alexpete
110 lines
5.1 KiB
C++
110 lines
5.1 KiB
C++
/*
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* All or portions of this file Copyright (c) Amazon.com, Inc. or its affiliates or
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* its licensors.
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*
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* For complete copyright and license terms please see the LICENSE at the root of this
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* distribution (the "License"). All use of this software is governed by the License,
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* or, if provided, by the license below or the license accompanying this file. Do not
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* remove or modify any license notices. This file is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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*
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*/
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#pragma once
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// include the required headers
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#include <AzCore/RTTI/TypeInfo.h>
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#include "StandardHeaders.h"
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#include "Algorithms.h"
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namespace MCore
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{
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/**
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* The compressed / packed float class.
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* The class can automatically compresses a float of type 'float' into a float that
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* represents this value inside the 'StorageType' type. An example would be a floating point value
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* (float=float) compressed into a CompressedFloat that stores the value as 8-bit byte.
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* This would reduce the float size from 4 bytes into 1 byte, at the trade of a bit loss in precision and CPU overhead for
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* uncompression into a float again. When used with care, the CPU overhead and precision loss are negligible.
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* During both compression and uncompression you also have to specify the range (minimum and maximum possible values) of the
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* value you want to compress/decompress. If you are dealing with normalized values, the minimum value
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* would be 0, and the maximum value would be +1. When uncompressing (converting back to a float) you
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* have to be sure you use the same minimum and maximum values as when you used to compress it! This is very important!
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* The bigger the range, the more precision loss. There is however no performance impact linked to the range.
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*/
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template <class StorageType>
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class TCompressedFloat
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{
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public:
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/**
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* Default constructor.
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* This leaves the member uninitialized, so if you get the uncompressed version, the result is unknown.
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*/
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MCORE_INLINE TCompressedFloat();
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/**
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* Constructor. Create a compressed float from an uncompressed one.
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* @param value The floating point value you want to compress.
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* @param minValue The minimum possible value of the uncompressed floating point value.
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* @param maxValue The maximum possible value of the uncompressed floating point value.
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*/
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MCORE_INLINE TCompressedFloat(float value, float minValue, float maxValue);
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/**
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* Constructor. Create a compressed float.
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* @param value The compessed floating point value.
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*/
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MCORE_INLINE TCompressedFloat(StorageType value);
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/**
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* Create a compressed float from an uncompressed one.
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* @param value The floating point value you want to compress.
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* @param minValue The minimum possible value of the uncompressed floating point value.
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* @param maxValue The maximum possible value of the uncompressed floating point value.
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*/
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MCORE_INLINE void FromFloat(float value, float minValue, float maxValue);
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/**
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* Uncompress this compressed floating point value into an uncompressed float.
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* Please note that the minimum and maximum values you specify are the same as when you created
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* this compressed floating point value or when you for the last time called the FromFloat method.
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* @param output The uncompressed floating point value to store the result in.
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* @param minValue The minimum possible value of the uncompressed floating point value.
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* @param maxValue The maximum possible value of the uncompressed floating point value.
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*/
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MCORE_INLINE void UnCompress(float* output, float minValue, float maxValue) const;
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/**
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* Uncompress this compressed floating point value into an uncompressed float.
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* Please note that the minimum and maximum values you specify are the same as when you created
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* this compressed floating point value or when you for the last time called the FromFloat method.
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* @param minValue The minimum possible value of the uncompressed floating point value.
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* @param maxValue The maximum possible value of the uncompressed floating point value.
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* @result The uncompressed version of this floating point value.
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*/
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MCORE_INLINE float ToFloat(float minValue, float maxValue) const;
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public:
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StorageType mValue; /**< The compressed/packed value. */
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// the number of steps within the specified range
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enum
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{
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CONVERT_VALUE = (1 << (sizeof(StorageType) << 3)) - 1
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};
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};
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// include the inline code
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#include "CompressedFloat.inl"
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// declare standard types
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typedef TCompressedFloat<uint16> Compressed16BitFloat;
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typedef TCompressedFloat<uint8> Compressed8BitFloat;
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} // namespace MCore
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namespace AZ
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{
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AZ_TYPE_INFO_TEMPLATE(MCore::TCompressedFloat, "{BFA1578B-66F8-4536-8CA6-FF5CC3E441AD}", AZ_TYPE_INFO_CLASS);
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}
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