From 925a2707c1f2d0f5e256f6e70050b7b2242d99e8 Mon Sep 17 00:00:00 2001
From: quou <quou@disroot.org>
Date: Sun, 5 Jan 2025 19:32:35 +1100
Subject: implement metalness

---
 intermediate/bricks.mat   |  2 +-
 intermediate/surface.glsl | 14 ++++++++++----
 2 files changed, 11 insertions(+), 5 deletions(-)

diff --git a/intermediate/bricks.mat b/intermediate/bricks.mat
index 1ed5535..4e676bc 100644
--- a/intermediate/bricks.mat
+++ b/intermediate/bricks.mat
@@ -1,5 +1,5 @@
 [params]
-metalness: 1.0
+metalness: 0.4
 roughness: 0.3
 ao: 1.0
 albedo: ffffff
diff --git a/intermediate/surface.glsl b/intermediate/surface.glsl
index 2d5d470..5feb09f 100644
--- a/intermediate/surface.glsl
+++ b/intermediate/surface.glsl
@@ -137,10 +137,10 @@ float specular_brdf(vec2 uv, vec3 l, vec3 v, vec3 n) {
 	float D =
 		a2 / (pi * b * b);
 	float G = specular_G1(a, l, n) * specular_G1(a, v, n);
-	float F0 = G;
+	float F0 = 0.04;
 	float F = F0 + (1.0 - F0) *
 		pow(2, ((-5.55473 * ndr - 6.98316), ndr));
-	return (D * F * G) / (4.0 * ndl * ndv);
+	return (D * F * G) / (4.0 * ndl * ndv + 0.001);
 }
 
 void main() {
@@ -159,15 +159,21 @@ void main() {
 	vec3 col = texture(albedo, uv).rgb * material.albedo;
 	float cos_theta_i = max(dot(nrm, light_dir), 0.0);
 	vec3 view_dir = normalize(material.camera_pos - p);
+	float met = texture(metal, uv).r * material.metalness;
 
 	vec3 diffuse =
 		diffuse_brdf(uv) *
+		(1.0 - met) *
 		cos_theta_i;
-	float spec =
+	vec3 spec =
+		mix(1.0.xxx, col, met) *
 		specular_brdf(uv, light_dir, view_dir, nrm) *
 		cos_theta_i;
+	vec3 ambient =
+		min(col, 0.05) *
+		texture(ao, uv).r;
 
-	colour = vec4(diffuse + vec3(spec), 1.0);
+	colour = vec4(ambient + diffuse + spec, 1.0);
 }
 
 #endif
-- 
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