mutter/clutter/cogl/cogl-fixed.h
Emmanuele Bassi d30c52ffd4 2008-10-30 Emmanuele Bassi <ebassi@linux.intel.com>
* clutter/cogl/cogl-color.h:
	* clutter/cogl/cogl-fixed.h:
	* clutter/cogl/cogl-offscreen.h:
	* clutter/cogl/cogl-path.h:
	* clutter/cogl/cogl-shader.h:
	* clutter/cogl/cogl-texture.h:
	* clutter/cogl/cogl-types.h: Add copyright and licensing
	notice to the newly added files.
2008-10-30 17:57:41 +00:00

756 lines
16 KiB
C

/* cogl-fixed.h: Fixed point API
* This file is part of Clutter
*
* Copyright (C) 2008 Intel Corporation.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library. If not, see <http://www.gnu.org/licenses/>.
*/
#if !defined(__COGL_H_INSIDE__) && !defined(CLUTTER_COMPILATION)
#error "Only <cogl/cogl.h> can be included directly."
#endif
#ifndef __COGL_FIXED_H__
#define __COGL_FIXED_H__
#include <cogl/cogl-types.h>
/**
* SECTION:cogl-fixed
* @short_description: Fixed Point API
*
* COGL has a fixed point API targeted at platforms without a floating
* point unit, such as embedded devices. On such platforms this API should
* be preferred to the floating point one as it does not trigger the slow
* path of software emulation, relying on integer math for fixed-to-floating
* and floating-to-fixed notations conversion.
*
* It is not recommened for use on platforms with a floating point unit
* (e.g. desktop systems), nor for use in language bindings.
*
* Basic rules of Fixed Point arithmethic:
* <itemizedlist>
* <listitem>
* <para>Two fixed point numbers can be directly added, subtracted and
* have their modulus taken.</para>
* </listitem>
* <listitem>
* <para>To add other numerical type to a fixed point number it has to
* be first converted to fixed point.</para>
* </listitem>
* <listitem>
* <para>A fixed point number can be directly multiplied or divided by
* an integer.</para>
* </listitem>
* <listitem>
* <para>Two fixed point numbers can only be multiplied and divided by
* the provided %COGL_FIXED_MUL and %COGL_FIXED_DIV macros.</para>
* </listitem>
* </itemizedlist>
*
* The fixed point API is available since COGL 1.0.
*/
G_BEGIN_DECLS
/**
* COGL_FIXED_BITS:
*
* Evaluates to the number of bits used by the #CoglFixed type.
*
* Since: 1.0
*/
#define COGL_FIXED_BITS (32)
/**
* COGL_FIXED_Q:
*
* Evaluates to the number of bits used for the non-integer part
* of the #CoglFixed type.
*
* Since: 1.0
*/
#define COGL_FIXED_Q (COGL_FIXED_BITS - 16)
/**
* COGL_FIXED_1:
*
* The number 1 expressed as a #CoglFixed number.
*
* Since: 1.0
*/
#define COGL_FIXED_1 (1 << COGL_FIXED_Q)
/**
* COGL_FIXED_0_5:
*
* The number 0.5 expressed as a #CoglFixed number.
*
* Since: 1.0
*/
#define COGL_FIXED_0_5 (32768)
/**
* COGL_FIXED_EPSILON:
*
* A very small number expressed as a #CoglFixed number.
*
* Since: 1.0
*/
#define COGL_FIXED_EPSILON (1)
/**
* COGL_FIXED_MAX:
*
* The biggest number representable using #CoglFixed
*
* Since: 1.0
*/
#define COGL_FIXED_MAX (0x7fffffff)
/**
* COGL_FIXED_MIN:
*
* The smallest number representable using #CoglFixed
*
* Since: 1.0
*/
#define COGL_FIXED_MIN (0x80000000)
/**
* COGL_FIXED_PI:
*
* The number pi, expressed as a #CoglFixed number.
*
* Since: 1.0
*/
#define COGL_FIXED_PI (0x0003243f)
/**
* COGL_FIXED_2_PI:
*
* Two times pi, expressed as a #CoglFixed number.
