深度测试

我们将在本教程中了解深度测试。 我们将绘制两个四边形，一个四边形距离相机更近，另一个更近。 我们将在最后画出更远的四边形，以突出显示深度测试的重要性。 如果不进行深度测试，则距离较远的四边形将显示在距离较近的四边形的前面，因为它是次要的。

深度测试

当像素片段从像素着色器中移出时，OM（输出合并）会将该像素片段的z值（深度值）与渲染目标上当前像素的z值进行比较。
像素片段是使其成为像素着色器的像素。并非所有到达像素着色器的像素都是渲染目标上的最终像素颜色。渲染目标上的最终像素颜色取决于深度/模板测试以及混合（像素着色器实际上可以通过使用HLSL剪辑（clip）功能阻止像素片段将其变为OM，稍后我们将提供快速教程） 。
深度测试将导致距离摄像机更近的对象出现在距离摄像机更远的对象前面，即使距离更远的对象是在距离更近的对象之后绘制的。没有深度测试，最后绘制的内容将始终覆盖之前绘制的内容。
深度存储在称为深度/模板缓冲区的缓冲区中。深度模板缓冲区的格式为D32，其中24位是深度值，而8位是模板值。我将在以后的教程中讨论模板测试。
深度/模板缓冲区的宽度和高度与渲染目标相同，因此渲染目标上的每个像素都有一个深度值，该值存储在深度/模板缓冲区中。
深度测试是一个非常简单的想法，上面的内容基本上涵盖了所有内容，因此让我们进入代码。

新全局变量

我们需要一种资源来存储深度/模板数据，以及深度/模板描述符堆来存储深度/模板缓冲区描述符。

ID3D12Resource* depthStencilBuffer; // This is the memory for our depth buffer. it will also be used for a stencil buffer in a later tutorial
ID3D12DescriptorHeap* dsDescriptorHeap; // This is a heap for our depth/stencil buffer descriptor

启用深度/模板测试

创建PSO时，我们需要设置深度/模板状态。 为此，我们填写了一个D3D12_DEPTH_STENCIL_DESC结构，该结构描述了深度/模板状态。 为简单起见，我使用d3dx12帮助程序结构CD3DX12_DEPTH_STENCIL_DESC并传递D3D12_DEFAULT，这将为我们提供默认的深度测试状态。 但是因为知道如何自定义此状态很重要，所以我将解释D3D12_DEPTH_STENCIL_DESC结构，因为这是PSO描述的DepthStencilState成员正在寻找的结构，以及CD3DX12_DEPTH_STENCIL_DESC基本上创建的结构。

typedef struct D3D12_DEPTH_STENCIL_DESC {
  BOOL                       DepthEnable;
  D3D12_DEPTH_WRITE_MASK     DepthWriteMask;
  D3D12_COMPARISON_FUNC      DepthFunc;
  BOOL                       StencilEnable;
  UINT8                      StencilReadMask;
  UINT8                      StencilWriteMask;
  D3D12_DEPTH_STENCILOP_DESC FrontFace;
  D3D12_DEPTH_STENCILOP_DESC BackFace;
} D3D12_DEPTH_STENCIL_DESC;

• • 
    
• DepthEnable-这表示是否启用深度测试。将其设置为true进行深度测试
• DepthWriteMask-D3D12_DEPTH_WRITE_MASK枚举，指定可以将深度数据写入深度/模板缓冲区的哪一部分。现在，要么全部，要么全无。如果要启用深度测试，则需要将其设置为D3D12_DEPTH_WRITE_MASK_ALL。
• DepthFunc-一个D3D12_COMPARISON_FUNC枚举，用于指定将像素片段的深度与渲染目标上已有像素的深度进行比较时要使用的比较函数。通常，您将使用D3D12_COMPARISON_FUNC_LESS，它表示如果目标像素深度（已位于渲染目标上的像素）小于当前像素片段深度，则将这个新像素片段绘制到渲染目标上。您可以将其设置为D3D12_COMPARISON_FUNC_LESS_EQUAL，表示现有像素小于或等于，但通常效率不及D3D12_COMPARISON_FUNC_LESS，因为更多像素将通过深度测试。如果深度测试通过，则将新的像素片段绘制到渲染目标上。
• StencilEnable-如果要启用模板测试，则为True。
• StencilReadMask-这是模板测试可读取的深度/模板缓冲区的一部分
• StencilWriteMask-这是模板测试可以写入的深度/模板缓冲区的一部分
• FrontFace-这是D3D12_DEPTH_STENCILOP_DESC结构，该结构描述了深度或模版测试应该对表面法线朝向相机的像素（如三角形的正面）进行的操作
• BackFace-这也是D3D12_DEPTH_STENCILOP_DESC结构，它描述了深度或模版测试应该对像素执行的操作，但是其表面法线背对相机（例如三角形的背面）
  • 
    

typedef struct D3D12_DEPTH_STENCILOP_DESC {
  D3D12_STENCIL_OP      StencilFailOp;
  D3D12_STENCIL_OP      StencilDepthFailOp;
  D3D12_STENCIL_OP      StencilPassOp;
  D3D12_COMPARISON_FUNC StencilFunc;
} D3D12_DEPTH_STENCILOP_DESC;

