/********************************************************************************/
/*                                                                              */
/*    Noble Shaders                                                             */
/*    Copyright (C) 2026  Belmu                                                 */
/*                                                                              */
/*    This program is free software: you can redistribute it and/or modify      */
/*    it under the terms of the GNU General Public License as published by      */
/*    the Free Software Foundation, either version 3 of the License, or         */
/*    (at your option) any later version.                                       */
/*                                                                              */
/*    This program is distributed in the hope that it will be useful,           */
/*    but WITHOUT ANY WARRANTY; without even the implied warranty of            */
/*    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the             */
/*    GNU General Public License for more details.                              */
/*                                                                              */
/*    You should have received a copy of the GNU General Public License         */
/*    along with this program.  If not, see <https://www.gnu.org/licenses/>.    */
/*                                                                              */
/********************************************************************************/

#include "/settings.glsl"
#include "/include/taau_scale.glsl"

#if defined STAGE_VERTEX

    out vec2 textureCoords;
    out vec2 vertexCoords;
    
    flat out vec3 directIlluminance;
    flat out vec3 skyIlluminance;

    uniform sampler2D colortex5;

    void main() {
        gl_Position    = vec4(gl_Vertex.xy * 2.0 - 1.0, 1.0, 1.0);
        gl_Position.xy = gl_Position.xy * RENDER_SCALE + (RENDER_SCALE - 1.0) * gl_Position.w; + (RENDER_SCALE - 1.0);
        textureCoords  = gl_Vertex.xy;
        vertexCoords   = gl_Vertex.xy * RENDER_SCALE;

        #if defined WORLD_OVERWORLD || defined WORLD_END

            directIlluminance = texelFetch(IRRADIANCE_BUFFER, ivec2(0, 0), 0).rgb;
            skyIlluminance    = texelFetch(IRRADIANCE_BUFFER, ivec2(0, 1), 0).rgb;
            
        #endif
    }

#elif defined STAGE_FRAGMENT

    /* RENDERTARGETS: 11 */

    layout (location = 0) out uvec2 fog;

    in vec2 textureCoords;
    in vec2 vertexCoords;

    flat in vec3 directIlluminance;
    flat in vec3 skyIlluminance;

    #include "/include/common.glsl"

    #include "/include/utility/rng.glsl"

    #include "/include/utility/phase.glsl"
    #include "/include/atmospherics/constants.glsl"

    #if defined WORLD_OVERWORLD || defined WORLD_END
        #include "/include/atmospherics/atmosphere.glsl"
    #endif

    #include "/include/fragment/shadows.glsl"
    #include "/include/atmospherics/fog.glsl"

    void main() {
        fog = uvec2(0);

        #if DOWNSCALED_RENDERING == 1
            vec2 fragCoords = gl_FragCoord.xy * texelSize;
            if (!insideScreenBounds(fragCoords, RENDER_SCALE)) { return; }
        #endif

        float depth0 = texture(depthtex0, vertexCoords).r;
        float depth1 = texture(depthtex1, vertexCoords).r;

        float farPlane = far;

        mat4 projectionInverse = gbufferProjectionInverse;

        #if defined CHUNK_LOADER_MOD_ENABLED

            farPlane = modFarPlane;

            #if defined VOXY
                float modDepth1 = texture(modDepthTex1, textureCoords).r;
            #else
                float modDepth1 = texture(modDepthTex1, vertexCoords).r;
            #endif

            if (depth1 >= 1.0 && ((isEyeInWater == 0) || (isEyeInWater == 1 && modDepth1 < 1.0)) && (depth1 >= 1.0 && depth0 >= 1.0)) {
        
                #if defined VOXY
                    depth0 = texture(modDepthTex0, textureCoords).r;
                    depth1 = modDepth1;
                #else
                    depth0 = texture(modDepthTex0, vertexCoords).r;
                    depth1 = modDepth1;
                #endif
                
                projectionInverse = modProjectionInverse;
            }
            
        #endif

        vec3 viewPosition0  = screenToView(vec3(textureCoords, depth0), projectionInverse, true);
        vec3 viewPosition1  = screenToView(vec3(textureCoords, depth1), projectionInverse, true);
        vec3 scenePosition0 = viewToWorld(viewPosition0);

        vec3 directIlluminanceFinal = directIlluminance;
        
        #if defined WORLD_OVERWORLD || defined WORLD_END

            vec3 tmp = normalize(scenePosition0 - gbufferModelViewInverse[3].xyz);

