|
|
@@ -9,12 +9,13 @@ Introduction
|
|
|
Light sources emit light that mixes with the materials and produces a visible
|
|
|
result. Light can come from several types of sources in a scene:
|
|
|
|
|
|
-- From the Material itself in the form of the emission color (though
|
|
|
- it does not affect nearby objects unless baked).
|
|
|
-- Light Nodes: Directional, Omni and Spot.
|
|
|
-- Ambient Light in the
|
|
|
- :ref:`Environment <class_Environment>`.
|
|
|
-- Baked Light (read :ref:`doc_using_lightmap_gi`).
|
|
|
+- From the material itself, in the form of the emission color (though it does
|
|
|
+ not affect nearby objects unless baked or screen-space indirect lighting is enabled).
|
|
|
+- Light nodes: DirectionalLight3D, OmniLight3D and SpotLight3D.
|
|
|
+- Ambient light in the :ref:`Environment <class_Environment>` or
|
|
|
+ :ref:`doc_reflection_probes`.
|
|
|
+- Global illumination (:ref:`LightmapGI <doc_using_lightmap_gi>`,
|
|
|
+ :ref:`VoxelGI <doc_using_voxel_gi>` or :ref:`SDFGI <doc_using_sdfgi>`).
|
|
|
|
|
|
The emission color is a material property. You can read more about it
|
|
|
in the :ref:`doc_standard_material_3d` tutorial.
|
|
|
@@ -22,30 +23,73 @@ in the :ref:`doc_standard_material_3d` tutorial.
|
|
|
Light nodes
|
|
|
-----------
|
|
|
|
|
|
-There are three types of light nodes: `Directional light`_,
|
|
|
-`Omni light`_ and `Spot light`_. Let's take a look at the common
|
|
|
+There are three types of light nodes: :ref:`class_DirectionalLight3D`,
|
|
|
+:ref:`class_OmniLight3D` and :ref:`class_SpotLight3D`. Let's take a look at the common
|
|
|
parameters for lights:
|
|
|
|
|
|
.. image:: img/light_params.png
|
|
|
|
|
|
-Each one has a specific function:
|
|
|
+Each property has a specific function:
|
|
|
|
|
|
-- **Color**: Base color for emitted light.
|
|
|
-- **Energy**: Energy multiplier. This is useful for saturating lights or working with :ref:`doc_high_dynamic_range`.
|
|
|
-- **Indirect Energy**: Secondary multiplier used with indirect light (light bounces). This works in baked light or GIProbe.
|
|
|
-- **Negative**: Light becomes subtractive instead of additive. It's sometimes useful to manually compensate some dark corners.
|
|
|
-- **Specular**: Affects the intensity of the specular blob in objects affected by this light. At zero, this light becomes a pure diffuse light.
|
|
|
-- **Bake Mode**: Sets the bake mode for the light. For more information see :ref:`doc_using_lightmap_gi`
|
|
|
-- **Cull Mask**: Objects that are in the selected layers below will be affected by this light.
|
|
|
- Note that objects disabled via this cull mask will still cast shadows.
|
|
|
- If you don't want disabled objects to cast shadows, adjust the ``cast_shadow`` property on the
|
|
|
- GeometryInstance to the desired value.
|
|
|
+- **Color:** Base color for emitted light.
|
|
|
+- **Energy:** Energy multiplier. This is useful for saturating lights or working with :ref:`doc_high_dynamic_range`.
|
|
|
+- **Indirect Energy:** Secondary multiplier used with indirect light (light bounces). This works with :ref:`doc_using_lightmap_gi`, VoxelGI or SDFGI.
|
|
|
+- **Volumetric Fog Energy:** Secondary multiplier used with volumetric fog. This only has an effect when volumetric fog is enabled.
|
|
|
+- **Negative:** Light becomes subtractive instead of additive. It's sometimes useful to manually compensate some dark corners.
|
|
|
+- **Specular:** Affects the intensity of the specular blob in objects affected by this light. At zero, this light becomes a pure diffuse light.
|
|
|
+- **Bake Mode:** Sets the bake mode for the light. See :ref:`doc_using_lightmap_gi`.
|
|
|
+- **Cull Mask:** Objects that are in the selected layers below will be affected by this light.
|
|
|
+ Note that objects disabled via this cull mask will still cast shadows.
|
|
|
+ If you don't want disabled objects to cast shadows, adjust the **Cast Shadow**
|
|
|
+ property on the GeometryInstance3D to the desired value.
|
|
|
|
|
|
.. seealso::
|
|
|
|
|
|
See :ref:`doc_physical_light_and_camera_units` if you wish to use real world
|
|
|
units to configure your lights' intensity and color temperature.