• • 
    
• StencilFailOp-一个D3D12_STENCIL_OP枚举，它说明当像素片段未通过模板测试时模板操作应执行的操作。
• StencilDepthFailOp-一个D3D12_STENCIL_OP枚举，它说明在模版测试通过但深度测试失败时，模版操作应该做什么
• StencilPassOp-一个D3D12_STENCIL_OP枚举，说明在模版和深度测试均通过时模版操作应执行的操作
• StencilFunc-一个D3D12_COMPARISON_FUNC枚举，表示模版测试应使用的功能。
  • 
    

现在为CD3DX12_DEPTH_STENCIL_DESC的默认值。 我们正在使用这种结构为我们填充D3D12_DEPTH_STENCIL_DESC。 这是将D3D12_DEFAULT传递给它时获得的默认值：

DepthEnable = TRUE; // enable depth testing
DepthWriteMask = D3D12_DEPTH_WRITE_MASK_ALL; // can write depth data to all of the depth/stencil buffer
DepthFunc = D3D12_COMPARISON_FUNC_LESS; // pixel fragment passes depth test if destination pixel's depth is less than pixel fragment's
StencilEnable = FALSE; // disable stencil test
StencilReadMask = D3D12_DEFAULT_STENCIL_READ_MASK; // a default stencil read mask (doesn't matter at this point since stencil testing is turned off)
StencilWriteMask = D3D12_DEFAULT_STENCIL_WRITE_MASK; // a default stencil write mask (also doesn't matter)
const D3D12_DEPTH_STENCILOP_DESC defaultStencilOp = // a stencil operation structure, again does not really matter since stencil testing is turned off
{ D3D12_STENCIL_OP_KEEP, D3D12_STENCIL_OP_KEEP, D3D12_STENCIL_OP_KEEP, D3D12_COMPARISON_FUNC_ALWAYS };
FrontFace = defaultStencilOp; // both front and back facing polygons get the same treatment
BackFace = defaultStencilOp;

我感觉我应该已经在代码中创建了一个D3D12_DEPTH_STENCIL_DESC并使用了它而不是使用CD3DX12_DEPTH_STENCIL_DESC，但是我们只需要一个默认描述及其较少的代码，这就是为什么我决定使用辅助结构。

psoDesc.DepthStencilState = CD3DX12_DEPTH_STENCIL_DESC(D3D12_DEFAULT); // a default depth stencil state

添加第二个四边形

我们修改了顶点和索引列表，使其包含第二个四边形，该第二个四边形距离相机更远，并且位于第一个四边形的后面。 这将使我们看到深度测试正在工作，因为我们在第一个四边形之后绘制了第二个四边形。 如果深度测试被禁用，我们将看到第二个四边形位于第一个四边形的前面，但是如果深度测试正在进行，即使绘制了更远的四边形，第一个四边形仍将显示在第二个（更远的四边形）的前面 在更接近的四边形之后。
为了简化此操作，我将只使用一个顶点缓冲区，并绘制顶点缓冲区的子集，一个子集用于第一个quad，一个子集用于第二个quad。

// a triangle
Vertex vList[] = {
// first quad (closer to camera, blue)
    { -0.5f,  0.5f, 0.5f, 0.0f, 0.0f, 1.0f, 1.0f },
    {  0.5f, -0.5f, 0.5f, 0.0f, 0.0f, 1.0f, 1.0f },
    { -0.5f, -0.5f, 0.5f, 0.0f, 0.0f, 1.0f, 1.0f },
    {  0.5f,  0.5f, 0.5f, 0.0f, 0.0f, 1.0f, 1.0f },

// second quad (further from camera, green)
    { -0.75f,  0.75f,  0.7f, 0.0f, 1.0f, 0.0f, 1.0f },
    {   0.0f,  0.0f, 0.7f, 0.0f, 1.0f, 0.0f, 1.0f },
    { -0.75f,  0.0f, 0.7f, 0.0f, 1.0f, 0.0f, 1.0f },
    {   0.0f,  0.75f,  0.7f, 0.0f, 1.0f, 0.0f, 1.0f }
};

由于两个四边形基本上以相同的方式定义，因此我们仍然可以使用仅定义一个四边形的索引缓冲区：

DWORD iList[] = {
    // first quad (blue)
    0, 1, 2, // first triangle
    0, 3, 1, // second triangle
};

当我们开始绘制四边形时，如果您还没有看到的话，我将解释这是如何工作的。

创建深度/模板描述符堆

该堆将用于存储我们的深度/模板描述符（视图），我们将为OM提供它以用于深度测试。

// create a depth stencil descriptor heap so we can get a pointer to the depth stencil buffer
D3D12_DESCRIPTOR_HEAP_DESC dsvHeapDesc = {};
dsvHeapDesc.NumDescriptors = 1;
dsvHeapDesc.Type = D3D12_DESCRIPTOR_HEAP_TYPE_DSV;
dsvHeapDesc.Flags = D3D12_DESCRIPTOR_HEAP_FLAG_NONE;
hr = device->CreateDescriptorHeap(&dsvHeapDesc, IID_PPV_ARGS(&dsDescriptorHeap));
if (FAILED(hr))
{
    Running = false;
}

