2 varying mediump vec2 vTexCoord;
3 uniform sampler2D sTexture;
4 uniform mediump float uDelta;
8 vec4 color = vec4(0.0);
9 vec2 texCoord = vTexCoord * 2. - 1.;
10 mat2 rotation = mat2(cos(uDelta), -sin(uDelta), sin(uDelta), cos(uDelta));
11 texCoord = (rotation * texCoord) * .5 + .5;
12 color += texture2D( sTexture, texCoord );