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) 2015 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/shader-effects/shader-effect.h>
  23
  24 namespace Dali
  25 {
  26
  27 namespace Toolkit
  28 {
  29
  30 /**
  31  * @brief Creates a new Alpha discard effect
  32  *
  33  * Alpha discard effect is used to discard fragments when the alpha colour value is below a threshold.
  34  * This is useful for stenciling.
  35  *
  36  * Usage example:
  37  *
  38  *   ImageActor actor = ImageActor::New( Image( EXAMPLE_IMAGE_PATH ) );
  39  *   ShaderEffect alphaDiscardEffect = CreateAlphaDiscardEffect();
  40  *   actor.SetShaderEffect( alphaDiscardEffect );
  41  *
  42  * @return A handle to a newly allocated ShaderEffect.
  43  */
  44 inline ShaderEffect CreateAlphaDiscardEffect()
  45 {
  46   const char* ALPHA_DISCARD_FRAGMENT_SHADER_SOURCE =
  47       "void main()                                                    \n"
  48       "{                                                              \n"
  49       "  mediump vec4 color = texture2D( sTexture, vTexCoord );       \n"
  50       "  if(color.a <= 0.0001)                                        \n"
  51       "  {                                                            \n"
  52       "    discard;                                                   \n"
  53       "  }                                                            \n"
  54       "  gl_FragColor = color * uColor;                               \n"
  55       "}                                                              \n";
  56
  57   return ShaderEffect::New( "", // Use default
  58                             ALPHA_DISCARD_FRAGMENT_SHADER_SOURCE );
  59 }
  60
  61 } // namespace Toolkit
  62
  63 } // namespace Dali
  64
  65 #endif // __DALI_TOOLKIT_ALPHA_DISCARD_EFFECT_H__