o3de/Gems/Atom/Asset/ImageProcessingAtom/External/CubeMapGen/CImageSurface.cpp

/*
 * Copyright (c) Contributors to the Open 3D Engine Project.
 * For complete copyright and license terms please see the LICENSE at the root of this distribution.
 *
 * SPDX-License-Identifier: Apache-2.0 OR MIT
 *
 */

//--------------------------------------------------------------------------------------
//CImageSurface
// Class for storing, manipulating, and copying image data to and from D3D Surfaces
//
//--------------------------------------------------------------------------------------
// (C) 2005 ATI Research, Inc., All rights reserved.
//--------------------------------------------------------------------------------------
// Modified from original

#include "CImageSurface.h"

namespace ImageProcessingAtom
{
    //--------------------------------------------------------------------------------------
    // convert D3D 16 bit float to standard 32 bit float
    // Format:
    // 
    // 1 sign bit in MSB, (s) 
    // 5 bits of biased exponent, (e) 
    // 10 bits of fraction, (f), with an additional hidden bit 
    // A float16 value, v, made from the format above takes the following meaning:
    //
    // (a) if e == 31 and f != 0, then v is NaN regardless of s 
    // (b) if e == 31 and f == 0, then v = (-1)^s * infinity (signed infinity) 
    // (c) if 0 < e < 31, then v = (-1)^s * 2^(e-15) * (1.f) 
    // (d) if e == 0 and f != 0, then v = (-1)^s * 2^(e-14) * (0.f) (denormalized numbers) 
    // (e) if e == 0 and f == 0, then v = (-1)^s *0 (signed zero) 
    //
    //--------------------------------------------------------------------------------------
    float CPf16Tof32(uint16 aVal)
    {
        uint32 signVal = (aVal >> 15);              //sign bit in MSB
        uint32 exponent = ((aVal >> 10) & 0x01f);   //next 5 bits after signbit
        uint32 mantissa = (aVal & 0x03ff);          //lower 10 bits
        uint32 rawFloat32Data;                      //raw binary float data

        //convert s10e5  5-bit exponent to IEEE754 s23e8  8-bit exponent
        if (exponent == 31)
        {  // infinity or Nan depending on mantissa
            exponent = 255;
        }
        else if (exponent == 0)
        {  //  denormalized floats  mantissa is treated as = 0.f
            exponent = 0;
        }
        else
        {  //change 15base exponent to 127base exponent 
           //normalized floats mantissa is treated as = 1.f
            exponent += (127 - 15);
        }

        //convert 10-bit mantissa to 23-bit mantissa
        mantissa <<= (23 - 10);

        //assemble s23e8 number using logical operations
        rawFloat32Data = (signVal << 31) | (exponent << 23) | mantissa;

        //treat raw data as a 32 bit float
        return *((float *)&rawFloat32Data);
    }


    //--------------------------------------------------------------------------------------
    // convert standard 32 bit float to D3D 16 bit float
    //
    // 16-bit float format:
    // 
    // 1 sign bit in MSB, (s) 
    // 5 bits of biased exponent, (e) 
    // 10 bits of fraction, (f), with an additional hidden bit 
    // A float16 value, v, made from the format above takes the following meaning:
    //
    // (a) if e == 31 and f != 0, then v is NaN regardless of s 
    // (b) if e == 31 and f == 0, then v = (-1)s*infinity (signed infinity) 
    // (c) if 0 < e < 31, then v = (-1)s*2(e-15)*(1.f) 
    // (d) if e == 0 and f != 0, then v = (-1)s*2(e-14)*(0.f) (denormalized numbers) 
    // (e) if e == 0 and f == 0, then v = (-1)s*0 (signed zero) 
    //--------------------------------------------------------------------------------------
    uint16 CPf32Tof16(float aVal)
    {
        uint32 rawf32Data = *((uint32 *)&aVal); //raw binary float data

        uint32 signVal = (rawf32Data >> 31);              //sign bit in MSB
        uint32 exponent = ((rawf32Data >> 23) & 0xff);    //next 8 bits after signbit
        uint32 mantissa = (rawf32Data & 0x7fffff);        //mantissa = lower 23 bits

        uint16 rawf16Data;

