From 86d9ee56d2ddedd977f3d3f1ad3fd75fb2946267 Mon Sep 17 00:00:00 2001
From: samcake <samuel.gateau@gmail.com>
Date: Mon, 18 Jul 2016 03:56:11 -0700
Subject: [PATCH] Downsampling shader pass

---
 .../surfaceGeometry_downsampleDepthNormal.slf | 70 +++++++++++++++++++
 1 file changed, 70 insertions(+)
 create mode 100644 libraries/render-utils/src/surfaceGeometry_downsampleDepthNormal.slf

diff --git a/libraries/render-utils/src/surfaceGeometry_downsampleDepthNormal.slf b/libraries/render-utils/src/surfaceGeometry_downsampleDepthNormal.slf
new file mode 100644
index 0000000000..049a357776
--- /dev/null
+++ b/libraries/render-utils/src/surfaceGeometry_downsampleDepthNormal.slf
@@ -0,0 +1,70 @@
+<@include gpu/Config.slh@>
+<$VERSION_HEADER$>
+//  Generated on <$_SCRIBE_DATE$>
+//
+//  Created by Sam Gateau on 6/3/16.
+//  Copyright 2016 High Fidelity, Inc.
+//
+//  Distributed under the Apache License, Version 2.0.
+//  See the accompanying file LICENSE or http://www.apache.org/licenses/LICENSE-2.0.html
+//
+
+
+
+
+uniform sampler2D linearDepthMap;
+uniform sampler2D normalMap;
+
+
+vec2 signNotZero(vec2 v) {
+    return vec2((v.x >= 0.0) ? +1.0 : -1.0, (v.y >= 0.0) ? +1.0 : -1.0);
+}
+
+vec3 oct_to_float32x3(in vec2 e) {
+    vec3 v = vec3(e.xy, 1.0 - abs(e.x) - abs(e.y));
+    if (v.z < 0) {
+        v.xy = (1.0 - abs(v.yx)) * signNotZero(v.xy);
+    }
+    return normalize(v);
+}
+
+vec2 unorm8x3_to_snorm12x2(vec3 u) {
+    u *= 255.0;
+    u.y *= (1.0 / 16.0);
+    vec2 s = vec2(  u.x * 16.0 + floor(u.y),
+    fract(u.y) * (16.0 * 256.0) + u.z);
+    return clamp(s * (1.0 / 2047.0) - 1.0, vec2(-1.0), vec2(1.0));
+}
+vec3 unpackNormal(in vec3 p) {
+    return oct_to_float32x3(unorm8x3_to_snorm12x2(p));
+}
+
+in vec2 varTexCoord0;
+
+out vec4 outLinearDepth;
+out vec4 outNormal;
+
+void main(void) {
+    float Zeye = texture(linearDepthMap, varTexCoord0).x;
+
+    ivec2 texpos = ivec2(gl_FragCoord.xy) * 2;
+    
+    vec3 rawNormals[4];
+    rawNormals[0] = texelFetch(normalMap, texpos, 0).xyz;
+    rawNormals[1] = texelFetch(normalMap, texpos + ivec2(0, 1), 0).xyz;
+    rawNormals[2] = texelFetch(normalMap, texpos + ivec2(1, 0), 0).xyz;
+    rawNormals[3] = texelFetch(normalMap, texpos + ivec2(1, 1), 0).xyz;
+
+    vec3 normal = vec3(0.0);
+
+    normal += unpackNormal( rawNormals[0] );
+    normal += unpackNormal( rawNormals[1] );
+    normal += unpackNormal( rawNormals[2] );
+    normal += unpackNormal( rawNormals[3] );
+  
+    normal = normalize(normal);
+
+    outLinearDepth = vec4(Zeye, 0.0, 0.0, 0.0);
+    outNormal = vec4((normal + vec3(1.0)) * 0.5, 0.0);
+}
+