d3d12 超大图片渲染代码

如果您想要使用 Direct3D 12 渲染超大纹理图片，以下是一些可能的代码实现:

1. 分割纹理: 将超大的纹理图像分割成多个小的纹理图像，然后在渲染时将它们拼接起来。这种方法需要您自己编写代码来实现分割和拼接。

2. 使用虚拟纹理: 在渲染时，只加载需要的部分纹理图像。这种方法可以借助 Direct3D 12 的虚拟纹理技术来实现。具体实现方法可以参考 Microsoft 的官方文档。

3. 使用纹理数组: 将多个小的纹理图像打包成一个纹理数组，然后在渲染时按需要进行调用。这种方法需要您自己编写代码来实现纹理数组的创建和调用。

4. 使用纹理压缩: 使用支持的纹理压缩算法，将纹理图像压缩后再进行渲染。这种方法需要您自己编写代码来实现纹理压缩的处理。

以上是一些可能的解决方案，具体实现需要根据您的需求和场景来进行选择。希望这些信息能够帮到您。

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d3d12 超大图片渲染 代码

下面是使用DirectX 12渲染超大图片的基本代码：

#include <d3d12.h>
#include <dxgi1_4.h>
#include <DirectXMath.h>
#include <DirectXTex.h>
#include <wrl/client.h>

using Microsoft::WRL::ComPtr;

// 渲染窗口大小
const UINT WindowWidth = 800;
const UINT WindowHeight = 600;

// 超大图片大小
const UINT ImageWidth = 10000;
const UINT ImageHeight = 10000;

// 超大图片文件名
const wchar_t* ImageFilename = L"UltraLargeImage.jpg";

// 全局变量
ComPtr<ID3D12Device> g_Device;
ComPtr<IDXGISwapChain3> g_SwapChain;
ComPtr<ID3D12CommandQueue> g_CommandQueue;
ComPtr<ID3D12CommandAllocator> g_CommandAllocator;
ComPtr<ID3D12GraphicsCommandList> g_CommandList;
ComPtr<ID3D12Resource> g_BackBuffer[2];
ComPtr<ID3D12Fence> g_Fence;
UINT64 g_FenceValue = 0;
HANDLE g_FenceEvent;

// 初始化设备、命令队列等
bool InitializeDevice()
{
    // 创建设备
    HRESULT hr = D3D12CreateDevice(nullptr, D3D_FEATURE_LEVEL_11_0, IID_PPV_ARGS(&g_Device));
    if (FAILED(hr))
        return false;

    // 创建命令队列
    D3D12_COMMAND_QUEUE_DESC commandQueueDesc = {};
    commandQueueDesc.Type = D3D12_COMMAND_LIST_TYPE_DIRECT;
    commandQueueDesc.Priority = D3D12_COMMAND_QUEUE_PRIORITY_NORMAL;
    commandQueueDesc.Flags = D3D12_COMMAND_QUEUE_FLAG_NONE;
    commandQueueDesc.NodeMask = 0;
    hr = g_Device->CreateCommandQueue(&commandQueueDesc, IID_PPV_ARGS(&g_CommandQueue));
    if (FAILED(hr))
        return false;

    // 创建交换链
    DXGI_SWAP_CHAIN_DESC1 swapChainDesc = {};
    swapChainDesc.Width = WindowWidth;
    swapChainDesc.Height = WindowHeight;
    swapChainDesc.Format = DXGI_FORMAT_R8G8B8A8_UNORM;
    swapChainDesc.Stereo = FALSE;
    swapChainDesc.SampleDesc.Count = 1;
    swapChainDesc.SampleDesc.Quality = 0;
    swapChainDesc.BufferUsage = DXGI_USAGE_RENDER_TARGET_OUTPUT;
    swapChainDesc.BufferCount = 2;
    swapChainDesc.Scaling = DXGI_SCALING_STRETCH;
    swapChainDesc.SwapEffect = DXGI_SWAP_EFFECT_FLIP_DISCARD;
    swapChainDesc.AlphaMode = DXGI_ALPHA_MODE_UNSPECIFIED;
    swapChainDesc.Flags = DXGI_SWAP_CHAIN_FLAG_ALLOW_MODE_SWITCH;
    ComPtr<IDXGIFactory4> dxgiFactory;
    hr = CreateDXGIFactory1(IID_PPV_ARGS(&dxgiFactory));
    if (FAILED(hr))
        return false;
    hr = dxgiFactory->CreateSwapChainForHwnd(g_CommandQueue.Get(), GetForegroundWindow(), &swapChainDesc, nullptr, nullptr, &g_SwapChain);
    if (FAILED(hr))
        return false;

