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MDX 2 - DrawUserPrimitives()

Started by B_old May 18, 2006 at 1:58 PM 4 replies 3.8k views

Original Post

May 18, 2006 at 1:58 PM

Hello, I'm trying to draw some line with DrawUserPrimitives() in MD3D 2. As I understand I need a GraphicsBuffer for that. But I can't figure out how to fill it with my data. I'm also wondering how I can tell the device about my vertexformat. Some advice would be nice, since some things seem to have changed in MDX 2 and the sdk samples use a earlier version.

Demirug

May 18, 2006 at 2:10 PM

You should use the generic version of a graphics buffer. This will allows you to use the write methods to add your vertexes.

You need to set your vertex format with the VertexFormat or VertexDeclaration property before you call any draw method.

PS: You should not use MDX 2 for a real project as it will never released in it’s current form. Better stay with MDX1 and wait for the XNA framework.

B_old

May 19, 2006 at 2:14 AM

I did not know that MDX 2 will go away.
What purpose does it serve then?

Demirug

May 19, 2006 at 2:36 AM

You should read this
blog entry from Tom Miller.

B_old

May 19, 2006 at 8:16 AM

Thanks, that was an interesting read.

I am trying to draw a line like this:

        Vertex_Colored[] vertices = new Vertex_Colored[2];        vertices[0] = new Vertex_Colored();        vertices[0].pos = new Vector3(0, 0, -5);        vertices[0].color = Color.White.ToArgb();        vertices[1] = new Vertex_Colored();        vertices[1].pos = new Vector3(0, 0, 5);        vertices[1].color = Color.White.ToArgb();        GraphicsBuffer<Vertex_Colored> gb = new GraphicsBuffer<Vertex_Colored>(2);        gb.Write(vertices);          rdevice.device.VertexFormat = VertexFormats.Position | VertexFormats.Diffuse;        rdevice.device.DrawUserPrimitives(PrimitiveType.LineList, 1, gb);        gb.Dispose();

I can see a line. But it is black rather than white.
I did call this beforehand: device.SetTextureState(0, TextureStates.ColorOperation, false);

[Edited by - B_old on May 19, 2006 9:16:28 AM]

wong_bo

May 30, 2006 at 11:13 PM

I am really surprised that you are using a structure called Vertex_Colored. It seems like a user-defined structure. I don't think DirectX will be able to recognize it.

Since you are using MDX2, you can just use the build-in structure PositionColored and the code should be like this:

	    PositionColored[] vertices = new PositionColored[2];	    vertices[0].Position = new Vector3(0, 0, -5);	    vertices[0].Color = Color.White;	    vertices[1].Position = new Vector3(0, 0, 5);	    vertices[1].Color = Color.White;	    GraphicsBuffer<PositionColored> gb = new GraphicsBuffer<PositionColored>(2);	    gb.Write(vertices);	    rdevice.device.VertexFormat = PositionColored.Format;	    rdevice.device.DrawUserPrimitives(PrimitiveType.LineList, 1, gb);	    gb.Dispose();

Don't forget to declare

using Microsoft.DirectX.Direct3D.CustomVertex;

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