Add SceneNormal.hx shader graph node.

hrt/shgraph/nodes/SceneNormal.hx

@@ -0,0 +1,62 @@
+package hrt.shgraph.nodes;
+
+using hxsl.Ast;
+
+@name("Scene Normal")
+@description("Get scene normal behind current pixel")
+@group("Property")
+class SceneNormal extends ShaderNodeHxsl {
+
+	static var SRC = {
+		@sgoutput var output : Vec3;
+
+        @global var depthMap : Channel;
+
+		@global var global : {
+			var pixelSize : Vec2;
+		}
+
+		@global var camera : {
+			var zNear : Float;
+			var zFar : Float;
+			var inverseViewProj : Mat4;
+		};
+
+        var calculatedUV : Vec2;
+
+		// //! function not supported in shader graph
+		// function getWPos(uv : Vec2) : Vec3 {
+		// 	var depth = depthMap.get(uv);
+		// 	var ruv = vec4(uvToScreen(uv), depth, 1);
+		// 	var ppos = ruv * camera.inverseViewProj;
+		// 	return ppos.xyz / ppos.w;
+		// }
+
+		function fragment() {
+			var size = depthMap.size();
+
+			var rightUV = calculatedUV + vec2(1.0, 0.0) * global.pixelSize.x;
+			var botUV = calculatedUV + vec2(0.0, 1.0) * global.pixelSize.y;
+
+			var depth = depthMap.get(calculatedUV);
+			var ruv = vec4(uvToScreen(calculatedUV), depth, 1);
+			var ppos = ruv * camera.inverseViewProj;
+			var wpos = ppos.xyz / ppos.w;
+
+			var depth = depthMap.get(rightUV);
+			var ruv = vec4(uvToScreen(rightUV), depth, 1);
+			var ppos = ruv * camera.inverseViewProj;
+			var right = ppos.xyz / ppos.w;
+
+			var depth = depthMap.get(botUV);
+			var ruv = vec4(uvToScreen(botUV), depth, 1);
+			var ppos = ruv * camera.inverseViewProj;
+			var bot = ppos.xyz / ppos.w;
+
+			// var wpos = getWPos(calculatedUV);
+			// var right = getWPos(rightUV);
+			// var bot = getWPos(botUV);
+			output = cross(normalize(right - wpos), normalize(bot - wpos)).normalize();
+		}
+	};
+}