Displaying a non-planar face

Hello,

I remember this was not possible in BVE and openBVE as it was creating artifacts and the texture was never applied correctly. Is that still the case? Can it be fixed, or not at all?

Thanks. :-)

I can't think why it wouldn't work, certainly shouldn't be any technical reason why not.

If you find it doesn't, produce a simple example and I'll take a look.

Ok, I will try to do that. Just give me a few.

Well, this has a  concave part and it does not display properly with a rectangular texture.

Code:

;;sleeper1
CreateMeshBuilder,
Addvertex,-0.76, -0.169, 0.295,
Addvertex,-0.76, -0.169, 0.491,
Addvertex,-0.63, -0.169, 0.491,
Addvertex,-0.35, -0.195, 0.491,
Addvertex,0.35, -0.195, 0.491,
Addvertex,0.63, -0.169, 0.491,
Addvertex,0.76, -0.169, 0.491,
Addvertex,0.76, -0.169, 0.295,
Addvertex,0.63, -0.169, 0.295,
Addvertex,0.35, -0.195, 0.295,
Addvertex,-0.35, -0.195, 0.295,
Addvertex,-0.63, -0.169, 0.295,
AddFace,0,1,2,3,4,5,6,7,8,9,10,11
LoadTexture,Prazec1.png,
SetTextureCoordinates,0, 0, 1,
SetTextureCoordinates,1, 0, 0,
SetTextureCoordinates,2, 0.1, 0,
SetTextureCoordinates,3, 0.28, 0,
SetTextureCoordinates,4, 0.72, 0,
SetTextureCoordinates,5, 0.9, 0,
SetTextureCoordinates,6, 1, 0,
SetTextureCoordinates,7, 1, 1,
SetTextureCoordinates,8, 0.9, 1,
SetTextureCoordinates,9, 0.72, 1,
SetTextureCoordinates,10, 0.28, 1,
SetTextureCoordinates,11, 0.1, 1,


The shape of the object gets f***** up...



Yet when I separate the Meshes, it gets displayed normally... there is no difference between the two in terms of shape.

Code:

CreateMeshBuilder,
Addvertex,-0.76, -0.169, 0.295,
Addvertex,-0.76, -0.169, 0.491,
Addvertex,-0.63, -0.169, 0.491,
Addvertex,-0.63, -0.169, 0.295,
AddFace,0,1,2,3
LoadTexture,Prazec1.png,
SetTextureCoordinates,0, 0, 1,
SetTextureCoordinates,1, 0, 0,
SetTextureCoordinates,2, 0.1, 0,
SetTextureCoordinates,3, 0.1, 1,

CreateMeshBuilder,
Addvertex,-0.63, -0.169, 0.295,
Addvertex,-0.63, -0.169, 0.491,
Addvertex,-0.35, -0.195, 0.491,
Addvertex,-0.35, -0.195, 0.295,
AddFace,0,1,2,3
LoadTexture,Prazec1.png,
SetTextureCoordinates,0, 0.1, 1,
SetTextureCoordinates,1, 0.1, 0,
SetTextureCoordinates,2, 0.28, 0,
SetTextureCoordinates,3, 0.28, 1,

CreateMeshBuilder,
Addvertex,-0.35, -0.195, 0.295,
Addvertex,-0.35, -0.195, 0.491,
Addvertex,0.35, -0.195, 0.491,
Addvertex,0.35, -0.195, 0.295,
AddFace,0,1,2,3
LoadTexture,Prazec1.png,
SetTextureCoordinates,0, 0.28, 1,
SetTextureCoordinates,1, 0.28, 0,
SetTextureCoordinates,2, 0.72, 0,
SetTextureCoordinates,3, 0.72, 1,

CreateMeshBuilder,
Addvertex,0.35, -0.195, 0.295,
Addvertex,0.35, -0.195, 0.491,
Addvertex,0.63, -0.169, 0.491,
Addvertex,0.63, -0.169, 0.295,
AddFace,0,1,2,3
LoadTexture,Prazec1.png,
SetTextureCoordinates,0, 0.72, 1,
SetTextureCoordinates,1, 0.72, 0,
SetTextureCoordinates,2, 0.9, 0,
SetTextureCoordinates,3, 0.9, 1,

CreateMeshBuilder,
Addvertex,0.63, -0.169, 0.295,
Addvertex,0.63, -0.169, 0.491,
Addvertex,0.76, -0.169, 0.491,
Addvertex,0.76, -0.169, 0.295,
AddFace,0,1,2,3
LoadTexture,Prazec1.png,
SetTextureCoordinates,0, 0.9, 1,
SetTextureCoordinates,1, 0.9, 0,
SetTextureCoordinates,2, 1, 0,
SetTextureCoordinates,3, 1, 1,

I believe it's the marked angle that causes the problem (the frame is taken from the separate meshes version, otherwise it wouldn't have been displayed)

This is not working either, it displays broken...

