/**
 * @ Version: SCREEN SPACE SHADERS - UPDATE 18
 * @ Description: Rain patch normal
 * @ Modified time: 2023-10-09 07:25
 * @ Author: https://www.moddb.com/members/ascii1457
 * @ Mod: https://www.moddb.com/mods/stalker-anomaly/addons/screen-space-shaders
 */

#include "common.h"
#include "lmodel.h"
#include "shadow.h"

#include "screenspace_common_ripples.h"

uniform float4 ssfx_wetsurfaces_1; // Ripples [ Size, Speed, Min Speed, Int ]
uniform float4 ssfx_wetsurfaces_2; // FallWater [ Size, Speed, Min Speed, Int ]

Texture2D	s_water;
Texture2D	s_waterFall;

float4 RainFallof;

float3	GetWaterFall( Texture2D s_texture, float2 tc)
{
	// 0.75 1.5 0.2 0.5

	// Num of columns
	float col_num = 50;
	float col_scale = 1.0 / col_num;

	// Original UV Coors
	float2 tc_ori = tc * ssfx_wetsurfaces_2.x;

	// UV Columns
	float2 col_tc = float2(frac(tc_ori.x * col_num), tc_ori.y);

	// Column ID to add a random offset and adjust horizontal offset
	half col_id = ceil(tc_ori.x * col_num);

	// Random Y-Offset for each column
	float col_offset = hash22(float2(col_id, 1.0));

	// Limit min speed
	col_offset = (col_offset < ssfx_wetsurfaces_2.z ? col_offset * 3.0f : col_offset);

	// Animate
	col_offset += timers.x * col_offset * rain_params.x * ssfx_wetsurfaces_2.y;

	// Add wabbly
	//col_tc.x += sin((tc_ori.y + col_offset) * 20) * 0.5f + 0.5f;

	// Base Bump. Columns UVs, scale and apply offset.
	float3 water = s_texture.Sample(smp_base, (col_tc * float2(col_scale, 1.0f) + float2(col_scale * col_id, col_offset)));

	// Bump to -1.0 ~ 1.0
	water.xyz = water.xzy * 2.0f - 1.0f;

	// Intensity
	water.xyz *= ssfx_wetsurfaces_2.w;

	return water.xyz;
}

#ifndef ISAMPLE
	#define ISAMPLE 0
#endif

#ifdef MSAA_OPTIMIZATION
float4 main ( float2 tc : TEXCOORD0, float2 tcJ : TEXCOORD1, float4	Color	: COLOR, float4 pos2d : SV_Position, uint iSample : SV_SAMPLEINDEX  ) : SV_Target
#else
float4 main ( float2 tc : TEXCOORD0, float2 tcJ : TEXCOORD1, float4	Color	: COLOR, float4 pos2d : SV_Position ) : SV_Target
#endif
{

#ifdef MSAA_OPTIMIZATION
	gbuffer_data gbd = gbuffer_load_data( tc, pos2d, iSample );
#else
	gbuffer_data gbd = gbuffer_load_data( tc, pos2d, ISAMPLE );
#endif

	// Buffers
	float4 _P = float4( gbd.P, 1.0 );
	float3 _N = normalize(gbd.N.xyz);
	float3 _D = gbd.C;
	float _M = gbd.mtl;

	float4 PS = mul( m_shadow,  _P );
	float3 WorldP = mul( m_sunmask, _P );
	float3 WorldN = mul( m_sunmask, _N.xyz );

	// Read rain projection with some jetter. Also adding pixel normal 
	// factor to jitter to make rain strips more realistic.
	float Cover = shadow_rain( PS, WorldP.xz - WorldN.xz );  // Wet Surfaces fix by Diana.Petran

	// Distance
	float p_len = length( _P.xyz );
	bool is_flora = abs(_M - 0.15) < 0.04f;
	bool is_terrain = abs(_M - 0.95) < 0.04f;
	
	// Rain parameters ( Wetness > 0.5 = 100% | Rain Intensity > 0.66 = 100% )
	float Wetness = saturate(rain_params.y * 2.0f);
	float RainInt = clamp(rain_params.x * ssfx_wetsurfaces_1.y, ssfx_wetsurfaces_1.z * (rain_params.x > 0), 2.0f); // 1.5
	
	// [ BUMP ] -------------------------------------------
	float3 waterSplash = 0;
	waterSplash.xy = ssfx_rain_ripples( s_water, WorldP.xz * ssfx_wetsurfaces_1.x, float3(RainInt, ssfx_wetsurfaces_1.w, 6), _P.z); // 0.9

	// Blending weights ( We don't want splashes or fall water on FLORA )
	float3 weights = WorldN.xyz * !is_flora;

	// Water Fall
	float3 waterFallX = GetWaterFall( s_waterFall, WorldP.zy );
	float3 waterFallZ = GetWaterFall( s_waterFall, WorldP.xy );

	// Base bump - Splahes
	float3 water = waterSplash * smoothstep(0.75f, 0.8f, weights.y);

	// Adjust Water fall and add to the Normal
	weights.xz = saturate(abs(weights.xz) - 0.15f);

	weights.xz *= float2(weights.x > weights.z, weights.x < weights.z);

	water += waterFallX.yxz * weights.x;
	water += waterFallZ.zxy * weights.z;

	// HUD attenuations ( Remove Terrain & Flora )
	float HUD_Attenuation = smoothstep( 1.0f, 1.3f, p_len + (is_terrain * 1.3f) ) * !is_flora;

	// Apply attenuations
	water *= HUD_Attenuation * saturate(RainInt) * Cover;

	// Convert normal to view space
	water = mul( m_V, water );

	// Add water normal
	_N = normalize(_N + water.xyz);


	// [ GLOSS ] ------------------------------------------
	float Gloss = (0.15f + saturate(RainInt) * 0.05) * Wetness; // Wetness

	// Fade to full cover. ( RainFallof.y = far shadow rain rendering )
	Cover += smoothstep( RainFallof.y - 20, RainFallof.y, _P.z );

	// If gloss is high, remove cover factor
	Gloss *= HUD_Attenuation * saturate(Cover + (gbd.gloss > 0.3f));

	// Limit gloss on terrain ( Puddles )
	Gloss = (is_terrain && gbd.gloss > 0.3f) ? 0.15f : Gloss;

	// Remove rain gloss from bottom surfaces
	Gloss *= saturate(weights.y * 1.5f);

	//	Apply distance falloff
	Gloss *= smoothstep( 250, 200, p_len );

	return float4( _N.xyz, Gloss );
}