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General / Can't modify Vertex of a VertexArray

« on: June 29, 2013, 12:35:33 am »

Hi !

I use rbSFML in my project. It works like a charm but I can't figure out how to get VertexArray to work properly.
My code :

require 'sfml'

include SFML


class MainWindow
  def initialize(width, height)
    @window = RenderWindow.new([width, height], "VertexArray")
   
    @vertices = VertexArray.new(Triangles, 3)
   
    @vertices[0].position = [100, 100]
    @vertices[1].position = [200, 100]
    @vertices[2].position = [200, 200]
   
    @vertices[0].color = Color::Red
    @vertices[1].color = Color::Green
    @vertices[2].color = Color::Blue
   
    update
  end

  def update
    while @window.open?
      @window.each_event do |event|
         @window.close if event.type == Event::Closed
      end
      @window.clear
      @window.draw(@vertices)
      @window.display
    end
  end
 
end

MainWindow.new(640, 480)

But the triangle isn't drawn :/

I've done some testing and it seems that "@vertices[id]" return a new Vertex so I can't modify the Vertex of VertexArray.
For example, if I do something like that :

    @vertices = VertexArray.new(Triangles, 3)
    vertex = @vertices[0]
    vertex.position = [100, 100]
    p @vertices[0].position == vertex.position #=> false

The vertex in the VertexArray doesn't have the new position.

The only way I've find to do what I want is to clear the VertexArray and fill it with new Vertex (by using the "append" function) each time I want to modify a Vertex.

I've tried with a ruby array instead of a VertexArray. Works well but it's pretty slow.

So how can I easily change the Vertex position/color/texture of a VertexArray ?

I use the latest version of rbSFML on github and SFML2.0.



Thanks in advance