float(uint16_t us)349 ushort_to_float(uint16_t us)
350 {
351    return (float) us * (1.0f / 65535.0f);
352 }
353 
354 
355 /**
356  * Convert float in [0,1] to uint16_t in [0,65535] with clamping.
357  */
358 static inline uint16_t
float_to_ushort(float f)359 float_to_ushort(float f)
360 {
361    /* return 0 for NaN too */
362    if (!(f > 0.0f)) {
363       return (uint16_t) 0;
364    }
365    else if (f >= 1.0f) {
366       return (uint16_t) 65535;
367    }
368    else {
369       union fi tmp;
370       tmp.f = f;
371       tmp.f = tmp.f * (65535.0f/65536.0f) + 128.0f;
372       return (uint16_t) tmp.i;
373    }
374 }
375 
376 static inline float
byte_to_float_tex(int8_t b)377 byte_to_float_tex(int8_t b)
378 {
379    return (b == -128) ? -1.0F : b * 1.0F / 127.0F;
380 }
381 
382 static inline int8_t
float_to_byte_tex(float f)383 float_to_byte_tex(float f)
384 {
385    return (int8_t) (127.0F * f);
386 }
387 
388 /**
389  * Calc log base 2
390  */
391 static inline unsigned
util_logbase2(unsigned n)392 util_logbase2(unsigned n)
393 {
394 #if defined(HAVE___BUILTIN_CLZ)
395    return ((sizeof(unsigned) * 8 - 1) - __builtin_clz(n | 1));
396 #else
397    unsigned pos = 0;
398    if (n >= 1<<16) { n >>= 16; pos += 16; }
399    if (n >= 1<< 8) { n >>=  8; pos +=  8; }
400    if (n >= 1<< 4) { n >>=  4; pos +=  4; }
401    if (n >= 1<< 2) { n >>=  2; pos +=  2; }
402    if (n >= 1<< 1) {           pos +=  1; }
403    return pos;
404 #endif
405 }
406 
407 static inline uint64_t
util_logbase2_64(uint64_t n)408 util_logbase2_64(uint64_t n)
409 {
410 #if defined(HAVE___BUILTIN_CLZLL)
411    return ((sizeof(uint64_t) * 8 - 1) - __builtin_clzll(n | 1));
412 #else
413    uint64_t pos = 0ull;
414    if (n >= 1ull<<32) { n >>= 32; pos += 32; }
415    if (n >= 1ull<<16) { n >>= 16; pos += 16; }
416    if (n >= 1ull<< 8) { n >>=  8; pos +=  8; }
417    if (n >= 1ull<< 4) { n >>=  4; pos +=  4; }
418    if (n >= 1ull<< 2) { n >>=  2; pos +=  2; }
419    if (n >= 1ull<< 1) {           pos +=  1; }
420    return pos;
421 #endif
422 }
423 
424 /**
425  * Returns the ceiling of log n base 2, and 0 when n == 0. Equivalently,
426  * returns the smallest x such that n <= 2**x.
