varying vec2 v_vTexcoord; varying vec4 v_vColour; uniform vec4 color; void main() { float dist = abs(length(v_vTexcoord - .5) * 2. - 0.9); float a; vec4 c = vec4(0.); a = smoothstep(.1, .05, dist); c = mix(c, color, a); gl_FragColor = c; }