Hm, when using a buffer of type int4 for my input to the compute shader, everything works fine. The shader resource view has its format set to R32G32B32A32_SInt.

But when I try to create a buffer of type int3 (R32G32B32_Sint), I get this error "Additional information: Attempted to read or write protected memory. This is often an indication that other memory is corrupt.".

So, is the int3 value somehow padded up to 16 bytes?

Or is there some other cause behind this?

Yep. Each element is separately padded up to 16 for c buffers
What kind of buffer are you using, (cbuffer, tbuffer, strctured buffer?), Because the padding rule is only applicable for constant buffers?

Yep. Each element is separately padded up to 16 for c buffers
What kind of buffer are you using, (cbuffer, tbuffer, strctured buffer?), Because the padding rule is only applicable for constant buffers?

hm, a t buffer, i think
Buffer<int3> input : register(t0);

//=============================================================================
// Buffer<int3> input : register(t0);

inputBuffer = new Buffer(device, new BufferDescription()
{
StructureByteStride = Int3.SizeInBytes,
SizeInBytes = N * Int3.SizeInBytes,
Usage = ResourceUsage.Dynamic, // the cpu can write to it.
BindFlags = BindFlags.ShaderResource, // will be read-only by the GPU.
CpuAccessFlags = CpuAccessFlags.Write,
OptionFlags = ResourceOptionFlags.None,
});

// srView to our unput buffer
var srViewDesc = new ShaderResourceViewDescription();
srViewDesc.Format = Format.R32G32B32_SInt;
srViewDesc.Dimension = ShaderResourceViewDimension.Buffer;
srViewDesc.Buffer.FirstElement = 0;
srViewDesc.Buffer.ElementCount = N;
ShaderResourceView srView = new ShaderResourceView(device, inputBuffer, srViewDesc);
//=============================================================================

The error appears the second time i call UnmapSubresource

(I have a makeshift 'loop', using a goto statement)

//=============================================================================

DataStream dataStream;
context.MapSubresource(inputBuffer, MapMode.WriteDiscard, SharpDX.Direct3D11.MapFlags.None, out dataStream);

for(int i = 0; i < N; i++)
dataStream.Write(input);

context.UnmapSubresource(inputBuffer, 0);
dataStream.Dispose();

//=============================================================================

It works with single integers, two integers, and 4. But with 3, it crashes on the second attempt to update the buffer.

p.s. yeah, this is in SharpDX, on a D3D10 card.

Ok, I did some tests.

So, there are two ways to define a "typed" buffer.

Buffer of a custom structure type:

C#

bufferDesc.OptionFlags = ResourceOptionFlags.BufferStructured;

srViewDesc.Format = Format.Unknown;

HLSL

StructuredBuffer<int3> input : register(t0);

Primitive type Buffer:

C#

bufferDesc.OptionsFlags = ResourceOptionFlags.None

srViewDesc.Format = Format.R32G32B32_SInt;

HLSL

Buffer<int3> input : register(t0);

The structured buffer works for every type I tried.

Using a primitive type buffer works for int, int2, int4, but not int3.

So my question is, why?

Also, is there any difference in the two types of buffers, other than the fact that the structured buffer lets you use custom types?