|
|
|
|
|
|
+Light number limits
|
|
|
+-------------------
|
|
|
+
|
|
|
+When using the Forward+ renderer, Godot uses a *clustering* approach for
|
|
|
+real-time lighting. As many lights as desired can be added (as long as
|
|
|
+performance allows). However, there's still a default limit of 512 *clustered
|
|
|
+elements* that can be present in the current camera view. A clustered element is
|
|
|
+an omni light, a spot light, a :ref:`decal <doc_using_decals>` or a
|
|
|
+:ref:`reflection probe <doc_reflection_probes>`. This limit can be increased by
|
|
|
+adjusting the **Rendering > Limits > Cluster Builder > Max Clustered Elements**
|
|
|
+advanced project setting.
|
|
|
+
|
|
|
+When using the Forward Mobile renderer, there is a limitation of 8 OmniLights +
|
|
|
+8 SpotLights per mesh resource. There is also a limit of 256 OmniLights + 256
|
|
|
+SpotLights that can be rendered in the current camera view. These limits
|
|
|
+currently cannot be changed.
|
|
|
+
|
|
|
+When using the Compatibility renderer, up to 8 OmniLights + 8 SpotLights can be
|
|
|
+rendered per mesh resource. This limit can be increased in the advanced Project
|
|
|
+Settings by adjusting **Rendering > Limits > OpenGL > Max Renderable Lights**
|
|
|
+and/or **Rendering > Limits > OpenGL > Max Lights Per Object** at the cost of
|
|
|
+performance and longer shader compilation times. The limit can also be decreased
|
|
|
+to reduce shader compilation times and improve performance slightly.
|
|
|
+
|
|
|
+With all rendering methods, up to 8 DirectionalLights can be visible at a time.
|
|
|
+However, each additional DirectionalLight with shadows enabled will reduce the
|
|
|
+effective shadow resolution of each DirectionalLight. This is because
|
|
|
+directional shadow atlas is shared between all lights.
|
|
|
+
|
|
|
+If the rendering limit is exceeded, lights will start popping in and out during
|
|
|
+camera movement, which can be distracting. Enabling **Distance Fade** on light
|
|
|
+nodes can help reduce this issue while also improving performance. Splitting
|
|
|
+your meshes into smaller portions can also help, especially for level geometry
|
|
|
+(which also improves culling efficiency).
|
|
|
+
|
|
|
+If you need to render more lights than possible in a given rendering backend,
|
|
|
+consider using :ref:`baked lightmaps <doc_using_lightmap_gi>` with lights' bake
|
|
|
+mode set to **Static**. This allows lights to be fully baked, which also makes
|
|
|
+them much faster to render. You can also use emissive materials with any
|
|
|
+:ref:`global illumination <doc_introduction_to_global_illumination>` technique
|
|
|
+as a replacement for light nodes that emit light over a large area.
|
|
|
+
|
|
|
Shadow mapping
|
|
|
^^^^^^^^^^^^^^
|
|
|
|
|
|
@@ -53,30 +97,66 @@ Lights can optionally cast shadows. This gives them greater realism (light does
|
|
|
not reach occluded areas), but it can incur a bigger performance cost.
|
|
|
There is a list of generic shadow parameters, each also has a specific function:
|
|
|
|
|
|
-- **Enabled**: Check to enable shadow mapping in this light.
|
|
|
-- **Color**: Areas occluded are multiplied by this color. It is black by default, but it can be changed to tint shadows.
|
|
|
-- **Bias**: When this parameter is too small, self shadowing occurs. When too large, shadows separate from the casters. Tweak to what works best for you.
|
|
|
-- **Contact**: Performs a short screen-space raycast to reduce the gap generated by the bias. Contact shadows are only available when using the GLES3 backend.
|
|
|
-- **Reverse Cull Faces**: Some scenes work better when shadow mapping is rendered with face-culling inverted.
|
|
|
+- **Enabled:** Check to enable shadow mapping in this light.
|
|
|
+- **Opacity:** Areas occluded are darkened by this opacity factor. Shadows are
|
|
|
+ fully opaque by default, but this can be changed to make shadows translucent
|
|
|
+ for a given light.
|
|
|
+- **Bias:** When this parameter is too low, self-shadowing occurs. When too
|
|
|
+ high, shadows separate from the casters. Tweak to what works best for you.
|
|
|
+- **Normal Bias:** When this parameter is too low, self-shadowing occurs. When too
|
|
|
+ high, shadows appear misaligned from the casters. Tweak to what works best for you.
|
|
|
+- **Transmittance Bias:** When this parameter is too low, self-shadowing
|
|
|
+ occurs on materials that have transmittance enabled. When too high, shadows
|
|
|
+ will not affect materials that have transmittance enabled consistently. Tweak
|
|
|
+ to what works best for you.
|
|
|
+- **Reverse Cull Face:** Some scenes work better when shadow mapping is rendered
|
|
|
+ with face-culling inverted.
|
|
|
+- **Blur:** Multiplies the shadow blur radius for this light. This works with
|
|
|
+ both traditional shadow mapping and contact-hardening shadows (lights with
|
|
|
+ **Angular Distance** or **Size** greater than ``0.0``). Higher values result
|
|
|
+ in softer shadows, which will also appear to be more temporally stable for
|
|
|
+ moving objects. The downside of increasing shadow blur is that it will make
|
|
|
+ the grainy pattern used for filtering more noticeable.
