TextureFragmentShader.fragmentshader

#version 330 core

// Interpolated values from the vertex shaders
//in vec4 vs_vertexColor;
in vec2 UV;
in vec3 Position_worldspace;
in vec3 Normal_cameraspace;
in vec3 EyeDirection_cameraspace;
in vec3 LightDirection_cameraspace;
in vec3 Light1Direction_cameraspace;
in vec3 Light2Direction_cameraspace;

// Ouput data
out vec3 color;

// Values that stay constant for the whole mesh.
uniform mat4 MV;
uniform vec3 LightPosition_worldspace;
uniform vec3 Light1Position_worldspace;
uniform vec3 Light2Position_worldspace;
uniform sampler2D myTextureSampler;

void main(){

	// Light emission properties
	// You probably want to put them as uniforms
	vec3 LightColor = vec3(1,1,1);
        vec3 Light1Color = vec3(0.5,0,0.5);
        vec3 Light2Color = vec3(0.5,0.5,0);
        float LightPower = 200.0f;
        float Light1Power = 50.0f;
        float Light2Power = 50.0f;
	
	// Material properties
	//vec3 MaterialDiffuseColor = vs_vertexColor.rgb;
	vec3 MaterialDiffuseColor = texture( myTextureSampler, UV ).rgb;
        vec3 MaterialAmbientColor = vec3(0.9,0.9,0.9) * texture( myTextureSampler, UV ).rgb;
        vec3 MaterialSpecularColor = vec3(0.3,0.3,0.3) * texture( myTextureSampler, UV ).rgb;

	// Distance to the light
	float distance = length( LightPosition_worldspace - Position_worldspace );
        float distance1 = length(Light1Position_worldspace - Position_worldspace);
        float distance2 = length(Light2Position_worldspace - Position_worldspace);

	// Normal of the computed fragment, in camera space
	vec3 n = normalize( Normal_cameraspace );
	// Direction of the light (from the fragment to the light)
	vec3 l = normalize( LightDirection_cameraspace );
        vec3 l1 = normalize( Light1Direction_cameraspace );
        vec3 l2 = normalize( Light2Direction_cameraspace );
	// Cosine of the angle between the normal and the light direction, 
	// clamped above 0
	//  - light is at the vertical of the triangle -> 1
	//  - light is perpendicular to the triangle -> 0
	//  - light is behind the triangle -> 0
	float cosTheta = clamp( dot( n,l ), 0,1 );
        float cosTheta1 = clamp( dot( n, l1 ), 0, 1);
        float cosTheta2 = clamp( dot( n, l2 ), 0, 1);
	
	// Eye vector (towards the camera)
	vec3 E = normalize(EyeDirection_cameraspace);
	// Direction in which the triangle reflects the light
	vec3 R = reflect(-l,n);
        vec3 R1 = reflect(-l1, n);
        vec3 R2 = reflect(-l2, n);
	// Cosine of the angle between the Eye vector and the Reflect vector,
	// clamped to 0
	//  - Looking into the reflection -> 1
	//  - Looking elsewhere -> < 1
        float cosAlpha = clamp( dot( E,R ), 0,1 );
        float cosAlpha1 = clamp( dot( E, R1 ), 0, 1);
        float cosAlpha2 = clamp( dot( E, R2 ), 0, 1);
	
	//color = vs_vertexColor.rgb;
        //color = texture( myTextureSampler, UV ).rgb;

        color =
		// Ambient : simulates indirect lighting
		MaterialAmbientColor +
		// Diffuse : "color" of the object
		MaterialDiffuseColor * LightColor * LightPower * cosTheta / (distance*distance) +
                MaterialDiffuseColor * Light1Color * Light1Power * cosTheta1 / (distance1 * distance1) +
                MaterialDiffuseColor * Light2Color * Light2Power * cosTheta2 / (distance2 * distance2) +
		// Specular : reflective highlight, like a mirror
                MaterialSpecularColor * LightColor * LightPower * pow(cosAlpha,5) / (distance*distance) +
                MaterialSpecularColor * Light1Color * Light1Power * pow(cosAlpha1,5) / (distance1 * distance1) +
                MaterialSpecularColor * Light2Color * Light2Power * pow(cosAlpha2,5) / (distance2 * distance2);
}