Unity3D - Light deactivated when facing opposite direction - unity3d

I placed a light in my scene.
It is lighting the ground when i'm facing that light but when I turn the opposite direction, the light on the ground vanishes.
I think this might be some Unity's default behaviour.
Is there a way I can solve this issue?

Unity uses frustum culling to save performance, so it only draws items that are within the camera's viewing area. As a result of this, the particles behind you are not drawn, and any lights attached to them aren't either.
Scene-crucial lights aren't normally attached to particles, so it's normally not a concern if they're hidden along with their particles.
For conventional lights (not attached to particles), Unity should render the light as long as it affects objects within the camera frustum. If you use a conventional light, you should see better results.

Looks like you may have to disable occlusion culling. Unity3D Manual

Related

Custom 2D Lighting System in Unity

Ok so I've been trying to make a custom 2D lighting system in Unity, and I'm at that annoying stage where I know what I want to do but I'm not sure how to do it.
Here's the plan:
There will be dedicated light objects with their own meshes. These meshes determine the shape of the light.
Before the camera renders the whole scene, it does an extra render of just the light meshes with a black background to create a lightmap.
Then the camera renders the scene as normal (does NOT render the light meshes this time). Every object has a shader that will access the lightmap and shade itself appropriately depending on the color of the lightmap at that point.
That's the idea anyway. I sorta threw together a botched form of this. I used a separate camera to render the lightmap into a render texture with a culling mask so that it only rendered the light meshes, which are on their own layer. I then manually passed that texture to the shaders which use their screen uvs to sample from it.
This works sorta ok, but the scene view is completely messed up since it tries to light things as if you were looking at it from the perspective of the lighting camera. I feel like this would make the system hard to use, so I want to try to make some that feels a bit more cohesive.
Here's some screenshots to explain:
The tan-ish box is my "light," which gets rendered to the light cam, visible in scene. This next shot is what renders to the lightmap:
The black background is not from the big black box, the clear flag is just set to Black.
Now according to this lightmap, the middle of the screen should be lit up. and that's exactly what happens:
Notice that in the game view, since the light camera is set up with the same position/rotation/perspective settings as the game camera, it looks fine:
The main problem is figuring out that extra render. Is there anyway to create an extra pass for the main camera before the scene render that only renders the light meshes? I could probably figure out the rest from there. It would also be nice if I could make the lightmap a global shader variable, that way I don't have to pass it to each individual material, but one thing at a time, right?
Thanks so much to anyone who can shed some light on this subject. I'm still pretty new to shaders and rendering, so any help is much appreciated.
If I understand correctly, your problem is the appearance of your lights in Scene View, right ?
For that, you can create a custom Gizmos for them and hide the original objects. There's a tutorial:
https://learn.unity.com/tutorial/creating-custom-gizmos-for-development-2019-2#5fa30655edbc2a002192105c

How to get lighting information on a 2D Sprite's front-side?

I'm using 2D Sprites for NPCs in a 3D game. My problem is when a sprite NPC turns away from the light source (eg. Directional Light) it becomes completely dark. So for almost 180 degrees when not facing the light source the sprite is all black. I need to prevent this from happening and find a way to set a minimum light/color for my NPCs so the player can see them. What would be a good way to find out how much light is affecting the forward facing side of a gameobject?
Any help is appreciated. Thank you.
Not a complete answer, but I did spend a fair amount of time looking into this for a recent project.
One suggestion that might work is to map the graphics to quads instead of using the sprite renderer, since they will use the 3D-lighting.

How can I use baked lighting on sprites? / How to light up a large area in 2D?

I'm having trouble figuring out how to light up large area(s) of sprites in Unity 2D. My previous knowledge on Unity's lighting is zero.
I first tried using a large amount of point lights and using the "Sprites/Diffuse" material, but about only five would actually render at a time, so I guess there's a limit on that.
Then I tried putting in an area light. That didn't do anything, so that's when I started doing research about baked lighting on sprites (and baked lighting in general). I found stuff like this but I couldn't get it to work either because it's outdated or because I don't know what I'm doing. Other answers I've come across seem to assume that the reader knows anything about lighting in Unity in the first place which, to be honest, I don't. Unity's documentation website had some information on it, but no tutorials that go into how to set up baked lighting.
I've tried a bunch of different combinations of materials (like using the "Standard" shader for the sprites instead of "Sprites/Diffuse", emission, ect.) and I enabled "Baked Global Illumination" in Lighting>Settings.
If baked lighting isn't possible on sprites (or isn't worth the trouble), what are the alternatives?
Edit: I made sure not to have the lights pointing the wrong direction, and I do realise that Unity2D is just like painting onto a piece of paper in Unity3D. I was able to get point lights to work, but only a few at a time. I don't need to do the entire screen at once, I need to do a large specific area at once.
some tips...
working with sprites your in 2d... when you add a light, switch to 3d mode, and rotate to make sure your light is pointed at your objects, and oriented so as not to be on the same plane, or level with them, as this will cast all the light behind them.
if your trying to light up everything on the screen(in camera) attach an area light to the camera at the cameras position, point it where the camera points, and then in the inspector on the right, you can change its variables. intensity, range, width, height etc.
Emissive Texture:
https://www.youtube.com/watch?v=oa6kW5HhRd4
For some reason, I never even thought about going into the asset store. I found this for free, and it looks like it will work: Light2D.

