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// Copyright 2016 The SwiftShader Authors. All Rights Reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#ifndef sw_Half_hpp
#define sw_Half_hpp
namespace sw
{
class half
{
public:
half() = default;
explicit half(float f);
operator float() const;
half &operator=(half h);
half &operator=(float f);
private:
unsigned short fp16i;
};
inline half shortAsHalf(short s)
{
union
{
half h;
short s;
} hs;
hs.s = s;
return hs.h;
}
class RGB9E5
{
unsigned int R : 9;
unsigned int G : 9;
unsigned int B : 9;
unsigned int E : 5;
public:
void toRGB16F(half rgb[3]) const
{
constexpr int offset = 24; // Exponent bias (15) + number of mantissa bits per component (9) = 24
const float factor = (1u << E) * (1.0f / (1 << offset));
rgb[0] = half(R * factor);
rgb[1] = half(G * factor);
rgb[2] = half(B * factor);
}
};
class R11G11B10F
{
unsigned int R : 11;
unsigned int G : 11;
unsigned int B : 10;
static inline half float11ToFloat16(unsigned short fp11)
{
return shortAsHalf(fp11 << 4); // Sign bit 0
}
static inline half float10ToFloat16(unsigned short fp10)
{
return shortAsHalf(fp10 << 5); // Sign bit 0
}
public:
void toRGB16F(half rgb[3]) const
{
rgb[0] = float11ToFloat16(R);
rgb[1] = float11ToFloat16(G);
rgb[2] = float10ToFloat16(B);
}
};
}
#endif // sw_Half_hpp