I'm working on a pong game and have recently set up FBO rendering so that I can apply some post-processing shaders. This proceeds as so:

• Bind texture A to framebuffer
• Draw balls
• Bind texture B to framebuffer
• Draw texture A using fade shader on fullscreen quad
• Bind screen to framebuffer
• Draw texture B using normal textured quad shader

Neither texture A or B are cleared at any point, this way the balls leave trails on screen, see below for the fade shader.

Fade Shader

private final String fragmentShaderCode =
        "precision highp float;" +
        "uniform sampler2D u_Texture;" +
        "varying vec2 v_TexCoordinate;" +
        "vec4 color;" +
        "void main(void)" +
        "{" +
        "   color = texture2D(u_Texture, v_TexCoordinate);" +
        "   color.a *= 0.8;" +
        "   gl_FragColor = color;" +
        "}";

This works fine with the Samsung Galaxy S3/ Note2, but cause a strange effect doesnt work on Galaxy S2 or Note1. See pictures:

Galaxy S3/Note2

Galaxy S3/Note2

Galaxy S2/Note

Galaxy S2/Note

Can anyone explain the difference?