godot/thirdparty/libwebp/src/dsp/ssim.c

// Copyright 2017 Google Inc. All Rights Reserved.
//
// Use of this source code is governed by a BSD-style license
// that can be found in the COPYING file in the root of the source
// tree. An additional intellectual property rights grant can be found
// in the file PATENTS. All contributing project authors may
// be found in the AUTHORS file in the root of the source tree.
// -----------------------------------------------------------------------------
//
// distortion calculation
//
// Author: Skal ([email protected])

#include <assert.h>
#include <stdlib.h>  // for abs()

#include "src/dsp/dsp.h"

#if !defined(WEBP_REDUCE_SIZE)

//------------------------------------------------------------------------------
// SSIM / PSNR

// hat-shaped filter. Sum of coefficients is equal to 16.
static const uint32_t kWeight[2 * VP8_SSIM_KERNEL + 1] = …;
static const uint32_t kWeightSum = …;   // sum{kWeight}^2

static WEBP_INLINE double SSIMCalculation(
    const VP8DistoStats* const stats, uint32_t N  /*num samples*/) { … }

double VP8SSIMFromStats(const VP8DistoStats* const stats) { … }

double VP8SSIMFromStatsClipped(const VP8DistoStats* const stats) { … }

static double SSIMGetClipped_C(const uint8_t* src1, int stride1,
                               const uint8_t* src2, int stride2,
                               int xo, int yo, int W, int H) { … }

static double SSIMGet_C(const uint8_t* src1, int stride1,
                        const uint8_t* src2, int stride2) { … }

#endif  // !defined(WEBP_REDUCE_SIZE)

//------------------------------------------------------------------------------

#if !defined(WEBP_DISABLE_STATS)
static uint32_t AccumulateSSE_C(const uint8_t* src1,
                                const uint8_t* src2, int len) { … }
#endif

//------------------------------------------------------------------------------

#if !defined(WEBP_REDUCE_SIZE)
VP8SSIMGetFunc VP8SSIMGet;
VP8SSIMGetClippedFunc VP8SSIMGetClipped;
#endif
#if !defined(WEBP_DISABLE_STATS)
VP8AccumulateSSEFunc VP8AccumulateSSE;
#endif

extern VP8CPUInfo VP8GetCPUInfo;
extern void VP8SSIMDspInitSSE2(void);

WEBP_DSP_INIT_FUNC(VP8SSIMDspInit) { … }