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mutter/cogl/cogl-fixed.h
Robert Bragg 0f5f4e8645 cogl: improves header and coding style consistency 
We've had complaints that our Cogl code/headers are a bit "special" so
this is a first pass at tidying things up by giving them some
consistency. These changes are all consistent with how new code in Cogl
is being written, but the style isn't consistently applied across all
code yet.

There are two parts to this patch; but since each one required a large
amount of effort to maintain tidy indenting it made sense to combine the
changes to reduce the time spent re indenting the same lines.

The first change is to use a consistent style for declaring function
prototypes in headers. Cogl headers now consistently use this style for
prototypes:

 return_type
 cogl_function_name (CoglType arg0,
                     CoglType arg1);

Not everyone likes this style, but it seems that most of the currently
active Cogl developers agree on it.

The second change is to constrain the use of redundant glib data types
in Cogl. Uses of gint, guint, gfloat, glong, gulong and gchar have all
been replaced with int, unsigned int, float, long, unsigned long and char
respectively. When talking about pixel data; use of guchar has been
replaced with guint8, otherwise unsigned char can be used.

The glib types that we continue to use for portability are gboolean,
gint{8,16,32,64}, guint{8,16,32,64} and gsize.

The general intention is that Cogl should look palatable to the widest
range of C programmers including those outside the Gnome community so
- especially for the public API - we want to minimize the number of
foreign looking typedefs.
2010-02-12 14:05:00 +00:00

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/*
* Cogl
*
* An object oriented GL/GLES Abstraction/Utility Layer
*
* Copyright (C) 2007,2008,2009 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, write to the
* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
* Boston, MA 02111-1307, USA.
*/
#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) ((float) 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_FROM_DOUBLE:
* @x: a floating point number
*
* Converts @x from a double precision, floating point to a fixed
* point notation.
*
* Since: 1.0
*/
#define COGL_FIXED_FROM_DOUBLE(x) (cogl_double_to_fixed (x))
/**
* COGL_FIXED_TO_DOUBLE:
* @x: a #CoglFixed number
*
* Converts @x from a fixed point to a floating 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_tan:
* @angle: a #CoglFixed number
*
* Computes the tangent of @angle.
*
* Return value: the tangent of the passed angle, in fixed point notation
*
* Since: 1.0
*/
CoglFixed
cogl_fixed_tan (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 (unsigned int 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
*/
unsigned int
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
*/
unsigned int
cogl_fixed_pow (unsigned int 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
*/
int
cogl_sqrti (int 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
CoglFixed
cogl_double_to_fixed (double value);
int
cogl_double_to_int (double value);
unsigned int
cogl_double_to_unit (double value);
G_END_DECLS
#endif /* __COGL_FIXED_H__ */
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