|
|
|
+ See also :ref:`doc_lights_and_shadows_shadow_filter_mode`.
|
|
|
|
|
|
Below is an image of what tweaking bias looks like. Default values work for most
|
|
|
-cases, but in general it depends on the size and complexity of geometry.
|
|
|
+cases, but in general, it depends on the size and complexity of geometry.
|
|
|
+
|
|
|
+If the **Shadow Bias** or **Shadow Normal Bias** is set too low for a given light,
|
|
|
+the shadow will be "smeared" onto the objects. This will cause the light's
|
|
|
+intended appearance to darken, and is called *shadow acne*:
|
|
|
+
|
|
|
+.. image:: img/lights_and_shadows_acne.webp
|
|
|
+
|
|
|
+On the other hand, if the **Shadow Bias** or **Shadow Normal Bias** is set too
|
|
|
+high for a given light, the shadow may appear to be disconnected from the
|
|
|
+object. This is called *peter-panning*:
|
|
|
|
|
|
-.. image:: img/shadow_bias.png
|
|
|
+.. image:: img/lights_and_shadows_peter_panning.webp
|
|
|
|
|
|
-Finally, if gaps can't be solved, the **Contact** option can help:
|
|
|
+In general, increasing **Shadow Normal Bias** is preferred over increasing
|
|
|
+**Shadow Bias**. Increasing **Shadow Normal Bias** does not cause as much
|
|
|
+peter-panning as increasing **Shadow Normal Bias**, but it can still resolve
|
|
|
+most shadow acne issues efficiently. The downside of increasing **Shadow Normal
|
|
|
+Bias** is that it can make shadows appear thinner for certain objects.
|
|
|
|
|
|
-.. image:: img/shadow_contact.png
|
|
|
+Any sort of bias issues can be fixed by
|
|
|
+:ref:`increasing the shadow map resolution <doc_lights_and_shadows_balancing_performance_and_quality>`,
|
|
|
+at the cost of decreased performance.
|
|
|
|
|
|
-Any sort of bias issues can always be fixed by increasing the shadow map resolution,
|
|
|
-although that may lead to decreased performance on low-end hardware.
|
|
|
+.. note::
|
|
|
+
|
|
|
+ Tweaking shadow mapping settings is an art – there are no "one size fits
|
|
|
+ all" settings. To achieve the best visuals, you may need to use different
|
|
|
+ shadow bias values on a per-light basis.
|
|
|
|
|
|
Directional light
|
|
|
-~~~~~~~~~~~~~~~~~
|
|
|
+-----------------
|
|
|
|
|
|
-This is the most common type of light and represents a light source
|
|
|
-very far away (such as the sun). It is also the cheapest light to compute and should be used whenever possible
|
|
|
-(although it's not the cheapest shadow-map to compute, but more on that later).
|
|
|
+This is the most common type of light and represents a light source very far
|
|
|
+away (such as the sun). It is also the cheapest light to compute and should be
|
|
|
+used whenever possible (although it's not the cheapest shadow-map to compute,
|
|
|
+but more on that later).
|
|
|
|
|
|
Directional light models an infinite number of parallel light rays
|
|
|
covering the whole scene. The directional light node is represented by a big arrow which
|
|
|
@@ -85,70 +165,78 @@ does not affect the lighting at all and can be anywhere.
|
|
|
|
|
|
.. image:: img/light_directional.png
|
|
|
|
|
|
-Every face whose front-side is hit by the light rays is lit, while the others stay dark. Unlike most
|
|
|
-other light types directional lights, don't have specific parameters.
|
|
|
+Every face whose front-side is hit by the light rays is lit, while the others
|
|
|
+stay dark. Unlike most other light types directional lights, don't have specific
|
|
|
+parameters.
|
|
|
+
|
|
|
+The directional light also offers a **Angular Distance** property, which
|
|
|
+determines the light's angular size in degrees. Increasing this above ``0.0``
|
|
|
+will make shadows softer at greater distances from the caster, while also
|
|
|
+affecting the sun's appearance in procedural sky materials. This is called a
|
|
|
+*contact-hardening* shadow (also known as PCSS).
|
|
|
+
|
|
|
+For reference, the angular distance of the Sun viewed from the Earth is
|
|
|
+approximately ``0.5``. This kind of shadow is expensive, so check the
|
|
|
+recommendations in :ref:`doc_lights_and_shadows_pcss_recommendations` if setting
|
|
|
+this value above ``0.0`` on lights with shadows enabled.
|
|
|
|
|
|
Directional shadow mapping
|
|
|
^^^^^^^^^^^^^^^^^^^^^^^^^^
|
|
|
|
|
|
-To compute shadow maps, the scene is rendered (only depth) from an orthogonal point of view that covers
|
|
|
-the whole scene (or up to the max distance). There is, however, a problem with this approach because objects
|
|
|
-closer to the camera receive blocky shadows.
