I am making a an isometric game with a combination of 2d and 3d elements. I wish to know how to make my player and enemy sprites (all made up of 2d elemnts) not render behind or inside my 3d elements.
So I have tried messing about with renderQueue and setting the renderqueue of the materials these rocks and such have to a high value to have them drawn behind the 2d elements.
However through my searching I have found out that I actually need to be setting the ztest of the objects to correct this. This confused me a bit and I am unsure how to do it as I have not really used shaders that much. I could not find any decent references that explain exactly how to go about this just stuff written that assumes prior knowledge like this. I tried downloading the unity shaders and and opened the default sprite one but I was unsure where to change the ztest or tagging to solve this.
here is the standard sprite shader from unity:
// Unity built-in shader source. Copyright (c) 2016 Unity Technologies. MIT license (see license.txt)
#ifndef UNITY_SPRITES_INCLUDED
#define UNITY_SPRITES_INCLUDED
#include "UnityCG.cginc"
#ifdef UNITY_INSTANCING_ENABLED
UNITY_INSTANCING_BUFFER_START(PerDrawSprite)
// SpriteRenderer.Color while Non-Batched/Instanced.
UNITY_DEFINE_INSTANCED_PROP(fixed4, unity_SpriteRendererColorArray)
// this could be smaller but that's how bit each entry is regardless of type
UNITY_DEFINE_INSTANCED_PROP(fixed2, unity_SpriteFlipArray)
UNITY_INSTANCING_BUFFER_END(PerDrawSprite)
#define _RendererColor UNITY_ACCESS_INSTANCED_PROP(PerDrawSprite, unity_SpriteRendererColorArray)
#define _Flip UNITY_ACCESS_INSTANCED_PROP(PerDrawSprite, unity_SpriteFlipArray)
#endif // instancing
CBUFFER_START(UnityPerDrawSprite)
#ifndef UNITY_INSTANCING_ENABLED
fixed4 _RendererColor;
fixed2 _Flip;
#endif
float _EnableExternalAlpha;
CBUFFER_END
// Material Color.
fixed4 _Color;
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
};
inline float4 UnityFlipSprite(in float3 pos, in fixed2 flip)
{
return float4(pos.xy * flip, pos.z, 1.0);
}
v2f SpriteVert(appdata_t IN)
{
v2f OUT;
UNITY_SETUP_INSTANCE_ID (IN);
UNITY_INITIALIZE_VERTEX_OUTPUT_STEREO(OUT);
OUT.vertex = UnityFlipSprite(IN.vertex, _Flip);
OUT.vertex = UnityObjectToClipPos(OUT.vertex);
OUT.texcoord = IN.texcoord;
OUT.color = IN.color * _Color * _RendererColor;
#ifdef PIXELSNAP_ON
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
fixed4 alpha = tex2D (_AlphaTex, uv);
color.a = lerp (color.a, alpha.r, _EnableExternalAlpha);
#endif
return color;
}
fixed4 SpriteFrag(v2f IN) : SV_Target
{
fixed4 c = SampleSpriteTexture (IN.texcoord) * IN.color;
c.rgb *= c.a;
return c;
}
#endif // UNITY_SPRITES_INCLUDED


