Reviewed shaders and added comments

examples/resources/shaders/glsl330/phong.vs

@@ -0,0 +1,29 @@
+#version 330
+
+// Input vertex attributes
+in vec3 vertexPosition;
+in vec2 vertexTexCoord;
+in vec3 vertexNormal;
+
+// Input uniform values
+uniform mat4 mvpMatrix;
+
+// Output vertex attributes (to fragment shader)
+out vec2 fragTexCoord;
+out vec3 fragNormal;
+
+// NOTE: Add here your custom variables
+uniform mat4 modelMatrix;
+
+void main()
+{
+    // Send vertex attributes to fragment shader
+    fragTexCoord = vertexTexCoord;
+
+    // Calculate view vector normal from model
+    mat3 normalMatrix = transpose(inverse(mat3(modelMatrix)));
+    fragNormal = normalize(normalMatrix*vertexNormal);
+    
+    // Calculate final vertex position
+    gl_Position = mvpMatrix*vec4(vertexPosition, 1.0);
+}