|
|
|
+To compute shadow maps, the scene is rendered (only depth) from an orthogonal
|
|
|
+point of view that covers the whole scene (or up to the max distance). There is,
|
|
|
+however, a problem with this approach because objects closer to the camera
|
|
|
+receive low-resolution shadows that may appear blocky.
|
|
|
|
|
|
-.. image:: img/shadow_blocky.png
|
|
|
+To fix this, a technique named *Parallel Split Shadow Maps* (PSSM) is used.
|
|
|
+This splits the view frustum in 2 or 4 areas. Each area gets its own shadow map.
|
|
|
+This allows small areas close to the viewer to have the same shadow resolution
|
|
|
+as a huge, far-away area.
|
|
|
|
|
|
-To fix this, a technique named "Parallel Split Shadow Maps" (or PSSM) is used. This splits the view frustum in 2 or 4 areas. Each
|
|
|
-area gets its own shadow map. This allows small areas close to the viewer to have the same shadow resolution as a huge, far-away area.
|
|
|
-
|
|
|
-.. image:: img/pssm_explained.png
|
|
|
+.. image:: img/lights_and_shadows_pssm_explained.webp
|
|
|
|
|
|
With this, shadows become more detailed:
|
|
|
|
|
|
-.. image:: img/shadow_pssm.png
|
|
|
+.. image:: img/lights_and_shadows_directional_mode.webp
|
|
|
|
|
|
To control PSSM, a number of parameters are exposed:
|
|
|
|
|
|
-.. image:: img/directional_shadow_params.png
|
|
|
+.. image:: img/lights_and_shadows_directional_shadow_params.webp
|
|
|
|
|
|
Each split distance is controlled relative to the camera far (or shadow
|
|
|
-**Max Distance** if greater than zero), so *0.0* is the eye position and *1.0*
|
|
|
-is where the shadow ends at a distance. Splits are in-between. Default values
|
|
|
-generally work well, but tweaking the first split a bit is common to give more
|
|
|
-detail to close objects (like a character in a third person game).
|
|
|
-
|
|
|
-Always make sure to set a shadow *Max Distance* according to what the scene needs.
|
|
|
-A lower maximum distance will result in better-looking shadows.
|
|
|
-
|
|
|
-Sometimes, the transition between a split and the next can look bad. To fix this,
|
|
|
-the **"Blend Splits"** option can be turned on, which sacrifices detail in exchange
|
|
|
-for smoother transitions:
|
|
|
+**Max Distance** if greater than ``0.0``). ``0.0`` is the eye position and
|
|
|
+``1.0`` is where the shadow ends at a distance. Splits are in-between.
|
|
|
+Default values generally work well, but tweaking the first split a bit is common
|
|
|
+to give more detail to close objects (like a character in a third-person game).
|
|
|
+
|
|
|
+Always make sure to set a shadow **Max Distance** according to what the scene
|
|
|
+needs. A lower maximum distance will result in better-looking shadows and better
|
|
|
+performance, as fewer objects will need to be included in shadow rendering. You
|
|
|
+can also adjust **Fade Start** to control how aggressive the shadow fade-out
|
|
|
+should be at a distance. For scenes where the **Max Distance** fully covers the
|
|
|
+scene at any given camera position, you can increase **Fade Start** to ``1.0``
|
|
|
+to prevent the shadow from fading at a distance. This should not be done in
|
|
|
+scenes where **Max Distance** doesn't fully cover the scene, as the shadow will
|
|
|
+appear to be suddenly cut off at a distance.
|
|
|
+
|
|
|
+Sometimes, the transition between a split and the next can look bad. To fix
|
|
|
+this, the **Blend Splits** option can be turned on, which sacrifices detail and
|
|
|
+performance in exchange for smoother transitions:
|
|
|
|
|
|
.. image:: img/blend_splits.png
|
|
|
|
|
|
-The **"Normal Bias"** parameter can be used to fix special cases of self shadowing
|
|
|
-when objects are perpendicular to the light. The only downside is that it makes
|
|
|
-the shadow a bit thinner.
|
|
|
-
|
|
|
-.. image:: img/normal_bias.png
|
|
|
-
|
|
|
-The **"Bias Split Scale"** parameter can control extra bias for the splits that
|
|
|
-are far away. If self shadowing occurs only on the splits far away, this value can fix them.
|
|
|
-
|
|
|
-Finally, the **"Depth Range"** has two settings:
|
|
|
+The **Shadow > Normal Bias** parameter can be used to fix special cases of
|
|
|
+self-shadowing when objects are perpendicular to the light. The only downside is
|
|
|
+that it makes the shadow a bit thinner. Consider increasing **Shadow > Normal
|
|
|
+Bias** before increasing **Shadow > Bias** in most situations.