Code:

CreateMeshBuilder,
Addvertex,-0.63, -0.169, 0.295,
Addvertex,-0.63, -0.169, 0.491,
Addvertex,-0.35, -0.195, 0.491,
Addvertex,0.35, -0.195, 0.491,
Addvertex,0.63, -0.169, 0.491,
Addvertex,0.63, -0.169, 0.295,
Addvertex,0.35, -0.195, 0.295,
Addvertex,-0.35, -0.195, 0.295,
AddFace,0,1,2,3,4,5,6,7
LoadTexture,Prazec1.png,
SetTextureCoordinates,0, 0.1, 1,
SetTextureCoordinates,1, 0.1, 0,
SetTextureCoordinates,2, 0.28, 0,
SetTextureCoordinates,3, 0.72, 0,
SetTextureCoordinates,4, 0.9, 0,
SetTextureCoordinates,5, 0.9, 1,
SetTextureCoordinates,6, 0.72, 1,
SetTextureCoordinates,7, 0.28, 1,

I might be doing something wrong, but it seems that a non-planar face is displayed as something broken.

This (below) is not working either and creates a weirdly displayed thing. Weirdly textured as well. You can try all the examples with your random rectangular texture (no transparency).

Code:

CreateMeshBuilder,
Addvertex,-0.76, -0.21, 0.295, ;0
Addvertex,-0.76, -0.169, 0.295, ;1
Addvertex,-0.63, -0.169, 0.295, ;2
Addvertex,-0.35, -0.195, 0.295, ;3
Addvertex,0.35, -0.195, 0.295, ;4
Addvertex,0.63, -0.169, 0.295, ;5
Addvertex,0.76, -0.169, 0.295, ;6
Addvertex,0.76, -0.21, 0.295, ;7
AddFace,0,1,2,3,4,5,6,7
LoadTexture,Prazec1.png,
SetTextureCoordinates,0, 0, 0.9,
SetTextureCoordinates,1, 0, 1,
SetTextureCoordinates,2, 0.1, 1,
SetTextureCoordinates,3, 0.28, 1,
SetTextureCoordinates,4, 0.72, 1,
SetTextureCoordinates,5, 0.9, 1,
SetTextureCoordinates,6, 1, 1,
SetTextureCoordinates,7, 1, 0.9,

Separate meshes with same shape work as intended:

Code:

CreateMeshBuilder,
Addvertex,-0.76, -0.21, 0.295,
Addvertex,-0.76, -0.169, 0.295,
Addvertex,-0.63, -0.169, 0.295,
Addvertex,-0.63, -0.21, 0.295,
AddFace,0,1,2,3
LoadTexture,Prazec1.png,
SetTextureCoordinates,0, 0, 0.9,
SetTextureCoordinates,1, 0, 1,
SetTextureCoordinates,2, 0.1, 1,
SetTextureCoordinates,3, 0.1, 0.9,

CreateMeshBuilder,
Addvertex,-0.63, -0.21, 0.295,
Addvertex,-0.63, -0.169, 0.295,
Addvertex,-0.35, -0.195, 0.295,
Addvertex,-0.35, -0.21, 0.295,
AddFace,0,1,2,3
LoadTexture,Prazec1.png,
SetTextureCoordinates,0, 0.1, 0.9,
SetTextureCoordinates,1, 0.1, 1,
SetTextureCoordinates,2, 0.28, 1,
SetTextureCoordinates,3, 0.28, 0.9,

CreateMeshBuilder,
Addvertex,-0.35, -0.21, 0.295,
Addvertex,-0.35, -0.195, 0.295,
Addvertex,0.35, -0.195, 0.295,
Addvertex,0.35, -0.21, 0.295,
AddFace,0,1,2,3
LoadTexture,Prazec1.png,
SetTextureCoordinates,0, 0.28, 0.9,
SetTextureCoordinates,1, 0.28, 1,
SetTextureCoordinates,2, 0.72, 1,
SetTextureCoordinates,3, 0.72, 0.9,

CreateMeshBuilder,
Addvertex,0.35, -0.21, 0.295,
Addvertex,0.35, -0.195, 0.295,
Addvertex,0.63, -0.169, 0.295,
Addvertex,0.63, -0.21, 0.295,
AddFace,0,1,2,3
LoadTexture,Prazec1.png,
SetTextureCoordinates,0, 0.72, 0.9,
SetTextureCoordinates,1, 0.72, 1,
SetTextureCoordinates,2, 0.9, 1,
SetTextureCoordinates,3, 0.9, 0.9,

CreateMeshBuilder,
Addvertex,0.63, -0.21, 0.295,
Addvertex,0.63, -0.169, 0.295,
Addvertex,0.76, -0.169, 0.295,
Addvertex,0.76, -0.21, 0.295,
AddFace,0,1,2,3
LoadTexture,Prazec1.png,
SetTextureCoordinates,0, 0.9, 0.9,
SetTextureCoordinates,1, 0.9, 1,
SetTextureCoordinates,2, 1, 1,
SetTextureCoordinates,3, 1, 0.9,

Oh! Now I get what you're trying to do. No, faces have to be planar, non-planar faces aren't possible. The border vertices don't define the face, the renderer can't know how to connect which vertices. You'll always have to break those down.

I had the same thing on carriage roof corners where I had to show double curvature, the answer was to break it down in to triangles. With a custom normal or two thrown in the result was acceptable.

I think what you're forgetting is the winding of the face.
Think of it as a connect the dots puzzle working in threes, which must *always* go anti-clockwise to produce correct results.
Anything enclosed by the current set of three dots will be filled.

openGL in general just doesn't work the way you're trying to make it.

Yep, that explains a lot.