*
* Since: 1.0
*/
#define COGL_FIXED_2_PI (0x0006487f)
/**
* COGL_FIXED_PI_2:
*
* Half pi, expressed as a #CoglFixed number.
*
* Since: 1.0
*/
#define COGL_FIXED_PI_2 (0x00019220)
/**
* COGL_FIXED_PI_4:
*
* pi / 4, expressed as #CoglFixed number.
*
* Since: 1.0
*/
#define COGL_FIXED_PI_4 (0x0000c910)
/**
* COGL_FIXED_360:
*
* Evaluates to the number 360 in fixed point notation.
*
* Since: 1.0
*/
#define COGL_FIXED_360 (COGL_FIXED_FROM_INT (360))
/**
* COGL_FIXED_270:
*
* Evaluates to the number 270 in fixed point notation.
*
* Since: 1.0
*/
#define COGL_FIXED_270 (COGL_FIXED_FROM_INT (270))
/**
* COGL_FIXED_255:
*
* Evaluates to the number 255 in fixed point notation.
*
* Since: 1.0
*/
#define COGL_FIXED_255 (COGL_FIXED_FROM_INT (255))
/**
* COGL_FIXED_240:
*
* Evaluates to the number 240 in fixed point notation.
*
* Since: 1.0
*/
#define COGL_FIXED_240 (COGL_FIXED_FROM_INT (240))
/**
* COGL_FIXED_180:
*
* Evaluates to the number 180 in fixed point notation.
*
* Since: 1.0
*/
#define COGL_FIXED_180 (COGL_FIXED_FROM_INT (180))
/**
* COGL_FIXED_120:
*
* Evaluates to the number 120 in fixed point notation.
*
* Since: 1.0
*/
#define COGL_FIXED_120 (COGL_FIXED_FROM_INT (120))
/**
* COGL_FIXED_90:
*
* Evaluates to the number 90 in fixed point notation.
*
* Since: 1.0
*/
#define COGL_FIXED_90 (COGL_FIXED_FROM_INT (90))
/**
* COGL_FIXED_60:
*
* Evaluates to the number 60 in fixed point notation.
*
* Since: 1.0
*/
#define COGL_FIXED_60 (COGL_FIXED_FROM_INT (60))
/**
* COGL_FIXED_45:
*
* Evaluates to the number 45 in fixed point notation.
*
* Since: 1.0
*/
#define COGL_FIXED_45 (COGL_FIXED_FROM_INT (45))
/**
* COGL_FIXED_30:
*
* Evaluates to the number 30 in fixed point notation.
*
* Since: 1.0
*/
#define COGL_FIXED_30 (COGL_FIXED_FROM_INT (30))
/**
* COGL_RADIANS_TO_DEGREES:
*
* Evaluates to 180 / pi in fixed point notation.
*
* Since: 1.0
*/
#define COGL_RADIANS_TO_DEGREES (0x394bb8)
/*
* conversion macros
*/
/**
* COGL_FIXED_FROM_FLOAT:
* @x: a floating point number
*
* Converts @x from a floating point to a fixed point notation.
*
* Since: 1.0
*/
#define COGL_FIXED_FROM_FLOAT(x) (cogl_double_to_fixed (x))
/**
* COGL_FIXED_TO_FLOAT:
* @x: a #CoglFixed number
*
* Converts @x from a fixed point to a floating point notation, in
* single precision.
*
* Since: 1.0
*/
#define COGL_FIXED_TO_FLOAT(x) ((float) ((int)(x) / 65536.0))
/**
* COGL_FIXED_TO_FLOAT:
* @x: a #CoglFixed number
*
* Converts @x from a fixed point to a floatint point notation, in
* double precision.
*
* Since: 1.0
*/
#define COGL_FIXED_TO_DOUBLE(x) ((double) ((int)(x) / 65536.0))
/**
* COGL_FIXED_FROM_INT:
* @x: an integer number
*
* Converts @x from an integer to a fixed point notation.
*
* Since: 1.0
*/
#define COGL_FIXED_FROM_INT(x) ((x) << COGL_FIXED_Q)
/**
* COGL_FIXED_TO_INT:
* @x: a #CoglFixed number
*
* Converts @x from a fixed point notation to an integer, dropping
* the fractional part without rounding.
