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authorMatt A. Tobin <mattatobin@localhost.localdomain>2018-02-02 04:16:08 -0500
committerMatt A. Tobin <mattatobin@localhost.localdomain>2018-02-02 04:16:08 -0500
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Add m-esr52 at 52.6.0
Diffstat (limited to 'gfx/angle/src/common/mathutil.cpp')
-rwxr-xr-xgfx/angle/src/common/mathutil.cpp73
1 files changed, 73 insertions, 0 deletions
diff --git a/gfx/angle/src/common/mathutil.cpp b/gfx/angle/src/common/mathutil.cpp
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+//
+// 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
+{
+
+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);
+}
+
+} // namespace gl