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diff --git a/source/lessons/lighting/shaders/light_subject.fs.glsl b/source/lessons/lighting/shaders/light_subject.fs.glsl
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+#version 330 core
+
+/*
+@note: an explanation of why the light direction vector is taken from fragment to the 
+light source.
+Basic LA really, we need to calculate the angle between the direction of the 2 vectors:
+ a. The direction at which light incidents with the fragment
+ b. The normal vector
+The reason the light direction is taken from the fragment to the light source, is precisely so we can calculate
+the angle between the normal and the direction at which light would hit. This if taken as starting from the light
+source would actually be incorrect, since we would be calculating the angle between the light source in the direction
+of the fragment and the normal. Consider what happens when it is directly above. The angle becomes 180, not 0. This 
+is because the normal moves in the direction opposite to the lights direction if taken this way, which is not what
+we expect or want.
+Reversing this, allows us to consider the angle at the point in which light hits the fragment, and the normal vector
+of the fragment. 
+*/
+
+struct Material {
+  sampler2D diffuse;
+  sampler2D specular;
+  float shininess;
+};
+
+struct Light {
+  vec3 ambient;
+  vec3 diffuse;
+  vec3 specular;
+
+  vec3 position;
+};
+
+struct DirectionalLight {
+  vec3 direction;
+
+  vec3 ambient;
+  vec3 diffuse;
+  vec3 specular;
+};
+
+struct PointLight {
+  vec3 position;
+
+  vec3 ambient;
+  vec3 diffuse;
+  vec3 specular;
+
+  // attentuation factors
+  float kC;
+  float kL;
+  float kQ;
+};
+
+struct SpotLight {
+  vec3 position;
+
+  vec3 ambient;
+  vec3 diffuse;
+  vec3 specular;
+
+  // attenuation factors
+  float kC;
+  float kL;
+  float kQ;
+
+  // vector for the direction directly in front of the spotlight
+  vec3 front;
+
+  // spot radius
+  float radius_inner;
+  float radius_outer; // to smooth out the light
+
+};
+
+// this is the result of a light creation. This contains the multipliers for each kind of a light we want
+// to have.
+struct LightFactor {
+  vec3 ambient;
+  vec3 diffuse;
+  vec3 specular;
+};
+
+in vec2 texCoords;
+in vec3 fragNormal;
+in vec3 worldPosition;
+
+uniform Material  material;
+
+uniform Light     light;
+uniform DirectionalLight dirLight;
+uniform PointLight pointLight;
+uniform PointLight multiPointLight[4];
+uniform SpotLight spotLight;
+
+uniform vec3			cameraPosition;
+uniform vec3      lightColor;
+
+out vec4 FragColor;
+
+LightFactor make_directional_light(DirectionalLight light, vec3 CONST_viewDir) {
+  LightFactor res;
+
+  vec3 DL_lightDir = normalize(-light.direction);
+  res.ambient = light.ambient;
+
+  float DL_diffuseStrength = max(dot(DL_lightDir, fragNormal), 0.0);
+  res.diffuse = light.diffuse * DL_diffuseStrength;
+
+  vec3  DL_reflectDir	    = reflect(-DL_lightDir, fragNormal);
+  float DL_specularity		= max(dot(CONST_viewDir, DL_reflectDir), 0.0);
+  float DL_shinePower			= pow(DL_specularity, material.shininess);
+  res.specular	= light.specular * DL_shinePower;
+
+  return res;
+};
+
+LightFactor make_point_light(PointLight light, vec3 CONST_viewDir) {
+  LightFactor res;
+
+  float PL_lightDistance = length(light.position - worldPosition);
+  float PL_attenuationFactor = 1.0 / 