        //convert IEEE754 s23e8 8-bit exponent to s10e5  5-bit exponent      
        if (exponent == 255)
        {//special case 32 bit float is inf or NaN, use mantissa as is
            exponent = 31;
        }
        else if (exponent < ((127 - 15) - 10))
        {//special case, if  32-bit float exponent is out of 16-bit float range, then set 16-bit float to 0
            exponent = 0;
            mantissa = 0;
        }
        else if (exponent >= (127 + (31 - 15)))
        {  // max 15based exponent for s10e5 is 31
           // force s10e5 number to represent infinity by setting mantissa to 0
           //  and exponent to 31
            exponent = 31;
            mantissa = 0;
        }
        else if (exponent <= (127 - 15))
        {  //convert normalized s23e8 float to denormalized s10e5 float

           //add implicit 1.0 to mantissa to convert from 1.f to use as a 0.f mantissa
            mantissa |= (1 << 23);

            //shift over mantissa number of bits equal to exponent underflow
            mantissa = mantissa >> (1 + ((127 - 15) - exponent));

            //zero exponent to treat value as a denormalized number
            exponent = 0;
        }
        else
        {  //change 127base exponent to 15base exponent 
           // no underflow or overflow of exponent 
           //normalized floats mantissa is treated as= 1.f, so 
           // no denormalization or exponent derived shifts to the mantissa         
            exponent -= (127 - 15);
        }

        //convert 23-bit mantissa to 10-bit mantissa
        mantissa >>= (23 - 10);

        //assemble s10e5 number using logical operations
        rawf16Data = static_cast<uint16>((signVal << 15) | (exponent << 10) | mantissa);

        //return re-assembled raw data as a 32 bit float
        return rawf16Data;
    }


    //--------------------------------------------------------------------------------------
    //size of data types in bytes
    //--------------------------------------------------------------------------------------
    int32 CPTypeSizeOf(int32 a_Type)
    {
        switch (a_Type)
        {
        case CP_VAL_UNORM8:
        case CP_VAL_UNORM8_BGRA:
            return 1;
            break;
        case CP_VAL_UNORM16:
            return 2;
            break;
        case CP_VAL_FLOAT16:
            return 2;
            break;
        case CP_VAL_FLOAT32:
            return 4;
            break;
        default:
            return 1;
            break;
        }
    }


    //--------------------------------------------------------------------------------------
    //get value of data pointed to by a_Ptr given type information
    //--------------------------------------------------------------------------------------
    CP_ITYPE CPTypeGetVal(int32 a_Type, void *a_Ptr)
    {
        switch (a_Type)
        {
        case CP_VAL_UNORM8:
        case CP_VAL_UNORM8_BGRA:
            return (1.0f / 255.0f) * *((uint8 *)a_Ptr);
            break;
        case CP_VAL_UNORM16:
            return (1.0f / 65535.0f) * *((uint16 *)a_Ptr);
            break;
        case CP_VAL_FLOAT16:
            return CPf16Tof32(*((uint16 *)a_Ptr));
            break;
        case CP_VAL_FLOAT32:
            return *((float *)a_Ptr);
            break;
        default:
            return 0;
            break;
        }
    }


    //--------------------------------------------------------------------------------------
    //Given a CP_ITYPE value as input, convert it to the given type specified by a_Type
    //  and write the value to a_Ptr 
    //--------------------------------------------------------------------------------------
    void CPTypeSetVal(CP_ITYPE a_Val, int32 a_Type, void *a_Ptr)
    {
        CP_ITYPE clampVal;  //clamp value to 0-1 range to output UNORM types

        switch (a_Type)
        {
        case CP_VAL_UNORM8:
        case CP_VAL_UNORM8_BGRA:
            clampVal = VM_MIN(VM_MAX(a_Val, 0.0f), 1.0f);
            *((uint8 *)a_Ptr) = (uint8)(clampVal * 255.0f);
            break;
        case CP_VAL_UNORM16:
            clampVal = VM_MIN(VM_MAX(a_Val, 0.0f), 1.0f);
            *((uint16 *)a_Ptr) = (uint16)(clampVal * 65535.0f);
            break;
        case CP_VAL_FLOAT16:
            *((uint16 *)a_Ptr) = CPf32Tof16(a_Val);
            break;
        case CP_VAL_FLOAT32:
            *((float *)a_Ptr) = a_Val;
            break;
        default:
            break;
        }
    }


