From b312d390da577923c25156572017dfa7e310a8c1 Mon Sep 17 00:00:00 2001
From: ktyl <me@ktyl.dev>
Date: Fri, 13 Aug 2021 13:43:54 +0100
Subject: [PATCH] logarithmic depth

---
 shader/include/constants.glsl |  3 ++-
 shader/root/rt.glsl           |  6 ++++--
 shader/root/rtpre.glsl        | 18 ++++++++++++------
 src/cam.c                     |  2 +-
 4 files changed, 19 insertions(+), 10 deletions(-)

diff --git a/shader/include/constants.glsl b/shader/include/constants.glsl
index 7892915..bcba6b7 100644
--- a/shader/include/constants.glsl
+++ b/shader/include/constants.glsl
@@ -1,4 +1,5 @@
-const float INF = 17.0;
+const float INF = 100.0;
 const float PI = 3.14159;
+const float E = 2.71828;
 const int SAMPLES = 1;
 const int BOUNCES = 4;
diff --git a/shader/root/rt.glsl b/shader/root/rt.glsl
index 77362e7..e778f86 100644
--- a/shader/root/rt.glsl
+++ b/shader/root/rt.glsl
@@ -61,9 +61,11 @@ void main()
     pixel.xyz /= SAMPLES;
 
     vec4 d = imageLoad(_g0, ivec2(gl_GlobalInvocationID.xy));
-    float depth = d.x;
+    float depth = d.w;
+    vec3 normal = d.xyz*2.0-1.0; // unpack normal packaged into texture
 
-    pixel.xyz = mix(pixel.xyz, vec3(0), depth);
+    //pixel.xyz = mix(pixel.xyz, normal, 1.0-depth);
+    pixel.xyz = mix(pixel.xyz, vec3(1.0), depth);
 
     //pixel.a = 1.0;
 
diff --git a/shader/root/rtpre.glsl b/shader/root/rtpre.glsl
index dfb9019..793fc89 100644
--- a/shader/root/rtpre.glsl
+++ b/shader/root/rtpre.glsl
@@ -33,16 +33,22 @@ void main()
     Ray ray = createCameraRay(uv);
     RayHit hit = trace(ray);
 
-    //pixel.xyz = hit.normal;
-
-    // TODO: non-linear depth
-    float n = 1;
+    // n roughly correlates to steepness of log curve
+    // TODO: what does this mean in mathematical terms??
+    float n = 3;
     float f = INF;
     float z = hit.distance;
+    
+    float depth;
+    // linear depth
+    //depth = z/f;
 
-    float depth = (1.0/z-1.0/n)/(1.0/n-1.0/f);
+    // logarithmic depth
+    depth = log(z*pow(E,n)/f)/n;
 
-    pixel.x = z/f;
+    // pack normal into texture
+    pixel.xyz = hit.normal*0.5+0.5;
+    pixel.w = depth;
 
     imageStore(g0_output, pixelCoords, pixel);
 }
diff --git a/src/cam.c b/src/cam.c
index 675d9ad..a2864e5 100644
--- a/src/cam.c
+++ b/src/cam.c
@@ -8,7 +8,7 @@ void updateCameraUniforms(GLuint shaderProgram, float aspect)
 
     // wobble up dir
     vec3 cdir, cright, cup;
-    vec3 up = {0.1*sin(t),1.0,0.2*cos(t)};
+    vec3 up = {0.1*sin(t),1.0,0.05*cos(0.5*t)};
     glm_vec3_normalize(up);
 
     // camera and target pos