427  */
428 static inline unsigned
util_logbase2_ceil(unsigned n)429 util_logbase2_ceil(unsigned n)
430 {
431    if (n <= 1)
432       return 0;
433 
434    return 1 + util_logbase2(n - 1);
435 }
436 
437 static inline uint64_t
util_logbase2_ceil64(uint64_t n)438 util_logbase2_ceil64(uint64_t n)
439 {
440    if (n <= 1)
441       return 0;
442 
443    return 1ull + util_logbase2_64(n - 1);
444 }
445 
446 /**
447  * Returns the smallest power of two >= x
448  */
449 static inline unsigned
util_next_power_of_two(unsigned x)450 util_next_power_of_two(unsigned x)
451 {
452 #if defined(HAVE___BUILTIN_CLZ)
453    if (x <= 1)
454        return 1;
455 
456    return (1 << ((sizeof(unsigned) * 8) - __builtin_clz(x - 1)));
457 #else
458    unsigned val = x;
459 
460    if (x <= 1)
461       return 1;
462 
463    if (util_is_power_of_two_or_zero(x))
464       return x;
465 
466    val--;
467    val = (val >> 1) | val;
468    val = (val >> 2) | val;
469    val = (val >> 4) | val;
470    val = (val >> 8) | val;
471    val = (val >> 16) | val;
472    val++;
473    return val;
474 #endif
475 }
476 
477 static inline uint64_t
util_next_power_of_two64(uint64_t x)478 util_next_power_of_two64(uint64_t x)
479 {
480 #if defined(HAVE___BUILTIN_CLZLL)
481    if (x <= 1)
482        return 1;
483 
484    return (1ull << ((sizeof(uint64_t) * 8) - __builtin_clzll(x - 1)));
485 #else
486    uint64_t val = x;
487 
488    if (x <= 1)
489       return 1;
490 
491    if (util_is_power_of_two_or_zero64(x))
492       return x;
493 
494    val--;
495    val = (val >> 1)  | val;
496    val = (val >> 2)  | val;
497    val = (val >> 4)  | val;
498    val = (val >> 8)  | val;
499    val = (val >> 16) | val;
500    val = (val >> 32) | val;
501    val++;
502    return val;
503 #endif
504 }
505 
506 /**
507  * Reverse bits in n
508  * Algorithm taken from:
509  * http://stackoverflow.com/questions/9144800/c-reverse-bits-in-unsigned-integer
510  */
511 static inline unsigned
util_bitreverse(unsigned n)512 util_bitreverse(unsigned n)
513 {
514     n = ((n >> 1) & 0x55555555u) | ((n & 0x55555555u) << 1);
515     n = ((n >> 2) & 0x33333333u) | ((n & 0x33333333u) << 2);
516     n = ((n >> 4) & 0x0f0f0f0fu) | ((n & 0x0f0f0f0fu) << 4);
517     n = ((n >> 8) & 0x00ff00ffu) | ((n & 0x00ff00ffu) << 8);
518     n = ((n >> 16) & 0xffffu) | ((n & 0xffffu) << 16);
519     return n;
520 }
521 
522 /**
523  * Convert from little endian to CPU byte order.
524  */
525 
526 #if UTIL_ARCH_BIG_ENDIAN
527 #define util_le64_to_cpu(x) util_bswap64(x)
528 #define util_le32_to_cpu(x) util_bswap32(x)
529 #define util_le16_to_cpu(x) util_bswap16(x)
530 #else
531 #define util_le64_to_cpu(x) (x)
532 #define util_le32_to_cpu(x) (x)
533 #define util_le16_to_cpu(x) (x)
534 #endif
535 
536 #define util_cpu_to_le64(x) util_le64_to_cpu(x)
537 #define util_cpu_to_le32(x) util_le32_to_cpu(x)
538 #define util_cpu_to_le16(x) util_le16_to_cpu(x)
539 
540 /**
541  * Reverse byte order of a 32 bit word.
542  */
543 static inline uint32_t
util_bswap32(uint32_t n)544 util_bswap32(uint32_t n)
545 {
546 #if defined(HAVE___BUILTIN_BSWAP32)
547    return __builtin_bswap32(n);
548 #else
549    return (n >> 24) |
550           ((n >> 8) & 0x0000ff00) |
551           ((n << 8) & 0x00ff0000) |
552           (n << 24);
553 #endif
554 }
555 
556 /**
557  * Reverse byte order of a 64bit word.
558  */
559 static inline uint64_t
util_bswap64(uint64_t n)560 util_bswap64(uint64_t n)
561 {
562 #if defined(HAVE___BUILTIN_BSWAP64)
563    return __builtin_bswap64(n);
564 #else
565    return ((uint64_t)util_bswap32((uint32_t)n) << 32) |
566           util_bswap32((n >> 32));
567 #endif
568 }
569 
570 
571 /**
572  * Reverse byte order of a 16 bit word.
573  */
574 static inline uint16_t
util_bswap16(uint16_t n)575 util_bswap16(uint16_t n)
576 {
577    return (n >> 8) |
578           (n << 8);
579 }
580 
581 /**
582  * Extend sign.
