image: port some error diffusion dithering algorithms.

TODO

@@ -2,12 +2,16 @@
  Large projects
 ----------------
 
- - Add scripting support (lua?).
- - Tiler and Forge are almost the same, try to refactor them.
+  - Add scripting support (lua?).
+  - Tiler and Forge are almost the same, try to refactor them.
 
  Engine classes
 ----------------
 
+Scene:
+  - Remove uses of g_scene
+  - Maybe make Camera a world object instead?
+
 Image:
   - Handle pitch in SDL codec (and all others, actually)
   - Fix the Floyd-Steinberg ode in pixels.cpp
@@ -31,10 +35,7 @@ Image:
      · crop.cpp
      · dither.cpp
      · dither/dbs.cpp
-     · dither/ediff.cpp
      · dither/ordered.cpp
-     · dither/ostromoukhov.cpp
-     · dither/random.cpp
      · filter/blur.cpp
      · filter/color.cpp
      · filter/convolution.cpp

src/Makefile.am

@@ -116,6 +116,8 @@ liblolcore_sources = \
     image/codec/zed-image.cpp image/codec/zed-palette-image.cpp \
     image/codec/dummy-image.cpp \
     image/color/cie1931.cpp image/color/color.cpp \
+    image/dither/random.cpp image/dither/ediff.cpp \
+    image/dither/ostromoukhov.cpp \
     image/filter/autocontrast.cpp \
     image/render/noise.cpp image/render/screen.cpp \
     \

src/image/dither/ediff.cpp

@@ -1,25 +1,25 @@
-/*
- *  libpipi       Pathetic image processing interface library
- *  Copyright (c) 2004-2008 Sam Hocevar <sam@zoy.org>
- *                All Rights Reserved
- *
- *  $Id$
- *
- *  This library is free software. It comes without any warranty, to
- *  the extent permitted by applicable law. You can redistribute it
- *  and/or modify it under the terms of the Do What The Fuck You Want
- *  To Public License, Version 2, as published by Sam Hocevar. See
- *  http://sam.zoy.org/wtfpl/COPYING for more details.
- */
+//
+// Lol Engine
+//
+// Copyright: (c) 2004-2014 Sam Hocevar <sam@hocevar.net>
+//   This program is free software; you can redistribute it and/or
+//   modify it under the terms of the Do What The Fuck You Want To
+//   Public License, Version 2, as published by Sam Hocevar. See
+//   http://www.wtfpl.net/ for more details.
+//
+
+#if defined HAVE_CONFIG_H
+#   include "config.h"
+#endif
+
+#include "core.h"
 
 /*
- * ed.c: generic error diffusion functions
+ * Generic error diffusion functions
  */
 
-#include "config.h"
-
-#include "pipi.h"
-#include "pipi-internals.h"
+namespace lol
+{
 
 /* Perform a generic error diffusion dithering. The first non-zero
  * element in ker is treated as the current pixel. All other non-zero
@@ -27,60 +27,58 @@
  * Making the matrix generic is not terribly slower: the performance
  * hit is around 4% for Floyd-Steinberg and 13% for JaJuNi, with the
  * benefit of a lot less code. */
-pipi_image_t *pipi_dither_ediff(pipi_image_t *img, pipi_image_t *ker,
-                                pipi_scan_t scan)
+Image Image::DitherEdiff(Image &kernel, ScanMode scan) const
 {
-    pipi_image_t *dst;
-    pipi_pixels_t *dstp, *kerp;
-    float *dstdata, *kerdata;
-    int x, y, w, h, i, j, kx, kw, kh;
-
-    w = img->w;
-    h = img->h;
-    kw = ker->w;
-    kh = ker->h;
-
-    dst = pipi_copy(img);
-    dstp = pipi_get_pixels(dst, PIPI_PIXELS_Y_F32);
-    dstdata = (float *)dstp->pixels;
-
-    kerp = pipi_get_pixels(ker, PIPI_PIXELS_Y_F32);
-    kerdata = (float *)kerp->pixels;
-    for(kx = 0; kx < kw; kx++)
-        if(kerdata[kx] > 0)
+    Image dst = *this;
+
+    float *pixels = dst.Lock<PixelFormat::Y_F32>();
+    int w = dst.GetSize().x;
+    int h = dst.GetSize().y;
+
+    float *kerdata = kernel.Lock<PixelFormat::Y_F32>();
+    int kw = kernel.GetSize().x;
+    int kh = kernel.GetSize().y;
+
+    int kx;
+    for (kx = 0; kx < kw; kx++)
+        if (kerdata[kx] > 0.f)
             break;
 
