vec4 DistortShadow(vec4 shadowpos, float distortFactor) {
	shadowpos.xy *= 1.0 / distortFactor;
	shadowpos.z = shadowpos.z * 0.2;
	shadowpos = shadowpos * 0.5 + 0.5;

	return shadowpos;
}

void GetShadowSpace(inout vec3 worldposition, inout vec4 vlposition, float shadowdepth, vec2 texCoord) {
	vec4 viewPos = gbufferProjectionInverse * (vec4(texCoord, shadowdepth, 1.0) * 2.0 - 1.0);
	viewPos /= viewPos.w;

	vec4 wpos = gbufferModelViewInverse * viewPos;
	worldposition = wpos.xyz / wpos.w;
	wpos = shadowModelView * wpos;
	wpos = shadowProjection * wpos;
	wpos /= wpos.w;
	
	float distb = sqrt(wpos.x * wpos.x + wpos.y * wpos.y);
	float distortFactor = 1.0 - shadowMapBias + distb * shadowMapBias;
	wpos = DistortShadow(wpos,distortFactor);
	
	#if defined WATER_CAUSTICS && defined OVERWORLD && defined SMOKEY_WATER_LIGHTSHAFTS
		if (isEyeInWater == 1.0) {
			vec3 worldPos = ViewToWorld(viewPos.xyz);
			vec3 causticpos = worldPos.xyz + cameraPosition.xyz;
			float caustic = getCausticWaves(causticpos.xyz * 0.25);
			wpos.xy *= 1.0 + caustic * 0.0125;
		}
	#endif
	
	vlposition = wpos;
}

//Volumetric light from Robobo1221 (highly modified)
vec3 GetVolumetricRays(float depth0, float depth1, vec3 vlAlbedo, float dither, float cosS) {
	vec3 vl = vec3(0.0);

	#if AA > 1
		dither = fract(dither + frameTimeCounter * 16.0);
	#endif
	
	#ifdef OVERWORLD
		float visibility = 0.055;
		if (isEyeInWater == 1) visibility = 0.19;

		float endurance = 1.20;

		#if LIGHT_SHAFT_MODE == 2
			if (isEyeInWater == 0) endurance *= min(2.0 + rainStrengthS*rainStrengthS - sunVisibility * sunVisibility, 2.0);
			else visibility *= 1.0 + 2.0 * pow(max(cosS, 0.0), 128.0) * float(sunVisibility > 0.5) * (1.0 - rainStrengthS);

			if (endurance >= 1.0) visibility *= max((cosS + endurance) / (endurance + 1.0), 0.0);
			else visibility *= pow(max((cosS + 1.0) / 2.0, 0.0), (11.0 - endurance*10.0));
		#else
			if (isEyeInWater == 0) endurance *= min(1.0 + rainStrengthS*rainStrengthS, 2.0);
			else visibility *= 1.0 + 2.0 * pow(max(cosS, 0.0), 128.0) * float(sunVisibility > 0.5) * (1.0 - rainStrengthS);

			if (endurance >= 1.0) cosS = max((cosS + endurance) / (endurance + 1.0), 0.0);
			else cosS = pow(max((cosS + 1.0) / 2.0, 0.0), (11.0 - endurance*10.0));
		#endif
		#ifdef CAVE_SKY_FIX
			visibility *= 1.0 - isEyeInCave;
		#endif
	#endif
	
	#ifdef END
		float visibility = 0.14285;
	#endif

	if (visibility > 0.0) {
		#ifdef END
			float maxDist = 192.0 * (1.5 - isEyeInWater);
		#else
			float maxDist = 288.0;
			if (isEyeInWater == 1) maxDist = min(288.0, shadowDistance * 0.75);
		#endif
		
		vec3 worldposition = vec3(0.0);
		vec4 vlposition = vec4(0.0);
		
		vec3 watercol = underwaterColor.rgb / UNDERWATER_I;
		watercol = pow(watercol, vec3(2.3)) * 55.0;

		#ifdef END
			float minDistFactor = 5.0;
		#else
			float minDistFactor = 11.0;

			minDistFactor *= clamp(far, 128.0, 512.0) / 192.0;

			float fovFactor = gbufferProjection[1][1] / 1.37;
			float x = abs(texCoord.x - 0.5);
			x = 1.0 - x*x;
			x = pow(x, max(3.0 - fovFactor, 0.0));
			minDistFactor *= x;
			maxDist *= x;

