feat: map diffuse lighting to gradient

frag_lit.glsl

@@ -7,21 +7,22 @@ out vec4 FragColor;
 
 void main()
 {
-    vec3 objectColor = vec3(1.0, 0.5, 0.2);
+    vec3 objectColor = vec3(1.0, 1.0, 1.0);
     vec3 result;
 
     // Ambient lighting
     vec3 ambientLightColor = vec3(1.0, 1.0, 1.0);
-    float ambientStrength = 0.1;
+    float ambientStrength = 0.0;
     vec3 ambient = ambientStrength * ambientLightColor;
 
     // Directional lighting
-    vec3 directionalLightColor = vec3(1.0, 1.0, 1.0);
+    vec3 dirColorHi = vec3(.39, .40, .21) * 2.0;
+    vec3 dirColorLo = vec3(.45, .22, .33) * 2.0;
     vec3 lightPos = vec3(10.0, 7.0, -8.0);
     vec3 normal = normalize(Normal);
     vec3 lightDir = normalize(lightPos - FragPos);
-    float diff = max(dot(normal, lightDir), 0.0);
-    vec3 diffuse = diff * directionalLightColor;
+    float diff = dot(normal, lightDir) * .5 + .5;
+    vec3 diffuse = mix(dirColorLo, dirColorHi, diff);
 
     result = (ambient + diffuse) * objectColor;