Screen Space Lens Flare
The Screen Space Lens Flare override adds lens flares to your scene.
To calculate lens flares, the High-Definition Render Pipeline (HDRP) fetches bright areas of the current image, such as emissive lights and bright specular reflections. HDRP then draws the same areas back to the screen in different locations and using different effects such as stretch, blur, and chromatic aberration.
The Screen Space Lens Flare creates lens flares from the following:
- Emissive surfaces.
- Bright spots in your scene that appear depending on the camera view, for example a bright specular reflection on a shiny metal object, or a bright outside area viewed from a dark indoor area.
- All onscreen lights.
You can use the Lens Flare (SRP) component instead to create a flare for a light that has a specific position in the scene. You can also use both the Lens Flare (SRP) component and the Screen Space Lens Flare override in the same scene.
How screen space lens flares work
The bright areas HDRP uses to calculate screen space lens flares are the same areas the Bloom override brightens.
HDRP uses the same buffer as the Bloom override to fetch the bright areas and render the lens flares. The settings in the Bloom override affect the appearance of screen space lens flares.
You can create the following types of lens flare:
- Regular flares, which are a brightened distorted version of the bright areas of the screen.
- Reversed flares, which are regular flares flipped upside-down and reversed.
- Warped flares, which are regular flares transformed using polar coordinates, to mimic a circular camera lens.
- Streaks, which are flares stretched in one direction, to mimic an anamorphic camera lens.
You can control which types of flares appear and how many there are. You can also control the chromatic aberration effect HDRP adds to the flares.
The left image shows an emissive cube with bloom but no lens flares. The right image shows the same cube and a regular flare (top-left), a reversed flare (bottom-right), a warped flare (top-right) and streaks (to the left and right of the cube).
Enable screen space lens flares
To use this feature in your Scene, you must first enable it for your project and then enable it for your Cameras. To enable features in your project, you use the HDRP Asset and to enable features for your Cameras, you use Frame Settings. You can enable features either for all Cameras, using the Default Frame Settings, or for specific Cameras, by overriding each Camera's individual Frame Settings.
To enable screen space lens flares, follow these steps:
- Go to Edit > Project Settings > Graphics > HDRP Global Settings > Frame Settings (Default Values) > Rendering.
- Enable Lens Flare Screen Space.
Use screen space lens flares
- Add a Volume to your scene and select it.
- In the Inspector, select Add Override > Post-processing > Screen Space Lens Flare.
- Set Intensity to a value higher than 0.
- If you have a Bloom override in the volume, set Intensity in the Bloom override to a value higher than 0 or lens flares won't appear.
If lens flares don't appear, check the settings of the Bloom override in the default volume in Edit > Project Settings > Graphics > HDRP Global Settings > Frame Settings (Default Values) > Default Volume Profile Asset > Bloom.
API
To access and control this override at runtime, use the Volume scripting API. Because of how the Volume system works, you edit properties in a different way to standard Unity components. There are also other nuances to be aware of too, such as each property has an overrideState. This indicates to the Volume system whether to use the property value you set, or use the default value stored in the Volume Profile. For information on how to use the API correctly, see Volume scripting API.
Debug screen space lens flares
You can use the Rendering Debugger to display the lens flares HDRP generates.
- Select Window > Analysis > Rendering Debugger.
- Select Rendering.
- Set Debug Mode to LensFlareScreenSpace.
