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DX12 fix - some older machines require 256 byte alignment of upload buffer #26

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Atrix256 merged 1 commit into from
Mar 29, 2026
Merged

DX12 fix - some older machines require 256 byte alignment of upload buffer #26

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34 changes: 31 additions & 3 deletions thirteen.h
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Original file line number Diff line number Diff line change
Expand Up @@ -2,6 +2,9 @@
Thirteen v1.0.0
MIT licensed https://github.com/Atrix256/Thirteen

This define must be set in one cpp file before including this header, to create the implementation:
#define THIRTEEN_IMPLEMENTATION

Thirteen is a header-only C++ library that initializes a window and gives you a pointer to RGBA uint8 pixels to write to, which are copied to the screen every time you call Render().

It is inspired by the simplicity of the Mode 13h days where you initialized the graphics mode and then started writing pixels directly to the screen. Just include the header, initialize, and start drawing!
Expand Down Expand Up @@ -59,6 +62,7 @@ Chris Cascioli - GetWindowHandle() and warning cleanup
#pragma comment(lib, "xinput.lib")

#define DX12VALIDATION() (_DEBUG && false)
#define ALIGN(_alignment, _val) (((_val + _alignment - 1) / _alignment) * _alignment)
#endif

#ifdef THIRTEEN_PLATFORM_LINUX
Expand Down Expand Up @@ -417,12 +421,14 @@ namespace Thirteen
ID3D12CommandAllocator* commandAllocator = nullptr;
ID3D12GraphicsCommandList* commandList = nullptr;
ID3D12Resource* uploadBuffer = nullptr;
size_t uploadBufferPitch = 0;
ID3D12Fence* fence = nullptr;
HANDLE fenceEvent = nullptr;
UINT64 fenceValue = 0;
UINT frameIndex = 0;
UINT rtvDescriptorSize = 0;
bool tearingSupported = false;
bool unrestrictedBufferTextureCopyPitchSupported = false;

void WaitForGpu()
{
Expand Down Expand Up @@ -459,9 +465,11 @@ namespace Thirteen
D3D12_HEAP_PROPERTIES heapProps = {};
heapProps.Type = D3D12_HEAP_TYPE_UPLOAD;

uploadBufferPitch = unrestrictedBufferTextureCopyPitchSupported ? (width * 4) : ALIGN(D3D12_TEXTURE_DATA_PITCH_ALIGNMENT, (width * 4));

D3D12_RESOURCE_DESC bufferDesc = {};
bufferDesc.Dimension = D3D12_RESOURCE_DIMENSION_BUFFER;
bufferDesc.Width = width * height * 4;
bufferDesc.Width = uploadBufferPitch * height;
bufferDesc.Height = 1;
bufferDesc.DepthOrArraySize = 1;
bufferDesc.MipLevels = 1;
Expand Down Expand Up @@ -502,6 +510,13 @@ namespace Thirteen
if (FAILED(D3D12CreateDevice(nullptr, D3D_FEATURE_LEVEL_11_0, IID_PPV_ARGS(&device))))
return false;

// get unrestrictedBufferTextureCopyPitchSupported
{
D3D12_FEATURE_DATA_D3D12_OPTIONS13 options = {};
if (SUCCEEDED(device->CheckFeatureSupport(D3D12_FEATURE_D3D12_OPTIONS13, &options, sizeof(options))))
unrestrictedBufferTextureCopyPitchSupported = options.UnrestrictedBufferTextureCopyPitchSupported != FALSE;
}

#if DX12VALIDATION()
ID3D12InfoQueue* infoQueue = nullptr;
if (SUCCEEDED(device->QueryInterface(IID_PPV_ARGS(&infoQueue))))
Expand Down Expand Up @@ -662,7 +677,20 @@ namespace Thirteen
void* mappedData = nullptr;
D3D12_RANGE readRange = { 1, 0 };
uploadBuffer->Map(0, &readRange, &mappedData);
memcpy(mappedData, pixels, width * height * 4);

if (uploadBufferPitch != width * 4)
{
for (uint32 iy = 0; iy < height; ++iy)
{
uint8* dest = &((uint8*)mappedData)[iy * uploadBufferPitch];
const uint8* src = &pixels[iy * width * 4];
memcpy(dest, src, width * 4);
}
}
else
{
memcpy(mappedData, pixels, width * height * 4);
}
uploadBuffer->Unmap(0, nullptr);

commandAllocator->Reset();
Expand All @@ -688,7 +716,7 @@ namespace Thirteen
src.PlacedFootprint.Footprint.Width = width;
src.PlacedFootprint.Footprint.Height = height;
src.PlacedFootprint.Footprint.Depth = 1;
src.PlacedFootprint.Footprint.RowPitch = width * 4;
src.PlacedFootprint.Footprint.RowPitch = (UINT)uploadBufferPitch;

commandList->CopyTextureRegion(&dst, 0, 0, 0, &src, nullptr);

Expand Down
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