dali-toolkit/devel-api/shader-effects/alpha-discard-effect.h

   1 #ifndef DALI_TOOLKIT_ALPHA_DISCARD_EFFECT_H
   2 #define DALI_TOOLKIT_ALPHA_DISCARD_EFFECT_H
   3
   4 /*
   5  * Copyright (c) 2020 Samsung Electronics Co., Ltd.
   6  *
   7  * Licensed under the Apache License, Version 2.0 (the "License");
   8  * you may not use this file except in compliance with the License.
   9  * You may obtain a copy of the License at
  10  *
  11  * http://www.apache.org/licenses/LICENSE-2.0
  12  *
  13  * Unless required by applicable law or agreed to in writing, software
  14  * distributed under the License is distributed on an "AS IS" BASIS,
  15  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  16  * See the License for the specific language governing permissions and
  17  * limitations under the License.
  18  *
  19  */
  20
  21 // EXTERNAL INCLUDES
  22 #include <dali/public-api/object/property-map.h>
  23
  24 // INTERNAL INCLUDES
  25 #include <dali-toolkit/public-api/visuals/visual-properties.h>
  26
  27 namespace Dali
  28 {
  29 namespace Toolkit
  30 {
  31 /**
  32  * @brief Creates a new Alpha discard effect
  33  *
  34  * Alpha discard effect is used to discard fragments when the alpha colour value is below a threshold.
  35  * This is useful for stenciling.
  36  *
  37  * Usage example:
  38  *
  39  *   ImageView actor = ImageView::New( EXAMPLE_IMAGE_PATH );
  40  *   Property::Map alphaDiscardEffect = CreateAlphaDiscardEffect();
  41  *   actor.SetProperty( ImageView::Property::IMAGE, alphaDiscardEffect );
  42  *
  43  * @return A property map of the required shaders.
  44  */
  45 inline Property::Map CreateAlphaDiscardEffect()
  46 {
  47   const char* ALPHA_DISCARD_FRAGMENT_SHADER_SOURCE =
  48     "varying mediump vec2 vTexCoord;                                \n"
  49     "                                                               \n"
  50     "uniform sampler2D sTexture;                                    \n"
  51     "uniform lowp vec4 uColor;                                      \n"
  52     "void main()                                                    \n"
  53     "{                                                              \n"
  54     "  mediump vec4 color = texture2D( sTexture, vTexCoord );       \n"
  55     "  if(color.a <= 0.0001)                                        \n"
  56     "  {                                                            \n"
  57     "    discard;                                                   \n"
  58     "  }                                                            \n"
  59     "  gl_FragColor = color * uColor;                               \n"
  60     "}                                                              \n";
  61
  62   Property::Map map;
  63
  64   Property::Map customShader;
  65   customShader[Visual::Shader::Property::FRAGMENT_SHADER] = ALPHA_DISCARD_FRAGMENT_SHADER_SOURCE;
  66
  67   map[Toolkit::Visual::Property::SHADER] = customShader;
  68   return map;
  69 }
  70
  71 } // namespace Toolkit
  72
  73 } // namespace Dali
  74
  75 #endif // DALI_TOOLKIT_ALPHA_DISCARD_EFFECT_H