1

I am attempting to draw meshes inside an EditorWindow. Sounds easy: there’s a Graphics.DrawMeshNow() function that draws a mesh, and indeed in my editor’s OnGUI repaint event it draws the mesh wonderfully in orthographic projection. But the near/far planes are too close together!

So I’ve been looking at changing the projection matrix. Here’s the code:

			Matrix4x4 model = Matrix4x4.TRS(
				new Vector3(midCol.xMin + width/2,y + width/2,-50), 
				Quaternion.AngleAxis(180,new Vector3(0,0,1)) * Quaternion.AngleAxis(45,new Vector3(1,0,0)) * Quaternion.AngleAxis(Time.realtimeSinceStartup*60,new Vector3(0.0f,1.0f,0.0f)), 
				Vector3.one * 10 * mag);
	
			Matrix4x4 proj = Matrix4x4.identity;
			float f = 1000;
			float n = 0.01f;
			float sw = Screen.width;
			float sh = Screen.height;
			proj[0,0] = 2.0f / (sw);
			proj[1,1] = 2.0f / (-sh);
			proj[2,2] = -2.0f / (f - n);

			proj[3,0] = -1;
			proj[3,1] = 1;
			proj[3,2] = -( (f + n) / (f - n) );

			proj[3,3] = 1;

			if (sceneryMaterial.SetPass(0))
			{
				//GL.PushMatrix(); // does nothing since modifying GL matrix does nothing

				for (int i = 0; i < 4; i++)
					for (int j = 0; j < 4; j++)
						proj[i,j] = Random.Range(-1000,1000);

				Matrix4x4 gm = GUI.matrix;
				//GL.LoadProjectionMatrix(proj); // does nothing!
		
				GUI.matrix = proj; // DOES NOTHING SOMEBODY KILL ME

				Matrix4x4[] camProj = new Matrix4x4[Camera.allCamerasCount];
				for (int i = 0; i < Camera.allCamerasCount; i++) {
					camProj _= Camera.allCameras*.projectionMatrix; // Camera equivalent of GL.push/pop matrix*_

* } *

* //Camera.main.pixelRect = new Rect(100,100,100,100); // this messes with subsequent views unless reset*
* //Camera.main.projectionMatrix = proj; // GL.push/pop matrix have no effect on this; also, DOES NOTHING*

* for (int i = 0; i < Camera.allCamerasCount; i++) {*
_ Camera.allCameras*.projectionMatrix = proj; // Camera equivalent of GL.push/pop matrix*
* } *_

* Matrix4x4 mx = model; // used to try multiplying my own ortho projection matrix in here, with disastrous results*

* Graphics.DrawMeshNow(selectedGraphic.visualMesh, mx);*

* for (int i = 0; i < Camera.allCamerasCount; i++) {*
Camera.allCameras_.projectionMatrix = camProj*; // Camera equivalent of GL.push/pop matrix*
* }
GUI.matrix = gm; // restore the gui matrix FOR ALL THE GOOD IT DID ME*
* //GL.PopMatrix(); // does nothing*
* }*
NONE of these projection matrix modifications affects DrawMeshNow() in any way.
Let me be clear: I’ve messed with the GL matrix, every possible camera matrix AND the GUI matrix, and none of them change how DrawMeshNow() draws a mesh in an OnGUI repaint event.
I need answers! Does anyone know where I can put a projection matrix?
Thanks in advance!_

2

In the time-honoured tradition of answering my own questions, I have solved this issue, my particular issue that I had with the near/far planes. It is a hack, but it works. I squish down the z axis in the model matrix, so that the verts come out at zero on the z axis. Back-face culling means the model displays correctly. Obviously this could be changed to preserve some z information but I was so excited that I had to come post here first.

Here is the code:

   Matrix4x4 model = Matrix4x4.TRS(some_model_position_on_screen, some_rotation, Vector3.one * 10 * mag);
   model = Matrix4x4.TRS (Vector3.zero, Quaternion.identity, new Vector3(1,1,0)) * model;

The last line is the important one - after setting up the model matrix, I simply multiply in a matrix that zeroes the z axis.

The original problem I had was caused by having to scale up the model to roughly 80 times its normal size to be displayed correctly on-screen - something I could have avoided having to do if I had control of the projection matrix, either by setting the near/far planes where I wanted, or by changing it so my units made more sense on-screen.

Thanks for reading or whatever.