Runtime Preview (Thumbnail) Generator (Open Source)

Hello there,

I've just posted a script that lets you generate thumbnails for your GameObject's and/or materials during gameplay and wanted to share it here, as well. The generated thumbnail is in Texture2D format and supports transparent background.

Asset Store: https://assetstore.unity.com/packages/tools/camera/runtime-preview-generator-112860
Also available at: https://github.com/yasirkula/UnityRuntimePreviewGenerator
Discord: https://discord.gg/UJJt549AaV
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Should work on pretty much any platform that Unity supports.



FAQ

• Rendered thumbnail is empty, why?

If shouldIgnoreParticleSystems parameter is set to false, child particle systems of the model may force the camera to zoom out a lot. Or, on SRPs, your Forward Renderer asset's Opaque Layer Mask and/or Transparent Layer Mask might be excluding layer 22 (preview objects are temporarily assigned to this layer).

• Rendered thumbnail doesn't look correct, why?

If there are lighting issues and you're generating thumbnails in Awake, try Start instead. Otherwise, try disabling post-processing effects and see if it makes any difference. If it does, then you should temporarily disable post-processing while capturing thumbnails.

Enjoy!

 

Now available on Asset Store!

 

This is perfect ! You saved me a big headache. This is exactly what I was searching for my inventory system.

If you are interested I would like to offer you a special account into my video game. You can find my game at www.citywars.ca. We are still far away from having a playable game but piece by piece we get further from a prototype. Your system is now part of our inventory system.

 

It's nice to hear Thank you for your offer. I don't have free time for games nowadays but thanks again for your kindness, I appreciate it.

 

Yeah i understand. Well Thanks again. If you need anything lets us know !

Also if you change your mind latter you're still welcome ;P
Have a nice day !

 

nice

 

Hello! First of all, thank you so much for sharing this asset, it's wonderful and exactly what I needed.

I am having an issue however - has anybody figured the issue with this asset and Unity 2018? After upgrading, I recall seeing an error or warning about it, and since seeing that it's stopped working - annoyingly, there has been no error/warning since then, (I really wish I addressed it immediately - my next step is to make a new project and import to see if I can catch the error a second time) so I'm having trouble troubleshooting the issue.

I tried finding an upgrade guide for 2018 with changes/deprecation but couldn't - if anyone could help I'd be very thankful! And I'll post here if I find the solution myself of course.

 

I was able to test the following code with success on a new scene with no post-processing applied on Unity 2018.1.3f1:

Code (CSharp):

1. public RawImage img;
2. public Transform obj;
3. private void Start()
4. {
5.     img.texture = RuntimePreviewGenerator.GenerateModelPreview( obj );
6. }

There were no error or warning messages for me while importing the plugin.

 

Thanks for the help. I found that it actually no longer occurs on 2018.2.0f1. We've moved builds a few times in the last few weeks, so it must have been some temporary issue that resolved itself - works just fine after testing again (should've done that before posting. My apologies!)

 

Any idea about soft shadows but transparent backgrounds? My best solution so far is just having a fake shadow, a sprite, that is resized to the bounding box of the object you're rendering, and repositioned to right below the bounding box. You can probably do it with 'real' shadows if you use some special shader on a plane below the object (?)

 

Yes you could use such a special shader (this could be a good starting point). However, as an object's shadow may overflow its bounding box, parts of the shadow may not be visible in the generated thumbnail.

 

Yeah, depends on which direction you cast the shadow. I think a way to go around that issue would be to feather the thumbnail near the edges

 

Hi there, I just had a question regarding this thumbnail generator. Right now I have a video player, and I save the texture of the video player to a RawImage. I want to generate a thumbnail based on the texture of the RawImage, but every time I try calling RuntimePreviewGenerator.GenerateModelPreview I get a null object.

Code (CSharp):

1. image.texture = videoPlayer.texture;
2. thumbnail = RuntimePreviewGenerator.GenerateModelPreview(image.transform, 64, 64, true);
3.  

Am I calling runtime preview generator right or am I missing something?

