INPUT mediump vec2 vTexCoord;
INPUT mediump vec2 vPosition;
INPUT mediump vec2 vRectSize;
INPUT mediump float vCornerRadius;

uniform sampler2D sTexture;
uniform lowp vec4 uColor;
uniform lowp vec3 mixColor;
uniform lowp float preMultipliedAlpha;

void main()
{
  mediump float dist = length( max( abs( vPosition ), vRectSize ) - vRectSize ) - vCornerRadius;
  mediump float opacity = 1.0 - smoothstep( -1.0, 1.0, dist );

  OUT_COLOR = TEXTURE( sTexture, vTexCoord ) * uColor * vec4( mixColor, 1.0 );
  OUT_COLOR.a *= opacity;
  OUT_COLOR.rgb *= mix( 1.0, opacity, preMultipliedAlpha );
}