Use linear viewZ for accurate and controllable weighted filtering

assets/lumi/pipeline/color.json

@@ -70,7 +70,19 @@
 				{name: "TEXTURE_MIN_FILTER", val: "NEAREST"}, {name: "TEXTURE_MAG_FILTER", val: "NEAREST"},
 				{name: "TEXTURE_WRAP_S", val: "CLAMP_TO_EDGE"}, {name: "TEXTURE_WRAP_T", val: "CLAMP_TO_EDGE"}
 			]
-		}, 
+		},
+		{
+			name: "view_z",
+			lod: 0,
+			internalFormat: "R32F",
+			pixelFormat: "RED",
+			pixelDataType: "FLOAT",
+			target: "TEXTURE_2D",
+			texParams: [ 
+				{name: "TEXTURE_MIN_FILTER", val: "NEAREST"}, {name: "TEXTURE_MAG_FILTER", val: "NEAREST"},
+				{name: "TEXTURE_WRAP_S", val: "CLAMP_TO_EDGE"}, {name: "TEXTURE_WRAP_T", val: "CLAMP_TO_EDGE"},
+			]
+		},
 	],
 
 	programs: [
@@ -137,16 +149,24 @@
 			]
 		},
 		{
-			name: "ao2",
+			name: "ao_final",
 			vertexSource: "lumi:shaders/pass/basic.vert",
 			fragmentSource: "lumi:shaders/pass/ao2.frag",
 			samplers: [
-				"u_vanilla_depth",
+				"u_view_z",
 				"u_gbuffer_main_etc_copy",
 				"u_gbuffer_lightnormal",
 				"u_ao",
 			]
 		},
+		{
+			name: "depth_process",
+			vertexSource: "lumi:shaders/pass/basic.vert",
+			fragmentSource: "lumi:shaders/pass/depth.frag",
+			samplers: [
+				"u_vanilla_depth",
+			]
+		},
 	],
 
 	framebuffers: [
@@ -174,10 +194,23 @@
 			name: "ao_final",
 			colorAttachments: [{image: "gbuffer_main_etc", layer: 0}]
 		},
+		{
+			name: "depth_process",
+			colorAttachments: [{image: "view_z"}]
+		},
 	],
 
 	fabulous: {
 		passes: [
+			{
+				name: "depth_process",
+				program: "depth_process",
+				framebuffer: "depth_process",
+				samplerImages: [
+					"vanilla_depth",
+				],
+				toggleConfig: "ss_ao",
+			},
 			{
 				name: "ao",
 				program: "ao",
@@ -200,10 +233,10 @@
 			},
 			{
 				name: "ao_final",
-				program: "ao2",
+				program: "ao_final",
 				framebuffer: "ao_final",
 				samplerImages: [
-					"vanilla_depth",
+					"view_z",
 					"gbuffer_main_etc_copy",
 					"gbuffer_lightnormal",
 					"ao_result",

assets/lumi/pipeline/layers.json

@@ -120,7 +120,7 @@
 				{name: "TEXTURE_MIN_FILTER", val: "NEAREST"}, {name: "TEXTURE_MAG_FILTER", val: "NEAREST"},
 				{name: "TEXTURE_WRAP_S", val: "CLAMP_TO_EDGE"}, {name: "TEXTURE_WRAP_T", val: "CLAMP_TO_EDGE"}
 			]
-		}, 
+		},
 		{
 			name: "gbuffer_main_etc",
 			lod: 0,

assets/lumi/shaders/pass/ao.glsl

@@ -62,6 +62,8 @@ vec3 getViewPos(vec2 texcoord, in sampler2D target)
 
 void main()
 {
+	/* NOTE: using reconstructed normals doesn't really help reduce artifacts.
+	         and as minecraft is blocky the interpolated normals should be accurate anyway. */
 	vec3  viewPos = getViewPos(v_texcoord, u_vanilla_depth);
 	vec3  viewNormal = frx_normalModelMatrix * normalize(texture(u_gbuffer_lightnormal, vec3(v_texcoord, ID_SOLID_NORM)).xyz);
 

assets/lumi/shaders/pass/ao2.frag

@@ -6,7 +6,7 @@
   lumi:shaders/pass/ao2.frag
 ******************************************************/
 
-uniform sampler2D u_vanilla_depth;
+uniform sampler2D u_view_z;
 uniform sampler2D u_gbuffer_main_etc_copy;
 uniform sampler2DArray u_gbuffer_lightnormal;
 uniform sampler2D u_ao;
@@ -20,19 +20,21 @@ void main()
 	float totalAo = 0.0;
 	float total = 0.0;
 	vec3 normal = texture(u_gbuffer_lightnormal, vec3(v_texcoord, ID_SOLID_NORM)).xyz;
-	float depth = texture(u_vanilla_depth, v_texcoord).r;
+	float fragZ = texture(u_view_z, v_texcoord).r;
+
+	const float maxdZ = 1. / 8.; // height of snow and button to represent smallest possible separation of surfaces
 
 	// this blurring costs about 0.1 ms in my hardware, helps unreliable TAA
 	for (float x = -2.0; x < 2.2; x += 2.0) {
 	for (float y = -2.0; y < 2.2; y += 2.0) {
 		vec2 sampleUV = v_texcoord + vec2(x, y) * v_invSize;
 		vec3 sampleNormal = texture(u_gbuffer_lightnormal, vec3(sampleUV, ID_SOLID_NORM)).xyz;
-		float sampleDepth = texture(u_vanilla_depth, sampleUV).r;
+		float sampleZ = texture(u_view_z, sampleUV).r;
 
 		float NdN = max(0.0, dot(sampleNormal, normal));
-		float dW = l2_clampScale(0.005, 0.0, abs(sampleDepth - depth));
-		totalAo += texture(u_ao, sampleUV).r * NdN * dW;
-		total += NdN * dW;
+		float dZ = l2_clampScale(maxdZ, 0.0, abs(sampleZ - fragZ));
+		totalAo += texture(u_ao, sampleUV).r * NdN * dZ;
+		total += NdN * dZ;
 	}
 	}
 

assets/lumi/shaders/pass/depth.frag

@@ -0,0 +1,16 @@
+#include lumi:shaders/pass/header.glsl
+
+/******************************************************
+  lumi:shaders/pass/depth.frag
+******************************************************/
+
+uniform sampler2D u_vanilla_depth;
+
+out float viewZ;
+
+void main()
+{
+	float depth = texture(u_vanilla_depth, v_texcoord).r;
+	vec4 temp = frx_inverseProjectionMatrix * vec4(v_texcoord * 2.0 - 1.0, depth * 2.0 - 1.0, 1.0);
+	viewZ = -temp.z / temp.w;
+}