PA Particle Field - Superfast, GPU Based, Persistent Particles

@popupAsylum Sadly changing random seed made no difference. I've got a test project if it helps, nothing in it except PAParticleField but it is LWRP, so maybe that's where the problem lies. What a shame!
Let me know if you want me to send it to you in a PM

 

Hi,

Would it work with HDRP? We're really tempted to upgrade our project to HDRP but we're using PA Particle Field...

 

Yeah, we want to know if this works with LWRP and HDRP...

 

Hi,
I'm wondering how to change the Particle Size X and Y values by script in the Global Particle Properties. Any help would be amazing, Thanks.

 

@popupAsylum I see an issue where the particle field is no longer visible. I've attached the snow demo prefab to my player's camera and everything looks good for the most part. However, if you make the player look down at the ground then the snow effect disappears. Is there any way to solve this?

 

@magique Sounds like a culling issue. PAPF controls its Renderer's bounds, that Unity uses for frustum culling, by setting its Mesh's bounds to the field size plus 1 particle in each direction (this happens at the end of SetShaderValues).

Can you check that you don't have negative particle sizes, and if there's anything special about your camera's projection matrix?

 

Definitely no negative particle sizes. What should I look for special about the camera's projection matrix. As far as I can tell, there is nothing unusual.

 

@popupAsylum Weird, but I just set my character up again with a different model and now the issue doesn't occur. I even changed the camera settings to what I had before and it still works. So I have no idea what was causing the issue, but it's fine now.

 

Hi @popupAsylum do you have any update on URP support for this asset?
Are you actively working on it?

Thank you!

 

@popupAsylum I am also interested in URP support. I have PAPF in a project I'd like to upgrade to URP, but would have to eliminate PAPF it it won't be updated.

 

hi there.
have a problem
particles in build getting strech option adn got this strech. but if i start to change side force (for wind simulation) i see only vertical strech, other strech not coming and this looks ugly. this bug only in build, in editor all fine.

unity 5.6.6

 

found this message
tried to include all shaders. didnt helped

please. its important. custumer asking to fix bug in weather.

 

Hi @zelmund

Just to confirm, you're enabling stretch at runtime and in the editor the particles stretch and orient in the direction they are moving, but in the build they dont change orientation or stretch at all?

If that's the case it does sound like a shader variant issue. Can you locate the PAPF shader you're using (e.g. TransparentLit) in the Shaders folder of PAParticleField, open it in an editor and in the line:

Code (CSharp):

1. #pragma shader_feature _ DIRECTIONAL_ON SPIN_ON

Change

shader_feature

to

multi_compile

That will force the variant to be included and at least give us an indication that that was the problem.

The Lit shaders have 2 passes containing that line so if its a lit shader remember to change both.

Hope that helps, what platform are you building for?

 

@magique @NuclearC00kie I'm not working on URP support yet, it's API needs to stabilize a bit. How's your experience been working with it?

 

yes. thats the problem.

thats work!!!! thak you!!!
god, it saved alot of work.

im building for windows.
pa is v1.342

 

@zelmund glad its working, that means its a variant issue. Using

multi_compile

forces the variant you need to be included but may also add some variants to your build that you never use, increasing the build size by a couple of MB, this tends to be an issue for web and mobile projects where the prefab in the scene or using a shader variant collection is probably a cleaner way of handling it.

 

@popupAsylum Hi, I am trying to apply a custom volumetric fog (Aura 2) to the cloud particle field demo scene.
According to the documentation page 18 (https://drive.google.com/file/d/1x48tcAOcwnW7KKVZrAUy_ezIfvxXWbSh/view),
I have to compute the position in the vertex shader with :

float3 Aura2_GetFrustumSpaceCoordinates(float4 inVertex)

 

Hi @pierre92nicot,

You'll need to create a custom PAPF shader and a material that uses it, then change the field's material type to Custom and assign the material. I've written up an example customised shader with comments where changes have been made.

Spoiler: example shader

Code (CSharp):

