[gegl] Revert "algorithms: bake 2x2 division into a LUT"

[Øyvind Kolås <ok src gnome org>]

commit 857a35cba48ee27f31053c6b4c2f4f9d9c3f37bd
Author: Øyvind Kolås <pippin gimp org>
Date:   Mon Apr 9 03:56:12 2018 +0200

    Revert "algorithms: bake 2x2 division into a LUT"
    
    This reverts accidentally commited b5c64a323825396c9ca578d7e071462240d78d56.

 gegl/gegl-algorithms.c |  114 +++++++++++++++++++++++-------------------------
 perf/joblist           |    2 +-
 2 files changed, 56 insertions(+), 60 deletions(-)
---
diff --git a/gegl/gegl-algorithms.c b/gegl/gegl-algorithms.c
index f17401f..3f33741 100644
--- a/gegl/gegl-algorithms.c
+++ b/gegl/gegl-algorithms.c
@@ -111,7 +111,6 @@ gegl_downscale_2x2_generic (const Babl *format,
 #define LUT_DIVISOR 32
 
 static uint16_t lut_u8_to_u16[256];
-static uint16_t lut_u8_to_u14[256];
 static float    lut_u8_to_u16f[256];
 static uint8_t  lut_u16_to_u8[65536/LUT_DIVISOR];
 
@@ -132,7 +131,6 @@ void _gegl_init_u8_lut (void)
                 256);
   for (i = 0; i < 256; i++)
   {
-    lut_u8_to_u14[i] = lut_u8_to_u16[i]/LUT_DIVISOR/4;
     lut_u8_to_u16[i] = lut_u8_to_u16[i]/LUT_DIVISOR;
     lut_u8_to_u16f[i] = lut_u8_to_u16[i];
   }
@@ -850,18 +848,18 @@ gegl_downscale_2x2_u8_rgba (const Babl *format,
           uint8_t * ba = ((uint8_t *)(aa + src_rowstride));
           uint8_t * bb = ((uint8_t *)(aa + diag));
 
-          ((uint8_t *)dst)[0] = lut_u16_to_u8[ (lut_u8_to_u14[aa[0]] +
-                                                lut_u8_to_u14[ab[0]] +
-                                                lut_u8_to_u14[ba[0]] +
-                                                lut_u8_to_u14[bb[0]]) ];
-          ((uint8_t *)dst)[1] = lut_u16_to_u8[ (lut_u8_to_u14[aa[1]] +
-                                                lut_u8_to_u14[ab[1]] +
-                                                lut_u8_to_u14[ba[1]] +
-                                                lut_u8_to_u14[bb[1]]) ];
-          ((uint8_t *)dst)[2] = lut_u16_to_u8[ (lut_u8_to_u14[aa[2]] +
-                                                lut_u8_to_u14[ab[2]] +
-                                                lut_u8_to_u14[ba[2]] +
-                                                lut_u8_to_u14[bb[2]]) ];
+          ((uint8_t *)dst)[0] = lut_u16_to_u8[ (lut_u8_to_u16[aa[0]] +
+                                                lut_u8_to_u16[ab[0]] +
+                                                lut_u8_to_u16[ba[0]] +
+                                                lut_u8_to_u16[bb[0]])>>2 ];
+          ((uint8_t *)dst)[1] = lut_u16_to_u8[ (lut_u8_to_u16[aa[1]] +
+                                                lut_u8_to_u16[ab[1]] +
+                                                lut_u8_to_u16[ba[1]] +
+                                                lut_u8_to_u16[bb[1]])>>2 ];
+          ((uint8_t *)dst)[2] = lut_u16_to_u8[ (lut_u8_to_u16[aa[2]] +
+                                                lut_u8_to_u16[ab[2]] +
+                                                lut_u8_to_u16[ba[2]] +
+                                                lut_u8_to_u16[bb[2]])>>2 ];
           ((uint8_t *)dst)[3] = (aa[3] + ab[3] + ba[3] + bb[3])>>2;
 
           dst += bpp;
@@ -899,18 +897,18 @@ gegl_downscale_2x2_u8_rgb (const Babl *format,
           uint8_t * ba = ((uint8_t *)(aa + src_rowstride));
           uint8_t * bb = ((uint8_t *)(aa + diag));
 