|
|
|
|
|
|
-- **Stable**: Keeps the shadow stable while the camera moves, and the blocks that appear in the outline when close to the shadow edges remain in-place. This is the default and generally desired, but it reduces the effective shadow resolution.
|
|
|
-- **Optimized**: Tries to achieve the maximum resolution available at any given time. This may result in a "moving saw" effect on shadow edges, but at the same time the shadow looks more detailed (so this effect may be subtle enough to be forgiven).
|
|
|
-
|
|
|
-Just experiment which setting works better for your scene.
|
|
|
-
|
|
|
-Shadowmap size for directional lights can be changed in Project Settings -> Rendering -> Quality:
|
|
|
-
|
|
|
-.. image:: img/project_setting_shadow.png
|
|
|
-
|
|
|
-Increasing it can solve bias problems, but decrease performance. Shadow mapping is an art of tweaking.
|
|
|
+Lastly, **Pancake Size** is a property that can be adjusted to fix missing
|
|
|
+shadows when using large objects with unsubdivided meshes. Only change this
|
|
|
+value if you notice missing shadows that are not related to shadow biasing
|
|
|
+issues.
|
|
|
|
|
|
Omni light
|
|
|
-~~~~~~~~~~
|
|
|
+----------
|
|
|
|
|
|
Omni light is a point source that emits light spherically in all directions up to a given
|
|
|
radius.
|
|
|
@@ -158,7 +246,7 @@ radius.
|
|
|
In real life, light attenuation is an inverse function, which means omni lights don't have a radius.
|
|
|
This is a problem because it means computing several omni lights would become demanding.
|
|
|
|
|
|
-To solve this, a *Range* is introduced together with an attenuation function.
|
|
|
+To solve this, a **Range** parameter is introduced together with an attenuation function.
|
|
|
|
|
|
.. image:: img/light_omni_params.png
|
|
|
|
|
|
@@ -166,59 +254,114 @@ These two parameters allow tweaking how this works visually in order to find aes
|
|
|
|
|
|
.. image:: img/light_attenuation.png
|
|
|
|
|
|
+A **Size** parameter is also available in OmniLight3D. Increasing this value
|
|
|
+will make the light fade out slower and shadows appear blurrier when far away
|
|
|
+from the caster. This can be used to simulate area lights to an extent. This is
|
|
|
+called a *contact-hardening* shadow (also known as PCSS). This kind of shadow is
|
|
|
+expensive, so check the recommendations in
|
|
|
+:ref:`doc_lights_and_shadows_pcss_recommendations` if setting this value above
|
|
|
+``0.0`` on lights with shadows enabled.
|
|
|
|
|
|
Omni shadow mapping
|
|
|
^^^^^^^^^^^^^^^^^^^
|
|
|
|
|
|
-Omni light shadow mapping is relatively straightforward. The main issue that needs to be
|
|
|
-considered is the algorithm used to render it.
|
|
|
+Omni light shadow mapping is relatively straightforward. The main issue that
|
|
|
+needs to be considered is the algorithm used to render it.
|
|
|
+
|
|
|
+Omni Shadows can be rendered as either **Dual Paraboloid** or **Cube** mapped.
|
|
|
+**Dual Parabolid** renders quickly, but can cause deformations, while **Cube**
|
|
|
+is more correct, but slower. The default is **Cube**, but consider changing it
|
|
|
+to **Dual Parabolid** for lights where it doesn't make much of a visual
|
|
|
+difference.
|
|
|
+
|
|
|
+.. image:: img/lights_and_shadows_dual_parabolid_vs_cubemap.webp
|
|
|
+
|
|
|
+If the objects being rendered are mostly irregular and subdivided, Dual
|
|
|
+Paraboloid is usually enough. In any case, as these shadows are cached in a
|
|
|
+shadow atlas (more on that at the end), it may not make a difference in
|
|
|
+performance for most scenes.
|
|
|
|
|
|
-Omni Shadows can be rendered as either **"Dual Paraboloid" or "Cube Mapped"**.
|
|
|
-The former renders quickly, but can cause deformations,
|
|
|
-while the later is more correct, but costlier.
|
|
|
+Omni lights with shadows enabled can make use of projectors. The projector
|
|
|
+texture will *multiply* the light's color by the color at a given point on the
|
|
|
+texture. As a result, lights will usually appear to be darker once a projector
|
|
|
+texture is assigned; you can increase **Energy** to compensate for this.
|
|
|
|
|
|
-.. image:: img/shadow_omni_dp_cm.png
|
|
|
+Omni light projector textures require a special 360° panorama mapping, similar
|
|
|
+to :ref:`class_PanoramaSkyMaterial` textures.
|
|
|
|
|
|
-If the objects being rendered are mostly irregular, Dual Paraboloid is usually
|
|
|
-enough. In any case, as these shadows are cached in a shadow atlas (more on that at the end), it
|
|
|
-may not make a difference in performance for most scenes.
