Play around more with text rendering

Assets/Scripts/TextRenderTest.cs

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+using System.Collections;
+using System.Collections.Generic;
+using TMPro;
+using UnityEngine;
+using UnityEngine.Rendering;
+
+public class TextRenderTest : MonoBehaviour {
+    //[InspectorButton("go")] public bool button;
+
+    public Camera _camera;
+
+    public GameObject _cameraObject;
+
+    public TextMeshPro _tmp;
+    
+    public Material _blitMaterial;
+
+    public Material _targetMaterial;
+
+    public RenderTexture renderTex;
+    private float pixelDensity = 36;
+    private int MaxTextureSize = 4096;
+
+    public const TextureFormat TextTextureFormat = TextureFormat.RG16;
+    public const RenderTextureFormat TextRenderTextureFormat = RenderTextureFormat.R8;
+    
+    // Start is called before the first frame update
+    void Start() {
+        Debug.Log("starting...");
+
+        StartCoroutine(OnRender());
+    }
+
+    // Update is called once per frame
+    void Update() {
+    }
+
+    private void go() {
+        Debug.Log("starting...");
+    }
+
+    private IEnumerator OnRender() {
+        Debug.Log("starting...2");
+
+        // calculate camera and texture size
+        _tmp.ForceMeshUpdate();
+        var mesh = _tmp.mesh;
+        mesh.RecalculateBounds();
+        var bounds = mesh.bounds;
+        Debug.Log(bounds.size);
+
+        var width = Mathf.NextPowerOfTwo((int) (bounds.size.x * pixelDensity));
+        var height = Mathf.NextPowerOfTwo((int) (bounds.size.y * pixelDensity));
+        
+        Debug.Log($"width = {width}");
+        Debug.Log($"height = {height}");
+        
+        _camera.orthographicSize = height / pixelDensity / 2;
+        _camera.aspect = (float) width / height;
+
+        _cameraObject.transform.localPosition = new Vector3(bounds.center.x, bounds.center.y, -1);
+
+        width = Mathf.Min(width, MaxTextureSize);
+        height = Mathf.Min(height, MaxTextureSize);
+        
+        // setup texture
+        var texture = new Texture2D(width, height, TextTextureFormat, true);
+        _targetMaterial.mainTexture = texture;
+
+        // setup render texture
+        renderTex = RenderTexture.GetTemporary(width, height, 0, TextRenderTextureFormat, RenderTextureReadWrite.Linear, 1);
+        renderTex.autoGenerateMips = true;
+        _camera.targetTexture = renderTex;
+
+        // setup material
+        _blitMaterial.mainTexture = _tmp.font.atlas;
+
+        // draw the mesh
+        Graphics.DrawMesh(mesh, _tmp.renderer.localToWorldMatrix, _blitMaterial, 0, _camera, 0);
+        _camera.Render();
+
+        yield return null;
+
+        RenderTexture.active = renderTex;
+        texture.ReadPixels(new Rect(0, 0, width, height), 0, 0, true);
+        texture.Apply(false, true);
+        
+        RenderTexture.ReleaseTemporary(renderTex);
+    }
+}

Assets/Shaders/TMPBlit.shader

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+Shader "ConformalDecals/TMP_Blit"
+{
+    Properties
+    {
+        _MainTex("_MainTex (RGB spec(A))", 2D) = "white" {}
+
+    }
+    SubShader
+    {
+        Tags { "Queue" = "Transparent" }
+        Cull Off
+        ZWrite Off 
+        
+        Pass
+        {
+            Blend One One
+
+            CGPROGRAM
+            #pragma vertex vert
+            #pragma fragment frag
+
+            sampler2D _MainTex;
+
+            #include "UnityCG.cginc"
+            #include "Lighting.cginc"
+            #include "AutoLight.cginc"
+
+            struct v2f {
+                float4 pos : SV_POSITION;
+                float2 uv : TEXCOORD0;
+            };
+
+            v2f vert(float4 vertex : POSITION, float2 uv : TEXCOORD0) {
+                v2f o;
+                o.pos = UnityObjectToClipPos(vertex);
+                o.uv = uv;
+                return o;
+            }
+
+            fixed4 frag (v2f i) : SV_Target {
+                fixed4 c = 0;
+
+                c.r = tex2D(_MainTex,(i.uv)).a;
+
+                return c;
+            }
+
+            ENDCG
+        } 
+    }
+}