*
* Since: 1.0
*/
#define COGL_FIXED_TO_INT(x) ((x) >> COGL_FIXED_Q)
/**
* COGL_FLOAT_TO_INT:
* @x: a floatint point number
*
* Converts @x from a floating point notation to a signed integer.
*
* Since: 1.0
*/
#define COGL_FLOAT_TO_INT(x) (cogl_double_to_int ((x)))
/**
* COGL_FLOAT_TO_UINT:
* @x: a floatint point number
*
* Converts @x from a floating point notation to an unsigned integer.
*
* Since: 1.0
*/
#define COGL_FLOAT_TO_UINT(x) (cogl_double_to_uint ((x)))
/*
* fixed point math functions
*/
/**
* COGL_FIXED_FRACTION:
* @x: a #CoglFixed number
*
* Retrieves the fractionary part of @x.
*
* Since: 1.0
*/
#define COGL_FIXED_FRACTION(x) ((x) & ((1 << COGL_FIXED_Q) - 1))
/**
* COGL_FIXED_FLOOR:
* @x: a #CoglFixed number
*
* Rounds down a fixed point number to the previous integer.
*
* Since: 1.0
*/
#define COGL_FIXED_FLOOR(x) (((x) >= 0) ? ((x) >> COGL_FIXED_Q) \
: ~((~(x)) >> COGL_FIXED_Q))
/**
* COGL_FIXED_CEIL:
* @x: a #CoglFixed number
*
* Rounds up a fixed point number to the next integer.
*
* Since: 1.0
*/
#define COGL_FIXED_CEIL(x) (COGL_FIXED_FLOOR ((x) + 0xffff))
/**
* COGL_FIXED_MUL:
* @a: a #CoglFixed number
* @b: a #CoglFixed number
*
* Computes (a * b).
*
* Since: 1.0
*/
#define COGL_FIXED_MUL(a,b) (cogl_fixed_mul ((a), (b)))
/**
* COGL_FIXED_DIV:
* @a: a #CoglFixed number
* @b: a #CoglFixed number
*
* Computes (a / b).
*
* Since: 1.0
*/
#define COGL_FIXED_DIV(a,b) (cogl_fixed_div ((a), (b)))
/**
* COGL_FIXED_MUL_DIV:
* @a: a #CoglFixed number
* @b: a #CoglFixed number
* @c: a #CoglFixed number
*
* Computes ((a * b) / c). It is logically equivalent to:
*
* |[
* res = COGL_FIXED_DIV (COGL_FIXED_MUL (a, b), c);
* ]|
*
* But it is shorter to type.
*
* Since: 1.0
*/
#define COGL_FIXED_MUL_DIV(a,b,c) (cogl_fixed_mul_div ((a), (b), (c)))
/**
* COGL_FIXED_FAST_MUL:
* @a: a #CoglFixed number
* @b: a #CoglFixed number
*
* Fast version of %COGL_FIXED_MUL, implemented as a macro.
*
* <note>This macro might lose precision. If the precision of the result
* is important use %COGL_FIXED_MUL instead.</note>
*
* Since: 1.0
*/
#define COGL_FIXED_FAST_MUL(a,b) ((a) >> 8) * ((b) >> 8)
/**
* COGL_FIXED_FAST_DIV:
* @a: a #CoglFixed number
* @b: a #CoglFixed number
*
* Fast version of %COGL_FIXED_DIV, implemented as a macro.
*
* <note>This macro might lose precision. If the precision of the result
* is important use %COGL_FIXED_DIV instead.</note>
*
* Since: 1.0
*/
#define COGL_FIXED_FAST_DIV(a,b) ((((a) << 8) / (b)) << 8)
/**
* cogl_fixed_sin:
* @angle: a #CoglFixed number
*
* Computes the sine of @angle.
*
* Return value: the sine of the passed angle, in fixed point notation
*
* Since: 1.0
*/
CoglFixed cogl_fixed_sin (CoglFixed angle);
/**
* cogl_fixed_cos:
* @angle: a #CoglFixed number
*
* Computes the cosine of @angle.