|
|
|
+With the projector texture below, the following result is obtained:
|
|
|
+
|
|
|
+.. image:: img/lights_and_shadows_omni_projector_example.webp
|
|
|
+
|
|
|
+.. image:: img/lights_and_shadows_omni_projector.webp
|
|
|
+
|
|
|
+.. tip::
|
|
|
+
|
|
|
+ If you've acquired omni projectors in the form of cubemap images, you can use
|
|
|
+ `this web-based conversion tool <https://danilw.github.io/GLSL-howto/cubemap_to_panorama_js/cubemap_to_panorama.html>`__
|
|
|
+ to convert them to a single panorama image.
|
|
|
|
|
|
Spot light
|
|
|
-~~~~~~~~~~
|
|
|
+----------
|
|
|
|
|
|
Spot lights are similar to omni lights, except they emit light only into a cone
|
|
|
(or "cutoff"). They are useful to simulate flashlights,
|
|
|
car lights, reflectors, spots, etc. This type of light is also attenuated towards the
|
|
|
opposite direction it points to.
|
|
|
|
|
|
-.. image:: img/light_spot.png
|
|
|
-
|
|
|
-Spot lights share the same **Range** and **Attenuation** as **OmniLight**, and add two extra parameters:
|
|
|
+Spot lights share the same **Range**, **Attenuation** and **Size** as OmniLight3D,
|
|
|
+and add two extra parameters:
|
|
|
|
|
|
-- **Angle**: The aperture angle of the light
|
|
|
-- **Angle Attenuation**: The cone attenuation, which helps soften the cone borders.
|
|
|
+- **Angle:** The aperture angle of the light.
|
|
|
+- **Angle Attenuation:** The cone attenuation, which helps soften the cone borders.
|
|
|
|
|
|
Spot shadow mapping
|
|
|
^^^^^^^^^^^^^^^^^^^
|
|
|
|
|
|
-Spots don't need any parameters for shadow mapping. Keep in mind that, at more than 89 degrees of aperture, shadows
|
|
|
-stop functioning for spots, and you should consider using an Omni light instead.
|
|
|
+Spots feature the same parameters as omni lights for shadow mapping. Rendering
|
|
|
+spot shadow maps is significantly faster compared to omni lights, as only one
|
|
|
+shadow texture needs to be rendered (instead of rendering 6 faces, or 2 in dual
|
|
|
+parabolid mode).
|
|
|
|
|
|
-Shadow atlas
|
|
|
-~~~~~~~~~~~~
|
|
|
+Spot lights with shadows enabled can make use of projectors. The projector
|
|
|
+texture will *multiply* the light's color by the color at a given point on the
|
|
|
+texture. As a result, lights will usually appear to be darker once a projector
|
|
|
+texture is assigned; you can increase **Energy** to compensate for this.
|
|
|
|
|
|
-Unlike Directional lights, which have their own shadow texture, Omni and Spot lights are assigned to slots of a shadow atlas.
|
|
|
-This atlas can be configured in Project Settings -> Rendering -> Quality -> Shadow Atlas.
|
|
|
+Unlike omni light projectors, a spot light projector texture doesn't need to
|
|
|
+follow a special format to look correct. It will be mapped in a way similar to a
|
|
|
+:ref:`decal <doc_using_decals>`.
|
|
|
|
|
|
-.. image:: img/shadow_atlas.png
|
|
|
+With the projector texture below, the following result is obtained:
|
|
|
|
|
|
-The resolution applies to the whole Shadow Atlas. This atlas is divided into four quadrants:
|
|
|
+.. image:: img/lights_and_shadows_spot_projector_example.webp
|
|
|
|
|
|
-.. image:: img/shadow_quadrants.png
|
|
|
+.. image:: img/lights_and_shadows_spot_projector.webp
|
|
|
+
|
|
|
+.. note::
|
|
|
+
|
|
|
+ Spot lights with wide angles will have lower-quality shadows than spot
|
|
|
+ lights with narrow angles, as the shadow map is spread over a larger
|
|
|
+ surface. At angles wider than 89 degrees, spot light shadows will stop
|
|
|
+ working entirely. If you need shadows for wider lights, use an omni light
|
|
|
+ instead.
|
|
|
+
|
|
|
+.. _doc_lights_and_shadows_shadow_atlas:
|
|
|
+
|
|
|
+Shadow atlas
|
|
|
+------------
|
|
|
+
|
|
|
+Unlike Directional lights, which have their own shadow texture, omni and spot
|
|
|
+lights are assigned to slots of a shadow atlas. This atlas can be configured in
|
|
|
+the advanced Project Settings (**Rendering > Lights And Shadows > Positional Shadow**).
