From 96f1e23a54a8028cd771585a950c8f5a614dd443 Mon Sep 17 00:00:00 2001
From: Dane Johnson <dane_johnson@ymail.com>
Date: Thu, 21 Jan 2021 15:35:21 -0600
Subject: [PATCH] Fix diffuse lighting

---
 shaders/flat.frag | 8 ++++++--
 shaders/flat.vert | 2 +-
 2 files changed, 7 insertions(+), 3 deletions(-)

diff --git a/shaders/flat.frag b/shaders/flat.frag
index f099139..4abea14 100644
--- a/shaders/flat.frag
+++ b/shaders/flat.frag
@@ -39,7 +39,11 @@ void main() {
 
   if (!material.unshaded) {
     vec3 ambient = directionalLight.ambient * directionalLight.color;
-    vec3 diffuse = directionalLight.diffuse * reflect(directionalLight.direction, NORMAL) * directionalLight.color;
-    FragColor *= vec4(ambient, 1.0);
+    ambient = max(ambient, 0.0);
+    
+    vec3 diffuse = directionalLight.diffuse * dot(directionalLight.direction, NORMAL) * directionalLight.color;
+    diffuse = max(diffuse, 0.0);
+    
+    FragColor *= vec4(ambient + diffuse, 1.0);
   }
 }
diff --git a/shaders/flat.vert b/shaders/flat.vert
index 0c248b6..89102ab 100644
--- a/shaders/flat.vert
+++ b/shaders/flat.vert
@@ -15,5 +15,5 @@ void main() {
   vec4 vertex = PROJECTION * VIEW * MODEL * vec4(pos, 1.0);
   gl_Position = vertex;
   UV = vec3(uv * vertex.z, vertex.z);
-  NORMAL = normal;
+  NORMAL = (PROJECTION * VIEW * MODEL * vec4(normal, 0.0)).xyz;
 }