Why is my mesh only displayed every second frame? - directx

Question

I'm trying to draw a single triangle on-screen using SharpDX (DX11). For whatever reason, the triangle only seems to be drawn every second frame. My device initialization code looks like this:
public void Init()
{
renderForm = new RenderForm(Engine.GameTitle);
renderForm.ClientSize = new Size(Engine.Settings.Screen.Width, Engine.Settings.Screen.Height);
renderForm.MaximizeBox = false;
var desc = new SwapChainDescription()
{
BufferCount = 2,
ModeDescription = new ModeDescription(renderForm.ClientSize.Width, renderForm.ClientSize.Height, new Rational(60, 1), Format.R8G8B8A8_UNorm),
IsWindowed = true,
OutputHandle = renderForm.Handle,
SampleDescription = new SampleDescription(1, 0),
SwapEffect = SwapEffect.Sequential,
Usage = Usage.RenderTargetOutput
};
Device.CreateWithSwapChain(DriverType.Hardware, DeviceCreationFlags.Debug, desc, out device, out swapChain);
deviceContext = device.ImmediateContext;
var factory = swapChain.GetParent<Factory>();
factory.MakeWindowAssociation(renderForm.Handle, WindowAssociationFlags.IgnoreAll);
backBuffer = Texture2D.FromSwapChain<Texture2D>(swapChain, 0);
renderView = new RenderTargetView(device, backBuffer);
backBuffer.Dispose();
deviceContext.OutputMerger.SetTargets(renderView);
deviceContext.Rasterizer.SetViewports(new Viewport(0, 0, renderForm.ClientSize.Width, renderForm.ClientSize.Height, 0.0f, 1.0f));
ProjectionMatrix = Matrix.PerspectiveFovLH(
(float)(Math.PI / 4),
(float)(renderForm.ClientSize.Width / renderForm.ClientSize.Height),
nearPlane,
farPlane);
WorldMatrix = Matrix.Identity;
renderForm.Location = new Point(Screen.PrimaryScreen.Bounds.Width / 2 - Engine.Settings.Screen.Width / 2, Screen.PrimaryScreen.Bounds.Height / 2 - Engine.Settings.Screen.Height / 2);
}
The code for rendering the triangle looks like this:
public void Render()
{
DeviceContext context = D3DRenderer.Instance.GetDevice().ImmediateContext;
context.InputAssembler.SetVertexBuffers(0, new VertexBufferBinding(VertexBuffer, Utilities.SizeOf<Vertex>(), 0));
context.InputAssembler.SetIndexBuffer(IndexBuffer, Format.R32_UInt, 0);
context.InputAssembler.PrimitiveTopology = PrimitiveTopology.TriangleList;
}
public void RenderShader(int indexCount)
{
device.ImmediateContext.DrawIndexed(indexCount, 0, 0);
}
Whereas Render() is called before RenderShader().
There's no error message returned by any function except for an Direct3D warning:
D3D11: WARNING: ID3D11DeviceContext::DrawIndexed: The size of the Constant Buffer at slot 0 of the Vertex Shader unit is too small (64 bytes provided, 192 bytes, at least, expected).
My MatrixBuffer structure looks like the following:
[StructLayout(LayoutKind.Sequential)]
internal struct MatrixBuffer
{
public Matrix world;
public Matrix view;
public Matrix projection;
}
I have been clearing the backbuffer every other frame with a different color to make sure it's not an issue with not correctly swapping the backbuffer. This is working fine.
I am quite baffled as to why this isn't working right now. I hope anyone knows an answer to this.

Answer 1

Ladies and gentleman, learn a lesson today.. Never copy and paste tutorial code. Ever.
Turns out the issue was in the shader rendering code. The tutorial I copied the declarations from (and didn't post on here, otherwise it might've been pretty obvious to you guys) had the world/view/projection matrices declared as follows:
public Matrix WorldMatrix { get; private set; }
Then I tried to do this:
D3DRenderer.Instance.WorldMatrix.Transpose();
Which for now obvious reasons doesn't work. Interestingly it did seem to work every other frame. Why that is I have no idea. But after changing the matrix definitions from private set to set everything is now working fine.