|
|
|
+
|
|
|
+The resolution applies to the whole shadow atlas. This atlas is divided into four quadrants:
|
|
|
+
|
|
|
+.. image:: img/lights_and_shadows_shadow_quadrants.webp
|
|
|
|
|
|
Each quadrant can be subdivided to allocate any number of shadow maps; the following is the default subdivision:
|
|
|
|
|
|
-.. image:: img/shadow_quadrants2.png
|
|
|
+.. image:: img/lights_and_shadows_shadow_quadrants2.webp
|
|
|
|
|
|
The shadow atlas allocates space as follows:
|
|
|
|
|
|
@@ -231,20 +374,142 @@ Every frame, the following procedure is performed for all lights:
|
|
|
2. Check if any object affecting the shadow map has changed. If it did, re-render the light.
|
|
|
3. If neither of the above has happened, nothing is done, and the shadow is left untouched.
|
|
|
|
|
|
-If the slots in a quadrant are full, lights are pushed back to smaller slots, depending on size and distance.
|
|
|
+If the slots in a quadrant are full, lights are pushed back to smaller slots,
|
|
|
+depending on size and distance. If all slots in all quadrants are full, some
|
|
|
+lights will not be able to render shadows even if shadows are enabled on them.
|
|
|
+
|
|
|
+The default shadow allocation strategy allows rendering up to 88 lights with
|
|
|
+shadows enabled in the camera frustum (4 + 4 + 16 + 64):
|
|
|
+
|
|
|
+1. The first and most detailed quadrant can store 4 shadows.
|
|
|
+2. The second quadrant can store 4 other shadows.
|
|
|
+3. The third quadrant can store 16 shadows, with less detail.
|
|
|
+4. The fourth and least detailed quadrant can store 64 shadows, with even less detail.
|
|
|
+
|
|
|
+Using a higher number of shadows per quadrant allows supporting a greater amount
|
|
|
+of total lights with shadows enabled, while also improving performance (as
|
|
|
+shadows will be rendered at a lower resolution for each light). However,
|
|
|
+increasing the number of shadows per quadrant comes at the cost of lower shadow
|
|
|
+quality.
|
|
|
+
|
|
|
+In some cases, you may want to use a different allocation strategy. For example,
|
|
|
+in a top-down game where all lights are around the same size, you may want to
|
|
|
+set all quadrants to have the same subdivision so that all lights have shadows
|
|
|
+of similar quality level.
|
|
|
|
|
|
-This allocation strategy works for most games, but you may want to use a separate one in some cases (for example, a top-down game where
|
|
|
-all lights are around the same size and quadrants may all have the same subdivision).
|
|
|
+.. _doc_lights_and_shadows_balancing_performance_and_quality:
|
|
|
|
|
|
-Shadow filter quality
|
|
|
-~~~~~~~~~~~~~~~~~~~~~
|
|
|
+Balancing performance and quality
|
|
|
+---------------------------------
|
|
|
|
|
|
-The filter quality of shadows can be tweaked. This can be found in
|
|
|
-Project Settings -> Rendering -> Quality -> Shadows.
|
|
|
-Godot supports no filter, PCF5 and PCF13.
|
|
|
+Shadow rendering is a critical topic in 3D rendering performance. It's important
|
|
|
+to make the right choices here to avoid creating bottlenecks.
|
|
|
|
|
|
-.. image:: img/shadow_pcf1.png
|
|
|
+Directional shadow quality settings can be changed at run-time by calling the
|
|
|
+appropriate :ref:`class_RenderingServer` methods.
|
|
|
|
|
|
-It affects the blockiness of the shadow outline:
|
|
|
+Positional (omni/spot) shadow quality settings can be changed at run-time on the
|
|
|
+root :ref:`class_Viewport`.
|
|
|
+
|
|
|
+Shadow map size
|
|
|
+^^^^^^^^^^^^^^^
|
|
|
+
|
|
|
+High shadow resolutions result in sharper shadows, but at a significant
|
|
|
+performance cost. It should also be noted that *sharper shadows are not always
|
|
|
+more realistic*. In most cases, this should be kept at its default value of
|
|
|
+``4096`` or decreased to ``2048`` for low-end GPUs.
|
|
|
+
|
|
|
+If positional shadows become too blurry after decreasing the shadow map size,
|
|
|
+you can counteract this by adjusting the
|
|
|
+:ref:`shadow atlas <doc_lights_and_shadows_shadow_atlas>` quadrants to contain
|
|
|
+fewer shadows. This will allow each shadow to be rendered at a higher resolution.
|
|
|
+
|
|
|
+.. _doc_lights_and_shadows_shadow_filter_mode:
|
|
|
+
|
|
|
+Shadow filter mode
|
|
|
+^^^^^^^^^^^^^^^^^^
|
|
|
+
|
|
|
+Several shadow map quality settings can be chosen here. The default **Soft Low**
|
|
|
+is a good balance between performance and quality for scenes with detailed
|
|
|
+textures, as the texture detail will help make the dithering pattern less noticeable.
|
|
|
+
|
|
|
+However, in projects with less detailed textures, the shadow dithering pattern
|
|
|
+may be more visible. To hide this pattern, you can either enable
|
|
|
+:ref:`doc_3d_antialiasing_taa`, :ref:`doc_3d_antialiasing_fxaa`, or increase the
|
|
|
+shadow filter quality to **Soft Medium** or higher.