    //--------------------------------------------------------------------------------------
    //Error handling for imagesurface class
    //  Pop up dialog box, and terminate application
    //--------------------------------------------------------------------------------------
    void CImageSurface::FatalError([[maybe_unused]] const WCHAR *a_Msg)
    {
        AZ_Error("Image Processing", false, "CImageSurface Error: %s", a_Msg);
    }


    //--------------------------------------------------------------------------------------
    // Image surface
    //--------------------------------------------------------------------------------------
    CImageSurface::CImageSurface(void)
    {
        m_Width = 0;          //cubemap face width
        m_Height = 0;         //cubemap face height
        m_NumChannels = 0;    //number of channels
        m_ImgData = NULL;

    }


    //--------------------------------------------------------------------------------------
    // Clear
    //--------------------------------------------------------------------------------------
    void CImageSurface::Clear(void)
    {
        m_Width = 0;                        //cubemap face width
        m_Height = 0;                       //cubemap face height
        m_NumChannels = 0;                  //number of channels
        SAFE_DELETE_ARRAY(m_ImgData);       //safe delete old image data
    }


    //--------------------------------------------------------------------------------------
    // Initialize surface and associated memory
    //--------------------------------------------------------------------------------------
    void CImageSurface::Init(int32 a_Width, int32 a_Height, int32 a_NumChannels)
    {
        m_Width = a_Width;                 //cubemap face width
        m_Height = a_Height;               //cubemap face height
        m_NumChannels = a_NumChannels;     //number of channels

        SAFE_DELETE_ARRAY(m_ImgData);   //safe delete old image data

        m_ImgData = new CP_ITYPE[m_Width * m_Height * m_NumChannels];   //assume tight data packing
        if (!m_ImgData)
        {
            FatalError(L"Unable to allocate data for image in CImageSurface::Init.");
        }
    }


    //--------------------------------------------------------------------------------------
    //copy and convert data from external buffer into this surface
    //
    // note that srcPitch == the source pitch in bytes
    //--------------------------------------------------------------------------------------
    void CImageSurface::SetImageData(int32 a_SrcType, int32 a_SrcNumChannels, int32 a_SrcPitch, void *a_SrcDataPtr)
    {
        int32 i, j, k;

        CP_ITYPE *dstDataWalk = m_ImgData;
        uint8 *srcDataWalk = (uint8 *)a_SrcDataPtr;

        int32 srcValueSize = CPTypeSizeOf(a_SrcType);
        int32 srcTexelStep = srcValueSize * a_SrcNumChannels;
        int32 numChannelsSet = VM_MIN(a_SrcNumChannels, m_NumChannels);
        int32 srcChannelSelect;

        //loop over rows
        for (j = 0; j < m_Height; j++)
        {
            //pointer arithmetic to offset pointer by pitch in bytes
            srcDataWalk = ((uint8 *)a_SrcDataPtr + (j * a_SrcPitch));

            //loop over texels within row
            for (i = 0; i < m_Width; i++)
            {
                srcChannelSelect = 0;

                //loop over channels within texel
                for (k = 0; k < numChannelsSet; k++)
                {
                    if (a_SrcType == CP_VAL_UNORM8_BGRA) //swap channels 0, and 2 if in BGRA format
                    {
                        switch (k)
                        {
                        case 0:
                            *(dstDataWalk + 2) = CPTypeGetVal(a_SrcType, srcDataWalk + srcChannelSelect);
                            break;
                        case 2:
                            *(dstDataWalk + 0) = CPTypeGetVal(a_SrcType, srcDataWalk + srcChannelSelect);
                            break;
                        default:
                            *(dstDataWalk + k) = CPTypeGetVal(a_SrcType, srcDataWalk + srcChannelSelect);
                            break;
                        }
                    }
                    else
                    {
                        *(dstDataWalk + k) = CPTypeGetVal(a_SrcType, srcDataWalk + srcChannelSelect);
                    }

                    srcChannelSelect += srcValueSize;
                }

                dstDataWalk += m_NumChannels;
                srcDataWalk += srcTexelStep;
            }
        }
    }