*
* Return value: the cosine of the passed angle, in fixed point notation
*
* Since: 1.0
*/
CoglFixed cogl_fixed_cos (CoglFixed angle);
/**
* cogl_fixed_atani:
* @a: a #CoglFixed number
*
* Computes the arc tangent of @a.
*
* Return value: the arc tangent of the passed value, in fixed point notation
*
* Since: 1.0
*/
CoglFixed cogl_fixed_atani (CoglFixed a);
/**
* cogl_fixed_atan2:
* @a: the numerator as a #CoglFixed number
* @b: the denominator as a #CoglFixed number
*
* Computes the arc tangent of @a / @b but uses the sign of both
* arguments to return the angle in right quadrant.
*
* Return value: the arc tangent of the passed fraction, in fixed point
* notation
*
* Since: 1.0
*/
CoglFixed cogl_fixed_atan2 (CoglFixed a,
CoglFixed b);
/*< public >*/
/* Fixed point math routines */
G_INLINE_FUNC CoglFixed cogl_fixed_mul (CoglFixed a,
CoglFixed b);
G_INLINE_FUNC CoglFixed cogl_fixed_div (CoglFixed a,
CoglFixed b);
G_INLINE_FUNC CoglFixed cogl_fixed_mul_div (CoglFixed a,
CoglFixed b,
CoglFixed c);
/**
* COGL_SQRTI_ARG_MAX:
*
* Maximum argument that can be passed to cogl_sqrti() function.
*
* Since: 1.0
*/
#ifndef __SSE2__
#define COGL_SQRTI_ARG_MAX 0x3fffff
#else
#define COGL_SQRTI_ARG_MAX INT_MAX
#endif
/**
* COGL_SQRTI_ARG_5_PERCENT:
*
* Maximum argument that can be passed to cogl_sqrti() for which the
* resulting error is < 5%
*
* Since: 1.0
*/
#ifndef __SSE2__
#define COGL_SQRTI_ARG_5_PERCENT 210
#else
#define COGL_SQRTI_ARG_5_PERCENT INT_MAX
#endif
/**
* COGL_SQRTI_ARG_10_PERCENT:
*
* Maximum argument that can be passed to cogl_sqrti() for which the
* resulting error is < 10%
*
* Since: 1.0
*/
#ifndef __SSE2__
#define COGL_SQRTI_ARG_10_PERCENT 5590
#else
#define COGL_SQRTI_ARG_10_PERCENT INT_MAX
#endif
/**
* cogl_fixed_sqrt:
* @x: a #CoglFixed number
*
* Computes the square root of @x.
*
* Return value: the square root of the passed value, in floating point
* notation
*
* Since: 1.0
*/
CoglFixed cogl_fixed_sqrt (CoglFixed x);
/**
* cogl_fixed_log2:
* @x: value to calculate base 2 logarithm from
*
* Calculates base 2 logarithm.
*
* This function is some 2.5 times faster on x86, and over 12 times faster on
* fpu-less arm, than using libc log().
*
* Return value: base 2 logarithm.
*
* Since: 1.0
*/
CoglFixed cogl_fixed_log2 (guint x);
/**
* cogl_fixed_pow2:
* @x: a #CoglFixed number
*
* Calculates 2 to the @x power.
*
* This function is around 11 times faster on x86, and around 22 times faster
* on fpu-less arm than libc pow(2, x).
*
* Return value: the power of 2 to the passed value
*
* Since: 1.0
*/
guint cogl_fixed_pow2 (CoglFixed x);
/**
* cogl_fixed_pow:
* @x: base
* @y: #CoglFixed exponent
*
* Calculates @x to the @y power.
*
* Return value: the power of @x to the @y
*
* Since: 1.0
*/
guint cogl_fixed_pow (guint x,
CoglFixed y);
/**
* cogl_sqrti:
* @x: integer value
*
* Very fast fixed point implementation of square root for integers.
