CODEWITHSUNDEEP
c#openglxnaopentkmonogame
Gerharddc
Gerharddc

Reputation: 4089

Port OpenGl buffer to XNA

I am trying to port an application with some OpenTK (C# Opengl implementation) to XNA/MonoGame and I have come to a buffer, but I cannot figure out how to port this because there does not seem to be any direct equivilant of the buffer functions. I am trying to port this code:

public void RefillVBO()
        {
            if (positions == null) return;
            if (hasBuf)
                GL.DeleteBuffers(3, buf);
            GL.GenBuffers(3, buf);
            GL.BindBuffer(BufferTarget.ArrayBuffer, buf[0]);
            GL.BufferData(BufferTarget.ArrayBuffer, (IntPtr)(positions.Length * sizeof(float)), positions, BufferUsageHint.StaticDraw);
            if (normals != null)
            {
                GL.BindBuffer(BufferTarget.ArrayBuffer, buf[1]);
                GL.BufferData(BufferTarget.ArrayBuffer, (IntPtr)(normals.Length * sizeof(float)), normals, BufferUsageHint.StaticDraw);
            }
            GL.BindBuffer(BufferTarget.ElementArrayBuffer, buf[2]);
            GL.BufferData(BufferTarget.ElementArrayBuffer, (IntPtr)(elementsLength * sizeof(int)), elements, BufferUsageHint.StaticDraw);
            hasBuf = true;
        }

Could anyone please translate this for me and possibly explain what is going on because I have no idea?

Also, is there any porting guide or something for this because there are literally hundreds of other errors related to "Gl" functions.

Upvotes: 0

Views: 109

Answers (1)

Nico Schertler
Nico Schertler

Reputation: 32587

In XNA you usually create a struct type that contains the vertex' data (e.g. position, normal...). Based on that type you create a VertexDeclaration that tells the GPU how to interpret the data. Finally you create a VertexBuffer and set the data. Optionally you can create an index buffer.

Take a look at these links:

How To: Create and Use a Custom Vertex

Improving performance by using VertexBuffers and IndexBuffers

Upvotes: 1

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