Unity: How to Create a projection such that the local coordinates match the monitor coordinates - unity3d

Question

I'm learning about mesh rendering in unity.
I followed the documentation and was able to draw a blue quad on the screen.
However I can't figure out how render thinng such that the entire monitor is used.
I think what I'm missing is setting some sort of projections for this coordinate system to match. But how can I do that? Ideally I would like to do:
x_start = 0;
x_end = W;
y_start = 0;
y_end = H;
And have this quad cover the entire screen.
Here is the code:
using System.IO;
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.XR;
public class MeshRendererTest : MonoBehaviour
{
// Start is called before the first frame update
static Material mat;
float z;
float W;
float H;
Matrix4x4 projectionMatrix;
void Start(){
W = 2480.0f;
H = 2416.0f;
//projectionMatrix = Matrix4x4.Ortho(0, (int)W, (int)H, 0, -1, 100);
Shader shader = Shader.Find("Hidden/Internal-Colored");
//Shader shader2 = Shader.Find("Standard");
//Shader shader2 = Shader.Find("Unlit/UnlitAlphaWithFade");
mat = new Material(shader);
mat.hideFlags = HideFlags.HideAndDontSave;
//texMat.hideFlags = HideFlags.HideAndDontSave;
// Turn backface culling off
mat.SetInt("_Cull", (int)UnityEngine.Rendering.CullMode.Off);
//texMat.SetInt("_Cull", (int)UnityEngine.Rendering.CullMode.Off);
// Turn off depth writes
mat.SetInt("_ZWrite", 0);
//texMat.SetInt("_ZWrite", 0);
z = 999.0f;
mat.SetColor("_Color", Color.blue);
mat.SetPass(0);
MeshRenderer meshRenderer = gameObject.AddComponent<MeshRenderer>();
if (meshRenderer == null){
Debug.Log("Mesh Renderer is NUll");
return;
}
//meshRenderer.sharedMaterial = new Material(Shader.Find("Standard"));
meshRenderer.sharedMaterial = mat;
MeshFilter meshFilter = gameObject.AddComponent<MeshFilter>();
if (meshFilter == null){
Debug.Log("Mesh Filter is NUll");
return;
}
Mesh mesh = new Mesh();
float x_start = 0;
float x_end = x_start + 100;
float y_start = 0;
float y_end = y_start + 600;
Vector3[] vertices = new Vector3[4]
{
new Vector3(x_start, y_start, z),
new Vector3(x_end, y_start, z),
new Vector3(x_start, y_end, z),
new Vector3(x_end, y_end, z)
};
mesh.vertices = vertices;
int[] tris = new int[6]
{
// lower left triangle
0, 2, 1,
// upper right triangle
2, 3, 1
};
mesh.triangles = tris;
Vector3[] normals = new Vector3[4]
{
-Vector3.forward,
-Vector3.forward,
-Vector3.forward,
-Vector3.forward
};
mesh.normals = normals;
Vector2[] uv = new Vector2[4]
{
new Vector2(0, 0),
new Vector2(1, 0),
new Vector2(0, 1),
new Vector2(1, 1)
};
mesh.uv = uv;
meshFilter.mesh = mesh;
}
void OnRenderObject(){
TestStuff();
}
void TestStuff(){
Camera.main.ResetProjectionMatrix();
Matrix4x4 newProj = Matrix4x4.identity;
newProj = newProj * transform.localToWorldMatrix;
newProj = newProj * Camera.main.projectionMatrix;
newProj = newProj * projectionMatrix;
Camera.main.projectionMatrix = newProj;
}
}