# DX11 [D3D11] Simple textured triangle won't draw

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jdub    459

You might have seen my previous post about my textured quad not drawing.  This time, I wanted to just slightly modify the SlimDX SimpleTriangle example to see If I could get a simple textured triangle to draw.  This time, the application compiles and runs, but produces a black triangle instead of one with a texture on it.  Any Ideas on what's wrong?

Here's the C# code:

namespace SimpleTriangle
{

[StructLayout(LayoutKind.Explicit, Size = 20)]
public struct Vertex
{
[FieldOffset(0)]
public Vector3 Position;

[FieldOffset(12)]
public Vector2 TexCoord;
}

static class Program
{
static void Main()
{
Device device;
SwapChain swapChain;

var form = new RenderForm("Tutorial 3: Simple Triangle");
var description = new SwapChainDescription()
{
BufferCount = 2,
Usage = Usage.RenderTargetOutput,
OutputHandle = form.Handle,
IsWindowed = true,
ModeDescription = new ModeDescription(0, 0, new Rational(60, 1), Format.R8G8B8A8_UNorm),
SampleDescription = new SampleDescription(1, 0),
Flags = SwapChainFlags.AllowModeSwitch,
};

Device.CreateWithSwapChain(DriverType.Hardware, DeviceCreationFlags.Debug, description, out device, out swapChain);

// create a view of our render target, which is the backbuffer of the swap chain we just created
RenderTargetView renderTarget;
using (var resource = Resource.FromSwapChain<Texture2D>(swapChain, 0))
renderTarget = new RenderTargetView(device, resource);

// setting a viewport is required if you want to actually see anything
var context = device.ImmediateContext;
var viewport = new Viewport(0.0f, 0.0f, form.ClientSize.Width, form.ClientSize.Height);
context.OutputMerger.SetTargets(renderTarget);
context.Rasterizer.SetViewports(viewport);

{
}

String file = "C:/Users/Jared/Documents/Visual Studio 2010/Projects/Dx11Test/Dx11Test/Texture.bmp";
Texture2D texture = Texture2D.FromFile(device, file);

// create test vertex data, making sure to rewind the stream afterward
var vertices = new DataStream(Marshal.SizeOf(typeof(Vertex)) * 3, true, true);
vertices.Write(new Vertex() { Position = new Vector3(0.0f, 0.5f, 0.5f), TexCoord = new Vector2(0.5f, 0.0f) });
vertices.Write(new Vertex() { Position = new Vector3(0.5f, -0.5f, 0.5f), TexCoord = new Vector2(1.0f, 1.0f) });
vertices.Write(new Vertex() { Position = new Vector3(-0.5f, -0.5f, 0.5f), TexCoord = new Vector2(0.0f, 1.0f) });
vertices.Position = 0;

// create the vertex layout and buffer
var elements = new[] { new InputElement("POSITION", 0, Format.R32G32B32_Float, 0), new InputElement("TEXCOORD", 0, Format.R32G32_Float, 0) };
var layout = new InputLayout(device, inputSignature, elements);
var vertexBuffer = new SlimDX.Direct3D11.Buffer(device, vertices, Marshal.SizeOf(typeof(Vertex)) * 3, ResourceUsage.Default, BindFlags.VertexBuffer, CpuAccessFlags.None, ResourceOptionFlags.None, 0);

// configure the Input Assembler portion of the pipeline with the vertex data
context.InputAssembler.InputLayout = layout;
context.InputAssembler.PrimitiveTopology = PrimitiveTopology.TriangleList;
context.InputAssembler.SetVertexBuffers(0, new VertexBufferBinding(vertexBuffer, 20, 0));

// set the sampler
SamplerDescription sampleDescr = new SamplerDescription();
sampleDescr.Filter = Filter.MinMagMipLinear;
sampleDescr.MipLodBias = 0.0f;
sampleDescr.MaximumAnisotropy = 1;
sampleDescr.ComparisonFunction = Comparison.Always;
sampleDescr.BorderColor = System.Drawing.Color.White;
sampleDescr.MinimumLod = 0;
sampleDescr.MaximumLod = float.MaxValue;

SamplerState samplerState = SamplerState.FromDescription(device, sampleDescr);

// prevent DXGI handling of alt+enter, which doesn't work properly with Winforms
using (var factory = swapChain.GetParent<Factory>())
factory.SetWindowAssociation(form.Handle, WindowAssociationFlags.IgnoreAltEnter);

// handle alt+enter ourselves
form.KeyDown += (o, e) =>
{
if (e.Alt && e.KeyCode == Keys.Enter)
swapChain.IsFullScreen = !swapChain.IsFullScreen;
};

// handle form size changes
form.UserResized += (o, e) =>
{
renderTarget.Dispose();

swapChain.ResizeBuffers(2, 0, 0, Format.R8G8B8A8_UNorm, SwapChainFlags.AllowModeSwitch);
using (var resource = Resource.FromSwapChain<Texture2D>(swapChain, 0))
renderTarget = new RenderTargetView(device, resource);

context.OutputMerger.SetTargets(renderTarget);
};

MessagePump.Run(form, () =>
{
// clear the render target to a soothing blue
context.ClearRenderTargetView(renderTarget, new Color4(0.5f, 0.5f, 1.0f));

// draw the triangle
context.Draw(3, 0);
swapChain.Present(0, PresentFlags.None);
});

// clean up all resources
// anything we missed will show up in the debug output
vertices.Close();
vertexBuffer.Dispose();
layout.Dispose();
inputSignature.Dispose();
renderTarget.Dispose();
swapChain.Dispose();
device.Dispose();
}
}
}


SamplerState SamplerType;
Texture2D Texture;

{
float4 position : POSITION;
float2 TexCoord : TEXCOORD0;
};

{
float4 position : SV_POSITION;
float2 TexCoord : TEXCOORD0;
};

{

output.position = input.position;
output.TexCoord = input.TexCoord;

return output;
}

{
float4 textureSample = Texture.Sample(SamplerType, input.TexCoord);

return textureSample;
}


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Jason Z    6434

Usually a black texture result means either that the texture coordinates are out of range, or that the texture resource isn't properly bound to the pipeline.  Have you tried to use PIX and/or the VS2012 Graphics Debugger to inspect your rendered frames?  If not, it is worth the time to get acquainted with these tools, because they will help you understand what is going on with your application (both in times when things aren't working, and also when things are working but you want to collect data about your usage of the API)!

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jdub    459

Okay, got it fixed.  Turned out that I had bound the TextureResourceView to the wrong slot inside the shader.

I use PIX but I'm not exactly sure how I would read memory to figure this out.  From what I see, PIX only shows which resources I've created, not where/how they are bound to the pipeline.

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Jason Z    6434

Okay, got it fixed.  Turned out that I had bound the TextureResourceView to the wrong slot inside the shader.

I use PIX but I'm not exactly sure how I would read memory to figure this out.  From what I see, PIX only shows which resources I've created, not where/how they are bound to the pipeline.

If you capture a frame by hitting F12, then go to a draw call in the lower half of the screen, then you will be able to right click on the textures being bound in your Set* calls.  This is a quick and easy way to see if you are really doing what you think you are.

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