Volumetric light pixel shader

void PS_Phong(in float3 inNormal             : TEXCOORD,
              in float3 inCameraDir          : TEXCOORD1,
                          in float3 inWorldPos           : TEXCOORD2,
              out float4 outColor            : COLOR)
{
        outColor = float4(0.0f, 0.0f, 0.0f, 0.0f);

        //renormalize interpolated vectors
        inNormal = normalize(inNormal);
        inCameraDir = normalize(inCameraDir);

        const float shininess = 2;
        const float4 material_ambient = float4(0.05f, 0.05f, 0.05f, 1.0f);
        const float4 material_diffuse = float4(0.30f, 0.30f, 0.30f, 1.0f);
        const float4 material_specular = float4(0.20f, 0.20f, 0.20f, 1.0f);
        int i;

        const float opacity = 0.01;

        const float3 direction = inWorldPos-cameraPos;
        const float distance_to_wall = length(direction);

        float alpha_sum = 0;
        const float3 rayDirection = normalize(direction);

        for (i=0; i<4; i++)
        {
                if (cameraId == i)
                        continue;

                float3 position = cameraPos + normalize(direction)*0.1;

                int playerIndex = i;

                float3 value = float3(0, 0, 0);
                float alpha = 1;
                float distance_from_nearplane = 0;

                while(distance_from_nearplane < distance_to_wall)
                {
                        //float3 distance_2 = length(lightPos[playerIndex] - position);
                        //float lightAttenuation = 1 / pow(distance_2, cameraId+1);
                        float3 distance = lightPos[playerIndex] - position;
                        float lightAttenuation = 1 / dot(distance, distance);

                        float shadow = 1.0f;
                        float lightIntensity=1.1337f;

                        alpha = pow(1-opacity, distance_from_nearplane);
                        alpha_sum += alpha * opacity;
                        value.rgb = (alpha * opacity)*(lightColors[playerIndex] * lightIntensity * lightAttenuation * shadow);

                        distance_from_nearplane = length(position - cameraPos) - 0.1;
                        outColor += float4(value, 0);

                        float rayLength = length(lightPos[playerIndex] - position)/5;
                        position += rayDirection*(rayLength + 0.1);
                }
        }

        for (i = 0; i < MaxLights; ++i)
    {
                float3 lightDirection = (lightPos[i] - inWorldPos);
        float atten = 1.0f / (length(lightDirection)*linearLightFactor + dot(lightDirection, lightDirection)*quadraticLightFactor + constantLightFactor);

        lightDirection = normalize(lightDirection);
        float3 h = normalize(lightDirection + inCameraDir);

        float nDotL = saturate(dot(inNormal, lightDirection));
        float nDotH = saturate(dot(inNormal, h));

        float power = (nDotL == 0.0f) ? 0.0f : pow(nDotH, shininess);

                float4 color = (material_ambient) + (material_diffuse * nDotL);// + (material_specular * power);

                color *= atten;
                color *= shadowBrightness(inWorldPos, i);
                //color *= lightRad[i];

                outColor += color*(1-alpha_sum)*float4(lightColors[i], 1);
    }

        outColor.a = 1;
}