分类shader

shader/NormalCompress/Octahedron.glsl

@@ -0,0 +1,26 @@
+vec2 octahedronWrap(vec2 _val)
+{
+	// Reference(s):
+	// - Octahedron normal vector encoding
+	//   https://web.archive.org/web/20191027010600/https://knarkowicz.wordpress.com/2014/04/16/octahedron-normal-vector-encoding/comment-page-1/
+	return (1.0 - abs(_val.yx) )
+		 * mix(vec2_splat(-1.0), vec2_splat(1.0), vec2(greaterThanEqual(_val.xy, vec2_splat(0.0) ) ) );
+}
+
+vec2 EncodeNormal(vec3 _normal)
+{
+	_normal /= abs(_normal.x) + abs(_normal.y) + abs(_normal.z);
+	_normal.xy = _normal.z >= 0.0 ? _normal.xy : octahedronWrap(_normal.xy);
+	_normal.xy = _normal.xy * 0.5 + 0.5;
+	return _normal.xy;
+}
+
+vec3 DecodeNormal(vec2 _encodedNormal)
+{
+	_encodedNormal = _encodedNormal * 2.0 - 1.0;
+
+	vec3 normal;
+	normal.z  = 1.0 - abs(_encodedNormal.x) - abs(_encodedNormal.y);
+	normal.xy = normal.z >= 0.0 ? _encodedNormal.xy : octahedronWrap(_encodedNormal.xy);
+	return normalize(normal);
+}

shader/NormalCompress/SphereMap.glsl

@@ -0,0 +1,10 @@
+vec2 EncodeNormal(vec3 _normal)
+{
+	return normalize(_normal.xy) * sqrt(_normal.z * 0.5 + 0.5);
+}
+
+vec3 DecodeNormal(vec2 _encodedNormal)
+{
+	float zz = dot(_encodedNormal, _encodedNormal) * 2.0 - 1.0;
+	return vec3(normalize(_encodedNormal.xy) * sqrt(1.0 - zz*zz), zz);
+}