 

RuntimePreviewGenerator can only work on objects with Renderer components. For a thumbnail of an existing texture, you may want to use the TextureOps.Scale function here: https://github.com/yasirkula/UnityTextureOps

 

Hello,

thanks a lot for this asset

Is there a way to get the grey background completly transparent (Alpha)?

Thanks!

 

RuntimePreviewGenerator.TransparentBackground = true;

should do it.

 

Please checkout an In Editor and Component that allows merging of background images, etc. at https://github.com/klhurley/UnityPreviewGenerator

Wiki Documentation forthcoming

 

Perfect! Thanks

 

Hi, this tool is great and I see you have a ton of other clever content available. Thank you for that!

I do have a question though, do you think there's a way for GenerateMaterialPreview to ignore the Ambient Lighting so it always looks the same, similar to the Unity Inspector Material Preview?

Thanks

 

Ok so I seem to be successful by changing the ambient mode and then changing it back again:

Code (CSharp):

1.  
2. RenderSettings.ambientMode = UnityEngine.Rendering.AmbientMode.Flat;
3. float oldIntensity = RenderSettings.ambientIntensity;
4. RenderSettings.ambientIntensity = 1f;
5.  
6. sourceTexture = RuntimePreviewGenerator.GenerateMaterialPreview(prefab, PrimitiveType.Quad, 512, 512);
7.  
8. RenderSettings.ambientMode = UnityEngine.Rendering.AmbientMode.Skybox;
9. RenderSettings.ambientIntensity = oldIntensity;
10.  

I've also added a Layer to the GameObject, so I can exclude it from the Directional Light.

Perfect I would say.
Thanks!

 

I was about to suggest the same, good thinking!

 

Can you please post an example code? I read the readme file but still can't make it to work.

 

This code generates a thumbnail for the Target object and stores it inside the Result texture:

Code (CSharp):

1. public Transform target;
2. public Texture2D result;
3. public int thumbnailSize = 128;
4. void Start()
5. {
6.     RuntimePreviewGenerator.BackgroundColor = new Color( 0, 0, 0, 0 );
7.     result = RuntimePreviewGenerator.GenerateModelPreview( target, thumbnailSize, thumbnailSize );
8. }

 

Thanks a lot it works.
Just when I put "RuntimePreviewGenerator.TransparentBackground = true;" line to get transparent background I get error of does not contain a definition for 'TransparentBackground'

 

With the latest update, transparency now comes from the alpha value of BackgroundColor.

 

S*** I'm too noob in coding Can you please edit previous sample you just post and add this line too?

 

Why it stores the result as an Object.texture2D? And not just a texture variable?
Inside PlayMaker there is no way to get and store a texture2D from an Object.

 

Texture2D can be stored inside a Texture variable. I think I couldn't understand the question fully.

 

Can you please create a PlayMaker Action for this for people using PlayMaker? There is no action inside PLAY Maker to store a Texture2D inside a texture variable.

 

Will see what I can do.

 

Or please add the C# code that you're using to store Texture2D inside a Texture variable. for people like me who doesn't know much about C# it's hard to use this cool asset.

 

Texture2D class derives from Texture. So the following C# code is valid:

Code (CSharp):

1. Texture2D myTexture2DObject; // Texture2D variable
2. Texture texture = myTexture2DObject; // Can be assigned to Texture variable directly

 

@Crossway I've created PlayMaker actions for you.

 

Thank you million times Very useful.

 

This is the best free asset I have ever seen but today after I build my game I mentioned icons are too dark after game build! It looks good and normal inside Unity editor but too dark after game build (almost black) Can you please check this?

 

If the icons are created in Awake, try using Start instead. Or, try adding a 1-frame delay before the icons are generated. I've also encountered dark images when creating icons immediately after the scene is loaded. This has to be something with lights not being fully initialized at first frame.

 

Thanks for the great asset! I have it all working but my model thumbnails are pretty dark. I'm not calling the icon generation on scene load, I feel it has something to do with lights. Any ideas on how I could ensure even lighting or ideally get a flat unshaded thumbnail?

