[gegl/soc-2012-ops: 1/3] Emboss Operation

[Michael Murà <mmure src gnome org>]

commit 50f1bb0a54aa88e3848fc66e30eef367de925fa9
Author: Hans Lo <hansshulo gmail com>
Date:   Sat Jun 30 02:48:19 2012 -0400

    Emboss Operation
    
    Basically finished but slow, possibly due sampling more than needed.
    Parameters do not match original plug-in accurately.

 operations/common/emboss.c |  244 ++++++++++++++++++++++++++++++++++++++++++++
 1 files changed, 244 insertions(+), 0 deletions(-)
---
diff --git a/operations/common/emboss.c b/operations/common/emboss.c
new file mode 100644
index 0000000..8e7501e
--- /dev/null
+++ b/operations/common/emboss.c
@@ -0,0 +1,244 @@
+/* This file is an image processing operation for GEGL
+ *
+ * GEGL is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 3 of the License, or (at your option) any later version.
+ *
+ * GEGL 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
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with GEGL; if not, see <http://www.gnu.org/licenses/>.
+ * 
+ * Copyright 1997 Eric L. Hernes <erich rrnet com>
+ * Copyright 2012 Hans Lo <hansshulo gmail com>
+ */
+
+#include "config.h"
+#include <glib/gi18n-lib.h>
+
+#ifdef GEGL_CHANT_PROPERTIES
+
+gegl_chant_register_enum (gegl_emboss_type)
+  enum_value (GEGl_EMBOSS, "Emboss")
+  enum_value (GEGl_BUMPMAP, "Bumpmap")
+gegl_chant_register_enum_end (GeglEmboss)
+
+gegl_chant_enum (emboss_type, _("Function"), GeglEmboss, gegl_emboss_type,
+                 GEGl_EMBOSS, _("Emboss or Bumpmap"))
+
+gegl_chant_double (azimuth, _("Azimuth"), 0.0, 360.0, 10.0,
+                   _("Azimuth"))
+
+gegl_chant_double (elevation, _("Elevation"), 0.0, 180.0, 45.0,
+                   _("Elevation"))
+
+gegl_chant_double (depth, _("Depth"), 1.0, 100.0, 20.0,
+                   _("Depth"))
+
+#else
+
+#define GEGL_CHANT_TYPE_AREA_FILTER
+#define GEGL_CHANT_C_FILE       "emboss.c"
+
+#include "gegl-chant.h"
+#include <math.h>
+
+#define DtoR(d) ((d)*(G_PI/(gdouble)180))
+
+typedef struct {
+  gdouble      Lx;
+  gdouble      Ly;
+  gdouble      Lz;
+  gdouble      bg;
+  gint         Nz;
+  gint         Nz2;
+  gint         NzLz;
+  
+} LightVector;
+
+static void
+emboss_init (gdouble azimuth,
+             gdouble elevation,
+             gint depth,
+	     LightVector *vec)
+{
+  /*
+   * compute the light vector from the input parameters.
+   * normalize the length to pixelScale for fast shading calculation.
+   */
+  vec->Lx = cos (azimuth) * cos (elevation);
+  vec->Ly = sin (azimuth) * cos (elevation);
+  vec->Lz = sin (elevation);
+
+  /*
+   * constant z component of image surface normal - this depends on the
+   * image slope we wish to associate with an angle of 45 degrees, which
+   * depends on the width of the filter used to produce the source image.
+   */
+  vec->Nz = 1.0 / depth;
+  vec->Nz2 = vec->Nz * vec->Nz;
+  vec->NzLz = vec->Nz * vec->Lz;
+  
+  /* optimization for vertical normals: L.[0 0 1] */
+  vec->bg = vec->Lz;
+}
+
+static void
+emboss_pixel (gint x,
+	      gint y,
+	      LightVector vec,
+	      GeglSampler *sampler,
+	      gfloat* dst_pix,
+	      gint bytes) //may need emboss/bumpmap
+{
+  gfloat  M[3][3];
+    
+  gfloat   Nx, Ny, NdotL;
+  gfloat   shade;
+  gint     i, j, b;
+  gfloat   pix[2];
+  gfloat   center_p[bytes];
+  
+  for (i = 0; i < 3; i++)
+    for (j = 0; j < 3; j++)