583  */
584 static inline int64_t
util_sign_extend(uint64_t val,unsigned width)585 util_sign_extend(uint64_t val, unsigned width)
586 {
587 	assert(width > 0);
588 	if (val & (UINT64_C(1) << (width - 1))) {
589 		return -(int64_t)((UINT64_C(1) << width) - val);
590 	} else {
591 		return val;
592 	}
593 }
594 
595 static inline void*
util_memcpy_cpu_to_le32(void * restrict dest,const void * restrict src,size_t n)596 util_memcpy_cpu_to_le32(void * restrict dest, const void * restrict src, size_t n)
597 {
598 #if UTIL_ARCH_BIG_ENDIAN
599    size_t i, e;
600    assert(n % 4 == 0);
601 
602    for (i = 0, e = n / 4; i < e; i++) {
603       uint32_t * restrict d = (uint32_t* restrict)dest;
604       const uint32_t * restrict s = (const uint32_t* restrict)src;
605       d[i] = util_bswap32(s[i]);
606    }
607    return dest;
608 #else
609    return memcpy(dest, src, n);
610 #endif
611 }
612 
613 /**
614  * Clamp X to [MIN, MAX].
615  * This is a macro to allow float, int, uint, etc. types.
616  * We arbitrarily turn NaN into MIN.
617  */
618 #define CLAMP( X, MIN, MAX )  ( (X)>(MIN) ? ((X)>(MAX) ? (MAX) : (X)) : (MIN) )
619 
620 /* Syntax sugar occuring frequently in graphics code */
621 #define SATURATE( X ) CLAMP(X, 0.0f, 1.0f)
622 
623 #define MIN2( A, B )   ( (A)<(B) ? (A) : (B) )
624 #define MAX2( A, B )   ( (A)>(B) ? (A) : (B) )
625 
626 #define MIN3( A, B, C ) ((A) < (B) ? MIN2(A, C) : MIN2(B, C))
627 #define MAX3( A, B, C ) ((A) > (B) ? MAX2(A, C) : MAX2(B, C))
628 
629 #define MIN4( A, B, C, D ) ((A) < (B) ? MIN3(A, C, D) : MIN3(B, C, D))
630 #define MAX4( A, B, C, D ) ((A) > (B) ? MAX3(A, C, D) : MAX3(B, C, D))
631 
632 
633 /**
634  * Align a value up to an alignment value
635  *
636  * If \c value is not already aligned to the requested alignment value, it
637  * will be rounded up.
638  *
639  * \param value  Value to be rounded
640  * \param alignment  Alignment value to be used.  This must be a power of two.
641  *
642  * \sa ROUND_DOWN_TO()
643  */
644 
645 #if defined(ALIGN)
646 #undef ALIGN
647 #endif
648 static inline uintptr_t
ALIGN(uintptr_t value,int32_t alignment)649 ALIGN(uintptr_t value, int32_t alignment)
650 {
651    assert(util_is_power_of_two_nonzero(alignment));
652    return (((value) + (alignment) - 1) & ~((alignment) - 1));
653 }
654 
655 /**
656  * Like ALIGN(), but works with a non-power-of-two alignment.
657  */
658 static inline uintptr_t
ALIGN_NPOT(uintptr_t value,int32_t alignment)659 ALIGN_NPOT(uintptr_t value, int32_t alignment)
660 {
661    assert(alignment > 0);
662    return (value + alignment - 1) / alignment * alignment;
663 }
664 
665 /**
666  * Align a value down to an alignment value
667  *
668  * If \c value is not already aligned to the requested alignment value, it
669  * will be rounded down.
670  *
671  * \param value  Value to be rounded
672  * \param alignment  Alignment value to be used.  This must be a power of two.
673  *
674  * \sa ALIGN()
675  */
676 static inline uint64_t
ROUND_DOWN_TO(uint64_t value,int32_t alignment)677 ROUND_DOWN_TO(uint64_t value, int32_t alignment)
678 {
679    assert(util_is_power_of_two_nonzero(alignment));
680    return ((value) & ~(alignment - 1));
681 }
682 
683 /**
684  * Align a value, only works pot alignemnts.