    //--------------------------------------------------------------------------------------
    // Copy and convert data from external buffer into this surface set image data degamma 
    // and scale
    //
    //--------------------------------------------------------------------------------------
    void CImageSurface::SetImageDataClampDegammaScale(int32 a_SrcType, int32 a_SrcNumChannels, int32 a_SrcPitch,
        void *a_SrcDataPtr, float a_MaxClamp, float a_Gamma, float a_Scale)
    {
        int32 i, j, k;

        CP_ITYPE *dstDataWalk = m_ImgData;
        uint8 *srcDataWalk = (uint8 *)a_SrcDataPtr;

        int32 srcValueSize = CPTypeSizeOf(a_SrcType);
        int32 srcTexelStep = srcValueSize * a_SrcNumChannels;
        int32 numChannelsSet = VM_MIN(a_SrcNumChannels, m_NumChannels);
        int32 srcChannelSelect;

        //loop over rows
        for (j = 0; j < m_Height; j++)
        {
            //pointer arithmetic to offset pointer by pitch in bytes
            srcDataWalk = ((uint8 *)a_SrcDataPtr + (j * a_SrcPitch));

            //loop over texels within row
            for (i = 0; i < m_Width; i++)
            {
                srcChannelSelect = 0;

                //loop over channels within texel
                for (k = 0; k < numChannelsSet; k++)
                {
                    CP_ITYPE texelVal;

                    //get texel value from external buffer
                    texelVal = CPTypeGetVal(a_SrcType, srcDataWalk + srcChannelSelect);

                    //clamp texelVal using max value only 
                    // (using texelVal as the min clamping arguement means no minimum clamping)
                    VM_CLAMP(texelVal, texelVal, texelVal, a_MaxClamp);

                    if (k < 3)  //only apply gamma and scale to RGB channels
                    {
                        //degamma texel val, by raising to the power gamma 
                        texelVal = static_cast<CP_ITYPE>(pow(texelVal, a_Gamma));

                        //scale texel val in linear space (after degamma)
                        texelVal *= a_Scale;
                    }

                    //write data
                    if ((a_SrcType == CP_VAL_UNORM8_BGRA) && (k == 0))
                    {
                        *(dstDataWalk + 2) = texelVal;
                    }
                    else if ((a_SrcType == CP_VAL_UNORM8_BGRA) && (k == 2))
                    {
                        *(dstDataWalk + 0) = texelVal;
                    }
                    else
                    {
                        *(dstDataWalk + k) = texelVal;
                    }

                    srcChannelSelect += srcValueSize;
                }

                dstDataWalk += m_NumChannels;
                srcDataWalk += srcTexelStep;
            }
        }
    }


    //--------------------------------------------------------------------------------------
    //copy data from this image surface into an external buffer
    //
    //--------------------------------------------------------------------------------------
    void CImageSurface::GetImageData(int32 a_DstType, int32 a_DstNumChannels, int32 a_DstPitch, void *a_DstDataPtr)
    {
        int32 i, j, k;

        CP_ITYPE *srcDataWalk = m_ImgData;
        uint8 *dstDataWalk = (uint8 *)a_DstDataPtr;

        int32 dstValueSize = CPTypeSizeOf(a_DstType);
        int32 dstTexelStep = dstValueSize * a_DstNumChannels;

        int32 numChannelsSet = VM_MIN(a_DstNumChannels, m_NumChannels);
        int32 dstChannelSelect;

        //loop over rows
        for (j = 0; j < m_Height; j++)
        {
            //pointer arithmetic to offset pointer by pitch in bytes
            dstDataWalk = ((uint8 *)a_DstDataPtr + (j * a_DstPitch));

