Hi guys,
I'm wondering if it is possible to draw a triangle with the basic Starling code, so no graphics extension and such.
The most basic triangle, just like a Quad, would be sufficient and in fact the solution I'm after.
I'd probably take the Quad class as reference and set the vertices so that they form a triangle that suits my needs.
Possible or not?
Hey Al_Bridie, try this one out for regular polygons :
https://gist.github.com/PrimaryFeather/2352107
Sorry, I'll take that back.
Something really weird is happening. I just can't draw more than one Polygon on the screen.
One works fine and it actually represents a triangle. Add another polygon and they both come out as lines only.
_polygon1 = new Polygon(1, 3, 0xffffff); _polygon1.width = _polygon1.height = triangleDimensions; _polygon1.rotation = Math.PI * 0.5; addChild(_polygon1); _polygon2 = new Polygon(1, 3, 0xffffff); _polygon2.width = _polygon1.height = triangleDimensions; _polygon2.rotation = Math.PI * 0.5; addChild(_polygon2);
I suppose its best so you don't break quad batching that way even though you'll have twice as many triangles rendered, out of curiosity then, did you move two corners so that your triangle is made of two right triangles?
(additionally, if your hitTest/touch still works after that modification, I'm interested to know so i'll do the same)
Unsure how Al_Birdie did it, but I needed to do it and saw their post so dug in to figure it out. Here is how I did it:
var triangle:Quad = new Quad(20, 20, 0xFF0000 ); triangle.setVertexPosition(1, 10, 10);
So basically take one corner and move it to the center. Then you can rotate as needed.
Using a Quad wastes a vertex and triangle. Here’s code for making one from a Polygon.
var poly:Polygon = new Polygon(); poly.numVertices = 3; poly.setVertex(0, 0, 0); poly.setVertex(1, 0, 20); poly.setVertex(2, 20, 0); var mesh:Mesh = Mesh.fromPolyGon(poly);
You could also set up the VertexData and IndexData and pass them to the Mesh constructor, but for simple meshes like this that seems excessive. The Polygon I would make a static var which I re-use every time I generate a Mesh.
Awesome, always good to see the different ways to skin a cat. This is bit more code though. How much resources are being saved?
A Quad has four vertices and two triangles, one more of each than is needed for a triangle. On its own not a big deal but if you have a lot of them for e.g. a particle system it might add up, in memory and rendering cost, as it’s double the number of triangles you need.
Also the phantom vertex which lies half way along an edge in your code might make it tricky to colour the triangle: depending how it’s triangulated you might be able to ignore it, or you might have to work out the colour for it.
My code as written leaks a bit more memory, as it creates a Polygon each time. I would fix that by making the Polygon a static class variable, so it is re-used again and again each time you create a triangle.
All good info, thanks!
For my own needs, I seriously just needed one triangle to denote a pulldown menu, so nothing crazy, but still appreciate knowing what goes on under the hood 
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