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++ // Copyright (C) 2007-2022 Juan Linietsky, Ariel Manzur.
++ // Copyright (C) 2014-2022 Godot Engine contributors
++ // Copyright (C) 2023 The Qt Company Ltd.
++ // SPDX-License-Identifier: LicenseRef-Qt-Commercial OR GPL-3.0-only AND MIT
++
++ #ifdef QQ3D_SHADER_META
++ /*{
++ "uniforms": [
++ { "type": "vec2", "name": "qt_cameraProperties" },
++ { "type": "vec3", "name": "qt_cameraPosition", "multiview_dependent": true },
++ { "type": "vec4", "name": "qt_fogColor" },
++ { "type": "vec4", "name": "qt_fogDepthProperties" },
++ { "type": "vec4", "name": "qt_fogHeightProperties" },
++ { "type": "vec4", "name": "qt_fogTransmitProperties" }
++ ]
++ }*/
++ #endif // QQ3D_SHADER_META
++
++ // qt_fogColor = (fogColor.x, fogColor.y, fogColor.z, fogDensity)
++ // qt_fogDepthProperties = (fogDepthBegin, fogDepthEnd, fogDepthCurve, fogDepthEnabled ? 1.0 : 0.0)
++ // qt_fogHeightProperties = (fogHeightMin, fogHeightMax, fogHeightCurve, fogHeightEnabled ? 1.0 : 0.0)
++ // qt_fogTransmitProperties = (fogTransmitCurve, 0.0, 0.0, fogTransmitEnabled ? 1.0 : 0.0)
++
++ void calculateFog(inout vec3 emission, inout vec3 specular, inout vec3 diffuse) {
++ float fogAmount = 0.0;
++ vec3 fogColor = qt_fogColor.rgb;
++ if (qt_fogDepthProperties.w > 0.5) {
++ float fogFar = qt_fogDepthProperties.y > 0.0 ? qt_fogDepthProperties.y : qt_cameraProperties.y;
++ #if QSHADER_VIEW_COUNT >= 2
++ float fogZ = smoothstep(qt_fogDepthProperties.x, fogFar, length(qt_cameraPosition[qt_viewIndex] - qt_varWorldPos));
++ #else
++ float fogZ = smoothstep(qt_fogDepthProperties.x, fogFar, length(qt_cameraPosition - qt_varWorldPos));
++ #endif
++ fogAmount = pow(fogZ, qt_fogDepthProperties.z) * qt_fogColor.a;
++ if (qt_fogTransmitProperties.w > 0.5) {
++ vec3 totalLight = emission + specular + diffuse;
++ float transmit = pow(fogZ, qt_fogTransmitProperties.x);
++ fogColor = mix(max(totalLight, fogColor), fogColor, transmit);
++ }
++ }
++ if (qt_fogHeightProperties.w > 0.5) {
++ fogAmount = max(fogAmount, pow(smoothstep(qt_fogHeightProperties.x, qt_fogHeightProperties.y, qt_varWorldPos.y), qt_fogHeightProperties.w));
++ }
++ float fogMod = 1.0 - fogAmount;
++ emission = emission * fogMod + fogColor * fogAmount;
++ specular *= fogMod;
++ diffuse *= fogMod;
++ }