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scaler.cpp

/* ScummVM - Scumm Interpreter
 * Copyright (C) 2001  Ludvig Strigeus
 * Copyright (C) 2001-2005 The ScummVM project
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.

 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.

 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 *
 * $Header: /cvsroot/scummvm/scummvm/common/scaler.cpp,v 1.72.2.1 2005/10/18 02:11:18 sev Exp $
 *
 */

#include "common/scaler/intern.h"
#include "common/scaler/scalebit.h"
#include "common/util.h"


int gBitFormat = 565;

#ifndef DISABLE_HQ_SCALERS
// RGB-to-YUV lookup table
extern "C" {

#ifdef USE_NASM
// NOTE: if your compiler uses different mangled names, add another
//       condition here

#ifndef _WIN32
#define RGBtoYUV _RGBtoYUV
#define LUT16to32 _LUT16to32
#endif

#endif

// FIXME/TODO: The following two tables suck up 512 KB.
// They should at least be allocated on the heap, to reduce the size of the
// binary.
//
// Note: a memory lookup table is *not* necessarily faster than computing
// these things on the fly, because of its size. Both tables together, plus
// the code, plus the input/output GFX data, won't fit in the cache on many
// systems, so main memory has to be accessed, which is about the worst thing
// that can happen to code which tries to be fast...
//
// So we should think about ways to get these smaller / removed. The LUT16to32
// is only used by the HQX asm right now; maybe somebody can modify the code
// there to work w/o it (and do some benchmarking, too?). To do that, just
// do the conversion on the fly, or even do w/o it (as the C++ code manages to),
// by making different versions of the code based on gBitFormat (or by writing
// bit masks into registers which are computed based on gBitFormat).
//
// RGBtoYUV is also used by the C(++) version of the HQX code. Maybe we can
// use the same technique which is employed by our MPEG code to reduce the
// size of the lookup tables at the cost of some additional computations? That
// might actually result in a speedup, too, if done right (and the code code
// might actually be suitable for AltiVec/MMX/SSE speedup).
//
// Of course, the above is largely a conjecture, and the actual speed
// differences are likely to vary a lot between different architectures and
// CPUs.
uint RGBtoYUVstorage[65536];
uint *RGBtoYUV = RGBtoYUVstorage;
uint LUT16to32[65536];
}
#endif

static const uint16 dotmatrix_565[16] = {
      0x01E0, 0x0007, 0x3800, 0x0000,
      0x39E7, 0x0000, 0x39E7, 0x0000,
      0x3800, 0x0000, 0x01E0, 0x0007,
      0x39E7, 0x0000, 0x39E7, 0x0000
};
static const uint16 dotmatrix_555[16] = {
      0x00E0, 0x0007, 0x1C00, 0x0000,
      0x1CE7, 0x0000, 0x1CE7, 0x0000,
      0x1C00, 0x0000, 0x00E0, 0x0007,
      0x1CE7, 0x0000, 0x1CE7, 0x0000
};
static const uint16 *dotmatrix;

static void InitLUT(uint32 BitFormat);

void InitScalers(uint32 BitFormat) {
      if (BitFormat == 565) {
            dotmatrix = dotmatrix_565;
      } else if (BitFormat == 555) {
            dotmatrix = dotmatrix_555;
      } else {
            error("Unknown bit format %d", BitFormat);
      }

      gBitFormat = BitFormat;
      InitLUT(BitFormat);
}

void InitLUT(uint32 BitFormat) {
#ifndef DISABLE_HQ_SCALERS
      int r, g, b;
      int Y, u, v;
      int gInc, gShift;

      for (int i = 0; i < 65536; i++) {
            LUT16to32[i] = ((i & 0xF800) << 8) + ((i & 0x07E0) << 5) + ((i & 0x001F) << 3);
      }

      if (BitFormat == 565) {
            gInc = 256 >> 6;
            gShift = 6 - 3;
      } else {
            gInc = 256 >> 5;
            gShift = 5 - 3;
      }

      for (r = 0; r < 256; r += 8) {
            for (g = 0; g < 256; g += gInc) {
                  for (b = 0; b < 256; b += 8) {
                        Y = (r + g + b) >> 2;
                        u = 128 + ((r - b) >> 2);
                        v = 128 + ((-r + 2 * g - b) >> 3);
                        RGBtoYUV[ (r << (5 + gShift)) + (g << gShift) + (b >> 3) ] = (Y << 16) + (u << 8) + v;
                  }
            }
      }
#endif
}

