kc3-lang/angle/src/common/mathutil.cpp

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• Hash : 9d737966
  Author :
  Date : 2019-08-14T12:25:12
  

  Standardize copyright notices to project style
  
  For all "ANGLE Project" copyrights, standardize to the format specified
  by the style guide. Changes:
  - "Copyright (c)" and "Copyright(c)" changed to just "Copyright".
  - Removed the second half of date ranges ("Y1Y1-Y2Y2"->"Y1Y1").
  - Fixed a small number of files that had no copyright date using the
    initial commit year from the version control history.
  - Fixed one instance of copyright being "The ANGLE Project" rather than
    "The ANGLE Project Authors"
  
  These changes are applied both to the copyright of source file, and
  where applicable to copyright statements that are generated by
  templates.
  
  BUG=angleproject:3811
  
  Change-Id: I973dd65e4ef9deeba232d5be74c768256a0eb2e5
  Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/1754397
  Commit-Queue: Jamie Madill <jmadill@chromium.org>
  Reviewed-by: Jamie Madill <jmadill@chromium.org>
  

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• src/common/mathutil.cpp

• //
  // Copyright 2013 The ANGLE Project Authors. All rights reserved.
  // Use of this source code is governed by a BSD-style license that can be
  // found in the LICENSE file.
  //
  
  // mathutil.cpp: Math and bit manipulation functions.
  
  #include "common/mathutil.h"
  
  #include <math.h>
  #include <algorithm>
  
  namespace gl
  {
  
  namespace
  {
  
  struct RGB9E5Data
  {
      unsigned int R : 9;
      unsigned int G : 9;
      unsigned int B : 9;
      unsigned int E : 5;
  };
  
  // B is the exponent bias (15)
  constexpr int g_sharedexp_bias = 15;
  
  // N is the number of mantissa bits per component (9)
  constexpr int g_sharedexp_mantissabits = 9;
  
  // Emax is the maximum allowed biased exponent value (31)
  constexpr int g_sharedexp_maxexponent = 31;
  
  constexpr float g_sharedexp_max =
      ((static_cast<float>(1 << g_sharedexp_mantissabits) - 1) /
       static_cast<float>(1 << g_sharedexp_mantissabits)) *
      static_cast<float>(1 << (g_sharedexp_maxexponent - g_sharedexp_bias));
  
  }  // anonymous namespace
  
  unsigned int convertRGBFloatsTo999E5(float red, float green, float blue)
  {
      const float red_c   = std::max<float>(0, std::min(g_sharedexp_max, red));
      const float green_c = std::max<float>(0, std::min(g_sharedexp_max, green));
      const float blue_c  = std::max<float>(0, std::min(g_sharedexp_max, blue));
  
      const float max_c = std::max<float>(std::max<float>(red_c, green_c), blue_c);
      const float exp_p =
          std::max<float>(-g_sharedexp_bias - 1, floor(log(max_c))) + 1 + g_sharedexp_bias;
      const int max_s = static_cast<int>(
          floor((max_c / (pow(2.0f, exp_p - g_sharedexp_bias - g_sharedexp_mantissabits))) + 0.5f));
      const int exp_s =
          static_cast<int>((max_s < pow(2.0f, g_sharedexp_mantissabits)) ? exp_p : exp_p + 1);
  
      RGB9E5Data output;
      output.R = static_cast<unsigned int>(
          floor((red_c / (pow(2.0f, exp_s - g_sharedexp_bias - g_sharedexp_mantissabits))) + 0.5f));
      output.G = static_cast<unsigned int>(
          floor((green_c / (pow(2.0f, exp_s - g_sharedexp_bias - g_sharedexp_mantissabits))) + 0.5f));
      output.B = static_cast<unsigned int>(
          floor((blue_c / (pow(2.0f, exp_s - g_sharedexp_bias - g_sharedexp_mantissabits))) + 0.5f));
      output.E = exp_s;
  
      return bitCast<unsigned int>(output);
  }
  
  void convert999E5toRGBFloats(unsigned int input, float *red, float *green, float *blue)
  {
      const RGB9E5Data *inputData = reinterpret_cast<const RGB9E5Data *>(&input);
  
      *red =
          inputData->R * pow(2.0f, (int)inputData->E - g_sharedexp_bias - g_sharedexp_mantissabits);
      *green =
          inputData->G * pow(2.0f, (int)inputData->E - g_sharedexp_bias - g_sharedexp_mantissabits);
      *blue =
          inputData->B * pow(2.0f, (int)inputData->E - g_sharedexp_bias - g_sharedexp_mantissabits);
  }
  
  int BitCountPolyfill(uint32_t bits)
  {
      int ones = 0;
      while (bits)
      {
          ones += bool(bits & 1);
          bits >>= 1;
      }
      return ones;
  }
  
  }  // namespace gl
  

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