dali-toolkit/internal/text/rendering/vector-based/glyphy-shader/glyphy-sdf-glsl.h

   1 static const char *glyphy_sdf_glsl =
   2 "/*\n"
   3 " * Copyright 2012 Google, Inc. All Rights Reserved.\n"
   4 " *\n"
   5 " * Licensed under the Apache License, Version 2.0 (the \"License\");\n"
   6 " * you may not use this file except in compliance with the License.\n"
   7 " * You may obtain a copy of the License at\n"
   8 " *\n"
   9 " *     http://www.apache.org/licenses/LICENSE-2.0\n"
  10 " *\n"
  11 " * Unless required by applicable law or agreed to in writing, software\n"
  12 " * distributed under the License is distributed on an \"AS IS\" BASIS,\n"
  13 " * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.\n"
  14 " * See the License for the specific language governing permissions and\n"
  15 " * limitations under the License.\n"
  16 " *\n"
  17 " * Google Author(s): Behdad Esfahbod, Maysum Panju\n"
  18 " */\n"
  19 "\n"
  20 "#ifndef GLYPHY_TEXTURE1D_FUNC\n"
  21 "#define GLYPHY_TEXTURE1D_FUNC glyphy_texture1D_func\n"
  22 "#endif\n"
  23 "#ifndef GLYPHY_TEXTURE1D_EXTRA_DECLS\n"
  24 "#define GLYPHY_TEXTURE1D_EXTRA_DECLS\n"
  25 "#endif\n"
  26 "#ifndef GLYPHY_TEXTURE1D_EXTRA_ARGS\n"
  27 "#define GLYPHY_TEXTURE1D_EXTRA_ARGS\n"
  28 "#endif\n"
  29 "\n"
  30 "#ifndef GLYPHY_SDF_TEXTURE1D_FUNC\n"
  31 "#define GLYPHY_SDF_TEXTURE1D_FUNC GLYPHY_TEXTURE1D_FUNC\n"
  32 "#endif\n"
  33 "#ifndef GLYPHY_SDF_TEXTURE1D_EXTRA_DECLS\n"
  34 "#define GLYPHY_SDF_TEXTURE1D_EXTRA_DECLS GLYPHY_TEXTURE1D_EXTRA_DECLS\n"
  35 "#endif\n"
  36 "#ifndef GLYPHY_SDF_TEXTURE1D_EXTRA_ARGS\n"
  37 "#define GLYPHY_SDF_TEXTURE1D_EXTRA_ARGS GLYPHY_TEXTURE1D_EXTRA_ARGS\n"
  38 "#endif\n"
  39 "#ifndef GLYPHY_SDF_TEXTURE1D\n"
  40 "#define GLYPHY_SDF_TEXTURE1D(offset) GLYPHY_RGBA(GLYPHY_SDF_TEXTURE1D_FUNC (offset GLYPHY_TEXTURE1D_EXTRA_ARGS))\n"
  41 "#endif\n"
  42 "\n"
  43 "#ifndef GLYPHY_MAX_NUM_ENDPOINTS\n"
  44 "#define GLYPHY_MAX_NUM_ENDPOINTS 32\n"
  45 "#endif\n"
  46 "\n"
  47 "glyphy_arc_list_t\n"
  48 "glyphy_arc_list (const vec2 p, const ivec2 nominal_size GLYPHY_SDF_TEXTURE1D_EXTRA_DECLS)\n"
  49 "{\n"
  50 "  int cell_offset = glyphy_arc_list_offset (p, nominal_size);\n"
  51 "  vec4 arc_list_data = GLYPHY_SDF_TEXTURE1D (cell_offset);\n"
  52 "  return glyphy_arc_list_decode (arc_list_data, nominal_size);\n"
  53 "}\n"
  54 "\n"
  55 "float\n"
  56 "glyphy_sdf (const vec2 p, const ivec2 nominal_size GLYPHY_SDF_TEXTURE1D_EXTRA_DECLS)\n"
  57 "{\n"
  58 "  glyphy_arc_list_t arc_list = glyphy_arc_list (p, nominal_size  GLYPHY_SDF_TEXTURE1D_EXTRA_ARGS);\n"
  59 "\n"
  60 "  /* Short-circuits */\n"
  61 "  if (arc_list.num_endpoints == 0) {\n"
  62 "    /* far-away cell */\n"
  63 "    return GLYPHY_INFINITY * float(arc_list.side);\n"
  64 "  } if (arc_list.num_endpoints == -1) {\n"
  65 "    /* single-line */\n"
  66 "    float angle = arc_list.line_angle;\n"
  67 "    vec2 n = vec2 (cos (angle), sin (angle));\n"
  68 "    return dot (p - (vec2(nominal_size) * .5), n) - arc_list.line_distance;\n"
  69 "  }\n"
  70 "\n"
  71 "  float side = float(arc_list.side);\n"
  72 "  float min_dist = GLYPHY_INFINITY;\n"
  73 "  glyphy_arc_t closest_arc;\n"
  74 "\n"
