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Diffstat (limited to 'src/3rdparty/angle/src/common/mathutil.cpp')
-rw-r--r-- | src/3rdparty/angle/src/common/mathutil.cpp | 66 |
1 files changed, 66 insertions, 0 deletions
diff --git a/src/3rdparty/angle/src/common/mathutil.cpp b/src/3rdparty/angle/src/common/mathutil.cpp new file mode 100644 index 0000000000..20b3f0c113 --- /dev/null +++ b/src/3rdparty/angle/src/common/mathutil.cpp @@ -0,0 +1,66 @@ +// +// Copyright (c) 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 <algorithm> +#include <math.h> + +namespace gl +{ + +struct RGB9E5Data +{ + unsigned int R : 9; + unsigned int G : 9; + unsigned int B : 9; + unsigned int E : 5; +}; + +// B is the exponent bias (15) +static const int g_sharedexp_bias = 15; + +// N is the number of mantissa bits per component (9) +static const int g_sharedexp_mantissabits = 9; + +// Emax is the maximum allowed biased exponent value (31) +static const int g_sharedexp_maxexponent = 31; + +static const float g_sharedexp_max = ((pow(2.0f, g_sharedexp_mantissabits) - 1) / + pow(2.0f, g_sharedexp_mantissabits)) * + pow(2.0f, g_sharedexp_maxexponent - g_sharedexp_bias); + +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 = floor((max_c / (pow(2.0f, exp_p - g_sharedexp_bias - g_sharedexp_mantissabits))) + 0.5f); + const int exp_s = (max_s < pow(2.0f, g_sharedexp_mantissabits)) ? exp_p : exp_p + 1; + + RGB9E5Data output; + output.R = floor((red_c / (pow(2.0f, exp_s - g_sharedexp_bias - g_sharedexp_mantissabits))) + 0.5f); + output.G = floor((green_c / (pow(2.0f, exp_s - g_sharedexp_bias - g_sharedexp_mantissabits))) + 0.5f); + output.B = floor((blue_c / (pow(2.0f, exp_s - g_sharedexp_bias - g_sharedexp_mantissabits))) + 0.5f); + output.E = exp_s; + + return *reinterpret_cast<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); +} + +} |