float4 unity_LightColor[4];
float4 unity_LightPosition[4];
float4 unity_LightAtten[4];

float4x4 UNITY_MATRIX_MVP;
float4x4 UNITY_MATRIX_MV;
float4x4 UNITY_MATRIX_IT_MV;

struct appdata {
	float4 vertex : POSITION;
	float3 normal : NORMAL;
};

struct v2f {
	half4 pos : POSITION;
	half4 color : TEXCOORD0;
};

float3 ShadeMyVertexLights (float4 vertex, float3 normal)
{
	float3 viewpos = mul(UNITY_MATRIX_MV, vertex).xyz;
	float3 viewN = mul((float3x3) UNITY_MATRIX_IT_MV, normal);
	float3 lightColor = float3(0.0,0.0,0.0);
	
	for (int i = 0; i < 2; i++) {
		float3 toLight = unity_LightPosition[i].xyz - viewpos.xyz;
		float lengthSq = dot(toLight, toLight);
		float atten = 1.0 / (1.0 + lengthSq * unity_LightAtten[i].z);
		float diff = max (0, dot (viewN, normalize(toLight)));
		lightColor += unity_LightColor[i].rgb * (diff * atten);
	}
	return (lightColor * 2.0);
}

v2f main (appdata v)
{
	v2f o;
	o.pos = mul(UNITY_MATRIX_MVP, v.vertex);
	o.color = 0;

	for (int i = 0; i < 2; ++i)
		o.color += unity_LightColor[i];

	// same variable
	for (int i = 0; i < 4; ++i)
		o.color += unity_LightColor[i];

	// different start/end conditions
	for (int j = 3; j >= 0; j = j-1)
		o.color += unity_LightColor[j];

	// scope variables
	for (int i = 0; i < 2; ++i) {
		float4 l = unity_LightColor[i] * unity_LightAtten[i].x;
		o.color += l;
	}

	// scope variables again
	for (int i = 0; i < 2; ++i) {
		float4 l = unity_LightColor[i] * unity_LightAtten[i].z;
		o.color += l;
	}

	// weird loop construct
	int k = 1;
	for (; k < 3; )
	{
		o.color += unity_LightColor[k].x;
		int z = k + 1;
		k = z;
	}

	// nested loops
	for (int x = 0; x < 3; ++x)
	{
		for (int y = 0; y < 3; ++y)
			o.color.xy += float2(x,y);
	}

	return o; 
}