+  (light.kC + (light.kL * PL_lightDistance) + (light.kQ * PL_lightDistance * PL_lightDistance));
+  res.ambient = PL_attenuationFactor * light.ambient;
+
+  vec3 PL_lightDir = normalize(light.position - worldPosition);
+  float PL_diffuseStrength = max(dot(PL_lightDir, fragNormal), 0.0);
+  res.diffuse = PL_attenuationFactor * light.diffuse * PL_diffuseStrength;
+
+  vec3  PL_reflectDir		= reflect(-PL_lightDir, fragNormal);
+  float PL_specularity	= max(dot(CONST_viewDir, PL_reflectDir), 0.0);
+  float PL_shinePower		= pow(PL_specularity, material.shininess);
+  res.specular		      = PL_attenuationFactor * PL_shinePower * light.specular;
+
+  return res;
+}
+
+LightFactor make_spot_light(SpotLight light, vec3 CONST_viewDir) {
+  LightFactor res;
+
+  float SL_lightDistance = length(light.position - worldPosition);
+  float SL_attenuationFactor = 1.0 / 
+  (light.kC + (light.kL * SL_lightDistance) + (light.kQ * SL_lightDistance * SL_lightDistance));
+  vec3 SL_lightDir = normalize(light.position - worldPosition);
+
+  res.ambient = SL_attenuationFactor * light.ambient;
+
+  float SL_diffAmount = dot(SL_lightDir, normalize(-light.front));
+  float SL_spotLightFadeFactor = clamp((SL_diffAmount - light.radius_outer)/(light.radius_inner - light.radius_outer), 0.0f, 1.0f);
+  float SL_diffuseStrength = max(dot(SL_lightDir, fragNormal), 0.0);
+  res.diffuse = SL_spotLightFadeFactor * SL_attenuationFactor * light.diffuse * SL_diffuseStrength;
+
+  vec3  SL_reflectDir		= reflect(-SL_lightDir, fragNormal);
+  float SL_specularity	= max(dot(CONST_viewDir, SL_reflectDir), 0.0);
+  float SL_shinePower		= pow(SL_specularity, material.shininess);
+  res.specular		      = SL_spotLightFadeFactor * SL_attenuationFactor * SL_shinePower * light.specular;
+
+  return res;
+}
+
+void main() {
+     vec3  CONST_viewDir		  = normalize(cameraPosition - worldPosition);
+     vec3 combinedAmbience = vec3(0.0);
+     vec3 combinedDiffuse  = vec3(0.0);
+     vec3 combinedSpecular = vec3(0.0);
+
+     // directional light calculations and stuff
+     //LightFactor DL_factors = make_directional_light(dirLight, CONST_viewDir);
+     //combinedAmbience += DL_factors.ambient;
+     //combinedDiffuse += DL_factors.diffuse;
+     //combinedSpecular += DL_factors.specular;
+
+     // pointlight calculations and stuff
+     //LightFactor PL_factors = make_point_light(pointLight, CONST_viewDir);
+     //combinedAmbience += PL_factors.ambient;
+     //combinedDiffuse += PL_factors.diffuse;
+     //combinedSpecular += PL_factors.specular;
+
+     // multiple point lights
+     for (int i=0; i<4; i++)
+     {
+       PointLight pl = multiPointLight[i];
+       LightFactor MPL_factors = make_point_light(pl, CONST_viewDir);
+       combinedAmbience += MPL_factors.ambient;
+       combinedDiffuse += MPL_factors.diffuse;
+       combinedSpecular += MPL_factors.specular;
+     }
+
+     // spotlight calculations
+     LightFactor SL_factors = make_spot_light(spotLight, CONST_viewDir);
+     combinedAmbience += SL_factors.ambient;
+     combinedDiffuse += SL_factors.diffuse;
+     combinedSpecular += SL_factors.specular;
+
+     vec3 ambientLight  = combinedAmbience * vec3(texture(material.diffuse, texCoords));
+     vec3 diffuseLight  = combinedDiffuse  * vec3(texture(material.diffuse, texCoords));
+     vec3 specularLight = combinedSpecular * vec3(texture(material.specular, texCoords));
+
+     vec3 color = ambientLight + diffuseLight + specularLight;
+     FragColor = vec4(color, 1.0);
+}