Fix the text visual shaders to work with pre-multiplied alpha

[platform/core/uifw/dali-toolkit.git] / dali-toolkit / internal / visuals / text / text-visual.cpp

diff --git a/dali-toolkit/internal/visuals/text/text-visual.cpp b/dali-toolkit/internal/visuals/text/text-visual.cpp
index e8c97f6..d70edce 100755 (executable)
--- a/dali-toolkit/internal/visuals/text/text-visual.cpp
+++ b/dali-toolkit/internal/visuals/text/text-visual.cpp
@@ -106,6 +106,12 @@ const char* FRAGMENT_SHADER_SINGLE_COLOR_TEXT = DALI_COMPOSE_SHADER(
   uniform lowp vec4 uColor;\n
   uniform lowp vec3 mixColor;\n
   uniform lowp float opacity;\n
+  uniform lowp float preMultipliedAlpha;\n
+  \n
+  lowp vec4 visualMixColor()\n
+  {\n
+    return vec4( mixColor * mix( 1.0, opacity, preMultipliedAlpha ), opacity );\n
+  }\n
   \n
   void main()\n
   {\n
@@ -113,7 +119,7 @@ const char* FRAGMENT_SHADER_SINGLE_COLOR_TEXT = DALI_COMPOSE_SHADER(
     mediump float textTexture = texture2D( sTexture, texCoord ).r;\n
 
     // Set the color of the text to what it is animated to.
-    gl_FragColor = uTextColorAnimatable * textTexture * uColor * vec4( mixColor, opacity );
+    gl_FragColor = uTextColorAnimatable * textTexture * uColor * visualMixColor();
   }\n
 );
 
@@ -124,13 +130,20 @@ const char* FRAGMENT_SHADER_MULTI_COLOR_TEXT = DALI_COMPOSE_SHADER(
   uniform lowp vec4 uColor;\n
   uniform lowp vec3 mixColor;\n
   uniform lowp float opacity;\n
+  uniform lowp float preMultipliedAlpha;\n
+  \n
+  lowp vec4 visualMixColor()\n
+  {\n
+    return vec4( mixColor * mix( 1.0, opacity, preMultipliedAlpha ), opacity );\n
+  }\n
   \n
   void main()\n
   {\n
     mediump vec2 texCoord = clamp( mix( uAtlasRect.xy, uAtlasRect.zw, vTexCoord ), uAtlasRect.xy, uAtlasRect.zw );\n
     mediump vec4 textTexture = texture2D( sTexture, texCoord );\n
+    textTexture.rgb *= mix( 1.0, textTexture.a, preMultipliedAlpha );\n
 
-    gl_FragColor = textTexture * uColor * vec4( mixColor, opacity );
+    gl_FragColor = textTexture * uColor * visualMixColor();
   }\n
 );
 
@@ -143,6 +156,12 @@ const char* FRAGMENT_SHADER_SINGLE_COLOR_TEXT_WITH_STYLE = DALI_COMPOSE_SHADER(
   uniform lowp vec4 uColor;\n
   uniform lowp vec3 mixColor;\n
   uniform lowp float opacity;\n
+  uniform lowp float preMultipliedAlpha;\n
+  \n
+  lowp vec4 visualMixColor()\n
+  {\n
+    return vec4( mixColor * mix( 1.0, opacity, preMultipliedAlpha ), opacity );\n
+  }\n
   \n
   void main()\n
   {\n
@@ -151,7 +170,7 @@ const char* FRAGMENT_SHADER_SINGLE_COLOR_TEXT_WITH_STYLE = DALI_COMPOSE_SHADER(
     mediump vec4 styleTexture = texture2D( sStyle, texCoord );\n
 
     // Draw the text as overlay above the style
-    gl_FragColor = ( uTextColorAnimatable * textTexture + styleTexture * ( 1.0 - textTexture ) ) * uColor * vec4( mixColor, opacity );\n
+    gl_FragColor = ( uTextColorAnimatable * textTexture + styleTexture * ( 1.0 - textTexture ) ) * uColor * visualMixColor();\n
   }\n
 );
 
@@ -163,15 +182,22 @@ const char* FRAGMENT_SHADER_MULTI_COLOR_TEXT_WITH_STYLE = DALI_COMPOSE_SHADER(
   uniform lowp vec4 uColor;\n
   uniform lowp vec3 mixColor;\n
   uniform lowp float opacity;\n
+  uniform lowp float preMultipliedAlpha;\n
+  \n
+  lowp vec4 visualMixColor()\n
+  {\n
+    return vec4( mixColor * mix( 1.0, opacity, preMultipliedAlpha ), opacity );\n
+  }\n
   \n
   void main()\n
   {\n
     mediump vec2 texCoord = clamp( mix( uAtlasRect.xy, uAtlasRect.zw, vTexCoord ), uAtlasRect.xy, uAtlasRect.zw );\n
     mediump vec4 textTexture = texture2D( sTexture, texCoord );\n
     mediump vec4 styleTexture = texture2D( sStyle, texCoord );\n
+    textTexture.rgb *= mix( 1.0, textTexture.a, preMultipliedAlpha );\n
 