-    for(y = 0; y < h; y++)
+    for (int y = 0; y < h; y++)
     {
-        int reverse = (y & 1) && (scan == PIPI_SCAN_SERPENTINE);
+        bool reverse = (y & 1) && (scan == ScanMode::Serpentine);
 
-        for(x = 0; x < w; x++)
+        for (int x = 0; x < w; x++)
         {
-            float p, q, e;
             int x2 = reverse ? w - 1 - x : x;
             int s = reverse ? -1 : 1;
 
-            p = dstdata[y * w + x2];
-            q = p < 0.5 ? 0. : 1.;
-            dstdata[y * w + x2] = q;
+            float p = pixels[y * w + x2];
+            float q = p < 0.5f ? 0.f : 1.f;
+            pixels[y * w + x2] = q;
 
-            e = (p - q);
+            float e = (p - q);
 
-            for(j = 0; j < kh && y < h - j; j++)
-                for(i = 0; i < kw; i++)
+            for (int j = 0; j < kh && y < h - j; j++)
+                for (int i = 0; i < kw; i++)
                 {
-                    if(j == 0 && i <= kx)
+                    if (j == 0 && i <= kx)
                         continue;
 
-                    if(x + i - kx < 0 || x + i - kx >= w)
+                    if (x + i - kx < 0 || x + i - kx >= w)
                         continue;
 
-                    dstdata[(y + j) * w + x2 + (i - kx) * s]
+                    pixels[(y + j) * w + x2 + (i - kx) * s]
                        += e * kerdata[j * kw + i];
                 }
         }
     }
 
+    kernel.Unlock(kerdata);
+    dst.Unlock(pixels);
+
     return dst;
 }
 
+} /* namespace lol */
+

src/image/dither/ostromoukhov.cpp

@@ -1,117 +1,116 @@
-/*
- *  libpipi       Pathetic image processing interface library
- *  Copyright (c) 2004-2008 Sam Hocevar <sam@zoy.org>
- *                All Rights Reserved
- *
- *  $Id$
- *
- *  This library is free software. It comes without any warranty, to
- *  the extent permitted by applicable law. You can redistribute it
- *  and/or modify it under the terms of the Do What The Fuck You Want
- *  To Public License, Version 2, as published by Sam Hocevar. See
- *  http://sam.zoy.org/wtfpl/COPYING for more details.
- */
+//
+// Lol Engine
+//
+// Copyright: (c) 2004-2014 Sam Hocevar <sam@hocevar.net>
+//   This program is free software; you can redistribute it and/or
+//   modify it under the terms of the Do What The Fuck You Want To
+//   Public License, Version 2, as published by Sam Hocevar. See
+//   http://www.wtfpl.net/ for more details.
+//
+
+#if defined HAVE_CONFIG_H
+#   include "config.h"
+#endif
+
+#include "core.h"
 
 /*
- * ostromoukhov.c: Ostromoukhov dithering functions
+ * Ostromoukhov dithering functions
  *
  * This module implements Ostromoukhov's simple error diffusion algorithm,
  * as introduced in the paper "A Simple and Efficient Error-Diffusion
  * Algorithm", Proceedings of SIGGRAPH 2001, in ACM Computer Graphics,
  * Annual Conference Series, pp. 567--572, 2001.
  *
- * TODO: the table is actually a piecewise linear function, so it should
- * be easy to change it into something that works perfectly with floats.
+ * Note: the authors initially provided a large data table, but we
+ * manually converted it to a piecewise linear function.
  */
 