            //loop over texels within row
            for (i = 0; i < m_Width; i++)
            {
                dstChannelSelect = 0;

                //loop over channels within texel
                for (k = 0; k < numChannelsSet; k++)
                {
                    //write data
                    if ((a_DstType == CP_VAL_UNORM8_BGRA) && (k == 0))
                    {
                        CPTypeSetVal(*(srcDataWalk + 2), a_DstType, dstDataWalk + dstChannelSelect);
                    }
                    else if ((a_DstType == CP_VAL_UNORM8_BGRA) && (k == 2))
                    {
                        CPTypeSetVal(*(srcDataWalk + 0), a_DstType, dstDataWalk + dstChannelSelect);
                    }
                    else
                    {
                        CPTypeSetVal(*(srcDataWalk + k), a_DstType, dstDataWalk + dstChannelSelect);
                    }

                    dstChannelSelect += dstValueSize;
                }

                srcDataWalk += m_NumChannels;
                dstDataWalk += dstTexelStep;
            }
        }
    }


    //--------------------------------------------------------------------------------------
    // Scale and then apply gamma to image data, then copy image data into an external buffer
    //  note: only apply scale and gamma to RGB channels (e.g. first 3 channels)
    // 
    //--------------------------------------------------------------------------------------
    void CImageSurface::GetImageDataScaleGamma(int32 a_DstType, int32 a_DstNumChannels, int32 a_DstPitch,
        void *a_DstDataPtr, float a_Scale, float a_Gamma)
    {
        int32 i, j, k;

        CP_ITYPE *srcDataWalk = m_ImgData;
        uint8 *dstDataWalk = (uint8 *)a_DstDataPtr;

        int32 dstValueSize = CPTypeSizeOf(a_DstType);
        int32 dstTexelStep = dstValueSize * a_DstNumChannels;

        int32 numChannelsSet = VM_MIN(a_DstNumChannels, m_NumChannels);
        int32 dstChannelSelect;

        //loop over rows
        for (j = 0; j < m_Height; j++)
        {
            //pointer arithmetic to offset pointer by pitch in bytes
            dstDataWalk = ((uint8 *)a_DstDataPtr + (j * a_DstPitch));

            //loop over texels within row
            for (i = 0; i < m_Width; i++)
            {
                dstChannelSelect = 0;

                //loop over channels within texel
                for (k = 0; k < numChannelsSet; k++)
                {
                    CP_ITYPE texelVal;

                    texelVal = *(srcDataWalk + k);

                    if (k < 3)  //only apply gamma and scale to RGB channels
                    {
                        //scale texel val
                        texelVal *= a_Scale;

                        //apply gamma to texel val by raising the texelVal to the power of (1/gamma)
                        texelVal = static_cast<CP_ITYPE>(pow(texelVal, 1.0f / a_Gamma));
                    }

                    //write out texture value
                    if ((a_DstType == CP_VAL_UNORM8_BGRA) && (k == 0))
                    {
                        CPTypeSetVal(texelVal, a_DstType, dstDataWalk + (dstValueSize * 2));
                    }
                    else if ((a_DstType == CP_VAL_UNORM8_BGRA) && (k == 2))
                    {
                        CPTypeSetVal(texelVal, a_DstType, dstDataWalk + (dstValueSize * 0));
                    }
                    else
                    {
                        CPTypeSetVal(texelVal, a_DstType, dstDataWalk + dstChannelSelect);
                    }


                    dstChannelSelect += dstValueSize;
                }

                srcDataWalk += m_NumChannels;
                dstDataWalk += dstTexelStep;
            }
        }
    }


    //--------------------------------------------------------------------------------------
    //Set image channel a_ChannelIdx to a_ClearColor for all pixels.
    //
    //--------------------------------------------------------------------------------------
    void CImageSurface::ClearChannelConst(int32 a_ChannelIdx, CP_ITYPE a_ClearColor)
    {
        int32 u, v;
        CP_ITYPE *texelPtr;