			#if LIGHT_SHAFT_MODE == 2
			#else
				float lightBrightnessM = smoothstep(0.0, 1.0, 1.0 - pow2(1.0 - max(timeBrightness, moonBrightness)));
			#endif
		#endif

		#ifdef END
			int sampleCount = 9;
		#else
			float addition = 0.5;

			#if LIGHT_SHAFT_MODE == 2
				int sampleCount = 9;
				if (isEyeInWater == 0) {
					sampleCount = 7;
					minDistFactor *= 0.5;
				}
				float sampleIntensity = 2.5;
			#else
				int sampleCount = 9;
				float sampleIntensity = 1.95;
			#endif
			
			#if LIGHT_SHAFT_QUALITY == 2
				if (isEyeInWater == 0) {
					float qualityFactor = 1.42857;
					#if LIGHT_SHAFT_MODE == 2
						sampleCount = 10;
					#else
						sampleCount = 13;
					#endif
					sampleIntensity /= qualityFactor;
					minDistFactor /= 1.7; // pow(qualityFactor, 1.5)
					addition *= qualityFactor;
				}
			#endif
			#if LIGHT_SHAFT_QUALITY == 3
				if (isEyeInWater == 0) {
					int qualityFactor = 4;
					sampleCount *= qualityFactor;
					sampleIntensity /= qualityFactor;
					minDistFactor /= 8; // pow(qualityFactor, 1.5)
					addition *= qualityFactor;
				}
			#endif
		#endif

		for(int i = 0; i < sampleCount; i++) {
			#ifdef END
				float minDist = exp2(i + dither) - 0.9;
			#else
				float minDist = 0.0;
				if (isEyeInWater == 0) {
				#if LIGHT_SHAFT_MODE == 2
					minDist = pow(i + dither + addition, 1.5) * minDistFactor;
				#else
					minDist = pow(i + dither + addition, 1.5) * minDistFactor * (0.3 - 0.1 * lightBrightnessM);
				#endif	
				} else minDist = pow2(i + dither + 0.5) * minDistFactor * 0.045;
			#endif

			//if (depth0 >= far*0.9999) break;
			if (minDist >= maxDist) break;

			if (depth1 < minDist || (depth0 < minDist && vlAlbedo == vec3(0.0))) break;

			GetShadowSpace(worldposition, vlposition, GetDistX(minDist), texCoord.st);
			//vlposition.z += 0.00002;

			if (length(vlposition.xy * 2.0 - 1.0) < 1.0) {
				vec3 vlsample = vec3(shadow2D(shadowtex0, vlposition.xyz).z);
			
				if (depth0 < minDist) vlsample *= vlAlbedo;

				#ifdef END
					if (isEyeInWater == 1) vlsample *= watercol;
					vl += vlsample;
				#else
					if (isEyeInWater == 0) {
						#if LIGHT_SHAFT_MODE == 2
							vl += vlsample * sampleIntensity;
						#else
							vlsample *= cosS;

							vl += vlsample * sampleIntensity;
						#endif
					} else {
						vlsample *= watercol;
						float sampleFactor = sqrt(minDist / maxDist);

						#if LIGHT_SHAFT_MODE == 3
							vlsample *= cosS;
						#endif

						vl += vlsample * sampleFactor * 0.55;
					}
				#endif
			} else {
				vl += 1.0;
			}
		}
		vl = sqrt(vl * visibility);

		#ifdef END
		#else
			#if LIGHT_SHAFT_MODE == 2
				if (isEyeInWater == 0) {
					float vlPower = max(1.75 - rainStrengthS + sunVisibility*0.25, 1.0);
					vl = pow(vl, vec3(vlPower));
				}
			#else
				if (isEyeInWater == 0) {
					float vlPower = 2.0 - lightBrightnessM;
					vl = pow(vl, vec3(vlPower));
				}
			#endif
		#endif

		vl *= 0.9;
		vl += vl * dither * 0.19;
	}

	#ifdef GBUFFER_CODING
		vl = vec3(0.0);
	#endif
	
	return vl;
}