创建深度/模板缓冲区

首先，我们通过填充D3D12_DEPTH_STENCIL_VIEW_DESC结构来定义深度/模板缓冲区。 深度/模板缓冲区的元素是32位浮点值，其中前24位用于深度值，后8位用于模板值。

D3D12_DEPTH_STENCIL_VIEW_DESC depthStencilDesc = {};
depthStencilDesc.Format = DXGI_FORMAT_D32_FLOAT;
depthStencilDesc.ViewDimension = D3D12_DSV_DIMENSION_TEXTURE2D;
depthStencilDesc.Flags = D3D12_DSV_FLAG_NONE;

我们可以填写一个D3D12_CLEAR_VALUE结构。 这指定了我们在清除缓冲区时希望缓冲区元素为的值。 通过告诉DirectX清除值通常是什么，它可以优化清除缓冲区的操作。 深度的默认值是1.0，这是距离相机最远的像素。 进行深度测试时，它将像素片段的深度值与缓冲区中的深度值进行比较。 如果缓冲区中的深度小于像素片段的值，则像素片段将被绘制到渲染目标。

D3D12_CLEAR_VALUE depthOptimizedClearValue = {};
depthOptimizedClearValue.Format = DXGI_FORMAT_D32_FLOAT;
depthOptimizedClearValue.DepthStencil.Depth = 1.0f;
depthOptimizedClearValue.DepthStencil.Stencil = 0;

CreateCommittedResource创建资源以及存储该资源的资源堆。 我们将使用它来创建深度/模板缓冲区资源，以及用于存储深度/模板缓冲区的堆。
我们需要一个默认堆，它是仅GPU可以访问的内存。 我们不需要任何堆标志，因此我们将第二个参数设置为D3D12_HEAP_FLAG_NONE。 我们可以使用CD3DX12_RESOURCE_DESC帮助器来创建D3D12_RESOURCE_DESC。 然后，我们对深度/模板缓冲区进行描述。 深度/模板缓冲区的宽度和高度必须与渲染目标相同，它是32位浮点格式的缓冲区，并且我们允许将此资源用作深度/模板缓冲区。
下一个参数我们需要提供要在其中创建堆的状态。该堆仅由深度模板测试使用，因此我们仅在该状态下创建它。
我们给堆起一个名字，以便在调试时可以轻松地确定图形调试器中的堆。

device->CreateCommittedResource(
&CD3DX12_HEAP_PROPERTIES(D3D12_HEAP_TYPE_DEFAULT),
D3D12_HEAP_FLAG_NONE,
&CD3DX12_RESOURCE_DESC::Tex2D(DXGI_FORMAT_D32_FLOAT, Width, Height, 1, 0, 1, 0, D3D12_RESOURCE_FLAG_ALLOW_DEPTH_STENCIL),
D3D12_RESOURCE_STATE_DEPTH_WRITE,
&depthOptimizedClearValue,
IID_PPV_ARGS(&depthStencilBuffer)
    );
dsDescriptorHeap->SetName(L"Depth/Stencil Resource Heap");

最后，我们通过调用设备接口的CreateDepthStencilView方法来创建深度/模板视图。

device->CreateDepthStencilView(depthStencilBuffer, &depthStencilDesc, dsDescriptorHeap->GetCPUDescriptorHandleForHeapStart());

设置深度/模板缓冲区

我们必须告诉OM使用什么深度/模板缓冲区。 我们在设置渲染目标的同时设置深度/模板缓冲区。 为此，我们为OMSetRenderTargets命令提供了深度/模板缓冲区的描述符句柄。
我们可以使用辅助结构CD3DX12_CPU_DESCRIPTOR_HANDLE并调用我们的深度/模板描述符堆的GetCPUDescriptorHandleForHeapStart（）方法来获得深度/模板描述句柄。
现在我们有了深度/模板缓冲区的句柄，我们将其用作OMSetRenderTargets命令的第四个参数。

// get a handle to the depth/stencil buffer
CD3DX12_CPU_DESCRIPTOR_HANDLE dsvHandle(dsDescriptorHeap->GetCPUDescriptorHandleForHeapStart());

// set the render target for the output merger stage (the output of the pipeline)
commandList->OMSetRenderTargets(1, &rtvHandle, FALSE, &dsvHandle);

清除深度/模板缓冲区

在开始渲染帧之前，我们需要清除深度/模板缓冲区，以便可以绘制此帧而不会因前一帧而导致深度测试失败。 此命令会将深度模板缓冲区清除为我们告诉它的值。 我们希望将深度值清除为1.0，这是距离相机最远的像素可以通过深度测试的距离。

commandList->ClearDepthStencilView(dsDescriptorHeap->GetCPUDescriptorHandleForHeapStart(), D3D12_CLEAR_FLAG_DEPTH, 1.0f, 0, 0, nullptr);

清理

别忘了〜

SAFE_RELEASE(depthStencilBuffer);
SAFE_RELEASE(dsDescriptorHeap);

