29 lines
618 B
Text
29 lines
618 B
Text
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shader_type canvas_item;
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uniform float u_strength = 1.0;
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uniform bool u_flip_y = false;
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vec3 unpack_normal(vec4 rgba) {
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vec3 n = rgba.xzy * 2.0 - vec3(1.0);
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// Had to negate Z because it comes from Y in the normal map,
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// and OpenGL-style normal maps are Y-up.
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n.z *= -1.0;
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return n;
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}
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vec3 pack_normal(vec3 n) {
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n.z *= -1.0;
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return 0.5 * (n.xzy + vec3(1.0));
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}
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void fragment() {
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vec4 col = texture(TEXTURE, UV);
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vec3 n = unpack_normal(col);
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n = normalize(mix(n, vec3(-n.x, n.y, -n.z), 0.5 - 0.5 * u_strength));
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if (u_flip_y) {
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n.z = -n.z;
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}
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col.rgb = pack_normal(n);
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COLOR = vec4(col.rgb, 1.0);
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}
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