-#include "config.h"
-
-#include "pipi.h"
-#include "pipi-internals.h"
-
-static int const table[][3] =
+namespace lol
 {
-     {13, 0, 5}, {13, 0, 5}, {21, 0, 10}, {7, 0, 4},
-     {8, 0, 5}, {47, 3, 28}, {23, 3, 13}, {15, 3, 8},
-     {22, 6, 11}, {43, 15, 20}, {7, 3, 3}, {501, 224, 211},
-     {249, 116, 103}, {165, 80, 67}, {123, 62, 49}, {489, 256, 191},
-     {81, 44, 31}, {483, 272, 181}, {60, 35, 22}, {53, 32, 19},
-     {237, 148, 83}, {471, 304, 161}, {3, 2, 1}, {481, 314, 185},
-     {354, 226, 155}, {1389, 866, 685}, {227, 138, 125}, {267, 158, 163},
-     {327, 188, 220}, {61, 34, 45}, {627, 338, 505}, {1227, 638, 1075},
-     {20, 10, 19}, {1937, 1000, 1767}, {977, 520, 855}, {657, 360, 551},
-     {71, 40, 57}, {2005, 1160, 1539}, {337, 200, 247}, {2039, 1240, 1425},
-     {257, 160, 171}, {691, 440, 437}, {1045, 680, 627}, {301, 200, 171},
-     {177, 120, 95}, {2141, 1480, 1083}, {1079, 760, 513}, {725, 520, 323},
-     {137, 100, 57}, {2209, 1640, 855}, {53, 40, 19}, {2243, 1720, 741},
-     {565, 440, 171}, {759, 600, 209}, {1147, 920, 285}, {2311, 1880, 513},
-     {97, 80, 19}, {335, 280, 57}, {1181, 1000, 171}, {793, 680, 95},
-     {599, 520, 57}, {2413, 2120, 171}, {405, 360, 19}, {2447, 2200, 57},
-     {11, 10, 0}, {158, 151, 3}, {178, 179, 7}, {1030, 1091, 63},
-     {248, 277, 21}, {318, 375, 35}, {458, 571, 63}, {878, 1159, 147},
-     {5, 7, 1}, {172, 181, 37}, {97, 76, 22}, {72, 41, 17},
-     {119, 47, 29}, {4, 1, 1}, {4, 1, 1}, {4, 1, 1},
-     {4, 1, 1}, {4, 1, 1}, {4, 1, 1}, {4, 1, 1},
-     {4, 1, 1}, {4, 1, 1}, {65, 18, 17}, {95, 29, 26},
-     {185, 62, 53}, {30, 11, 9}, {35, 14, 11}, {85, 37, 28},
-     {55, 26, 19}, {80, 41, 29}, {155, 86, 59}, {5, 3, 2},
-     {5, 3, 2}, {5, 3, 2}, {5, 3, 2}, {5, 3, 2},
-     {5, 3, 2}, {5, 3, 2}, {5, 3, 2}, {5, 3, 2},
-     {5, 3, 2}, {5, 3, 2}, {5, 3, 2}, {5, 3, 2},
-     {305, 176, 119}, {155, 86, 59}, {105, 56, 39}, {80, 41, 29},
-     {65, 32, 23}, {55, 26, 19}, {335, 152, 113}, {85, 37, 28},
-     {115, 48, 37}, {35, 14, 11}, {355, 136, 109}, {30, 11, 9},
-     {365, 128, 107}, {185, 62, 53}, {25, 8, 7}, {95, 29, 26},
-     {385, 112, 103}, {65, 18, 17}, {395, 104, 101}, {4, 1, 1}
-};
-
-pipi_image_t *pipi_dither_ostromoukhov(pipi_image_t *img, pipi_scan_t scan)
+
+static inline vec3 GetDiffusion(float v)
 {
-    pipi_image_t *dst;
-    pipi_pixels_t *dstp;
-    float *dstdata;
-    int x, y, w, h;
+    static vec3 const table[] =
+    {
+        vec3(0.0000f, 0.2777f, 0.0000f),
+        vec3(0.0039f, 0.2777f, 0.0000f),
+        vec3(0.0117f, 0.3636f, 0.0000f),
+        vec3(0.0157f, 0.3846f, 0.0000f),
+        vec3(0.0392f, 0.2308f, 0.2308f),
+        vec3(0.0863f, 0.1667f, 0.3333f),
+        vec3(0.1255f, 0.3878f, 0.2041f),
+        vec3(0.2510f, 0.0000f, 0.4762f),
+        vec3(0.2824f, 0.0769f, 0.5385f),
+        vec3(0.3020f, 0.1667f, 0.1667f),
+        vec3(0.3333f, 0.1667f, 0.1667f),
+        vec3(0.3725f, 0.2000f, 0.3000f),
+        vec3(0.4196f, 0.2000f, 0.3000f),
+        vec3(0.4980f, 0.1667f, 0.1667f),
+        vec3(1.0000f, 0.1667f, 0.1667f), /* Safe value */
+    };
 
