varying vec4 diffuse,ambientGlobal, ambient;
varying vec3 normal,lightDir,halfVector;
varying float dist;

uniform sampler2D texture;

void main()
{
vec4 texel = texture2D(texture,gl_TexCoord[0].st);
	vec3 n,halfV;
	float NdotL,NdotHV;
	vec4 color = ambientGlobal;
	float att,spotEffect;
	
	/* a fragment shader can't write a verying variable, hence we need
	a new variable to store the normalized interpolated normal */
	n = normalize(normal);
	
	/* compute the dot product between normal and ldir */
	NdotL = max(dot(n,normalize(lightDir)),0.0);

	if (NdotL > 0.0) {
	
		spotEffect = dot(normalize(gl_LightSource[0].spotDirection), normalize(-lightDir));
		if (spotEffect > gl_LightSource[0].spotCosCutoff) {
			spotEffect = pow(spotEffect, gl_LightSource[0].spotExponent);
			att = spotEffect / (gl_LightSource[0].constantAttenuation +
					gl_LightSource[0].linearAttenuation * dist +
					gl_LightSource[0].quadraticAttenuation * dist * dist);
				
			color += att * (diffuse * NdotL + ambient) ;
			
			halfV = normalize(halfVector);
			NdotHV = max(dot(n,halfV),0.0);
			color += att * gl_FrontMaterial.specular * gl_LightSource[0].specular * pow(NdotHV,gl_FrontMaterial.shininess);
		}
	}

	gl_FragColor = color * texel.rgba;
}