1. Shader "PAPF_AuraTest" {
2.     Properties {
3.         _Color ("Color", Color) = (1, 1, 1, 1)
4.         _MainTex ("Texture Image", 2D) = "white" {}
5.     }
6.     SubShader {          
7.         Tags{
8.             "Queue"="Transparent"
9.             "RenderType"="Transparent"
10.             "IgnoreProjector"="True"
11.         }
12.         Pass {
13.             ZWrite Off
14.             Blend SrcAlpha OneMinusSrcAlpha
15.            
16.             CGPROGRAM
17.  
18.             #include "UnityCG.cginc"
19.             // Allow calls to PAPF functions (by absolute path)
20.             #include "Assets/PopupAsylum/PAParticleField/Shaders/ParticleField.cginc"
21.             // Allow calls to Aura 2
22.             #include "Assets/Aura 2/System/Code/Shaders/Aura.cginc"
23.            
24.             #pragma exclude_renderers flash
25.        
26.             #pragma vertex vert
27.             #pragma fragment frag
28.             #pragma multi_compile_fog
29.             #pragma target 3.0
30.  
31.             // Include the full PAPF feature set
32.             #pragma shader_feature _ DIRECTIONAL_ON SPIN_ON
33.             #pragma shader_feature _ SOFTPARTICLES_ON
34.             #pragma shader_feature _ WORLDSPACE_ON
35.             #pragma shader_feature _ SHAPE_SPHERE SHAPE_CYLINDER
36.             #pragma multi_compile _ EXCLUSION_ON      
37.             #pragma shader_feature _ TURBULENCE_SIMPLEX2D TURBULENCE_SIMPLEX
38.  
39.             uniform sampler2D _MainTex;          
40.             fixed4 _Color;          
41.             fixed _Softness;
42.  
43.             // -- Modified vertex output from ParticleField.cginc
44.             struct v2f {
45.                 float4 pos : SV_POSITION;
46.                 fixed4 color : COLOR;
47.                 float4 worldPos : TEXCOORD0;
48.                 float2 tex : TEXCOORD1;
49.                 UNITY_FOG_COORDS(2)
50.  
51.                 #ifdef LIGHTING_ON
52.                     LIGHTING_COORDS(3, 4)
53.                 #endif
54.                 #ifdef SOFTPARTICLES_ON
55.                     float4 projPos : TEXCOORD5;
56.                 #endif  
57.  
58.                 // -- Added member for Aura 2 Coords
59.                 float3 aura2Coords : TEXCOORD6;
60.             };
61.  
62.             // -- Modified vertex function (vertParticleFieldCube) from ParticleField.cginc
63.             v2f vert(appdata_full v)
64.             {
65.                 v2f o;
66.                 UNITY_INITIALIZE_OUTPUT(v2f, o);
67.  
68.                 PAParticleField(v);
69.  
70.                 // -- Pass through the aura coords
71.                 o.aura2Coords = Aura2_GetFrustumSpaceCoordinates(v.vertex);
72.  
73.                 o.color = v.color;
74.                 o.worldPos = float4(v.vertex.xyz, 1);
75.                 o.tex = v.texcoord;
76.  
77.                 #ifndef WORLDSPACE_ON
78.                     #ifdef LIGHTING_ON
79.                         TRANSFER_VERTEX_TO_FRAGMENT(o);
80.                     #endif
81.                 #endif
82.  
83.                 v.vertex = mul(_World2Object, o.worldPos);
84.  
85.                 #ifdef WORLDSPACE_ON
86.                     #ifdef LIGHTING_ON
87.                         TRANSFER_VERTEX_TO_FRAGMENT(o);
88.                     #endif
89.                 #endif
90.  
91.                 o.pos = PAPositionVertex(o.worldPos);
92.  
93.                 #ifdef SOFTPARTICLES_ON
94.                     o.projPos = ComputeScreenPos(o.pos);
95.                     #if UNITY_VERSION >= 550
96.                                     COMPUTE_EYEDEPTH(o.projPos.z);
97.                     #endif
98.                 #endif  
99.  
100.                 UNITY_TRANSFER_FOG(o, o.pos);
101.  
102.                 return o;
103.             }
104.  
105.             // -- Modified fragment function from ParticleFieldTransparent.shader
106.             float4 frag(v2f i) : COLOR
107.             {
108.                 #ifdef SOFTPARTICLES_ON
109.                 i.color.a *= GetAlphaFromDepth(i.projPos, _Softness);
110.                 #endif
111.            
112.                 fixed4 col = tex2D(_MainTex, i.tex.xy) * i.color * _Color;
113.                 #ifndef SHADER_API_MOBILE
114.                 clip(col.a - 0.01);
115.                 #endif
116.  
117.                 UNITY_APPLY_FOG(i.fogCoord, col);
118.                
119.                 // -- Applying Aura2 effect --
120.                 // Assuming lightingFactor is to allow the effect to be blended in
121.                 float lightingFactor = 1;
122.                 // Aura2_ApplyLighting expects a float3 so extract it
123.                 float3 colorToApply = col.rgb;
124.                 // Apply the lighting using the geneated coords, colorToApply will be modified
125.                 Aura2_ApplyLighting(/*inout*/ colorToApply, i.aura2Coords, lightingFactor);
126.                 Aura2_ApplyFog(/*inout*/ colorToApply, i.aura2Coords);
127.                 // copy the effected color back to the return value
128.                 col.rgb = colorToApply;
129.  
130.                 return col;
131.             }
132.        
133.             ENDCG
134.         }
135.        
136.     }
137.    
138.     Fallback "VertexLit"
139. }

I fully expect it will need tweaking but it hopefully will give you a good idea where to start

 

Thanks a lot !

 

@popupAsylum , is this still work with URP ?

 

Was also wondering if there is way to set the life time of the particles?

 

@castor76 URP support is unchanged, the Unlit shaders work as expected and I'm using it in a few URP projects now.

In terms of life time, the particles don't really have one, they last forever and are recycled when they reach the bounds of the field, what sort of effect are you trying to achieve?

 

Oh, I see. I wanted to simulate "dust particle effect" which I can do a twinkle with sprite sheet animation, but I guess I can never make them sort of hover around and then fade away without making them "move" or scroll to the edge of the bounding box.

So basically a simple life time based on a random range and then change color based on life time.

I guess the best work around is to have a huge amount of sprite animation frames and simulate "fade off" and then "fade in" again..

 

Hi 2 all! I changed to URP and the particles are showing up, yet I get this counting and counting.:

 

I am using my belowed "specks" in VR single pass. Unity 2019.4.18f1 . I am not using camera stacking (diesnt work correctly in 2019 ) and there is no post effects in scene

 

@RazT Its not ideal but URP doesn't seem to populate Camera.current, if you're not attempting to use soft particles (where the particles fade as they come into contact with other opaque objects) you can safely comment that line out

 

Hi there, I'm super interested in getting this asset, looks wonderful thank you. Quick question if I may please, is there any way for the particles to be affected by external forces? Specifically I'm thinking about wind as the use-case here.

Many thanks

John

 

There's a global 'Force' property that can be used to emulate wind, its a Vector3 that will be applied uniformly to all the particles in a field each update, you might normally combine it with a bit of turbulence.

 

@popupAsylum
Thank you for a wonderful asset! Been a great pair with mobile VR. Finally switching to URP so a humble +1 for URP support.

 

Hi, is there a way to make the PA transparent shader work with single pass instanced?