-          ((uint8_t *)dst)[0] = lut_u16_to_u8[ (lut_u8_to_u14[aa[0]] +
-                                                lut_u8_to_u14[ab[0]] +
-                                                lut_u8_to_u14[ba[0]] +
-                                                lut_u8_to_u14[bb[0]]) ];
-          ((uint8_t *)dst)[1] = lut_u16_to_u8[ (lut_u8_to_u14[aa[1]] +
-                                                lut_u8_to_u14[ab[1]] +
-                                                lut_u8_to_u14[ba[1]] +
-                                                lut_u8_to_u14[bb[1]]) ];
-          ((uint8_t *)dst)[2] = lut_u16_to_u8[ (lut_u8_to_u14[aa[2]] +
-                                                lut_u8_to_u14[ab[2]] +
-                                                lut_u8_to_u14[ba[2]] +
-                                                lut_u8_to_u14[bb[2]]) ];
+          ((uint8_t *)dst)[0] = lut_u16_to_u8[ (lut_u8_to_u16[aa[0]] +
+                                                lut_u8_to_u16[ab[0]] +
+                                                lut_u8_to_u16[ba[0]] +
+                                                lut_u8_to_u16[bb[0]])>>2 ];
+          ((uint8_t *)dst)[1] = lut_u16_to_u8[ (lut_u8_to_u16[aa[1]] +
+                                                lut_u8_to_u16[ab[1]] +
+                                                lut_u8_to_u16[ba[1]] +
+                                                lut_u8_to_u16[bb[1]])>>2 ];
+          ((uint8_t *)dst)[2] = lut_u16_to_u8[ (lut_u8_to_u16[aa[2]] +
+                                                lut_u8_to_u16[ab[2]] +
+                                                lut_u8_to_u16[ba[2]] +
+                                                lut_u8_to_u16[bb[2]])>>2 ];
           dst += bpp;
           aa += bpp * 2;
         }
@@ -920,45 +918,43 @@ gegl_downscale_2x2_u8_rgb (const Babl *format,
 
 GeglDownscale2x2Fun gegl_downscale_2x2_get_fun (const Babl *format)
 {
-  if (format == gegl_babl_rgba_u8())
-    return gegl_downscale_2x2_u8_rgba;
-  if (format == gegl_babl_rgb_u8())
-    return gegl_downscale_2x2_u8_rgb;
+  const Babl *comp_type = babl_format_get_type (format, 0);
+  const Babl *model     = babl_format_get_model (format);
 
+  if (gegl_babl_model_is_linear (model))
   {
-    const Babl *comp_type = babl_format_get_type (format, 0);
-    const Babl *model     = babl_format_get_model (format);
-
-    if (gegl_babl_model_is_linear (model))
+    if (comp_type == gegl_babl_float())
     {
-      if (comp_type == gegl_babl_float())
-      {
-        return gegl_downscale_2x2_float;
-      }
-      else if (comp_type == gegl_babl_u8())
-      {
-        return gegl_downscale_2x2_u8;
-      }
-      else if (comp_type == gegl_babl_u16())
-      {
-        return gegl_downscale_2x2_u16;
-      }
-      else if (comp_type == gegl_babl_u32())
-      {
-        return gegl_downscale_2x2_u32;
-      }
-      else if (comp_type == gegl_babl_double())
-      {
-        return gegl_downscale_2x2_double;
-      }
+      return gegl_downscale_2x2_float;
     }
-    if (comp_type == gegl_babl_u8())
+    else if (comp_type == gegl_babl_u8())
     {
-      if (babl_format_has_alpha (format))
-        return gegl_downscale_2x2_u8_nl_alpha;
-      else
-        return gegl_downscale_2x2_u8_nl;
+      return gegl_downscale_2x2_u8;
+    }
+    else if (comp_type == gegl_babl_u16())
+    {
+      return gegl_downscale_2x2_u16;
+    }
+    else if (comp_type == gegl_babl_u32())
+    {
+      return gegl_downscale_2x2_u32;
     }
+    else if (comp_type == gegl_babl_double())
+    {
+      return gegl_downscale_2x2_double;
+    }
+  }
+  if (comp_type == gegl_babl_u8())
+  {
+    if (format == gegl_babl_rgba_u8())
+      return gegl_downscale_2x2_u8_rgba;
+    if (format == gegl_babl_rgb_u8())
+      return gegl_downscale_2x2_u8_rgb;
+
+    if (babl_format_has_alpha (format))
+      return gegl_downscale_2x2_u8_nl_alpha;
+    else
+      return gegl_downscale_2x2_u8_nl;
   }
   return gegl_downscale_2x2_generic;
 }
diff --git a/perf/joblist b/perf/joblist
index 218a5fa..28a3dea 100644
--- a/perf/joblist
+++ b/perf/joblist
@@ -1,6 +1,6 @@
 HEAD
 
-master~40..master
+master~20..master
 
 # enable multi-thread by default