/**
 * Trivial 'scaler' - in fact it doesn't do any scaling but just copies the
 * source to the destionation.
 */
void Normal1x(const uint8 *srcPtr, uint32 srcPitch, uint8 *dstPtr, uint32 dstPitch,
                                          int width, int height) {
      while (height--) {
            memcpy(dstPtr, srcPtr, 2 * width);
            srcPtr += srcPitch;
            dstPtr += dstPitch;
      }
}

#ifndef DISABLE_SCALERS
/**
 * Trivial nearest-neighbour 2x scaler.
 */
void Normal2x(const uint8 *srcPtr, uint32 srcPitch, uint8 *dstPtr, uint32 dstPitch,
                                          int width, int height) {
      uint8 *r;

      assert(((long)dstPtr & 3) == 0);
      while (height--) {
            r = dstPtr;
            for (int i = 0; i < width; ++i, r += 4) {
                  uint32 color = *(((const uint16 *)srcPtr) + i);

                  color |= color << 16;

                  *(uint32 *)(r) = color;
                  *(uint32 *)(r + dstPitch) = color;
            }
            srcPtr += srcPitch;
            dstPtr += dstPitch << 1;
      }
}

/**
 * Trivial nearest-neighbour 3x scaler.
 */
void Normal3x(const uint8 *srcPtr, uint32 srcPitch, uint8 *dstPtr, uint32 dstPitch,
                                          int width, int height) {
      uint8 *r;
      const uint32 dstPitch2 = dstPitch * 2;
      const uint32 dstPitch3 = dstPitch * 3;

      assert(((long)dstPtr & 1) == 0);
      while (height--) {
            r = dstPtr;
            for (int i = 0; i < width; ++i, r += 6) {
                  uint16 color = *(((const uint16 *)srcPtr) + i);

                  *(uint16 *)(r + 0) = color;
                  *(uint16 *)(r + 2) = color;
                  *(uint16 *)(r + 4) = color;
                  *(uint16 *)(r + 0 + dstPitch) = color;
                  *(uint16 *)(r + 2 + dstPitch) = color;
                  *(uint16 *)(r + 4 + dstPitch) = color;
                  *(uint16 *)(r + 0 + dstPitch2) = color;
                  *(uint16 *)(r + 2 + dstPitch2) = color;
                  *(uint16 *)(r + 4 + dstPitch2) = color;
            }
            srcPtr += srcPitch;
            dstPtr += dstPitch3;
      }
}

#define INTERPOLATE           INTERPOLATE<bitFormat>
#define Q_INTERPOLATE   Q_INTERPOLATE<bitFormat>

/**
 * Trivial nearest-neighbour 1.5x scaler.
 */
template<int bitFormat>
void Normal1o5xTemplate(const uint8 *srcPtr, uint32 srcPitch, uint8 *dstPtr, uint32 dstPitch,
                                          int width, int height) {
      uint8 *r;
      const uint32 dstPitch2 = dstPitch * 2;
      const uint32 dstPitch3 = dstPitch * 3;
      const uint32 srcPitch2 = srcPitch * 2;

      assert(((long)dstPtr & 1) == 0);
      while (height > 0) {
            r = dstPtr;
            for (int i = 0; i < width; i += 2, r += 6) {
                  uint16 color0 = *(((const uint16 *)srcPtr) + i);
                  uint16 color1 = *(((const uint16 *)srcPtr) + i + 1);
                  uint16 color2 = *(((const uint16 *)(srcPtr + srcPitch)) + i);
                  uint16 color3 = *(((const uint16 *)(srcPtr + srcPitch)) + i + 1);

