Jump to content
  • Advertisement
Sign in to follow this  

[.net] textured quads in XNA

This topic is 3964 days old which is more than the 365 day threshold we allow for new replies. Please post a new topic.

If you intended to correct an error in the post then please contact us.

Recommended Posts

I'm trying to make textured quads in XNA but it ends up funny. Here's my code.
        public Quad(Vector3 origin, Color color, Vector3 up, float width, float height)
            Vertices = new VertexPositionColorTexture[4];
            Indices = new int[6];
            Origin = origin;
            this.color = color;
            Up = up;

            // Calculate the quad corners
            Left = Vector3.Left;
            UpperLeft = (Up * height / 2) + (Left * width / 2) + origin;
            UpperRight = UpperLeft + Vector3.Right * width;
            LowerLeft = UpperLeft + Vector3.Down * height;
            LowerRight = UpperRight + Vector3.Down * height;


        private void FillVertices()
            // Fill in texture coordinates to display full texture
            // on quad
            Vector2 textureUpperLeft = new Vector2(0.0f, 0.0f);
            Vector2 textureUpperRight = new Vector2(1.0f, 0.0f);
            Vector2 textureLowerLeft = new Vector2(0.0f, 1.0f);
            Vector2 textureLowerRight = new Vector2(1.0f, 1.0f);

            for (int i = 0; i < Vertices.Length; i++)
                Vertices.Color = color;

            // Set the position and texture coordinate for each
            // vertex
            Vertices[0].Position = LowerLeft;
            Vertices[0].TextureCoordinate = textureLowerLeft;
            Vertices[1].Position = UpperLeft;
            Vertices[1].TextureCoordinate = textureUpperLeft;
            Vertices[2].Position = LowerRight;
            Vertices[2].TextureCoordinate = textureLowerRight;
            Vertices[3].Position = UpperRight;
            Vertices[3].TextureCoordinate = textureUpperRight;

            // Set the index buffer for each vertex, using
            // clockwise winding
            Indices[0] = 0;
            Indices[1] = 1;
            Indices[2] = 2;
            Indices[3] = 2;
            Indices[4] = 1;
            Indices[5] = 3;

Does anyone have any advice as to why my texture ends up looking slanted, repeated and funny and why it seems to be wider than it ought to.

Share this post

Link to post
Share on other sites
Your vertex winding order and texture coordinates seem fine, but I can't make heads or tails of how you're calculating the vertex positions. It looks quite strange, and if incorrect would result in an incorrectly shaped and sized quad. I'd suggest taking a hard look at it and maybe simplifying the code.

[Edited by - gharen2 on February 2, 2008 1:14:12 PM]

Share this post

Link to post
Share on other sites
Actually I did notice an error but I don't think it would cause my error.

basically the error is that I'm setting the origin to be at the center no matter what I send it. So I need to fix that but otherwise if I send 1 x 90 then upperLeft is (-.5, 45, z) upperright is (.5, 45, z) and likewise for the lowerhalves with 45 now being negative. Is it the case that vertices can't be negative?

What's a working quard vertice order?

Thanks for your help.

Share this post

Link to post
Share on other sites
I think the way your calculate your quad corners would break if you pass anything other than Vector3.Up into the up parameter into the Quad method.

Share this post

Link to post
Share on other sites
After taking another look, I see what you're trying to do.

One problem I see in your code is that you're supplying an up vector, yet using Vector3.Down in some places in your code. Instead of Vector3.Down, use -up.

Try the following (this code is untested):

UpperLeft = origin;
UpperRight = origin + (Vector3.Right * width);
LowerLeft = origin + (-up * height);
LowerRight = origin + (Vector3.Right * width) + (-up * height);

Thus, the upper left corner of the quad is it's origin point.

[Edited by - gharen2 on February 2, 2008 2:17:54 PM]

Share this post

Link to post
Share on other sites
Sign in to follow this  

  • Advertisement

Important Information

By using GameDev.net, you agree to our community Guidelines, Terms of Use, and Privacy Policy.

GameDev.net is your game development community. Create an account for your GameDev Portfolio and participate in the largest developer community in the games industry.

Sign me up!