    // 创建命令分配器、命令列表
    hr = g_Device->CreateCommandAllocator(D3D12_COMMAND_LIST_TYPE_DIRECT, IID_PPV_ARGS(&g_CommandAllocator));
    if (FAILED(hr))
        return false;
    hr = g_Device->CreateCommandList(0, D3D12_COMMAND_LIST_TYPE_DIRECT, g_CommandAllocator.Get(), nullptr, IID_PPV_ARGS(&g_CommandList));
    if (FAILED(hr))
        return false;

    // 创建RTV
    CD3DX12_CPU_DESCRIPTOR_HANDLE rtvHandle(g_Device->GetDescriptorHandleIncrementSize(D3D12_DESCRIPTOR_HEAP_TYPE_RTV), 0);
    for (UINT i = 0; i < 2; i++)
    {
        hr = g_SwapChain->GetBuffer(i, IID_PPV_ARGS(&g_BackBuffer[i]));
        if (FAILED(hr))
            return false;
        g_Device->CreateRenderTargetView(g_BackBuffer[i].Get(), nullptr, rtvHandle);
        rtvHandle.Offset(1, g_Device->GetDescriptorHandleIncrementSize(D3D12_DESCRIPTOR_HEAP_TYPE_RTV));
    }

    // 创建围栏
    hr = g_Device->CreateFence(0, D3D12_FENCE_FLAG_NONE, IID_PPV_ARGS(&g_Fence));
    if (FAILED(hr))
        return false;
    g_FenceEvent = CreateEvent(nullptr, FALSE, FALSE, nullptr);
    if (g_FenceEvent == nullptr)
        return false;

    return true;
}

// 加载超大图片
ComPtr<ID3D12Resource> LoadImage()
{
    // 加载图片
    std::unique_ptr<DirectX::ScratchImage> image(new DirectX::ScratchImage());
    HRESULT hr = DirectX::LoadFromWICFile(ImageFilename, DirectX::WIC_FLAGS_NONE, nullptr, *image);
    if (FAILED(hr))
        return nullptr;

    // 创建纹理资源
    ComPtr<ID3D12Resource> texture;
    D3D12_RESOURCE_DESC textureDesc = {};
    textureDesc.Dimension = D3D12_RESOURCE_DIMENSION_TEXTURE2D;
    textureDesc.Alignment = 0;
    textureDesc.Width = ImageWidth;
    textureDesc.Height = ImageHeight;
    textureDesc.DepthOrArraySize = 1;
    textureDesc.MipLevels = 1;
    textureDesc.Format = image->GetMetadata().format;
    textureDesc.SampleDesc.Count = 1;
    textureDesc.SampleDesc.Quality = 0;
    textureDesc.Layout = D3D12_TEXTURE_LAYOUT_UNKNOWN;
    textureDesc.Flags = D3D12_RESOURCE_FLAG_NONE;
    hr = g_Device->CreateCommittedResource(&CD3DX12_HEAP_PROPERTIES(D3D12_HEAP_TYPE_DEFAULT), D3D12_HEAP_FLAG_NONE, &textureDesc, D3D12_RESOURCE_STATE_COPY_DEST, nullptr, IID_PPV_ARGS(&texture));
    if (FAILED(hr))
        return nullptr;

    // 上传图片数据
    const DirectX::Image* imageData = image->GetImage(0, 0, 0);
    D3D12_SUBRESOURCE_DATA textureData = {};
    textureData.pData = imageData->pixels;
    textureData.RowPitch = imageData->rowPitch;
    textureData.SlicePitch = imageData->slicePitch;
    UpdateSubresources(g_CommandList.Get(), texture.Get(), g_BackBuffer[0].Get(), 0, 0, 1, &textureData);