*
* This function is at least 6x faster than clib sqrt() on x86, and (this is
* not a typo!) about 500x faster on ARM without FPU. It's error is less than
* 5% for arguments smaller than %COGL_SQRTI_ARG_5_PERCENT and less than 10%
* for narguments smaller than %COGL_SQRTI_ARG_10_PERCENT. The maximum
* argument that can be passed to this function is %COGL_SQRTI_ARG_MAX.
*
* Return value: integer square root.
*
* Since: 1.0
*/
gint cogl_sqrti (gint x);
/**
* COGL_ANGLE_FROM_DEG:
* @x: an angle in degrees in floating point notation
*
* Converts an angle in degrees into a #CoglAngle.
*
* Since: 1.0
*/
#define COGL_ANGLE_FROM_DEG(x) (COGL_FLOAT_TO_INT (((float)(x) * 1024.0f) / 360.0f))
/**
* COGL_ANGLE_TO_DEG:
* @x: a #CoglAngle
*
* Converts a #CoglAngle into an angle in degrees, using floatint point
* notation.
*
* Since: 1.0
*/
#define COGL_ANGLE_TO_DEG(x) (((float)(x) * 360.0) / 1024.0)
/**
* COGL_ANGLE_FROM_DEGX:
* @x: an angle in degrees in fixed point notation
*
* Converts an angle in degrees into a #CoglAngle.
*
* Since: 1.0
*/
#define COGL_ANGLE_FROM_DEGX(x) (COGL_FIXED_TO_INT ((((x) / 360) * 1024) + COGL_FIXED_0_5))
/**
* COGL_ANGLE_TO_DEGX:
* @x: a #CoglAngle
*
* Converts a #CoglAngle into an angle in degrees, using fixed point notation
*
* Since: 1.0
*/
#define COGL_ANGLE_TO_DEGX(x) (COGL_FIXED_FROM_INT ((x) * 45) / 128)
/**
* cogl_angle_sin:
* @angle: an angle expressed using #CoglAngle
*
* Computes the sine of @angle
*
* Return value: the sine of the passed angle
*
* Since: 1.0
*/
CoglFixed cogl_angle_sin (CoglAngle angle);
/**
* cogl_angle_tan:
* @angle: an angle expressed using #CoglAngle
*
* Computes the tangent of @angle
*
* Return value: the tangent of the passed angle
*
* Since: 1.0
*/
CoglFixed cogl_angle_tan (CoglAngle angle);
/**
* cogl_angle_cos:
* @angle: an angle expressed using #CoglAngle
*
* Computes the cosine of @angle
*
* Return value: the cosine of the passed angle
*
* Since: 1.0
*/
CoglFixed cogl_angle_cos (CoglAngle angle);
/*< private >*/
#if defined (G_CAN_INLINE)
G_INLINE_FUNC CoglFixed
cogl_fixed_mul (CoglFixed a,
CoglFixed b)
{
# ifdef __arm__
int res_low, res_hi;
__asm__ ("smull %0, %1, %2, %3 \n"
"mov %0, %0, lsr %4 \n"
"add %1, %0, %1, lsl %5 \n"
: "=r"(res_hi), "=r"(res_low)\
: "r"(a), "r"(b), "i"(COGL_FIXED_Q), "i"(32 - COGL_FIXED_Q));
return (CoglFixed) res_low;
# else
long long r = (long long) a * (long long) b;
return (unsigned int)(r >> COGL_FIXED_Q);
# endif
}
#endif
#if defined (G_CAN_INLINE)
G_INLINE_FUNC CoglFixed
cogl_fixed_div (CoglFixed a,
CoglFixed b)
{
return (CoglFixed) ((((gint64) a) << COGL_FIXED_Q) / b);
}
#endif
#if defined(G_CAN_INLINE)
G_INLINE_FUNC CoglFixed
cogl_fixed_mul_div (CoglFixed a,
CoglFixed b,
CoglFixed c)
{
CoglFixed ab = cogl_fixed_mul (a, b);
CoglFixed quo = cogl_fixed_div (ab, c);
return quo;
}
#endif
extern CoglFixed cogl_double_to_fixed (double value);
extern gint cogl_double_to_int (double value);
extern guint cogl_double_to_unit (double value);
G_END_DECLS
#endif /* __COGL_FIXED_H__ */