Add Skybox Example (#5)

* added skybox example

* use existing resource directory

examples/models/resources/shaders/skybox.fs

@@ -8,24 +8,24 @@
 
 #version 330
 
-# Input vertex attributes (from vertex shader)
-in vec3 fragPos
+// Input vertex attributes (from vertex shader)
+in vec3 fragPosition;
 
-# Input uniform values
-uniform samplerCube environmentMap
+// Input uniform values
+uniform samplerCube environmentMap;
 
-# Output fragment color
-out vec4 finalColor
+// Output fragment color
+out vec4 finalColor;
 
 void main()
-[
-    # Fetch color from texture map
-    vec3 color = texture(environmentMap, fragPos).rgb
+{
+    // Fetch color from texture map
+    vec3 color = texture(environmentMap, fragPosition).rgb;
 
-    # Apply gamma correction
-    color = color/(color + vec3(1.0))
-    color = pow(color, vec3(1.0/2.2))
+    // Apply gamma correction
+    color = color/(color + vec3(1.0));
+    color = pow(color, vec3(1.0/2.2));
 
-    # Calculate final fragment color
-    finalColor = vec4(color, 1.0)
-]
+    // Calculate final fragment color
+    finalColor = vec4(color, 1.0);
+}