-    w = img->w;
-    h = img->h;
+    vec3 ret(0.1667f);
 
-    dst = pipi_copy(img);
-    dstp = pipi_get_pixels(dst, PIPI_PIXELS_Y_F32);
-    dstdata = (float *)dstp->pixels;
+    if (v > 0.5f)
+       v = 1.f - v;
+    if (v < 0.f)
+       v = 0.f;
 
-    for(y = 0; y < h; y++)
+    for (int i = 1; i < sizeof(table) / sizeof(table[0]); ++i)
     {
-        int reverse = (y & 1) && (scan == PIPI_SCAN_SERPENTINE);
-
-        for(x = 0; x < w; x++)
+        if (v <= table[i][0])
         {
-            float p, q, e;
-            int x2, s, i;
+            ret[1] = lol::mix(table[i - 1][1], table[i][1],
+                         (table[i][0] - v) / (table[i][0] - table[i - 1][0]));
+            ret[2] = lol::mix(table[i - 1][2], table[i][2],
+                         (table[i][0] - v) / (table[i][0] - table[i - 1][0]));
+            break;
+        }
+    }
+
+    ret[0] = 1.f - ret[1] - ret[2];
+    return ret;
+}
 
-            x2 = reverse ? w - 1 - x : x;
-            s = reverse ? -1 : 1;
+Image Image::DitherOstromoukhov(ScanMode scan) const
+{
+    Image dst = *this;
 
-            p = dstdata[y * w + x2];
-            q = p < 0.5 ? 0. : 1.;
-            dstdata[y * w + x2] = q;
+    float *pixels = dst.Lock<PixelFormat::Y_F32>();
+    int w = dst.GetSize().x;
+    int h = dst.GetSize().y;
 
-            e = p - q;
-            i = p * 255.9999;
-            if(i > 127) i = 255 - i;
-            if(i < 0) i = 0; /* XXX: no "else" here */
-            e /= table[i][0] + table[i][1] + table[i][2];
+    for (int y = 0; y < h; y++)
+    {
+        bool reverse = (y & 1) && (scan == ScanMode::Serpentine);
+
+        for (int x = 0; x < w; x++)
+        {
+            int x2 = reverse ? w - 1 - x : x;
+            int s = reverse ? -1 : 1;
+
+            float p = pixels[y * w + x2];
+            float q = p < 0.5f ? 0.f : 1.f;
+            pixels[y * w + x2] = q;
+
+            vec3 e = (p - q) * GetDiffusion(p);
 
             if(x < w - 1)
-                dstdata[y * w + x2 + s] += e * table[i][0];
+                pixels[y * w + x2 + s] += e[0];
             if(y < h - 1)
             {
                 if(x > 0)
-                    dstdata[(y + 1) * w + x2 - s] += e * table[i][1];
-                dstdata[(y + 1) * w + x2] += e * table[i][2];
+                    pixels[(y + 1) * w + x2 - s] += e[1];
+                pixels[(y + 1) * w + x2] += e[2];
             }
         }
     }
 
+    dst.Unlock(pixels);
+
     return dst;
 }
 
+} /* namespace lol */
+

src/image/dither/random.cpp

@@ -1,60 +1,42 @@
-/*
- *  libpipi       Pathetic image processing interface library
- *  Copyright (c) 2004-2008 Sam Hocevar <sam@zoy.org>
- *                All Rights Reserved
- *
- *  $Id$
- *
- *  This library is free software. It comes without any warranty, to
- *  the extent permitted by applicable law. You can redistribute it
- *  and/or modify it under the terms of the Do What The Fuck You Want
- *  To Public License, Version 2, as published by Sam Hocevar. See
- *  http://sam.zoy.org/wtfpl/COPYING for more details.
- */
+//
+// Lol Engine
+//
+// Copyright: (c) 2004-2014 Sam Hocevar <sam@hocevar.net>
+//   This program is free software; you can redistribute it and/or
+//   modify it under the terms of the Do What The Fuck You Want To
+//   Public License, Version 2, as published by Sam Hocevar. See
+//   http://www.wtfpl.net/ for more details.
+//
+
+#if defined HAVE_CONFIG_H
+#   include "config.h"
+#endif
+
+#include "core.h"
 