        //if channel does not exist, do not attempt to clear the channel
        if (a_ChannelIdx > (m_NumChannels - 1))
        {
            return;
        }

        for (v = 0; v < m_Height; v++)
        {
            for (u = 0; u < m_Width; u++)
            {
                texelPtr = GetSurfaceTexelPtr(u, v);

                *(texelPtr + a_ChannelIdx) = a_ClearColor;
            }
        }
    }


    //--------------------------------------------------------------------------------------
    //Gets texel ptr in a surface given u and v coordinates, 
    //   
    //--------------------------------------------------------------------------------------
    CP_ITYPE *CImageSurface::GetSurfaceTexelPtr(int32 u, int32 v)
    {
        return(m_ImgData + (((m_Width * v) + u) * m_NumChannels));
    }


    //--------------------------------------------------------------------------------------
    //flips surface image in place horizontally
    //
    //--------------------------------------------------------------------------------------
    void CImageSurface::InPlaceHorizonalFlip(void)
    {
        int32 u, v, k;
        CP_ITYPE *texelPtrTop, *texelPtrBottom;

        //iterate over V
        for (v = 0; v < (m_Height / 2); v++)
        {
            for (u = 0; u < m_Height; u++)
            {
                texelPtrTop = GetSurfaceTexelPtr(u, v);
                texelPtrBottom = GetSurfaceTexelPtr(u, (m_Height - 1) - v);

                //iterate over channels
                for (k = 0; k < m_NumChannels; k++)
                {
                    CP_ITYPE tmpTexelVal;

                    tmpTexelVal = *(texelPtrTop + k);
                    *(texelPtrTop + k) = *(texelPtrBottom + k);
                    *(texelPtrBottom + k) = tmpTexelVal;

                }
            }
        }
    }


    //--------------------------------------------------------------------------------------
    //flips surface image in place vertically
    //
    //--------------------------------------------------------------------------------------
    void CImageSurface::InPlaceVerticalFlip(void)
    {
        int32 u, v, k;
        CP_ITYPE *texelPtrLeft, *texelPtrRight;

        for (u = 0; u < (m_Width / 2); u++)
        {
            for (v = 0; v < m_Height; v++)
            {
                texelPtrLeft = GetSurfaceTexelPtr(u, v);
                texelPtrRight = GetSurfaceTexelPtr((m_Width - 1) - u, v);

                //iterate over channels
                for (k = 0; k < m_NumChannels; k++)
                {
                    CP_ITYPE tmpTexelVal;

                    tmpTexelVal = *(texelPtrLeft + k);
                    *(texelPtrLeft + k) = *(texelPtrRight + k);
                    *(texelPtrRight + k) = tmpTexelVal;
                }
            }
        }
    }


    //--------------------------------------------------------------------------------------
    //flip image around line defined by u = v  (effectively swaps the u and v axises)
    //--------------------------------------------------------------------------------------
    void CImageSurface::InPlaceDiagonalUVFlip(void)
    {
        int32 u, v, k;
        CP_ITYPE *texelPtrLeft, *texelPtrRight;

        if (m_Width != m_Height)
        { //only flip image if square
            return;
        }

        for (v = 0; v < m_Height; v++)
        {
            for (u = 0; u < v; u++) //only iterate over lower left triangle
            {
                texelPtrLeft = GetSurfaceTexelPtr(u, v);
                texelPtrRight = GetSurfaceTexelPtr(v, u);

                //iterate over channels
                for (k = 0; k < m_NumChannels; k++)
                {
                    CP_ITYPE tmpTexelVal;

                    tmpTexelVal = *(texelPtrLeft + k);
                    *(texelPtrLeft + k) = *(texelPtrRight + k);
                    *(texelPtrRight + k) = tmpTexelVal;
                }
            }
        }
    }

    //--------------------------------------------------------------------------------------
    // destructor, free all memory used
    //--------------------------------------------------------------------------------------
    CImageSurface::~CImageSurface()
    {
        SAFE_DELETE_ARRAY(m_ImgData);
    }
} // namespace ImageProcessingAtom