 

If you are generating the thumbnails in Awake or Start, try waiting for at least 1 frame in a coroutine via

yield return null;

. Also, you can call the GenerateModelPreviewWithShader function with

Shader.Find("Unlit/Texture")

shader and

string.Empty

replacementTag to use unlit shader for the thumbnail.

 

Thanks for the reply. Replacing the shader does work but I realized I do need some slight shadows to show perspective. Is there any way to attach a temporary directional light to the preview render camera so I can have a light pointing directly at the object when the thumbnail is captured?

Currently I'm readjusting the scene light to a rotation I've manually determined to light up the models nicely and then revert it back. ideally I want to programmatically determine the rotation for the directional light instead of setting it manually.

Code (CSharp):

1. directionalLight.rotation = Quaternion.Euler(50f, -140f, 0); // set light to point to object for proper illumination
2.         thumbnail = RuntimePreviewGenerator.GenerateModelPreview(modelToCapture);
3.         directionalLight.rotation = originalRotation; //reset light

 

I can see 3 alternatives here:

1. With your current approach, simply call

directionalLight.rotation = Quaternion.LookRotation(RuntimePreviewGenerator.PreviewDirection);

2. Use an unlit shader that supports shadows (you should be able to find such shaders on wiki/forums/answers)
3. You can add a Light component to RuntimePreviewGenerator's camera here and set its culling mask accordingly. But this light could have a performance impact even though it has a culling mask, I can't say for sure

 

This asset is absolutely stunning. Thank you for that!

I was wondering if you know why sometimes theres still a bit of space at the edges? Do you think theres a way to improve on that without making use of the padding option (and potentially cutting away parts of the image)?

It's not really that big of a deal though it makes my OCD kick in especially because one edge might have more space than the other haha

 

Enabling OrthographicMode can help with this issue. Other than that, I'm calculating the bounds of the input object and trying to position the camera correctly but I might be missing something. If you can spot the issue, I'd be happy to resolve it.

 

Absolutely one of my favorite assets, I already use it in several places.

Just one thing: Is there any way to make thumbnails of meshes that are generated at runtime? Like passing the transform of a mesh-renderer?

 

You can't pass a Mesh to the plugin, so you should have a dummy GameObject, change its MeshFilter with the procedural mesh and pass that GameObject to the plugin.

 

Hello,
Thank you for this plugin ! I used it in multiples projects, it is very useful !

But currently the generated texture contains only the background color, would you be aware of a situation like that ?
The plugin worked without problem before, and I must have changed something in my project that cause a problem but I don't know what

When I uncomment the #define DEBUG_BOUNDS line I still have nothing on texture, except the background color

 

Are you using a Scriptable Render Pipeline? Are you trying to generate thumbnail for a Canvas object or a static object? If the target object is a procedural mesh, do you call its RecalculateBounds function?

 

I use the Universal Render Pipeline in Unity 2019.4.15f1

I generate the thumbnails in the editor when the application is not playing, but the result is the same when the application is playing

The object is not static, and it is not a canvas

 

Hmm, was it working fine with URP before? If so, can you guess which options you've changed might've caused this issue? I want to pinpoint the issue as much as possible.

 

Oh sorry for the inconvenience, it is working now
I created a new ForwardRenderer asset and assigned it to the URP asset, and now the objet and the bounds debug appears on the thumbnail

In the past I added a feature to the ForwardRenderer asset that came from a plugin, then deleted the plugin without removing the feature from the ForwardRenderer, and I think that prevented the thumbnail generator to work properly somehow

 

I just found this asset and it solved a big problem for me! It's great!

I am having an issue though where the generated thumbnails have a transparent background when I run it in the editor (as intended), but when I run the game on an Android device the background of the thumbnails is opaque. The color of the background is correct, it just doesn't appear to honor the alpha channel when run on the device.

I am applying the thumbnail texture to a RawImage.

EDIT: I also tested on iOS, and the background was transparent as intended. It just doesn't work on Android.

Any ideas why this may be?