 /*
- * random.c: random dithering functions
+ * Random dithering
  */
 
-#include "config.h"
-
-#include "pipi.h"
-#include "pipi-internals.h"
-
-pipi_image_t *pipi_dither_random(pipi_image_t *img)
+namespace lol
 {
-    pipi_image_t *dst;
-    pipi_pixels_t *dstp;
-    float *dstdata;
-    unsigned int ctx = 1;
-    int x, y, w, h;
 
-    w = img->w;
-    h = img->h;
+Image Image::DitherRandom() const
+{
+    Image dst = *this;
 
-    dst = pipi_copy(img);
-    dstp = pipi_get_pixels(dst, PIPI_PIXELS_Y_F32);
-    dstdata = (float *)dstp->pixels;
+    float *pixels = dst.Lock<PixelFormat::Y_F32>();
+    int count = GetSize().x * GetSize().y;
 
-    for(y = 0; y < h; y++)
+    for (int n = 0; n < count; ++n)
     {
-        for(x = 0; x < w; x++)
-        {
-            long hi, lo;
-            float p, q;
-
-            hi = ctx / 12773L;
-            lo = ctx % 12773L;
-            ctx = 16807L * lo - 2836L * hi;
-            if(ctx <= 0)
-                ctx += 0x7fffffffL;
-
-            p = dstdata[y * w + x];
-            q = p > (double)((ctx % 65536) / 65535.) ? 1. : 0.;
-            dstdata[y * w + x] = q;
-        }
+        pixels[n] = (pixels[n] > lol::rand(0.5f)) ? 1.f : 0.f;
     }
 
+    dst.Unlock(pixels);
+
     return dst;
 }
 
+} /* namespace lol */
+

src/image/image-private.h

@@ -1,7 +1,7 @@
 //
 // Lol Engine
 //
-// Copyright: (c) 2010-2011 Sam Hocevar <sam@hocevar.net>
+// Copyright: (c) 2010-2014 Sam Hocevar <sam@hocevar.net>
 //   This program is free software; you can redistribute it and/or
 //   modify it under the terms of the Do What The Fuck You Want To
 //   Public License, Version 2, as published by Sam Hocevar. See
@@ -26,11 +26,16 @@ class ImageData
 public:
     ImageData()
       : m_size(0, 0),
+        m_wrap_x(WrapMode::Clamp),
+        m_wrap_y(WrapMode::Clamp),
         m_format(PixelFormat::Unknown)
     {}
 
     ivec2 m_size;
 
+    /* The wrap modes for pixel access */
+    WrapMode m_wrap_x, m_wrap_y;
+
     /* A map of the various available bitplanes */
     Map<int, void *> m_pixels;
     /* The last bitplane being accessed for writing */

src/image/image.cpp

@@ -124,7 +124,7 @@ Image::~Image()
 {
     for (int k : m_data->m_pixels.Keys())
     {
-        delete[] m_data->m_pixels[k];
+        delete[] (uint8_t *)m_data->m_pixels[k];
         m_data->m_pixels[k] = nullptr;
     }
     delete m_data;
@@ -170,6 +170,23 @@ void Image::SetSize(ivec2 size)
     }
 }
 