+      M[i][j] = 0.0;
+   
+  for (i = 0; i < 3; i++)
+    for (j = 0; j < 3; j++)
+      {
+	gegl_sampler_get (sampler,
+			  x + i,
+			  y + j,
+			  NULL,
+			  pix);
+	M[i][j] += pix[1] * pix[0];
+	if (i == 1 && j == 1)
+	  {
+	    for (b = 0; b < bytes; b++)
+	      center_p[b] = pix[b];
+	  }
+      }
+ 
+  Nx = M[0][0] + M[1][0] + M[2][0] - M[0][2] - M[1][2] - M[2][2];
+  Ny = M[2][0] + M[2][1] + M[2][2] - M[0][0] - M[0][1] - M[0][2];
+
+  /* shade with distant light source */
+  if ( Nx == 0 && Ny == 0 )
+    shade = vec.bg;
+  else if ( (NdotL = Nx * vec.Lx + Ny * vec.Ly + vec.NzLz) < 0 )
+    shade = 0.0;
+  else
+    shade = NdotL / sqrt(Nx*Nx + Ny*Ny + vec.Nz2);
+  
+  /* do something with the shading result */
+  if (bytes == 4) /* rgba, bumpmapping */
+    {
+      for (b = 0; b < 3; b++)
+	*dst_pix++ = center_p[b] * shade;
+      
+      *dst_pix = center_p[3];
+    }
+  else /* ya, emboss */
+    {
+      *dst_pix++ = shade;
+      *dst_pix = center_p[1];
+    }
+}
+
+static void prepare (GeglOperation *operation)
+{
+  GeglChantO *o                    = GEGL_CHANT_PROPERTIES (operation);
+  
+  const Babl *format;
+  if (o->emboss_type == GEGl_EMBOSS) 
+    format = babl_format ("YA float");
+  else
+    format = babl_format ("RGBA float");
+
+  gegl_operation_set_format (operation, "input", format);
+  gegl_operation_set_format (operation, "output", format);
+}
+
+static gboolean
+process (GeglOperation       *operation,
+         GeglBuffer          *input,
+         GeglBuffer          *output,
+         const GeglRectangle *result,
+         gint                 level)
+{
+  GeglChantO *o                    = GEGL_CHANT_PROPERTIES (operation);
+  
+  gfloat *dst_buf;
+  GeglSampler *sampler;
+  LightVector vec;
+  gfloat *dst_pix;
+  gint x, y;
+  gint n_pixels;
+  const Babl *format;
+  gint bytes;
+  
+  if (o->emboss_type == GEGl_EMBOSS)
+    {
+      format = babl_format ("YA float");
+      bytes  = 2;
+    }
+  else 
+    {
+      format = babl_format ("RGBA float");
+      bytes  = 4;
+    }
+  
+  dst_buf = g_slice_alloc (result->width * result->height * bytes * sizeof(gfloat));
+  dst_pix = dst_buf;
+  sampler = gegl_buffer_sampler_new (input,
+				     format,
+				     GEGL_SAMPLER_CUBIC);
+  
+  emboss_init(DtoR(o->azimuth), DtoR(o->elevation), o->depth, &vec);
+  x = result->x;
+  y = result->y;
+  n_pixels = result->width * result->height;
+  while (n_pixels--)
+    {
+      emboss_pixel(x, y, vec, sampler, dst_pix, bytes);
+      dst_pix += bytes;
+      x++;
+      if (x == result->x + result->width)
+	{
+	  x = result->x;
+	  y++;
+	}
+    }
+
+  g_object_unref (sampler);
+  gegl_buffer_set (output, result, 0, format, dst_buf, GEGL_AUTO_ROWSTRIDE);
+  g_slice_free1 (result->width * result->height * bytes * sizeof(gfloat), dst_buf);
+
+  return TRUE;
+}
+
+static void
+gegl_chant_class_init (GeglChantClass *klass)
+{
+  GeglOperationClass            *operation_class;
+  GeglOperationFilterClass  *filter_class;
+
+  operation_class = GEGL_OPERATION_CLASS (klass);
+  filter_class = GEGL_OPERATION_FILTER_CLASS (klass);
+
+  filter_class->process = process;
+  
+  operation_class->prepare = prepare;
+
+  gegl_operation_class_set_keys (operation_class,
+      "name"       , "gegl:emboss",
+      "categories" , "distort",
+      "description", _("Emulate an emboss effect."),
+      NULL);
+}
+
+#endif