Now have multiple lights.

13-multiple-lights/shaders/11-lightsource.frag.glsl

@@ -0,0 +1,16 @@
+#version 330 core
+out vec4 FragColor;
+
+struct Light {
+  vec3 position;
+  vec3 ambient;
+  vec3 diffuse;
+  vec3 specular;
+};
+
+uniform Light light;
+
+void main()
+{
+    FragColor = vec4(light.diffuse, 1.0); // set all 4 vector values to 1.0
+}