shader_type canvas_item;
uniform vec4 stripe_a : source_color;
uniform vec4 stripe_b : source_color;
uniform float band_px = 16.0;    // 16px bands per README
uniform float vignette = 0.55;   // edge darkening strength
void fragment() {
	// 135deg diagonal stripe: sum of pixel coords, banded.
	vec2 px = FRAGCOORD.xy;
	float diag = px.x + px.y;
	float band = mod(floor(diag / band_px), 2.0);
	vec4 base = mix(stripe_a, stripe_b, band);
	// radial vignette centred slightly high (README: 50% 38%).
	float d = distance(UV, vec2(0.5, 0.38));
	base.rgb *= 1.0 - clamp(d * vignette, 0.0, 1.0);
	COLOR = base;
}