Why does my shaders stop rendering at a certain angle? - unity3d

Question

I'm trying to make a nice looking forest to a new game im working on.
But theres a problem with the rendering of my shaders. I have it currently setup to render close by trees with an 2d-sprite renderer. And the other trees that arent close enough will get render using the shader instead. But the problem is with the trees that are using the shader. Cause when i look at them and move my camera up they just stop rendering.. why?
Here's a gif of what i mean.
https://gyazo.com/64acbf5cadd9a89b0ba2cd5f123605ce
And here's my shader script.
Shader "Custom/Tree_Billboard"
{
Properties
{
[PerRendererData] _MainTex("Sprite Texture", 2D) = "white" {}
_Color("Tint", Color) = (1,1,1,1)
//_Time ("Time", Float) = 0
[MaterialToggle] PixelSnap("Pixel snap", Float) = 0
}
SubShader
{
Tags
{
"Queue" = "Transparent"
"DisableBatching" = "True"
"SortingLayer" = "Resources_Sprites"
"IgnoreProjector" = "True"
"RenderType" = "Transparent"
"PreviewType" = "Plane"
"CanUseSpriteAtlas" = "True"
}
Cull Off
Lighting Off
ZWrite Off
Blend One OneMinusSrcAlpha
Pass
{
CGPROGRAM
#pragma vertex vert
#pragma fragment frag
#pragma target 2.0
#pragma multi_compile _ PIXELSNAP_ON
#pragma multi_compile _ ETC1_EXTERNAL_ALPHA
#include "UnityCG.cginc"
// uniform Float _Time;
struct appdata_t
{
float4 vertex : POSITION;
float4 color : COLOR;
float2 texcoord : TEXCOORD0;
UNITY_VERTEX_INPUT_INSTANCE_ID
};
struct v2f
{
float4 vertex : SV_POSITION;
fixed4 color : COLOR;
float2 texcoord : TEXCOORD0;
UNITY_VERTEX_OUTPUT_STEREO
};
fixed4 _Color;
v2f vert(appdata_t IN)
{
v2f OUT;
UNITY_SETUP_INSTANCE_ID(IN);
UNITY_INITIALIZE_VERTEX_OUTPUT_STEREO(OUT);
// OUT.vertex = UnityObjectToClipPos(IN.vertex);
OUT.texcoord = IN.texcoord;
OUT.color = IN.color * _Color;
// #ifdef PIXELSNAP_ON
OUT.vertex = mul(UNITY_MATRIX_P,
mul(UNITY_MATRIX_MV, float4(0.0, 4.1, 0.0, 1.0))
- float4(IN.vertex.x, -IN.vertex.y, 0.0, 0.0)
* float4(6.0, 8.0, 1.0, 1.0));
// OUT.vertex = UnityPixelSnap (OUT.vertex);
// #endif
return OUT;
}
sampler2D _MainTex;
sampler2D _AlphaTex;
fixed4 SampleSpriteTexture(float2 uv)
{
fixed4 color = tex2D(_MainTex, uv);
#if ETC1_EXTERNAL_ALPHA
// get the color from an external texture (usecase: Alpha support for ETC1 on android)
color.a = tex2D(_AlphaTex, uv).r;
#endif //ETC1_EXTERNAL_ALPHA
return color;
}
fixed4 frag(v2f IN) : SV_Target
{
fixed4 c = SampleSpriteTexture(IN.texcoord) * IN.color;
c.rgb *= c.a;
return c;
}
ENDCG
}
}
}

Answer 1

Here's what "jvo3dc" said on the Unity Forum's
"The objects get frustum culled. The culling is done on the bounding box of the object.
You're adjusting the vertices in the shader so they fall outside the original bounding box. This means the culling process can sometimes assume they are invisible, while they actually are visible.
The solution is to match the bounding box with the actual maximum displacement in the vertex shader."
So i went and searched a bit on Google and found a solution. I created a new quad-gameObject. Added a new scripts and added this to the Start() method and that seems to have fixed it.
transform.GetChild(0).GetComponent<MeshFilter>().sharedMesh.bounds = new Bounds(new Vector3(0, 0, 0), new Vector3(1, 1,1) * 10.0f);
(Here's the Unity forum post)

Answer 2

This is clearly not a shader problem but a problem with your clip plane. Check your camera settings first.