完整的代码

VertexShader.hlsl

struct VS_INPUT
{
    float3 pos : POSITION;
    float4 color: COLOR;
};

struct VS_OUTPUT
{
    float4 pos: SV_POSITION;
    float4 color: COLOR;
};

VS_OUTPUT main(VS_INPUT input)
{
    VS_OUTPUT output;
    output.pos = float4(input.pos, 1.0f);
    output.color = input.color;
    return output;
}

PixelShader.hlsl

struct VS_OUTPUT
{
    float4 pos: SV_POSITION;
    float4 color: COLOR;
};

float4 main(VS_OUTPUT input) : SV_TARGET
{
    // return interpolated color
    return input.color;
}

stdafx.h

#pragma once

#ifndef WIN32_LEAN_AND_MEAN
#define WIN32_LEAN_AND_MEAN    // Exclude rarely-used stuff from Windows headers.
#endif

#include <windows.h>
#include <d3d12.h>
#include <dxgi1_4.h>
#include <D3Dcompiler.h>
#include <DirectXMath.h>
#include "d3dx12.h"
#include <string>

// this will only call release if an object exists (prevents exceptions calling release on non existant objects)
#define SAFE_RELEASE(p) { if ( (p) ) { (p)->Release(); (p) = 0; } }

// Handle to the window
HWND hwnd = NULL;

// name of the window (not the title)
LPCTSTR WindowName = L"BzTutsApp";

// title of the window
LPCTSTR WindowTitle = L"Bz Window";

// width and height of the window
int Width = 800;
int Height = 600;

// is window full screen?
bool FullScreen = false;

// we will exit the program when this becomes false
bool Running = true;

// create a window
bool InitializeWindow(HINSTANCE hInstance,
int ShowWnd,
bool fullscreen);

// main application loop
void mainloop();

// callback function for windows messages
LRESULT CALLBACK WndProc(HWND hWnd,
UINT msg,
WPARAM wParam,
LPARAM lParam);

// direct3d stuff
const int frameBufferCount = 3; // number of buffers we want, 2 for double buffering, 3 for tripple buffering

ID3D12Device* device; // direct3d device

IDXGISwapChain3* swapChain; // swapchain used to switch between render targets

ID3D12CommandQueue* commandQueue; // container for command lists

ID3D12DescriptorHeap* rtvDescriptorHeap; // a descriptor heap to hold resources like the render targets

ID3D12Resource* renderTargets[frameBufferCount]; // number of render targets equal to buffer count

ID3D12CommandAllocator* commandAllocator[frameBufferCount]; // we want enough allocators for each buffer * number of threads (we only have one thread)

ID3D12GraphicsCommandList* commandList; // a command list we can record commands into, then execute them to render the frame

ID3D12Fence* fence[frameBufferCount];    // an object that is locked while our command list is being executed by the gpu. We need as many 
//as we have allocators (more if we want to know when the gpu is finished with an asset)

HANDLE fenceEvent; // a handle to an event when our fence is unlocked by the gpu

UINT64 fenceValue[frameBufferCount]; // this value is incremented each frame. each fence will have its own value

int frameIndex; // current rtv we are on

int rtvDescriptorSize; // size of the rtv descriptor on the device (all front and back buffers will be the same size)
// function declarations

bool InitD3D(); // initializes direct3d 12

void Update(); // update the game logic

void UpdatePipeline(); // update the direct3d pipeline (update command lists)

void Render(); // execute the command list

void Cleanup(); // release com ojects and clean up memory

void WaitForPreviousFrame(); // wait until gpu is finished with command list

ID3D12PipelineState* pipelineStateObject; // pso containing a pipeline state

ID3D12RootSignature* rootSignature; // root signature defines data shaders will access

D3D12_VIEWPORT viewport; // area that output from rasterizer will be stretched to.

D3D12_RECT scissorRect; // the area to draw in. pixels outside that area will not be drawn onto

ID3D12Resource* vertexBuffer; // a default buffer in GPU memory that we will load vertex data for our triangle into
ID3D12Resource* indexBuffer; // a default buffer in GPU memory that we will load index data for our triangle into

D3D12_VERTEX_BUFFER_VIEW vertexBufferView; // a structure containing a pointer to the vertex data in gpu memory
// the total size of the buffer, and the size of each element (vertex)

D3D12_INDEX_BUFFER_VIEW indexBufferView; // a structure holding information about the index buffer

ID3D12Resource* depthStencilBuffer; // This is the memory for our depth buffer. it will also be used for a stencil buffer in a later tutorial
ID3D12DescriptorHeap* dsDescriptorHeap; // This is a heap for our depth/stencil buffer descriptor

main.cpp

#include "stdafx.h"

using namespace DirectX; // we will be using the directxmath library

struct Vertex {
Vertex(float x, float y, float z, float r, float g, float b, float a) : pos(x, y, z), color(r, g, b, z) {}
XMFLOAT3 pos;
XMFLOAT4 color;
};

int WINAPI WinMain(HINSTANCE hInstance,    //Main windows function
HINSTANCE hPrevInstance,
LPSTR lpCmdLine,
int nShowCmd)