+/* Wrap-around mode for some operations */
+WrapMode Image::GetWrapX() const
+{
+    return m_data->m_wrap_x;
+}
+
+WrapMode Image::GetWrapY() const
+{
+    return m_data->m_wrap_y;
+}
+
+void Image::SetWrap(WrapMode wrap_x, WrapMode wrap_y)
+{
+    m_data->m_wrap_x = wrap_x;
+    m_data->m_wrap_y = wrap_y;
+}
+
 /* The Lock() method */
 template<PixelFormat T> typename PixelType<T>::type *Image::Lock()
 {

src/image/pixels.cpp

@@ -43,13 +43,26 @@ PixelFormat Image::GetFormat() const
 
 void Image::SetFormat(PixelFormat fmt)
 {
-    ivec2 size = GetSize();
-    int count = size.x * size.y;
+    PixelFormat old_fmt = m_data->m_format;
+
+    /* Preliminary intermediate conversions */
+    if (old_fmt == PixelFormat::RGBA_8 && fmt == PixelFormat::Y_F32)
+        SetFormat(PixelFormat::RGBA_F32);
+    else if (old_fmt == PixelFormat::RGB_8 && fmt == PixelFormat::Y_F32)
+        SetFormat(PixelFormat::RGBA_F32);
+    else if (old_fmt == PixelFormat::Y_F32 && fmt == PixelFormat::RGBA_8)
+        SetFormat(PixelFormat::RGBA_F32);
+    else if (old_fmt == PixelFormat::Y_F32 && fmt == PixelFormat::RGB_8)
+        SetFormat(PixelFormat::RGBA_F32);
+
+    old_fmt = m_data->m_format;
 
     /* Set the new active pixel format */
-    PixelFormat old_fmt = m_data->m_format;
     m_data->m_format = fmt;
 
+    ivec2 size = GetSize();
+    int count = size.x * size.y;
+
     /* If we never used this format, allocate a new buffer: we will
      * obviously need it. */
     if (m_data->m_pixels[(int)fmt] == nullptr)
@@ -62,18 +75,6 @@ void Image::SetFormat(PixelFormat fmt)
     if (fmt == old_fmt || old_fmt == PixelFormat::Unknown)
         return;
 
-#if 0
-    /* Preliminary conversions */
-    if (old_fmt == PixelFormat::RGBA_8 && fmt == PixelFormat::Y_F32)
-        pipi_get_pixels(img, PixelFormat::RGBA_F32);
-    else if (old_fmt == PixelFormat::BGR_U8 && fmt == PixelFormat::Y_F32)
-        pipi_get_pixels(img, PixelFormat::RGBA_F32);
-    else if (old_fmt == PixelFormat::Y_F32 && fmt == PixelFormat::RGBA_8)
-        pipi_get_pixels(img, PixelFormat::RGBA_F32);
-    else if (old_fmt == PixelFormat::Y_F32 && fmt == PixelFormat::BGR_U8)
-        pipi_get_pixels(img, PixelFormat::RGBA_F32);
-#endif
-
     /* Convert pixels */
     if (old_fmt == PixelFormat::RGBA_8 && fmt == PixelFormat::RGBA_F32)
     {

src/image/stock.cpp

@@ -1,7 +1,7 @@
 //
 // Lol Engine
 //
-// Copyright: (c) 2004-2013 Sam Hocevar <sam@hocevar.net>
+// Copyright: (c) 2004-2014 Sam Hocevar <sam@hocevar.net>
 //   This program is free software; you can redistribute it and/or
 //   modify it under the terms of the Do What The Fuck You Want To
 //   Public License, Version 2, as published by Sam Hocevar. See
@@ -59,7 +59,7 @@ bool Image::Stock(char const *name)
 
