#ifdef GL_ES precision mediump float; precision mediump int; #endif // transmit from the vertex shader varying vec2 v_propPos; varying vec4 v_colorTansition; uniform vec4 EW_border; uniform vec4 EW_background; void main(void) { // prevent origin moving ... gl_FragColor = vec4(v_propPos.y, v_propPos.x, 1.0, 1.0); if( v_propPos.x == 1.0 && v_propPos.y == 1.0) { gl_FragColor = v_colorTansition; } else if ( v_propPos.x == 0.0 || v_propPos.y == 0.0) { gl_FragColor = EW_background; } else { gl_FragColor = EW_border; } }