varying mediump vec2 vTexCoord;
uniform sampler2D sTexture;
uniform sampler2D sMask;
uniform lowp vec4 uTextColorAnimatable;
uniform lowp vec4 uColor;
uniform lowp vec3 mixColor;

void main()
{
  mediump vec4 textTexture = texture2D( sTexture, vTexCoord );
  mediump float maskTexture = texture2D( sMask, vTexCoord ).r;

  // 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 float vstep = step( 0.0001, textTexture.a );
  textTexture.rgb = mix( textTexture.rgb, uTextColorAnimatable.rgb, vstep * maskTexture );

  // Draw the text as overlay above the style
  gl_FragColor = textTexture * uColor * vec4( mixColor, 1.0 );
}