{
// create the window
if (!InitializeWindow(hInstance, nShowCmd, FullScreen))
    {
MessageBox(0, L"Window Initialization - Failed",
L"Error", MB_OK);
return 1;
    }

// initialize direct3d
if (!InitD3D())
    {
MessageBox(0, L"Failed to initialize direct3d 12",
L"Error", MB_OK);
Cleanup();
return 1;
    }

// start the main loop
mainloop();

// we want to wait for the gpu to finish executing the command list before we start releasing everything
WaitForPreviousFrame();

// close the fence event
CloseHandle(fenceEvent);

// clean up everything
Cleanup();

return 0;
}

// create and show the window
bool InitializeWindow(HINSTANCE hInstance,
int ShowWnd,
bool fullscreen)

{
if (fullscreen)
    {
HMONITOR hmon = MonitorFromWindow(hwnd,
MONITOR_DEFAULTTONEAREST);
MONITORINFO mi = { sizeof(mi) };
GetMonitorInfo(hmon, &mi);

Width = mi.rcMonitor.right - mi.rcMonitor.left;
Height = mi.rcMonitor.bottom - mi.rcMonitor.top;
    }

WNDCLASSEX wc;

wc.cbSize = sizeof(WNDCLASSEX);
wc.style = CS_HREDRAW | CS_VREDRAW;
wc.lpfnWndProc = WndProc;
wc.cbClsExtra = NULL;
wc.cbWndExtra = NULL;
wc.hInstance = hInstance;
wc.hIcon = LoadIcon(NULL, IDI_APPLICATION);
wc.hCursor = LoadCursor(NULL, IDC_ARROW);
wc.hbrBackground = (HBRUSH)(COLOR_WINDOW + 2);
wc.lpszMenuName = NULL;
wc.lpszClassName = WindowName;
wc.hIconSm = LoadIcon(NULL, IDI_APPLICATION);

if (!RegisterClassEx(&wc))
    {
MessageBox(NULL, L"Error registering class",
L"Error", MB_OK | MB_ICONERROR);
return false;
    }

hwnd = CreateWindowEx(NULL,
WindowName,
WindowTitle,
WS_OVERLAPPEDWINDOW,
CW_USEDEFAULT, CW_USEDEFAULT,
Width, Height,
NULL,
NULL,
hInstance,
NULL);

if (!hwnd)
    {
MessageBox(NULL, L"Error creating window",
L"Error", MB_OK | MB_ICONERROR);
return false;
    }

if (fullscreen)
    {
SetWindowLong(hwnd, GWL_STYLE, 0);
    }

ShowWindow(hwnd, ShowWnd);
UpdateWindow(hwnd);

return true;
}

void mainloop() {
MSG msg;
ZeroMemory(&msg, sizeof(MSG));

while (Running)
    {
if (PeekMessage(&msg, NULL, 0, 0, PM_REMOVE))
        {
if (msg.message == WM_QUIT)
break;

TranslateMessage(&msg);
DispatchMessage(&msg);
        }
else {
// run game code
Update(); // update the game logic
Render(); // execute the command queue (rendering the scene is the result of the gpu executing the command lists)
        }
    }
}

LRESULT CALLBACK WndProc(HWND hwnd,
UINT msg,
WPARAM wParam,
LPARAM lParam)

{
switch (msg)
    {
case WM_KEYDOWN:
if (wParam == VK_ESCAPE) {
if (MessageBox(0, L"Are you sure you want to exit?",
L"Really?", MB_YESNO | MB_ICONQUESTION) == IDYES)
            {
Running = false;
DestroyWindow(hwnd);
            }
        }
return 0;

case WM_DESTROY: // x button on top right corner of window was pressed
Running = false;
PostQuitMessage(0);
return 0;
    }
return DefWindowProc(hwnd,
msg,
wParam,
lParam);
}

bool InitD3D()
{
HRESULT hr;

// -- Create the Device -- //

IDXGIFactory4* dxgiFactory;
hr = CreateDXGIFactory1(IID_PPV_ARGS(&dxgiFactory));
if (FAILED(hr))
    {
return false;
    }

IDXGIAdapter1* adapter; // adapters are the graphics card (this includes the embedded graphics on the motherboard)

int adapterIndex = 0; // we'll start looking for directx 12  compatible graphics devices starting at index 0

bool adapterFound = false; // set this to true when a good one was found

// find first hardware gpu that supports d3d 12
while (dxgiFactory->EnumAdapters1(adapterIndex, &adapter) != DXGI_ERROR_NOT_FOUND)
    {
DXGI_ADAPTER_DESC1 desc;
adapter->GetDesc1(&desc);

if (desc.Flags & DXGI_ADAPTER_FLAG_SOFTWARE)
        {
// we dont want a software device
continue;
        }

// we want a device that is compatible with direct3d 12 (feature level 11 or higher)
hr = D3D12CreateDevice(adapter, D3D_FEATURE_LEVEL_11_0, _uuidof(ID3D12Device), nullptr);
if (SUCCEEDED(hr))
        {
adapterFound = true;
break;
        }

adapterIndex++;
    }

if (!adapterFound)
    {
return false;
    }

// Create the device
hr = D3D12CreateDevice(
adapter,
D3D_FEATURE_LEVEL_11_0,
IID_PPV_ARGS(&device)
        );
if (FAILED(hr))
    {
return false;
    }