            #if defined WORLD_OVERWORLD
                float VdotL = dot(tmp, shadowLightVectorWorld);
            #elif defined WORLD_END
                float VdotL = dot(tmp, starVector);
            #endif

        #else

            directIlluminanceFinal = getBlockLightColor();
            float VdotL = 0.0;
            
        #endif

        bool  sky             = depth0 == 1.0;
        bool  skyTranslucents = depth1 == 1.0;

        float skylight = 0.0;

        vec3 scatteringLayer0    = vec3(0.0);
        vec3 transmittanceLayer0 = vec3(1.0);

        vec3 scatteringLayer1    = vec3(0.0);
        vec3 transmittanceLayer1 = vec3(1.0);

        vec3 scatteringLayer2    = vec3(0.0);
        vec3 transmittanceLayer2 = vec3(1.0);

        if (!sky) {
            uvec4 dataTexture = texelFetch(GBUFFERS_DATA, ivec2(vertexCoords * viewSize), 0);

            skylight = getSkylightFalloff(unpackLightmap(dataTexture.x).y);

            if (viewPosition0.z != viewPosition1.z && texture(MAIN_BUFFER, textureCoords).a < 0.99) {

                //////////////////////////////////////////////////////////
                /*---------------- FRONT TO BACK FOG -------------------*/
                //////////////////////////////////////////////////////////

                vec3 scenePosition1 = viewToWorld(viewPosition1);

                if (isEyeInWater != 1 && isWater(unpackId(dataTexture.x))) {

                    #if defined WORLD_OVERWORLD || defined WORLD_END

                        #if WATER_FOG == 0
                            computeWaterFogApproximation(scatteringLayer0, transmittanceLayer0, scenePosition0, scenePosition1, VdotL, directIlluminanceFinal, skyIlluminance, skylight);
                        #else
                            computeVolumetricWaterFog(scatteringLayer0, transmittanceLayer0, scenePosition0, scenePosition1, farPlane, VdotL, directIlluminanceFinal, skyIlluminance, skylight, skyTranslucents);
                        #endif

                    #endif

                } else {

                    #if AIR_FOG == 1
                        computeVolumetricAirFog(scatteringLayer0, transmittanceLayer0, scenePosition0, scenePosition1, viewPosition0, farPlane, VdotL, directIlluminanceFinal, skyIlluminance, skyTranslucents);
                    #elif AIR_FOG == 2
                        computeAirFogApproximation(scatteringLayer0, transmittanceLayer0, viewPosition0, farPlane, VdotL, directIlluminanceFinal, skyIlluminance, skylight);
                    #endif

                }

            }
        } else {
            skylight = 1.0;
        }

        //////////////////////////////////////////////////////////
        /*------------------ EYE TO FRONT FOG ------------------*/
        //////////////////////////////////////////////////////////

        if (isEyeInWater == 1) {

            #if defined WORLD_OVERWORLD || defined WORLD_END

                #if WATER_FOG == 0
                    computeWaterFogApproximation(scatteringLayer1, transmittanceLayer1, gbufferModelViewInverse[3].xyz, scenePosition0, VdotL, directIlluminanceFinal, skyIlluminance, skylight);
                #else
                    computeVolumetricWaterFog(scatteringLayer1, transmittanceLayer1, gbufferModelViewInverse[3].xyz, scenePosition0, farPlane, VdotL, directIlluminanceFinal, skyIlluminance, skylight, sky);
                #endif

            #endif

        } else {

            #if AIR_FOG == 1
                computeVolumetricAirFog(scatteringLayer1, transmittanceLayer1, gbufferModelViewInverse[3].xyz, scenePosition0, viewPosition0, farPlane, VdotL, directIlluminanceFinal, skyIlluminance, sky);
            #elif AIR_FOG == 2
                computeAirFogApproximation(scatteringLayer1, transmittanceLayer1, viewPosition0, farPlane, VdotL, directIlluminanceFinal, skyIlluminance, skylight);
            #endif

        }

        vec3 scattering    = scatteringLayer0    * transmittanceLayer1 + scatteringLayer1 * transmittanceLayer2 + scatteringLayer2;
        vec3 transmittance = transmittanceLayer0 * transmittanceLayer1 * transmittanceLayer2;

        if (scattering != vec3(0.0)) fog.x = encodeRGBE(scattering);
        if (scattering != vec3(1.0)) fog.y = encodeRGBE(transmittance);
    }

#endif