  75 "  glyphy_arc_endpoint_t endpoint_prev, endpoint;\n"
  76 "  endpoint_prev = glyphy_arc_endpoint_decode (GLYPHY_SDF_TEXTURE1D (arc_list.offset), nominal_size);\n"
  77 "  for (int i = 1; i < GLYPHY_MAX_NUM_ENDPOINTS; i++)\n"
  78 "  {\n"
  79 "    if (i >= arc_list.num_endpoints) {\n"
  80 "      break;\n"
  81 "    }\n"
  82 "    endpoint = glyphy_arc_endpoint_decode (GLYPHY_SDF_TEXTURE1D (arc_list.offset + i), nominal_size);\n"
  83 "    glyphy_arc_t a = glyphy_arc_t (endpoint_prev.p, endpoint.p, endpoint.d);\n"
  84 "    endpoint_prev = endpoint;\n"
  85 "    if (glyphy_isinf (a.d)) continue;\n"
  86 "\n"
  87 "    if (glyphy_arc_wedge_contains (a, p))\n"
  88 "    {\n"
  89 "      float sdist = glyphy_arc_wedge_signed_dist (a, p);\n"
  90 "      float udist = abs (sdist) * (1. - GLYPHY_EPSILON);\n"
  91 "      if (udist <= min_dist) {\n"
  92 "       min_dist = udist;\n"
  93 "       side = sign (sdist);"
  94 "      }\n"
  95 "    } else {\n"
  96 "      float udist = min (distance (p, a.p0), distance (p, a.p1));\n"
  97 "      if (udist < min_dist) {\n"
  98 "       min_dist = udist;\n"
  99 "       side = 0.; /* unsure */\n"
 100 "       closest_arc = a;\n"
 101 "      } else if (side == 0. && udist == min_dist) {\n"
 102 "       /* If this new distance is the same as the current minimum,\n"
 103 "        * compare extended distances.  Take the sign from the arc\n"
 104 "        * with larger extended distance. */\n"
 105 "       float old_ext_dist = glyphy_arc_extended_dist (closest_arc, p);\n"
 106 "       float new_ext_dist = glyphy_arc_extended_dist (a, p);\n"
 107 "\n"
 108 "       float ext_dist = abs (new_ext_dist) <= abs (old_ext_dist) ?\n"
 109 "                        old_ext_dist : new_ext_dist;\n"
 110 "\n"
 111 "#ifdef GLYPHY_SDF_PSEUDO_DISTANCE\n"
 112 "       /* For emboldening and stuff: */\n"
 113 "       min_dist = abs (ext_dist);\n"
 114 "#endif\n"
 115 "       side = sign (ext_dist);\n"
 116 "      }\n"
 117 "    }\n"
 118 "  }\n"
 119 "\n"
 120 "  if (side == 0.) {\n"
 121 "    // Technically speaking this should not happen, but it does.  So try to fix it.\n"
 122 "    float ext_dist = glyphy_arc_extended_dist (closest_arc, p);\n"
 123 "    side = sign (ext_dist);\n"
 124 "  }\n"
 125 "\n"
 126 "  return min_dist * side;\n"
 127 "}\n"
 128 "\n"
 129 "float\n"
 130 "glyphy_point_dist (const vec2 p, const ivec2 nominal_size GLYPHY_SDF_TEXTURE1D_EXTRA_DECLS)\n"
 131 "{\n"
 132 "  glyphy_arc_list_t arc_list = glyphy_arc_list (p, nominal_size  GLYPHY_SDF_TEXTURE1D_EXTRA_ARGS);\n"
 133 "\n"
 134 "  float side = float(arc_list.side);\n"
 135 "  float min_dist = GLYPHY_INFINITY;\n"
 136 "\n"
 137 "  if (arc_list.num_endpoints == 0)\n"
 138 "    return min_dist;\n"
 139 "\n"
 140 "  glyphy_arc_endpoint_t endpoint;\n"
 141 "  for (int i = 0; i < GLYPHY_MAX_NUM_ENDPOINTS; i++)\n"
 142 "  {\n"
 143 "    if (i >= arc_list.num_endpoints) {\n"
 144 "      break;\n"
 145 "    }\n"
 146 "    endpoint = glyphy_arc_endpoint_decode (GLYPHY_SDF_TEXTURE1D (arc_list.offset + i), nominal_size);\n"
 147 "    if (glyphy_isinf (endpoint.d)) continue;\n"
 148 "    min_dist = min (min_dist, distance (p, endpoint.p));\n"
 149 "  }\n"
 150 "  return min_dist;\n"
 151 "}\n"
 152 ;