// -- Create a direct command queue -- //

D3D12_COMMAND_QUEUE_DESC cqDesc = {};
cqDesc.Flags = D3D12_COMMAND_QUEUE_FLAG_NONE;
cqDesc.Type = D3D12_COMMAND_LIST_TYPE_DIRECT; // direct means the gpu can directly execute this command queue

hr = device->CreateCommandQueue(&cqDesc, IID_PPV_ARGS(&commandQueue)); // create the command queue
if (FAILED(hr))
    {
return false;
    }

// -- Create the Swap Chain (double/tripple buffering) -- //

DXGI_MODE_DESC backBufferDesc = {}; // this is to describe our display mode
backBufferDesc.Width = Width; // buffer width
backBufferDesc.Height = Height; // buffer height
backBufferDesc.Format = DXGI_FORMAT_R8G8B8A8_UNORM; // format of the buffer (rgba 32 bits, 8 bits for each chanel)

// describe our multi-sampling. We are not multi-sampling, so we set the count to 1 (we need at least one sample of course)
DXGI_SAMPLE_DESC sampleDesc = {};
sampleDesc.Count = 1; // multisample count (no multisampling, so we just put 1, since we still need 1 sample)

// Describe and create the swap chain.
DXGI_SWAP_CHAIN_DESC swapChainDesc = {};
swapChainDesc.BufferCount = frameBufferCount; // number of buffers we have
swapChainDesc.BufferDesc = backBufferDesc; // our back buffer description
swapChainDesc.BufferUsage = DXGI_USAGE_RENDER_TARGET_OUTPUT; // this says the pipeline will render to this swap chain
swapChainDesc.SwapEffect = DXGI_SWAP_EFFECT_FLIP_DISCARD; // dxgi will discard the buffer (data) after we call present
swapChainDesc.OutputWindow = hwnd; // handle to our window
swapChainDesc.SampleDesc = sampleDesc; // our multi-sampling description
swapChainDesc.Windowed = !FullScreen; // set to true, then if in fullscreen must call SetFullScreenState with true for full screen to get uncapped fps

IDXGISwapChain* tempSwapChain;

dxgiFactory->CreateSwapChain(
commandQueue, // the queue will be flushed once the swap chain is created
&swapChainDesc, // give it the swap chain description we created above
&tempSwapChain // store the created swap chain in a temp IDXGISwapChain interface
        );

swapChain = static_cast<IDXGISwapChain3*>(tempSwapChain);

frameIndex = swapChain->GetCurrentBackBufferIndex();

// -- Create the Back Buffers (render target views) Descriptor Heap -- //

// describe an rtv descriptor heap and create
D3D12_DESCRIPTOR_HEAP_DESC rtvHeapDesc = {};
rtvHeapDesc.NumDescriptors = frameBufferCount; // number of descriptors for this heap.
rtvHeapDesc.Type = D3D12_DESCRIPTOR_HEAP_TYPE_RTV; // this heap is a render target view heap

// This heap will not be directly referenced by the shaders (not shader visible), as this will store the output from the pipeline
// otherwise we would set the heap's flag to D3D12_DESCRIPTOR_HEAP_FLAG_SHADER_VISIBLE
rtvHeapDesc.Flags = D3D12_DESCRIPTOR_HEAP_FLAG_NONE;
hr = device->CreateDescriptorHeap(&rtvHeapDesc, IID_PPV_ARGS(&rtvDescriptorHeap));
if (FAILED(hr))
    {
return false;
    }

// get the size of a descriptor in this heap (this is a rtv heap, so only rtv descriptors should be stored in it.
// descriptor sizes may vary from device to device, which is why there is no set size and we must ask the 
// device to give us the size. we will use this size to increment a descriptor handle offset
rtvDescriptorSize = device->GetDescriptorHandleIncrementSize(D3D12_DESCRIPTOR_HEAP_TYPE_RTV);

// get a handle to the first descriptor in the descriptor heap. a handle is basically a pointer,
// but we cannot literally use it like a c++ pointer.
CD3DX12_CPU_DESCRIPTOR_HANDLE rtvHandle(rtvDescriptorHeap->GetCPUDescriptorHandleForHeapStart());

// Create a RTV for each buffer (double buffering is two buffers, tripple buffering is 3).
for (int i = 0; i < frameBufferCount; i++)
    {
// first we get the n'th buffer in the swap chain and store it in the n'th
// position of our ID3D12Resource array
hr = swapChain->GetBuffer(i, IID_PPV_ARGS(&renderTargets[i]));
if (FAILED(hr))
        {
return false;
        }

// the we "create" a render target view which binds the swap chain buffer (ID3D12Resource[n]) to the rtv handle
device->CreateRenderTargetView(renderTargets[i], nullptr, rtvHandle);

// we increment the rtv handle by the rtv descriptor size we got above
rtvHandle.Offset(1, rtvDescriptorSize);
    }

