/*
--------------------------------------------------------------------------------

  Photon Shader by SixthSurge

  program/gbuffer/weather.glsl:
  Handle rain and snow particles

--------------------------------------------------------------------------------
*/

#include "/include/global.glsl"


//----------------------------------------------------------------------------//
#if defined vsh

out vec2 uv;

flat out vec4 tint;

// ------------
//   Uniforms
// ------------

uniform mat4 gbufferModelView;
uniform mat4 gbufferModelViewInverse;

uniform vec3 cameraPosition;

uniform int frameCounter;

uniform vec2 taa_offset;
uniform vec2 view_pixel_size;

void main() {
	uv = mat2(gl_TextureMatrix[0]) * gl_MultiTexCoord0.xy + gl_TextureMatrix[0][3].xy;

	tint = gl_Color;

	vec3 view_pos = transform(gl_ModelViewMatrix, gl_Vertex.xyz);

#ifdef SLANTED_RAIN
	const float rain_tilt_amount = 0.25;
	const float rain_tilt_angle  = 30.0 * degree;
	const vec2  rain_tilt_offset = rain_tilt_amount * vec2(cos(rain_tilt_angle), sin(rain_tilt_angle));

	vec3 scene_pos = transform(gbufferModelViewInverse, view_pos);
	vec3 world_pos = scene_pos + cameraPosition;

	float tilt_wave = 0.7 + 0.3 * sin(dot(world_pos, vec3(5.0)));
	scene_pos.xz -= rain_tilt_offset * tilt_wave * scene_pos.y;

	view_pos = transform(gbufferModelView, scene_pos);
#endif

	vec4 clip_pos = project(gl_ProjectionMatrix, view_pos);

#if   defined TAA && defined TAAU
	clip_pos.xy  = clip_pos.xy * taau_render_scale + clip_pos.w * (taau_render_scale - 1.0);
	clip_pos.xy += taa_offset * clip_pos.w;
#elif defined TAA
	clip_pos.xy += taa_offset * clip_pos.w * 0.66;
#endif

	gl_Position = clip_pos;
}

#endif
//----------------------------------------------------------------------------//



//----------------------------------------------------------------------------//
#if defined fsh

layout (location = 0) out vec4 scene_color;
layout (location = 1) out vec4 gbuffer_data;

/* RENDERTARGETS: 0,1 */

in vec2 uv;

flat in vec4 tint;

// ------------
//   Uniforms
// ------------

uniform sampler2D gtexture;

uniform int frameCounter;

uniform vec3 sun_dir;

uniform vec2 taa_offset;
uniform vec2 view_pixel_size;

uniform float biome_may_snow;

#include "/include/light/colors/weather_color.glsl"
#include "/include/utility/encoding.glsl"

const uint rain_flag = 253u;
const uint snow_flag = 254u;

void main() {
#if defined TAA && defined TAAU
	vec2 coord = gl_FragCoord.xy * view_pixel_size * rcp(taau_render_scale);
	if (clamp01(coord) != coord) discard;
#endif

	vec4 base_color = texture(gtexture, uv);
	if (base_color.a < 0.1) discard;

	bool is_rain = (abs(base_color.r - base_color.b) > eps);

	scene_color = is_rain
		? vec4(get_rain_color(), RAIN_OPACITY * base_color.a) * tint
		: vec4(get_snow_color(), SNOW_OPACITY * base_color.a) * tint;

	uint material_mask = is_rain ? rain_flag : snow_flag;

	gbuffer_data.x  = pack_unorm_2x8(base_color.rg);
	gbuffer_data.y  = pack_unorm_2x8(base_color.b, float(material_mask) * rcp(255.0));
	gbuffer_data.z  = pack_unorm_2x8(encode_unit_vector(vec3(0.0, 1.0, 0.0)));
	gbuffer_data.w  = pack_unorm_2x8(vec2(1.0));
}

#endif
//----------------------------------------------------------------------------//