Unity3D: Why is particle lighting making directional shadows disappear?

UPDATE: As #BenHayward suspected, this is a bug. <link>
I have a very simple setup of cubes on a plane comprising a grid of quads. A directional light is shining down at the scene at an angle, producing a set of shadows from the cubes onto the quads.
Now I'm trying to produce an explosion effect with Unity's particle system, but when I add a point light to the particle system it causes all the directional-lighting shadows to disappear, whether they're in line of sight of the particle or not.
The shadows reappear when the particle is destroyed. Replicating the particle effect with pure C# doesn't cause any problems.
(Oh, and obviously I'm using the deferred rendering path.)
Any ideas? This is driving me off the wall.
[EDIT: I should have mentioned that the point light added to the particle system is set to cast shadows. The Unity standard particle pack has shadow-casting disabled by default. They too cause the problem when I turn the shadow-casting on.]
Based on the project that you linked to, it seems as though the particle system is causing the shadow cast from the directional light to flicker on and off quickly. I suspect this is a bug, since if it were intended behaviour, I wouldn't expect it to flicker in this manner.
In cases where this is not a bug, the problem can be caused by a couple of issues:
You can only have a certain number of dynamic (shadow casting) lights in your scene which are seen by the camera frustum. By default, this number is quite low (I think it's 4). You can increase this number by going to Edit > Project Settings > Quality. Set the Pixel Light count higher from its default value. You will need to increase this value to be greater than the total number of lights in your effect. Higher values will allow more lights to be rendered on the screen, but this reduces performance.
It depends on the shaders which you are using to receive the shadows. Some shaders will only render shadows for one directional light. The light which is used isn't necessarily too easy to determine. If you are using the standard Unity shader this shouldn't be a problem. But if you are using a mobile compatible surface shader or something you've written yourself then this could be the cause of the problem.
Also, for an explosion, I'd recommend using just one single point light (not lights attached to each particle), as this is all that is required. Any more lights would result in considerable performance impact on the GPU especially if there are more than one explosion in the scene at any one time.
I recreated the scene as you described, i can't recreate your issue.
i mostly followed this tutorial, and added a few cubes in a plane:
https://unity3d.com/learn/tutorials/topics/graphics/adding-lighting-particles
I will need a screenshot of your lights componnents, both the directional and the point light, the particles, and the cubes (mostly the material); I cannot comment because i dont have enough reputation yet, so i'll delete this once you add the screenshots;

How to make this lighting effect in HaxeFlixel or Unity?

How do I create this lighting effect in HaxeFlixel or Unity ?
I will tell you how it was created in this specific case. This question is very broad and there are very many ways to create lighting effects in both Unity and HaxeFlixel.
The image is of the game Beneath the City by Deepnight, accessible on his website. The game uses haxe although not with HaxeFlixel. It's deepnight's personal engine that works with the flash target. The source code is available here. The class where lighting takes place is in src/Level.hx and more specifically in the renderLights method. From what I gather, a light layer is layered above the sprites of the level. This layer (or bitmap data) has lights drawn as rectangles on it. This layer is then blurred, so that the lights don't appear as solid rectangles, but as faded blurs of spreading light. This takes place with flash blur filters. Blend modes are used to make the light Add in luminosity. A dark mask is then layered above the blur layer, presumably to prevent light in certain locations, such as in the fog of the game. (?). This all takes place between lines 208 and 248.
This game truly does have gorgous visuals, but the lighting goes beyond the initial blurred lights. Particles float around in the game that really add to the lightings aesthetic.
This is all how he does it though. How you do it is up to you. For HaxeFlixel, I would first consider alternatives such as this geometric lighting or this method of applying lighting to scenes, which looks closer to screenshot or even a very simple circle based lighting alternative. Searching Unity 2D lighting brings up plenty of options.
You've got plenty of options on how to approach the issue. I didn't answer this with a direct tutorial because the question isn't at the code level.