    // 转换资源状态
    CD3DX12_RESOURCE_BARRIER barrier = CD3DX12_RESOURCE_BARRIER::Transition(texture.Get(), D3D12_RESOURCE_STATE_COPY_DEST, D3D12_RESOURCE_STATE_PIXEL_SHADER_RESOURCE);
    g_CommandList->ResourceBarrier(1, &barrier);

    return texture;
}

// 渲染函数
void Render()
{
    // 等待上一帧完成
    const UINT currentBackBufferIndex = g_SwapChain->GetCurrentBackBufferIndex();
    if (g_Fence->GetCompletedValue() < g_FenceValue)
    {
        hr = g_Fence->SetEventOnCompletion(g_FenceValue, g_FenceEvent);
        if (FAILED(hr))
            return;
        WaitForSingleObject(g_FenceEvent, INFINITE);
    }

    // 开始渲染
    g_CommandAllocator->Reset();
    g_CommandList->Reset(g_CommandAllocator.Get(), nullptr);

    // 设置渲染目标
    CD3DX12_RESOURCE_BARRIER barrierToRenderTarget = CD3DX12_RESOURCE_BARRIER::Transition(g_BackBuffer[currentBackBufferIndex].Get(), D3D12_RESOURCE_STATE_PRESENT, D3D12_RESOURCE_STATE_RENDER_TARGET);
    g_CommandList->ResourceBarrier(1, &barrierToRenderTarget);
    CD3DX12_CPU_DESCRIPTOR_HANDLE rtvHandle(g_Device->GetDescriptorHandleIncrementSize(D3D12_DESCRIPTOR_HEAP_TYPE_RTV), currentBackBufferIndex);
    g_CommandList->OMSetRenderTargets(1, &rtvHandle, FALSE, nullptr);

    // 清空渲染目标
    const float clearColor[] = { 0.0f, 0.0f, 0.0f, 1.0f };
    g_CommandList->ClearRenderTargetView(rtvHandle, clearColor, 0, nullptr);

    // 绘制超大图片
    // ...

    // 结束渲染
    CD3DX12_RESOURCE_BARRIER barrierToPresent = CD3DX12_RESOURCE_BARRIER::Transition(g_BackBuffer[currentBackBufferIndex].Get(), D3D12_RESOURCE_STATE_RENDER_TARGET, D3D12_RESOURCE_STATE_PRESENT);
    g_CommandList->ResourceBarrier(1, &barrierToPresent);
    g_CommandList->Close();

    // 提交命令列表
    ID3D12CommandList* commandLists[] = { g_CommandList.Get() };
    g_CommandQueue->ExecuteCommandLists(_countof(commandLists), commandLists);

    // 信号围栏
    g_FenceValue++;
    hr = g_CommandQueue->Signal(g_Fence.Get(), g_FenceValue);
    if (FAILED(hr))
        return;

    // 呈现画面
    g_SwapChain->Present(1, 0);
}

// 程序入口
int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nCmdShow)
{
    // 初始化窗口等
    // ...

    // 初始化设备、命令队列等
    if (!InitializeDevice())
        return -1;

    // 加载超大图片
    ComPtr<ID3D12Resource> texture = LoadImage();
    if (texture == nullptr)
        return -1;

    // 进入消息循环
    // ...
}

其中，`LoadImage`函数用于加载超大图片，返回一个纹理资源。在绘制超大图片时，可以使用多次绘制来分批渲染，或者使用视口和裁剪矩形来渲染部分区域，以避免一次渲染过多数据。

d3d12 超大图片渲染纹理切割代码

以下是使用DirectX 12渲染超大纹理并进行切割的代码示例：

首先，需要创建一个用于渲染的纹理对象：

D3D12_HEAP_PROPERTIES heapProps = CD3DX12_HEAP_PROPERTIES(D3D12_HEAP_TYPE_DEFAULT);
D3D12_RESOURCE_DESC resDesc = CD3DX12_RESOURCE_DESC::Tex2D(format, width, height, 1, mipLevels);
resDesc.Flags |= D3D12_RESOURCE_FLAG_ALLOW_RENDER_TARGET;
resDesc.Flags |= D3D12_RESOURCE_FLAG_ALLOW_UNORDERED_ACCESS;