// -- Create the Command Allocators -- //

for (int i = 0; i < frameBufferCount; i++)
    {
hr = device->CreateCommandAllocator(D3D12_COMMAND_LIST_TYPE_DIRECT, IID_PPV_ARGS(&commandAllocator[i]));
if (FAILED(hr))
        {
return false;
        }
    }

// -- Create a Command List -- //

// create the command list with the first allocator
hr = device->CreateCommandList(0, D3D12_COMMAND_LIST_TYPE_DIRECT, commandAllocator[frameIndex], NULL, IID_PPV_ARGS(&commandList));
if (FAILED(hr))
    {
return false;
    }

// -- Create a Fence & Fence Event -- //

// create the fences
for (int i = 0; i < frameBufferCount; i++)
    {
hr = device->CreateFence(0, D3D12_FENCE_FLAG_NONE, IID_PPV_ARGS(&fence[i]));
if (FAILED(hr))
        {
return false;
        }
fenceValue[i] = 0; // set the initial fence value to 0
    }

// create a handle to a fence event
fenceEvent = CreateEvent(nullptr, FALSE, FALSE, nullptr);
if (fenceEvent == nullptr)
    {
return false;
    }

// create root signature

CD3DX12_ROOT_SIGNATURE_DESC rootSignatureDesc;
rootSignatureDesc.Init(0, nullptr, 0, nullptr, D3D12_ROOT_SIGNATURE_FLAG_ALLOW_INPUT_ASSEMBLER_INPUT_LAYOUT);

ID3DBlob* signature;
hr = D3D12SerializeRootSignature(&rootSignatureDesc, D3D_ROOT_SIGNATURE_VERSION_1, &signature, nullptr);
if (FAILED(hr))
    {
return false;
    }

hr = device->CreateRootSignature(0, signature->GetBufferPointer(), signature->GetBufferSize(), IID_PPV_ARGS(&rootSignature));
if (FAILED(hr))
    {
return false;
    }

// create vertex and pixel shaders

// when debugging, we can compile the shader files at runtime.
// but for release versions, we can compile the hlsl shaders
// with fxc.exe to create .cso files, which contain the shader
// bytecode. We can load the .cso files at runtime to get the
// shader bytecode, which of course is faster than compiling
// them at runtime

// compile vertex shader
ID3DBlob* vertexShader; // d3d blob for holding vertex shader bytecode
ID3DBlob* errorBuff; // a buffer holding the error data if any
hr = D3DCompileFromFile(L"VertexShader.hlsl",
nullptr,
nullptr,
"main",
"vs_5_0",
D3DCOMPILE_DEBUG | D3DCOMPILE_SKIP_OPTIMIZATION,
0,
&vertexShader,
&errorBuff);
if (FAILED(hr))
    {
OutputDebugStringA((char*)errorBuff->GetBufferPointer());
return false;
    }

// fill out a shader bytecode structure, which is basically just a pointer
// to the shader bytecode and the size of the shader bytecode
D3D12_SHADER_BYTECODE vertexShaderBytecode = {};
vertexShaderBytecode.BytecodeLength = vertexShader->GetBufferSize();
vertexShaderBytecode.pShaderBytecode = vertexShader->GetBufferPointer();

// compile pixel shader
ID3DBlob* pixelShader;
hr = D3DCompileFromFile(L"PixelShader.hlsl",
nullptr,
nullptr,
"main",
"ps_5_0",
D3DCOMPILE_DEBUG | D3DCOMPILE_SKIP_OPTIMIZATION,
0,
&pixelShader,
&errorBuff);
if (FAILED(hr))
    {
OutputDebugStringA((char*)errorBuff->GetBufferPointer());
return false;
    }

// fill out shader bytecode structure for pixel shader
D3D12_SHADER_BYTECODE pixelShaderBytecode = {};
pixelShaderBytecode.BytecodeLength = pixelShader->GetBufferSize();
pixelShaderBytecode.pShaderBytecode = pixelShader->GetBufferPointer();

// create input layout

// The input layout is used by the Input Assembler so that it knows
// how to read the vertex data bound to it.

D3D12_INPUT_ELEMENT_DESC inputLayout[] =
    {
        { "POSITION", 0, DXGI_FORMAT_R32G32B32_FLOAT, 0, 0, D3D12_INPUT_CLASSIFICATION_PER_VERTEX_DATA, 0 },
        { "COLOR", 0, DXGI_FORMAT_R32G32B32A32_FLOAT, 0, 12, D3D12_INPUT_CLASSIFICATION_PER_VERTEX_DATA, 0 }
    };

// fill out an input layout description structure
D3D12_INPUT_LAYOUT_DESC inputLayoutDesc = {};

// we can get the number of elements in an array by "sizeof(array) / sizeof(arrayElementType)"
inputLayoutDesc.NumElements = sizeof(inputLayout) / sizeof(D3D12_INPUT_ELEMENT_DESC);
inputLayoutDesc.pInputElementDescs = inputLayout;

// create a pipeline state object (PSO)

// In a real application, you will have many pso's. for each different shader
// or different combinations of shaders, different blend states or different rasterizer states,
// different topology types (point, line, triangle, patch), or a different number
// of render targets you will need a pso

// VS is the only required shader for a pso. You might be wondering when a case would be where
// you only set the VS. It's possible that you have a pso that only outputs data with the stream
// output, and not on a render target, which means you would not need anything after the stream
// output.

