CODEWITHSUNDEEP
c#opengl3drenderingopentk
Murten101
Murten101

Reputation: 23

how am i supposed to use multiple buffers in OpenGL

i want to use different arrays to store different data like the color postion and texture coords from my mesh but when i try and bind multiple buffers nothing is showing on screen.

if you have any idea on thow to fix please let me know

this is my render class:

    class Renderer
    {
        public int VertextArrayObject;

        public int VertexBufferObject;

        public int IndexBuffer;

        public int TextureCoordBuffer;

        public Renderer()
        {
            VertextArrayObject = GL.GenVertexArray();

            VertexBufferObject = GL.GenBuffer();

            TextureCoordBuffer = GL.GenBuffer();

            IndexBuffer = GL.GenBuffer();

            GL.ClearColor(0.2f, 0.3f, 0.3f, 1.0f);

        }

        public void Draw(Shader shader, Matrix4 transform, Mesh mesh, Game game)
        {
            shader.Use();

            GL.BindVertexArray(VertextArrayObject);

            GL.BindBuffer(BufferTarget.ElementArrayBuffer, IndexBuffer);
            GL.BufferData(BufferTarget.ElementArrayBuffer, new IntPtr(sizeof(uint) * mesh.vertexIndices.Length), mesh.vertexIndices, BufferUsageHint.StaticDraw);

            GL.BindBuffer(BufferTarget.ArrayBuffer, VertexBufferObject);
            GL.BufferData(BufferTarget.ArrayBuffer, new IntPtr(sizeof(float) * (mesh.vertices.Length * 3)), mesh.vertices, BufferUsageHint.StaticDraw);

            GL.BindVertexArray(0);
            GL.BindBuffer(BufferTarget.ArrayBuffer, 0);
            GL.BindBuffer(BufferTarget.ElementArrayBuffer, 0);

            shader.SetMatrix4("model", transform);
            shader.SetMatrix4("view", game.view);
            shader.SetMatrix4("projection", game.projection);

            GL.BindBuffer(BufferTarget.ArrayBuffer, VertexBufferObject);
            int vertexLocation = shader.GetAttribute("aPosition");
            GL.VertexAttribPointer(vertexLocation, 3, VertexAttribPointerType.Float, false, 0, 0);

            GL.BindBuffer(BufferTarget.ArrayBuffer, TextureCoordBuffer);
            int texCoordLocation = shader.GetAttribute("aTexCoord");
            GL.VertexAttribPointer(texCoordLocation, 2, VertexAttribPointerType.UnsignedInt, false, 0, 0);

            GL.BindBuffer(BufferTarget.ElementArrayBuffer, IndexBuffer);

            GL.DrawElements(PrimitiveType.Triangles, mesh.vertexIndices.Length, DrawElementsType.UnsignedInt, 0);
        }

    }

if there is a better way of doing this other then the multi buffer thing i would love to hear it.

Upvotes: 2

Views: 367

Answers (1)

Rabbid76
Rabbid76

Reputation: 211230

You need to enable the vertex attributes:

GL.BindBuffer(BufferTarget.ArrayBuffer, VertexBufferObject);
int vertexLocation = shader.GetAttribute("aPosition");
GL.EnableVertexAttribArray(vertexLocation);
GL.VertexAttribPointer(vertexLocation 3, VertexAttribPointerType.Float, false, 0, 0);

GL.BindBuffer(BufferTarget.ArrayBuffer, TextureCoordBuffer);
texCoordLocation = shader.GetAttribute("aTexCoord");
GL.EnableVertexAttribArray(texCoordLocation);
GL.VertexAttribPointer(texCoordLocation, 2, VertexAttribPointerType.UnsignedInt, false, 0, 0);

See also Vertex Array Object

Upvotes: 1

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