forked from Qortal/Brooklyn
142 lines
3.7 KiB
C
142 lines
3.7 KiB
C
/*
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Copyright (c) 2012, Broadcom Europe Ltd
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All rights reserved.
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Redistribution and use in source and binary forms, with or without
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modification, are permitted provided that the following conditions are met:
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* Redistributions of source code must retain the above copyright
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notice, this list of conditions and the following disclaimer.
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* Redistributions in binary form must reproduce the above copyright
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notice, this list of conditions and the following disclaimer in the
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documentation and/or other materials provided with the distribution.
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* Neither the name of the copyright holder nor the
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names of its contributors may be used to endorse or promote products
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derived from this software without specific prior written permission.
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THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
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ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY
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DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
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(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
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ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
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SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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static INLINE bool clean_boolean(int b)
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{
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return !!b;
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}
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/*
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clean_float(float f)
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Implementation notes:
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'Cleans' a floating point number by converting -INF to -FLT_MAX, INF to FLT_MAX and
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any NaN to zero. Khronos spec says nothing about what happens if an unclean float is
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passed to a function, so this at least guarantees reasonable behaviour.
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Preconditions:
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-
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Postconditions:
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result r is not NaN or infinite
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*/
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static INLINE float clean_float(float f)
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{
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uint32_t u = float_to_bits(f);
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if (u == 0x7f800000)
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return FLT_MAX;
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if (u == (uint32_t)0xff800000)
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return -FLT_MAX;
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if ((u & 0x7f800000) == 0x7f800000)
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return 0; // force NaN to zero
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return f;
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}
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/*
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clampf(float x, float l, float u)
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Implementation notes:
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Khronos makes frequent use of the datatype clampf, which is defined as
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floating-point value clamped to [0, 1]
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This function is used in many places to clamp a floating point value to lie in a range
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(almost always 0..1) and also to implicitly remove any NaNs or infinities.
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Preconditions:
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l and u are not NaN or infinity and l <= u
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Postconditions:
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result r is not NaN or an infinity, and l <= r <= u
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*/
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static INLINE float clampf(float x, float l, float u)
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{
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vcos_assert(l <= u);
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x = clean_float(x);
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return _maxf(_minf(x, u), l);
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}
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/*
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fixed_to_float(int f)
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Implementation notes:
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OpenGL ES 1.1 makes use of the datatype 'fixed' which is defined as a:
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signed 2s complement 16.16 scaled integer
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This function is used to convert a fixed value to its floating point equivalent, with
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some loss of precision. We believe this is justified as the state tables in the spec
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talk about storing all these values as type R (floating-point number).
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Preconditions:
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-
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Postconditions:
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result r is not NaN or an infinity
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*/
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static INLINE float fixed_to_float(int f)
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{
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return (float)f / 65536.0f;
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}
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/*
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clampi(int x, int l, int u)
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Implementation notes:
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Preconditions:
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l <= u
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Postconditions:
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result r satisfies l <= r <= u
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*/
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static INLINE int clampi(int x, int l, int u)
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{
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vcos_assert(l <= u);
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return (int) _max(_min( (int32_t)x, (int32_t)u), (int32_t)l);
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}
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