         if (!strcmp(name + 6, "fs"))
         {
-            float const myker[] =
+            static float const myker[] =
             {
                    0.,     1.,  7./16,
                 3./16,  5./16,  1./16,
@@ -68,7 +68,7 @@ bool Image::Stock(char const *name)
         }
         else if (!strcmp(name + 6, "jajuni"))
         {
-            float const myker[] =
+            static float const myker[] =
             {
                    0.,     0.,     1.,  7./48,  5./48,
                 3./48,  5./48,  7./48,  5./48,  3./48,
@@ -78,7 +78,7 @@ bool Image::Stock(char const *name)
         }
         else if (!strcmp(name + 6, "atkinson"))
         {
-            float const myker[] =
+            static float const myker[] =
             {
                   0.,    1.,  1./8,  1./8,
                 1./8,  1./8,  1./8,    0.,
@@ -88,7 +88,7 @@ bool Image::Stock(char const *name)
         }
         else if (!strcmp(name + 6, "fan"))
         {
-            float const myker[] =
+            static float const myker[] =
             {
                    0.,     0.,     1.,  7./16,
                 1./16,  3./16,  5./16,     0.,
@@ -97,7 +97,7 @@ bool Image::Stock(char const *name)
         }
         else if (!strcmp(name + 6, "shiaufan"))
         {
-            float const myker[] =
+            static float const myker[] =
             {
                   0.,    0.,    1.,  1./2,
                 1./8,  1./8,  1./4,    0.,
@@ -106,7 +106,7 @@ bool Image::Stock(char const *name)
         }
         else if (!strcmp(name + 6, "shiaufan2"))
         {
-            float const myker[] =
+            static float const myker[] =
             {
                    0.,     0.,    0.,    1.,  1./2,
                 1./16,  1./16,  1./8,  1./4,    0.,
@@ -115,7 +115,7 @@ bool Image::Stock(char const *name)
         }
         else if (!strcmp(name + 6, "stucki"))
         {
-            float const myker[] =
+            static float const myker[] =
             {
                    0.,     0.,     1.,  8./42,  4./42,
                 2./42,  4./42,  8./42,  4./42,  2./42,
@@ -125,7 +125,7 @@ bool Image::Stock(char const *name)
         }
         else if (!strcmp(name + 6, "burkes"))
         {
-            float const myker[] =
+            static float const myker[] =
             {
                    0.,     0.,     1.,  4./16,  2./16,
                 1./16,  2./16,  4./16,  2./16,  1./16,
@@ -134,7 +134,7 @@ bool Image::Stock(char const *name)
         }
         else if (!strcmp(name + 6, "sierra"))
         {
-            float const myker[] =
+            static float const myker[] =
             {
                    0.,     0.,     1.,  5./32,  3./32,
                 2./32,  4./32,  5./32,  4./32,  2./32,
@@ -144,7 +144,7 @@ bool Image::Stock(char const *name)
         }
         else if (!strcmp(name + 6, "sierra2"))
         {
-            float const myker[] =
+            static float const myker[] =
             {
                    0.,     0.,     1.,  4./16,  3./16,
                 1./16,  2./16,  3./16,  2./16,  1./16,
@@ -153,7 +153,7 @@ bool Image::Stock(char const *name)
         }
         else if (!strcmp(name + 6, "lite"))
         {
-            float const myker[] =
+            static float const myker[] =
             {
                   0.,    1.,  1./2,
                 1./4,  1./4,    0.,

src/lol/image/image.h

@@ -1,7 +1,7 @@
 //
 // Lol Engine
 //
-// Copyright: (c) 2010-2013 Sam Hocevar <sam@hocevar.net>
+// Copyright: (c) 2010-2014 Sam Hocevar <sam@hocevar.net>
 //   This program is free software; you can redistribute it and/or
 //   modify it under the terms of the Do What The Fuck You Want To
 //   Public License, Version 2, as published by Sam Hocevar. See
@@ -29,6 +29,18 @@ template<> struct PixelType<PixelFormat::Y_F32> { typedef float type; };
 template<> struct PixelType<PixelFormat::RGB_F32> { typedef vec3 type; };
 template<> struct PixelType<PixelFormat::RGBA_F32> { typedef vec4 type; };
 
+enum class WrapMode : uint8_t
+{
+    Clamp,
+    Repeat,
+};
+
+enum class ScanMode : uint8_t
+{
+    Raster,
+    Serpentine,
+};
+
 class Image
 {
 public:
@@ -53,6 +65,10 @@ public:
     PixelFormat GetFormat() const;
     void SetFormat(PixelFormat fmt);
 
+    WrapMode GetWrapX() const;
+    WrapMode GetWrapY() const;
+    void SetWrap(WrapMode wrap_x, WrapMode wrap_y);
+
     template<PixelFormat T = PixelFormat::Unknown>
         typename PixelType<T>::type *Lock();
     void Unlock(void const *pixels);
@@ -67,6 +83,9 @@ public:
 
     /* Image processing */
     Image AutoContrast() const;
+    Image DitherRandom() const;
+    Image DitherEdiff(Image &kernel, ScanMode scan = ScanMode::Raster) const;
+    Image DitherOstromoukhov(ScanMode scan = ScanMode::Raster) const;
 
 private:
     class ImageData *m_data;