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Source/Engine/Level/Actors/ExponentialHeightFog.h

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+// Copyright (c) 2012-2020 Wojciech Figat. All rights reserved.
+
+#pragma once
+
+#include "../Actor.h"
+#include "Engine/Scripting/ScriptingObjectReference.h"
+#include "Engine/Renderer/DrawCall.h"
+#include "Engine/Content/Assets/Shader.h"
+#include "Engine/Content/AssetReference.h"
+#include "Engine/Graphics/GPUPipelineStatePermutations.h"
+
+/// <summary>
+/// Used to create fogging effects such as clouds but with a density that is related to the height of the fog.
+/// </summary>
+API_CLASS() class FLAXENGINE_API ExponentialHeightFog : public Actor, public IFogRenderer
+{
+DECLARE_SCENE_OBJECT(ExponentialHeightFog);
+private:
+
+    AssetReference<Shader> _shader;
+    GPUPipelineStatePermutationsPs<2> _psFog;
+
+public:
+
+    /// <summary>
+    /// The fog density factor.
+    /// </summary>
+    API_FIELD(Attributes="EditorOrder(10), DefaultValue(0.02f), Limit(0.000001f, 0.8f, 0.001f), EditorDisplay(\"Exponential Height Fog\")")
+    float FogDensity = 0.02f;
+
+    /// <summary>
+    /// The fog height density factor that controls how the density increases as height decreases. The smaller values produce more visible transition larger.
+    /// </summary>
+    API_FIELD(Attributes="EditorOrder(20), DefaultValue(0.2f), Limit(0.001f, 2.0f, 0.001f), EditorDisplay(\"Exponential Height Fog\")")
+    float FogHeightFalloff = 0.2f;
+
+    /// <summary>
+    /// Color of the fog.
+    /// </summary>
+    API_FIELD(Attributes="EditorOrder(30), DefaultValue(typeof(Color), \"0.448,0.634,1.0\"), EditorDisplay(\"Exponential Height Fog\")")
+    Color FogInscatteringColor = Color(0.448f, 0.634f, 1.0f);
+
+    /// <summary>
+    /// Maximum opacity of the fog.
+    /// A value of 1 means the fog can become fully opaque at a distance and replace scene color completely.
+    /// A value of 0 means the fog color will not be factored in at all.
+    /// </summary>
+    API_FIELD(Attributes="EditorOrder(40), DefaultValue(1.0f), Limit(0, 1, 0.001f), EditorDisplay(\"Exponential Height Fog\")")
+    float FogMaxOpacity = 1.0f;
+
+    /// <summary>
+    /// Distance from the camera that the fog will start, in world units.
+    /// </summary>
+    API_FIELD(Attributes="EditorOrder(50), DefaultValue(0.0f), Limit(0), EditorDisplay(\"Exponential Height Fog\")")
+    float StartDistance = 0.0f;
+
+    /// <summary>
+    /// Scene elements past this distance will not have fog applied. This is useful for excluding skyboxes which already have fog baked in.
+    /// </summary>
+    API_FIELD(Attributes="EditorOrder(60), DefaultValue(0.0f), Limit(0), EditorDisplay(\"Exponential Height Fog\")")
+    float FogCutoffDistance = 0.0f;
+
+public:
+
+    /// <summary>
+    /// Directional light used for Directional Inscattering.
+    /// </summary>
+    API_FIELD(Attributes="EditorOrder(200), DefaultValue(null), EditorDisplay(\"Directional Inscattering\", \"Light\")")
+    ScriptingObjectReference<DirectionalLight> DirectionalInscatteringLight;
+
+    /// <summary>
+    /// Controls the size of the directional inscattering cone, which is used to approximate inscattering from a directional light.
+    /// Note: there must be a directional light enabled for DirectionalInscattering to be used. Range: 2-64.
+    /// </summary>
+    API_FIELD(Attributes="EditorOrder(210), DefaultValue(4.0f), Limit(2, 64, 0.1f), EditorDisplay(\"Directional Inscattering\", \"Exponent\")")
+    float DirectionalInscatteringExponent = 4.0f;
+
+    /// <summary>
+    /// Controls the start distance from the viewer of the directional inscattering, which is used to approximate inscattering from a directional light.
+    /// Note: there must be a directional light enabled for DirectionalInscattering to be used.
+    /// </summary>
+    API_FIELD(Attributes="EditorOrder(220), DefaultValue(10000.0f), Limit(0), EditorDisplay(\"Directional Inscattering\", \"Start Distance\")")
+    float DirectionalInscatteringStartDistance = 10000.0f;
+
+    /// <summary>
+    /// Controls the color of the directional inscattering, which is used to approximate inscattering from a directional light.