ThrowIfFailed(device->CreateCommittedResource(
    &heapProps,
    D3D12_HEAP_FLAG_NONE,
    &resDesc,
    D3D12_RESOURCE_STATE_RENDER_TARGET,
    nullptr,
    IID_PPV_ARGS(&m_RenderTarget)));

然后，可以使用此纹理对象创建一个渲染目标视图：

D3D12_RENDER_TARGET_VIEW_DESC rtvDesc = {};
rtvDesc.Format = format;
rtvDesc.ViewDimension = D3D12_RTV_DIMENSION_TEXTURE2D;

CD3DX12_CPU_DESCRIPTOR_HANDLE rtvHandle(m_RTVDescriptorHeap->GetCPUDescriptorHandleForHeapStart(), m_frameIndex, m_RTVDescriptorSize);
device->CreateRenderTargetView(m_RenderTarget.Get(), &rtvDesc, rtvHandle);

接下来，可以使用此纹理对象创建一个无序访问视图：

D3D12_UNORDERED_ACCESS_VIEW_DESC uavDesc = {};
uavDesc.Format = format;
uavDesc.ViewDimension = D3D12_UAV_DIMENSION_TEXTURE2D;
uavDesc.Texture2D.MipSlice = 0;

CD3DX12_CPU_DESCRIPTOR_HANDLE uavHandle(m_UAVDescriptorHeap->GetCPUDescriptorHandleForHeapStart(), m_frameIndex, m_UAVDescriptorSize);
device->CreateUnorderedAccessView(m_RenderTarget.Get(), nullptr, &uavDesc, uavHandle);

现在，可以使用渲染目标和无序访问视图进行渲染。例如，可以将纹理切割成多个小纹理，每个小纹理的大小为256x256：

const int nTilesX = (width + 255) / 256;
const int nTilesY = (height + 255) / 256;

for (int y = 0; y < nTilesY; ++y)
{
    for (int x = 0; x < nTilesX; ++x)
    {
        // Set viewport and scissor rect for current tile
        D3D12_VIEWPORT viewport = { x * 256.0f, y * 256.0f, 256.0f, 256.0f, 0.0f, 1.0f };
        D3D12_RECT scissorRect = { x * 256, y * 256, (x + 1) * 256, (y + 1) * 256 };

        // Set render target and clear color
        D3D12_CPU_DESCRIPTOR_HANDLE rtvHandle(m_RTVDescriptorHeap->GetCPUDescriptorHandleForHeapStart(), m_frameIndex, m_RTVDescriptorSize);
        device->OMSetRenderTargets(1, &rtvHandle, FALSE, nullptr);
        float clearColor[] = { 0.0f, 0.0f, 0.0f, 1.0f };
        commandList->ClearRenderTargetView(rtvHandle, clearColor, 0, nullptr);

        // Draw using current viewport and scissor rect
        commandList->RSSetViewports(1, &viewport);
        commandList->RSSetScissorRects(1, &scissorRect);
        // Draw code goes here
    }
}

最后，需要将渲染目标的内容拷贝到CPU可访问的纹理中：

D3D12_RESOURCE_BARRIER barrier = CD3DX12_RESOURCE_BARRIER::Transition(m_RenderTarget.Get(), D3D12_RESOURCE_STATE_RENDER_TARGET, D3D12_RESOURCE_STATE_COPY_SOURCE);
commandList->ResourceBarrier(1, &barrier);

CD3DX12_TEXTURE_COPY_LOCATION src(m_RenderTarget.Get(), 0);
CD3DX12_TEXTURE_COPY_LOCATION dst(m_StagingTexture.Get(), D3D12CalcSubresource(0, 0, 1));
commandList->CopyTextureRegion(&dst, 0, 0, 0, &src, nullptr);

barrier = CD3DX12_RESOURCE_BARRIER::Transition(m_RenderTarget.Get(), D3D12_RESOURCE_STATE_COPY_SOURCE, D3D12_RESOURCE_STATE_RENDER_TARGET);
commandList->ResourceBarrier(1, &barrier);

这样就可以使用DirectX 12渲染超大纹理并进行切割了。