                  *(uint16 *)(r + 0) = color0;
                  *(uint16 *)(r + 2) = INTERPOLATE(color0, color1);
                  *(uint16 *)(r + 4) = color1;
                  *(uint16 *)(r + 0 + dstPitch) = INTERPOLATE(color0, color2);
                  *(uint16 *)(r + 2 + dstPitch) = Q_INTERPOLATE(color0, color1, color2, color3);
                  *(uint16 *)(r + 4 + dstPitch) = INTERPOLATE(color1, color3);
                  *(uint16 *)(r + 0 + dstPitch2) = color2;
                  *(uint16 *)(r + 2 + dstPitch2) = INTERPOLATE(color2, color3);
                  *(uint16 *)(r + 4 + dstPitch2) = color3;
            }
            srcPtr += srcPitch2;
            dstPtr += dstPitch3;
            height -= 2;
      }
}
MAKE_WRAPPER(Normal1o5x)

/**
 * The Scale2x filter, also known as AdvMame2x.
 * See also http://scale2x.sourceforge.net
 */
void AdvMame2x(const uint8 *srcPtr, uint32 srcPitch, uint8 *dstPtr, uint32 dstPitch,
                                           int width, int height) {
      scale(2, dstPtr, dstPitch, srcPtr - srcPitch, srcPitch, 2, width, height);
}

/**
 * The Scale3x filter, also known as AdvMame3x.
 * See also http://scale2x.sourceforge.net
 */
void AdvMame3x(const uint8 *srcPtr, uint32 srcPitch, uint8 *dstPtr, uint32 dstPitch,
                                           int width, int height) {
      scale(3, dstPtr, dstPitch, srcPtr - srcPitch, srcPitch, 2, width, height);
}

template<int bitFormat>
void TV2xTemplate(const uint8 *srcPtr, uint32 srcPitch, uint8 *dstPtr, uint32 dstPitch,
                              int width, int height) {
      const uint32 nextlineSrc = srcPitch / sizeof(uint16);
      const uint16 *p = (const uint16 *)srcPtr;

      const uint32 nextlineDst = dstPitch / sizeof(uint16);
      uint16 *q = (uint16 *)dstPtr;

      while (height--) {
            for (int i = 0, j = 0; i < width; ++i, j += 2) {
                  uint16 p1 = *(p + i);
                  uint32 pi;

                  pi = (((p1 & redblueMask) * 7) >> 3) & redblueMask;
                  pi |= (((p1 & greenMask) * 7) >> 3) & greenMask;

                  *(q + j) = p1;
                  *(q + j + 1) = p1;
                  *(q + j + nextlineDst) = (uint16)pi;
                  *(q + j + nextlineDst + 1) = (uint16)pi;
            }
            p += nextlineSrc;
            q += nextlineDst << 1;
      }
}
MAKE_WRAPPER(TV2x)

static inline uint16 DOT_16(uint16 c, int j, int i) {
      return c - ((c >> 2) & *(dotmatrix + ((j & 3) << 2) + (i & 3)));
}

// FIXME: This scaler doesn't quite work. Either it needs to know where on the
// screen it's drawing, or the dirty rects will have to be adjusted so that
// access to the dotmatrix array are made in a consistent way. (Doing that in
// a way that also works together with aspect-ratio correction is left as an
// exercise for the reader.)

void DotMatrix(const uint8 *srcPtr, uint32 srcPitch, uint8 *dstPtr, uint32 dstPitch,
                              int width, int height) {
      const uint32 nextlineSrc = srcPitch / sizeof(uint16);
      const uint16 *p = (const uint16 *)srcPtr;

      const uint32 nextlineDst = dstPitch / sizeof(uint16);
      uint16 *q = (uint16 *)dstPtr;

      for (int j = 0, jj = 0; j < height; ++j, jj += 2) {
            for (int i = 0, ii = 0; i < width; ++i, ii += 2) {
                  uint16 c = *(p + i);
                  *(q + ii) = DOT_16(c, jj, ii);
                  *(q + ii + 1) = DOT_16(c, jj, ii + 1);
                  *(q + ii + nextlineDst) = DOT_16(c, jj + 1, ii);
                  *(q + ii + nextlineDst + 1) = DOT_16(c, jj + 1, ii + 1);
            }
            p += nextlineSrc;
            q += nextlineDst << 1;
      }
}

#endif

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