Code

package de.simagdo.simagdoRPG.engineTester;

import de.simagdo.simagdoRPG.entities.Camera;
import de.simagdo.simagdoRPG.entities.Entity;
import de.simagdo.simagdoRPG.renderEngine.DisplayManager;
import de.simagdo.simagdoRPG.renderEngine.Loader;
import de.simagdo.simagdoRPG.renderEngine.OBJLoader;
import de.simagdo.simagdoRPG.renderEngine.EntityRenderer;
import de.simagdo.simagdoRPG.models.RawModel;
import de.simagdo.simagdoRPG.models.TextureModel;
import de.simagdo.simagdoRPG.shaders.StaticShader;
import de.simagdo.simagdoRPG.textures.ModelTexture;
import org.lwjgl.opengl.Display;
import org.lwjgl.util.vector.Vector3f;

public class MainGameLoop {

    public static void main(String[] args) {
        DisplayManager.createDisplay();
        Loader loader = new Loader();
        StaticShader shader = new StaticShader();
        Renderer renderer = new Renderer(shader);

        RawModel model = OBJLoader.loadObjModel("stall",loader);
        TextureModel staticModel = new TextureModel(model, new ModelTexture(loader.loadTexture("stallTexture")));
        System.out.println(staticModel.toString());

        Entity entity = new Entity(staticModel, new Vector3f(0, 0, -50), 0, 0, 0, 1);

        Camera camera = new Camera();

        while (!Display.isCloseRequested()) {
            entity.increaseRotation(0, 1, 0);
            camera.move();
            renderer.prepare();
            shader.start();
            shader.loadViewMatrix(camera);
            renderer.render(entity, shader);
            shader.stop();
            DisplayManager.updateDisplay();
        }

        shader.clear();
        loader.clear();
        DisplayManager.closeDisplay();
    }

}

#version 400 core

in vec3 position;
in vec2 textureCoordinates;
in vec3 normal;

out vec2 pass_textureCoordinates;
out vec3 surfaceNormal;
out vec3 toLightVector[4];
out vec3 toCameraVector;
out float visibility;

uniform mat4 transformationMatrix;
uniform mat4 projectionMatrix;
uniform mat4 viewMatrix;
uniform vec3 lightPosition[4];

const float density = 0.007;
const float gradient = 1.5;

void main(void){

	vec4 worldPosition = transformationMatrix * vec4(position,1.0);
	vec4 positionRelativeToCamera = viewMatrix * worldPosition;
	gl_Position = projectionMatrix * positionRelativeToCamera;
	pass_textureCoordinates = textureCoordinates;

	surfaceNormal = (transformationMatrix * vec4(normal,0.0)).xyz;

    for(int i = 0; i < 4; i++) {
        toLightVector[i] = lightPosition[i] - worldPosition.xyz;
    }

	toCameraVector = (inverse(viewMatrix) * vec4(0.0,0.0,0.0,1.0)).xyz - worldPosition.xyz;

    float distance = length(positionRelativeToCamera.xyz);
    visibility = exp(-pow((distance*density),gradient));
    visibility = clamp(visibility,0.0,1.0);

}