Have a basic outlining thing with stencils but required a bit of hacking to make it work in Scene::render.

18-depth-testing/shaders/18-frag.glsl

@@ -55,6 +55,10 @@ uniform DirLight dirLights[MAX_LIGHTS];
 uniform int spotLightCount = 0;
 uniform SpotLight spotLights[MAX_LIGHTS];
 
+
+float near = 0.1;
+float far = 100.0;
+
 vec3 CalcDirLight(DirLight light, vec3 normal, vec3 viewDir)
 {
   vec3 mat_tex = vec3(texture(material.diffuse, TexCoords));
@@ -137,6 +141,13 @@ vec3 CalcSpotLight(SpotLight light, vec3 normal, vec3 fragPos, vec3 viewDir)
   return ambient + diffuse + specular;
 }
 
+float LinearizeDepth(float depth)
+{
+  float ndc = depth * 2.0 - 1.0;
+  return (2.0 * near * far) / (far + near - ndc * (far - near));
+}
+
+
 void main()
 {
   vec3 norm = normalize(Normal);
@@ -159,4 +170,7 @@ void main()
   }
 
   FragColor = vec4(result, 1.0);
+
+  // float depth = LinearizeDepth(gl_FragCoord.z) / far;
+  // FragColor = vec4(vec3(depth), 1.0);
 }

18-depth-testing/shaders/18-outline.glsl

@@ -0,0 +1,6 @@
+#version 330 core
+out vec4 FragColor;
+
+void main() {
+  FragColor = vec4(1.0, 0.0, 0.0, 1.0);
+}