Properties
To edit properties in any Volume component override, enable the checkbox to the left of the property. This also tells HDRP to use the property value you specify for the Volume component rather than the default value. If you disable the checkbox, HDRP ignores the property you set and uses the Volume’s default value for that property instead.
| Property | Description |
|---|---|
| Intensity | Set the strength of all the types of lens flares. If the value is 0, HDRP doesn't calculate or render any lens flares. The default is 0. |
| Tint Color | Set the color HDRP uses to tint all the types of lens flares. The default is white. |
| Bloom Mip Bias | Set the mipmap level HDRP uses to sample the Bloom pyramid and create the lens flares. The higher the mipmap level, the smaller and more pixelated the sample source, and the blurrier the result. The range is 0 through 5. 0 is the full-resolution mipmap level. The default is 1. Refer to Mipmaps introduction for more information. This property only appears if you open the More (⋮) menu and select Show Additional Properties. |
Flares
Use the Flares settings to control regular flares, reversed flares and warped flares.
| Property | Description | |
|---|---|---|
| Regular Multiplier | Set the strength of regular flares. If the value is 0, HDRP doesn't calculate or render regular flares. The default is 1. | |
| Reversed Multiplier | Set the strength of reversed flares. If the value is 0, HDRP doesn't calculate or render reversed flares. The default is 1. | |
| Warped Multipler | Set the strength of warped flares. If the value is 0, HDRP doesn't calculate or render warped flares. The default is 1. | |
| Scale | Scale the width (x) and height (y) of warped flares. The defaults are 1. This property only appears if you open the More (⋮) menu and select Show Additional Properties. | |
| Samples | Set the number of times HDRP repeats the regular, reversed and warped flares. The range is 1 through 3. The default is 1. Increasing Samples has a big impact on performance. | |
| Sample Dimmer | Set the strength of the lens flares HDRP adds if you set Samples to 2 or 3. The higher the value, the less intense the flares. This property only appears if you open the More (⋮) menu and select Show Additional Properties. | |
| Vignette Effect | Set the strength of the regular, reversed and warped flares in a circular area in the center of the screen. Use Vignette Effect to avoid lens flare obscuring the scene too much. The default value is 1, which means HDRP doesn't render flares at the center of the screen. | |
| Starting Position | Control how far the position of the regular, reversed and warped flares differ from the bright area they're sampled from, in metres. If the value is 0, HDRP places the lens flares at the same position as the bright areas they're sampled from. The range is 1 through 3. The default is 1.25. | |
| Scale | Set the size of regular, reversed and warped lens flares. The range is 1 through 4. The default is 1.5. |
Streaks
Use the Streaks settings to control flares stretched in one direction.
| Property | Description | |
|---|---|---|
| Multiplier | Set the strength of streaks. If the value is 0, HDRP doesn't calculate or render streaks. The default is 1. | |
| Length | Set the length of streaks. The range is 0 through 1. 1 is the approximate width of the screen. The default value is 0.5. | |
| Orientation | Set the angle of streaks, in degrees. The default value is 0, which creates horizontal streaks. | |
| Threshold | Control how localized the streak effect is. The higher the Threshold, the more localized the effect. The range is 0 through 1. The default value is 0.25. | |
| Resolution | Control the resolution detail of streaks. HDRP renders lower-resolution streaks faster. The options are Half, Quarter and Eighth full resolution. This property only appears if you open the More (⋮) menu and select Show Additional Properties. |
The effect of changing Threshold from 0 (a larger flare effect) to 1 (a smaller flare effect).
Chromatic Aberration
Use the Chromatic Aberration settings to control chromatic aberration on all the lens flare types. Chromatic aberration splits light into its color components, which mimics the effect that a real-world camera produces when its lens fails to join all colors to the same point.
The chromatic aberration effect is strongest at the edges of the screen, and decreases in strength towards the center of the screen.
| Property | Description |
|---|---|
| Spectral Lut | Assign a spectral lookup table texture that specifies how HDRP splits the light into color components, for example green and purple. You can create a custom spectral lookup table texture in any image editing software, or use a spectral lookup table texture from the Additional Post-Processing Data sample package. Leave this field empty to use a default texture that splits the light into red, green, and blue. |
| Intensity | Set the strength of the chromatic aberration effect. If the value is 0, HDRP doesn't split the colors. |
| Samples | Set the number of samples HDRP uses for the effect. The higher the number of samples, the smoother the gradient between the split color components, but the higher the impact on performance. The range is 3 through 8. The default is 3. |