+    /// Note: there must be a directional light enabled for DirectionalInscattering to be used.
+    /// </summary>
+    API_FIELD(Attributes="EditorOrder(230), DefaultValue(typeof(Color), \"0.25,0.25,0.125\"), EditorDisplay(\"Directional Inscattering\", \"Color\")")
+    Color DirectionalInscatteringColor = Color(0.25, 0.25f, 0.125f);
+
+public:
+
+    /// <summary>
+    /// Whether to enable Volumetric fog. Graphics quality settings control the resolution of the fog simulation.
+    /// </summary>
+    API_FIELD(Attributes="EditorOrder(300), DefaultValue(false), EditorDisplay(\"Volumetric Fog\", \"Enable\")")
+    bool VolumetricFogEnable = false;
+
+    /// <summary>
+    /// Controls the scattering phase function - how much incoming light scatters in various directions.
+    /// A distribution value of 0 scatters equally in all directions, while 0.9 scatters predominantly in the light direction.
+    /// In order to have visible volumetric fog light shafts from the side, the distribution will need to be closer to 0. Range: -0.9-0.9.
+    /// </summary>
+    API_FIELD(Attributes="EditorOrder(310), DefaultValue(0.2f), Limit(-0.9f, 0.9f, 0.001f), EditorDisplay(\"Volumetric Fog\", \"Scattering Distribution\")")
+    float VolumetricFogScatteringDistribution = 0.2f;
+
+    /// <summary>
+    /// The height fog particle reflectiveness used by volumetric fog.
+    /// Water particles in air have an albedo near white, while dust has slightly darker value.
+    /// </summary>
+    API_FIELD(Attributes="EditorOrder(320), DefaultValue(typeof(Color), \"1,1,1,1\"), EditorDisplay(\"Volumetric Fog\", \"Albedo\")")
+    Color VolumetricFogAlbedo = Color::White;
+
+    /// <summary>
+    /// Light emitted by height fog. This is a density so more light is emitted the further you are looking through the fog.
+    /// In most cases using a Skylight is a better choice, however, it may be useful in certain scenarios.
+    /// </summary>
+    API_FIELD(Attributes="EditorOrder(330), DefaultValue(typeof(Color), \"0,0,0,1\"), EditorDisplay(\"Volumetric Fog\", \"Emissive\")")
+    Color VolumetricFogEmissive = Color::Black;
+
+    /// <summary>
+    /// Scales the height fog particle extinction amount used by volumetric fog.
+    /// Values larger than 1 cause fog particles everywhere absorb more light. Range: 0.1-10.
+    /// </summary>
+    API_FIELD(Attributes="EditorOrder(340), DefaultValue(1.0f), Limit(0.1f, 10, 0.1f), EditorDisplay(\"Volumetric Fog\", \"Extinction Scale\")")
+    float VolumetricFogExtinctionScale = 1.0f;
+
+    /// <summary>
+    /// Distance over which volumetric fog should be computed. Larger values extend the effect into the distance but expose under-sampling artifacts in details.
+    /// </summary>
+    API_FIELD(Attributes="EditorOrder(350), DefaultValue(6000.0f), Limit(0), EditorDisplay(\"Volumetric Fog\", \"Distance\")")
+    float VolumetricFogDistance = 6000.0f;
+
+private:
+
+#if COMPILE_WITH_DEV_ENV
+    void OnShaderReloading(Asset* obj)
+    {
+        _psFog.Release();
+    }
+#endif
+
+public:
+
+    // [Actor]
+#if USE_EDITOR
+    BoundingBox GetEditorBox() const override
+    {
+        const Vector3 size(50);
+        return BoundingBox(_transform.Translation - size, _transform.Translation + size);
+    }
+#endif
+    void Draw(RenderContext& renderContext) override;
+    void Serialize(SerializeStream& stream, const void* otherObj) override;
+    void Deserialize(DeserializeStream& stream, ISerializeModifier* modifier) override;
+    bool HasContentLoaded() const override;
+    bool IntersectsItself(const Ray& ray, float& distance, Vector3& normal) override;
+
+    // [IFogRenderer]
+    void GetVolumetricFogOptions(VolumetricFogOptions& result) const override;
+    void GetExponentialHeightFogData(const RenderView& view, ExponentialHeightFogData& result) const override;
+    void DrawFog(GPUContext* context, RenderContext& renderContext, GPUTextureView* output) override;
+
+protected:
+
+    // [Actor]
+    void OnEnable() override;
+    void OnDisable() override;
+    void OnTransformChanged() override;
+};