Fix CSGMesh not working with procedural ArrayMesh

[ghost]

I was trying to make some procedural CSG geometry using a CSGMesh and the triangles were not visible at all. To test, I made an empty scene with a camera at the origin (translation [0,0,0], rotation [0,0,0]), and a spatial node with the following script:

extends Spatial

func _ready():
	var vertices = PoolVector3Array()
	
	var mesh = ArrayMesh.new()
	var arrays = []
	arrays.resize(ArrayMesh.ARRAY_MAX)
	vertices.push_back(Vector3(0,1,-2))
	vertices.push_back(Vector3(1,1,-2))
	vertices.push_back(Vector3(1,0,-2))
	arrays[ArrayMesh.ARRAY_VERTEX] = vertices
	
	mesh.add_surface_from_arrays(Mesh.PRIMITIVE_TRIANGLES, arrays)
	
	var body = CSGMesh.new()
	body.mesh = mesh
	add_child(body)

This should show a single triangle, but currently it doesn't. After some inspection, it looks like CSGMesh::_build_brush() had some typos with the input vertex and output vertex count switched around, and was not merging the vertices correctly. With my changes, the above code runs correctly and shows a triangle.

[NewNodeGames]

Seems to work well with the example script but now when I add a CSGMesh node and select a shape nothing appears (GLES2)

servers/visual_server.cpp:969 - Condition ' array_len == 0 ' is true.
scene/resources/mesh.cpp:796 - Condition ' len == 0 ' is true.
drivers/gles2/rasterizer_storage_gles2.cpp:2004 - Index p_surface=0 out of size (mesh->surfaces.size()=0)
modules/csg/csg_shape.cpp:171 - Condition ' !n ' is true.
servers/visual_server.cpp:969 - Condition ' array_len == 0 ' is true.
scene/resources/mesh.cpp:796 - Condition ' len == 0 ' is true.
drivers/gles2/rasterizer_storage_gles2.cpp:2004 - Index p_surface=0 out of size (mesh->surfaces.size()=0)

Related: 7aea850#commitcomment-31031330

[Zireael07]

I'm not sure CSG works with GLES2...

[NewNodeGames]

I'm not sure CSG works with GLES2...

It works but have some performance problems and errors with CSGPolygon and CSGMesh.

[ghost]

I was able to see it with GLES2. This patch does not touch the renderer.

[ghost]

This should be tested with an index array before merging, I will be able to try that out later this evening.

[ghost]

Tested again with the following script, it seems to work as expected:

extends Spatial

func _ready():
	var vertices = PoolVector3Array()
	var indices = PoolIntArray()
	
	var mesh = ArrayMesh.new()
	var arrays = []
	arrays.resize(ArrayMesh.ARRAY_MAX)
	vertices.push_back(Vector3(0,1,-2))
	vertices.push_back(Vector3(1,1,-2))
	vertices.push_back(Vector3(1,0,-2))
	indices.push_back(0)
	indices.push_back(1)
	indices.push_back(2)
	arrays[ArrayMesh.ARRAY_VERTEX] = vertices
	arrays[ArrayMesh.ARRAY_INDEX] = indices
	
	mesh.add_surface_from_arrays(Mesh.PRIMITIVE_TRIANGLES, arrays)
	
	var body = CSGMesh.new()
	body.mesh = mesh
	add_child(body)

[ghost]

@NewNodeGames The shape not updating in the editor appears to be a separate editor bug. I noticed if you change to CubeMesh/SphereMesh/etc and no mesh is visible, you can get it to show up by changing another property on the CSGMesh. I may get some time to look more into that tomorrow.

[NewNodeGames]

Tested again with the following script, it seems to work as expected:

extends Spatial

func _ready():
	var vertices = PoolVector3Array()
	var indices = PoolIntArray()
	
	var mesh = ArrayMesh.new()
	var arrays = []
	arrays.resize(ArrayMesh.ARRAY_MAX)
	vertices.push_back(Vector3(0,1,-2))
	vertices.push_back(Vector3(1,1,-2))
	vertices.push_back(Vector3(1,0,-2))
	indices.push_back(0)
	indices.push_back(1)
	indices.push_back(2)
	arrays[ArrayMesh.ARRAY_VERTEX] = vertices
	arrays[ArrayMesh.ARRAY_INDEX] = indices
	
	mesh.add_surface_from_arrays(Mesh.PRIMITIVE_TRIANGLES, arrays)
	
	var body = CSGMesh.new()
	body.mesh = mesh
	add_child(body)

With this script appears the triangle without apply your patch and csg mesh node shows the primitives again.

[reduz]

I did a fix in a bit less intrusive way, but thanks for finding out about this

[akien-mga]

Those variables could really use more explicit names... :)