685  */
686 static inline int
align(int value,int alignment)687 align(int value, int alignment)
688 {
689    return (value + alignment - 1) & ~(alignment - 1);
690 }
691 
692 static inline uint64_t
align64(uint64_t value,unsigned alignment)693 align64(uint64_t value, unsigned alignment)
694 {
695    return (value + alignment - 1) & ~((uint64_t)alignment - 1);
696 }
697 
698 /**
699  * Works like align but on npot alignments.
700  */
701 static inline size_t
util_align_npot(size_t value,size_t alignment)702 util_align_npot(size_t value, size_t alignment)
703 {
704    if (value % alignment)
705       return value + (alignment - (value % alignment));
706    return value;
707 }
708 
709 static inline unsigned
u_minify(unsigned value,unsigned levels)710 u_minify(unsigned value, unsigned levels)
711 {
712     return MAX2(1, value >> levels);
713 }
714 
715 #ifndef COPY_4V
716 #define COPY_4V( DST, SRC )         \
717 do {                                \
718    (DST)[0] = (SRC)[0];             \
719    (DST)[1] = (SRC)[1];             \
720    (DST)[2] = (SRC)[2];             \
721    (DST)[3] = (SRC)[3];             \
722 } while (0)
723 #endif
724 
725 
726 #ifndef COPY_4FV
727 #define COPY_4FV( DST, SRC )  COPY_4V(DST, SRC)
728 #endif
729 
730 
731 #ifndef ASSIGN_4V
732 #define ASSIGN_4V( DST, V0, V1, V2, V3 ) \
733 do {                                     \
734    (DST)[0] = (V0);                      \
735    (DST)[1] = (V1);                      \
736    (DST)[2] = (V2);                      \
737    (DST)[3] = (V3);                      \
738 } while (0)
739 #endif
740 
741 
742 static inline uint32_t
util_unsigned_fixed(float value,unsigned frac_bits)743 util_unsigned_fixed(float value, unsigned frac_bits)
744 {
745    return value < 0 ? 0 : (uint32_t)(value * (1<<frac_bits));
746 }
747 
748 static inline int32_t
util_signed_fixed(float value,unsigned frac_bits)749 util_signed_fixed(float value, unsigned frac_bits)
750 {
751    return (int32_t)(value * (1<<frac_bits));
752 }
753 
754 unsigned
755 util_fpstate_get(void);
756 unsigned
757 util_fpstate_set_denorms_to_zero(unsigned current_fpstate);
758 void
759 util_fpstate_set(unsigned fpstate);
760 
761 /**
762  * For indexed draw calls, return true if the vertex count to be drawn is
763  * much lower than the vertex count that has to be uploaded, meaning
764  * that the driver should flatten indices instead of trying to upload
765  * a too big range.
766  *
767  * This is used by vertex upload code in u_vbuf and glthread.
768  */
769 static inline bool
util_is_vbo_upload_ratio_too_large(unsigned draw_vertex_count,unsigned upload_vertex_count)770 util_is_vbo_upload_ratio_too_large(unsigned draw_vertex_count,
771                                    unsigned upload_vertex_count)
772 {
773    if (draw_vertex_count > 1024)
774       return upload_vertex_count > draw_vertex_count * 4;
775    else if (draw_vertex_count > 32)
776       return upload_vertex_count > draw_vertex_count * 8;
777    else
778       return upload_vertex_count > draw_vertex_count * 16;
779 }
780 
781 bool util_invert_mat4x4(float *out, const float *m);
782 
783 /* Quantize the lod bias value to reduce the number of sampler state
784  * variants in gallium because apps use it for smooth mipmap transitions,
785  * thrashing cso_cache and degrading performance.
786  *
787  * This quantization matches the AMD hw specification, so having more
788  * precision would have no effect anyway.
789  */
790 static inline float
util_quantize_lod_bias(float lod)791 util_quantize_lod_bias(float lod)
792 {
793    lod = CLAMP(lod, -16, 16);
794    return roundf(lod * 256) / 256;
795 }
796 
797 #ifdef __cplusplus
798 }
799 #endif
800 
801 #endif /* U_MATH_H */
802