|
|
|
+
|
|
|
+The **Soft Very Low** setting will automatically decrease shadow blur to make
|
|
|
+artifacts from the low sample count less visible. Conversely, the **Soft High**
|
|
|
+and **Soft Ultra** settings will automatically increase shadow blur to better
|
|
|
+make use of the increased sample count.
|
|
|
+
|
|
|
+16-bits versus 32-bit
|
|
|
+^^^^^^^^^^^^^^^^^^^^^
|
|
|
+
|
|
|
+By default, Godot uses 16-bit depth textures for shadow map rendering. This is
|
|
|
+recommended in most cases as it performs better without a noticeable difference
|
|
|
+in quality.
|
|
|
+
|
|
|
+If **16 Bits** is disabled, 32-bit depth textures will be used instead. This
|
|
|
+can result in less artifacting in large scenes and large lights with shadows
|
|
|
+enabled. However, the difference is often barely visible, yet this can have a
|
|
|
+significant performance cost.
|
|
|
+
|
|
|
+Light/shadow distance fade
|
|
|
+^^^^^^^^^^^^^^^^^^^^^^^^^^
|
|
|
|
|
|
-.. image:: img/shadow_pcf2.png
|
|
|
+OmniLight3D and SpotLight3D offer several properties to hide distant lights.
|
|
|
+This can improve performance significantly in large scenes with dozens of lights
|
|
|
+or more.
|
|
|
+
|
|
|
+- **Enabled:** Controls whether distance fade (a form of :abbr:`LOD (Level of Detail)`)
|
|
|
+ is enabled. The light will fade out over **Begin + Length**, after which it
|
|
|
+ will be culled and not sent to the shader at all. Use this to reduce the number
|
|
|
+ of active lights in a scene and thus improve performance.
|
|
|
+- **Begin:** The distance from the camera at which the light begins to fade away
|
|
|
+ (in 3D units).
|
|
|
+- **Shadow:** The distance from the camera at which the shadow begins to fade away
|
|
|
+ (in 3D units). This can be used to fade out shadows sooner compared to the light,
|
|
|
+ further improving performance. Only available if shadows are enabled for the light.
|
|
|
+- **Length:** The distance over which the light and shadow fades (in 3D units).
|
|
|
+ The light becomes slowly more transparent over this distance and is completely
|
|
|
+ invisible at the end. Higher values result in a smoother fade-out transition,
|
|
|
+ which is more suited when the camera moves fast.
|
|
|
+
|
|
|
+.. _doc_lights_and_shadows_pcss_recommendations:
|
|
|
+
|
|
|
+PCSS recommendations
|
|
|
+^^^^^^^^^^^^^^^^^^^^
|
|
|
+
|
|
|
+Percentage-closer soft shadows (PCSS) provide a more realistic shadow mapping
|
|
|
+appearance, with the penumbra size varying depending on the distance between the
|
|
|
+caster and the surface receiving the shadow. This comes at a high performance
|
|
|
+cost, especially for directional lights.
|
|
|
+
|
|
|
+To avoid performance issues, it's recommended to:
|
|
|
+
|
|
|
+- Only use a handful of lights with PCSS shadows enabled at a given time. The
|
|
|
+ effect is generally most visible on large, bright lights. Secondary light
|
|
|
+ sources that are more faint usually don't benefit much from using PCSS
|
|
|
+ shadows.
|
|
|
+- Provide a setting for users to disable PCSS shadows. On directional lights,
|
|
|
+ this can be done by setting the DirectionalLight3D's
|
|
|
+ ``light_angular_distance`` property to ``0.0`` in a script. On positional
|
|
|
+ lights, this can be done by setting the OmniLight3D or SpotLight3D's
|
|
|
+ ``light_size`` property to ``0.0`` in a script.
|
|
|
+
|
|
|
+Projector filter mode
|
|
|
+^^^^^^^^^^^^^^^^^^^^^
|
|
|
+
|
|
|
+The way projectors are rendered also has an impact on performance. The
|
|
|
+**Rendering > Textures > Light Projectors > Filter** advanced project setting
|
|
|
+lets you control how projector textures should be filtered. **Nearest/Linear** do
|
|
|
+not use mipmaps, which makes them faster to render. However, projectors will
|
|
|
+look grainy at distance. **Nearest/Linear Mipmaps** will look smoother at a
|
|
|
+distance, but projectors will look blurry when viewed from oblique angles. This
|
|
|
+can be resolved by using **Nearest/Linear Mipmaps Anisotropic**, which is the
|
|
|
+highest-quality mode but also the most expensive.
|
|
|
+
|
|
|
+If your project has a pixel art style, consider setting the filter to one of the
|
|
|
+**Nearest** values so that projectors use nearest-neighbor filtering. Otherwise,
|
|
|
+stick to **Linear**.
|
Rémi Verschelde
