# DX11 [solved] SharpDX: Draw a simple triangle using drawindexed() [help, please]

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I got stuck to draw a triangle using an index and DrawIndexed(), the triangle is not drawn. The windows just renders the blue background. While looking at other tutorials I think I did everything necessary to use an index, but maybe I am missing something?!

Edit: Solved (thx Unbird), the array data type did not match the format in SetIndexBuffer, changing it back to int to match the format did the trick. I updated the code below for the next one using indices for SharpDX
1) Index array and buffer at the class variables

        // Vertices
private VertexPositionColor[] vertices = new VertexPositionColor[]

{
new VertexPositionColor(new Vector3(-0.5f, 0.5f, 0.0f), SharpDX.Color.Red),
new VertexPositionColor(new Vector3(0.5f, 0.5f, 0.0f), SharpDX.Color.Green),
new VertexPositionColor(new Vector3(-0.5f, -0.5f, 0.0f), SharpDX.Color.Blue),

};

// Indices
private uint[] indices = new uint[] { 0, 1, 2 };
// Vertice-Buffer / Index-Buffer
private D3D11.Buffer vertexBuffer;
private D3D11.Buffer indexBuffer;

2) Set the indexbuffer

        private void InitializeTriangle()
{
vertexBuffer = D3D11.Buffer.Create(d3dDevice, D3D11.BindFlags.VertexBuffer, vertices);
indexBuffer = D3D11.Buffer.Create(d3dDevice, D3D11.BindFlags.IndexBuffer, indices);
}

3) Draw-Method:

        /// <summary>
/// Draw the scene.
/// </summary>

private void Draw()
{
//Re-Initialize triangle
InitializeTriangle();

// Set back buffer as current render target view
d3dDeviceContext.OutputMerger.SetRenderTargets(renderTargetView);
// Clear the screen
d3dDeviceContext.ClearRenderTargetView(renderTargetView, new SharpDX.Color(32, 103, 178));

// Draw the triangle on the screen
d3dDeviceContext.InputAssembler.PrimitiveTopology = PrimitiveTopology.TriangleList;
d3dDeviceContext.InputAssembler.SetVertexBuffers(0, new D3D11.VertexBufferBinding(vertexBuffer, Utilities.SizeOf<VertexPositionColor>(), 0));
d3dDeviceContext.InputAssembler.SetIndexBuffer(indexBuffer, Format.R32_UInt, 0);

d3dDeviceContext.DrawIndexed(3, 0, 0);

// Swap front and back buffer
swapChain.Present(1, PresentFlags.None);
}

.

Edited by joergz

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uint -> Format.R32_UInt

ushort -> Format.R16_UInt

Edit : Note that even after the edit you still use signed integers. Won't matter here though

Edited by unbird

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That was the error, thank you!!

Edit: damn you're right. Edited once again :-)

Edited by joergz

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