     // Draw the text as overlay above the style
-    gl_FragColor = ( textTexture + styleTexture * ( 1.0 - textTexture.a ) ) * uColor * vec4( mixColor, opacity );\n
+    gl_FragColor = ( textTexture + styleTexture * ( 1.0 - textTexture.a ) ) * uColor * visualMixColor();\n
   }\n
 );
 
@@ -184,6 +210,12 @@ const char* FRAGMENT_SHADER_SINGLE_COLOR_TEXT_WITH_EMOJI = DALI_COMPOSE_SHADER(
   uniform lowp vec4 uColor;\n
   uniform lowp vec3 mixColor;\n
   uniform lowp float opacity;\n
+  uniform lowp float preMultipliedAlpha;\n
+  \n
+  lowp vec4 visualMixColor()\n
+  {\n
+    return vec4( mixColor * mix( 1.0, opacity, preMultipliedAlpha ), opacity );\n
+  }\n
   \n
   void main()\n
   {\n
@@ -194,12 +226,11 @@ const char* FRAGMENT_SHADER_SINGLE_COLOR_TEXT_WITH_EMOJI = DALI_COMPOSE_SHADER(
     // Set the color of non-transparent pixel in text to what it is animated to.
     // Markup text with multiple text colors are not animated (but can be supported later on if required).
     // Emoji color are not animated.
-    mediump vec4 textColor = textTexture * textTexture.a;\n
-    mediump float vstep = step( 0.0001, textColor.a );\n
-    textColor.rgb = mix( textColor.rgb, uTextColorAnimatable.rgb, vstep * maskTexture );\n
+    mediump float vstep = step( 0.0001, textTexture.a );\n
+    textTexture.rgb = mix( textTexture.rgb, uTextColorAnimatable.rgb, vstep * maskTexture ) * mix( 1.0, textTexture.a, preMultipliedAlpha );\n
 
     // Draw the text as overlay above the style
-    gl_FragColor = textColor * uColor * vec4( mixColor, opacity );\n
+    gl_FragColor = textTexture * uColor * visualMixColor();\n
   }\n
 );
 
@@ -214,6 +245,12 @@ const char* FRAGMENT_SHADER_SINGLE_COLOR_TEXT_WITH_STYLE_AND_EMOJI = DALI_COMPOS
   uniform lowp vec4 uColor;\n
   uniform lowp vec3 mixColor;\n
   uniform lowp float opacity;\n
+  uniform lowp float preMultipliedAlpha;\n
+  \n
+  lowp vec4 visualMixColor()\n
+  {\n
+    return vec4( mixColor * mix( 1.0, opacity, preMultipliedAlpha ), opacity );\n
+  }\n
   \n
   void main()\n
   {\n
@@ -225,12 +262,11 @@ const char* FRAGMENT_SHADER_SINGLE_COLOR_TEXT_WITH_STYLE_AND_EMOJI = DALI_COMPOS
     // Set the color of non-transparent pixel in text to what it is animated to.
     // Markup text with multiple text colors are not animated (but can be supported later on if required).
     // Emoji color are not animated.
-    mediump vec4 textColor = textTexture * textTexture.a;\n
-    mediump float vstep = step( 0.0001, textColor.a );\n
-    textColor.rgb = mix( textColor.rgb, uTextColorAnimatable.rgb, vstep * maskTexture * ( 1.0 - uHasMultipleTextColors ) );\n
+    mediump float vstep = step( 0.0001, textTexture.a );\n
+    textTexture.rgb = mix( textTexture.rgb, uTextColorAnimatable.rgb, vstep * maskTexture * ( 1.0 - uHasMultipleTextColors ) ) * mix( 1.0, textTexture.a, preMultipliedAlpha );\n
 
     // Draw the text as overlay above the style
-    gl_FragColor = ( textColor + styleTexture * ( 1.0 - textTexture.a ) ) * uColor * vec4( mixColor, opacity );\n
+    gl_FragColor = ( textTexture + styleTexture * ( 1.0 - textTexture.a ) ) * uColor * visualMixColor();\n
   }\n
 );
 
@@ -430,6 +466,9 @@ void TextVisual::DoSetOnStage( Actor& actor )
   mImpl->mRenderer = Renderer::New( geometry, shader );
   mImpl->mRenderer.SetProperty( Dali::Renderer::Property::DEPTH_INDEX, Toolkit::DepthIndex::CONTENT );
 
+  // Enable the pre-multiplied alpha to improve the text quality
+  EnablePreMultipliedAlpha(true);
+
   const Vector4& defaultColor = mController->GetTextModel()->GetDefaultColor();
   Dali::Property::Index shaderTextColorIndex = mImpl->mRenderer.RegisterProperty( "uTextColorAnimatable", defaultColor );