Point Light with Shadow Casting

Code:
    /////////////////////////////////

    // Caclulate shadow (if any)

    

    @ifdef UseShadowMap && LightType_Spot

        

        @ifdef UseGobo

        @else

            vec4 vProjectedUv = a_mtxSpotViewProj * vec4(vPos,1.0);

        @endif

            

        ////////////////////////

        // No Smoothing

        @ifdef ShadowMapQuality_Low

        

            fAttenuatuion *= shadow2DProj(aShadowMap, vProjectedUv).x;

                    

        ///////////////////////

        // Smoothing

        @else    

            //Set up variables

            float fShadowSum = 0;

            float fJitterZ =0;

            vec2 vScreenJitterCoord = gl_FragCoord.xy * $ShadowJitterLookupMul;

            

            vScreenJitterCoord.y = fract(vScreenJitterCoord.y);     //Make sure the coord is in 0 - 1 range

            vScreenJitterCoord.y *= 1.0 / $ShadowJitterSamplesDiv2;     //Access only first texture piece

                        

                

            ////////////////

            // Shader Model 3, Dynamic Branching available

            @ifdef ShaderModel_4

                ////////////////

                // Cheap pre-test

                //  Note1: division must occur when getting samples else gfx card gets angry.)

                //  Note2: It _must_ be division! doing sample * 1/8 will fail!!

                for(int i=0; i<2.0; i++)

                {

                    vec2 vJitterLookupCoord = vec2(vScreenJitterCoord.x, vScreenJitterCoord.y + fJitterZ);

                    

                    vec4 vOffset = texture2D(aShadowOffsetMap, vJitterLookupCoord) *2.0-1.0;

                                    

                    fShadowSum += ShadowOffsetLookup(aShadowMap, vProjectedUv, vec2(vOffset.xy) * avShadowMapOffsetMul ) / 4.0;

                    fShadowSum += ShadowOffsetLookup(aShadowMap, vProjectedUv, vec2(vOffset.zw) * avShadowMapOffsetMul ) / 4.0;

                                

                    fJitterZ += 1.0 / $ShadowJitterSamplesDiv2;

                }

                

                ////////////////

                // Check if in penumbra

                if( (fShadowSum-1.0) * fShadowSum * fLDotN != 0)

                {     

                    //Multiply, so the X presamples only affect their part (X/all_samples) of samples taken.

                    fShadowSum *= 4.0 / $ShadowJitterSamples; 

                                

                    ////////////////

                    // Fullscale filtering

                    for(int i=0; i<$ShadowJitterSamplesDiv2-2.0; i++)

                    {

                        vec2 vJitterLookupCoord = vec2(vScreenJitterCoord.x, vScreenJitterCoord.y + fJitterZ); //Not that coords are 0-1!

                    

                        vec4 vOffset = texture2D(aShadowOffsetMap, vJitterLookupCoord) *2.0 - 1.0;

                                                            

                        fShadowSum += ShadowOffsetLookup(aShadowMap, vProjectedUv, vec2(vOffset.xy) * avShadowMapOffsetMul ) / $ShadowJitterSamples;

                        fShadowSum += ShadowOffsetLookup(aShadowMap, vProjectedUv, vec2(vOffset.zw) * avShadowMapOffsetMul ) / $ShadowJitterSamples;

                        

                        fJitterZ += 1.0 / $ShadowJitterSamplesDiv2;

                    }

                    

                    //vDiffuse.xyz = vec3(0,0,1);

                }

                /*else

                {

                    if(fShadowSum>0.5)     vDiffuse.xyz = vec3(1,0,0);    

                    else             vDiffuse.xyz = vec3(0,1,0);

                    

                    //fAttenuatuion *= fShadowSum;    

                }*/

            /////////////////////

            // No Dynamic Branching

            @else

                for(int i=0; i<$ShadowJitterSamplesDiv2; i++)

                {

                    vec2 vJitterLookupCoord = vec2(vScreenJitterCoord.x, vScreenJitterCoord.y + fJitterZ);

                    

                    vec4 vOffset = texture2D(aShadowOffsetMap, vJitterLookupCoord) *2.0 - 1.0;

                    

                    fShadowSum += ShadowOffsetLookup(aShadowMap, vProjectedUv, vec2(vOffset.xy) * avShadowMapOffsetMul );

                    fShadowSum += ShadowOffsetLookup(aShadowMap, vProjectedUv, vec2(vOffset.zw) * avShadowMapOffsetMul );

                                

                    fJitterZ += 1.0 / $ShadowJitterSamplesDiv2;

                }

                

                fShadowSum /= $ShadowJitterSamples;

            @endif

            

            

            /////////////////////

            // Add shadow sum to attenuation

            fAttenuatuion *= fShadowSum;

        @endif

        

    

    @endif