D3D12_GRAPHICS_PIPELINE_STATE_DESC psoDesc = {}; // a structure to define a pso
psoDesc.InputLayout = inputLayoutDesc; // the structure describing our input layout
psoDesc.pRootSignature = rootSignature; // the root signature that describes the input data this pso needs
psoDesc.VS = vertexShaderBytecode; // structure describing where to find the vertex shader bytecode and how large it is
psoDesc.PS = pixelShaderBytecode; // same as VS but for pixel shader
psoDesc.PrimitiveTopologyType = D3D12_PRIMITIVE_TOPOLOGY_TYPE_TRIANGLE; // type of topology we are drawing
psoDesc.RTVFormats[0] = DXGI_FORMAT_R8G8B8A8_UNORM; // format of the render target
psoDesc.SampleDesc = sampleDesc; // must be the same sample description as the swapchain and depth/stencil buffer
psoDesc.SampleMask = 0xffffffff; // sample mask has to do with multi-sampling. 0xffffffff means point sampling is done
psoDesc.RasterizerState = CD3DX12_RASTERIZER_DESC(D3D12_DEFAULT); // a default rasterizer state.
psoDesc.BlendState = CD3DX12_BLEND_DESC(D3D12_DEFAULT); // a default blent state.
psoDesc.NumRenderTargets = 1; // we are only binding one render target
psoDesc.DepthStencilState = CD3DX12_DEPTH_STENCIL_DESC(D3D12_DEFAULT); // a default depth stencil state

// create the pso
hr = device->CreateGraphicsPipelineState(&psoDesc, IID_PPV_ARGS(&pipelineStateObject));
if (FAILED(hr))
    {
return false;
    }

// Create vertex buffer

// a triangle
Vertex vList[] = {
// first quad (closer to camera, blue)
        { -0.5f,  0.5f, 0.5f, 0.0f, 0.0f, 1.0f, 1.0f },
        {  0.5f, -0.5f, 0.5f, 0.0f, 0.0f, 1.0f, 1.0f },
        { -0.5f, -0.5f, 0.5f, 0.0f, 0.0f, 1.0f, 1.0f },
        {  0.5f,  0.5f, 0.5f, 0.0f, 0.0f, 1.0f, 1.0f },

// second quad (further from camera, green)
        { -0.75f,  0.75f,  0.7f, 0.0f, 1.0f, 0.0f, 1.0f },
        {   0.0f,  0.0f, 0.7f, 0.0f, 1.0f, 0.0f, 1.0f },
        { -0.75f,  0.0f, 0.7f, 0.0f, 1.0f, 0.0f, 1.0f },
        {   0.0f,  0.75f,  0.7f, 0.0f, 1.0f, 0.0f, 1.0f }
    };

int vBufferSize = sizeof(vList);

// create default heap
// default heap is memory on the GPU. Only the GPU has access to this memory
// To get data into this heap, we will have to upload the data using
// an upload heap
device->CreateCommittedResource(
&CD3DX12_HEAP_PROPERTIES(D3D12_HEAP_TYPE_DEFAULT), // a default heap
D3D12_HEAP_FLAG_NONE, // no flags
&CD3DX12_RESOURCE_DESC::Buffer(vBufferSize), // resource description for a buffer
D3D12_RESOURCE_STATE_COPY_DEST, // we will start this heap in the copy destination state since we will copy data
// from the upload heap to this heap
nullptr, // optimized clear value must be null for this type of resource. used for render targets and depth/stencil buffers
IID_PPV_ARGS(&vertexBuffer));

// we can give resource heaps a name so when we debug with the graphics debugger we know what resource we are looking at
vertexBuffer->SetName(L"Vertex Buffer Resource Heap");

// create upload heap
// upload heaps are used to upload data to the GPU. CPU can write to it, GPU can read from it
// We will upload the vertex buffer using this heap to the default heap
ID3D12Resource* vBufferUploadHeap;
device->CreateCommittedResource(
&CD3DX12_HEAP_PROPERTIES(D3D12_HEAP_TYPE_UPLOAD), // upload heap
D3D12_HEAP_FLAG_NONE, // no flags
&CD3DX12_RESOURCE_DESC::Buffer(vBufferSize), // resource description for a buffer
D3D12_RESOURCE_STATE_GENERIC_READ, // GPU will read from this buffer and copy its contents to the default heap
nullptr,
IID_PPV_ARGS(&vBufferUploadHeap));
vBufferUploadHeap->SetName(L"Vertex Buffer Upload Resource Heap");

// store vertex buffer in upload heap
D3D12_SUBRESOURCE_DATA vertexData = {};
vertexData.pData = reinterpret_cast<BYTE*>(vList); // pointer to our vertex array
vertexData.RowPitch = vBufferSize; // size of all our triangle vertex data
vertexData.SlicePitch = vBufferSize; // also the size of our triangle vertex data

// we are now creating a command with the command list to copy the data from
// the upload heap to the default heap
UpdateSubresources(commandList, vertexBuffer, vBufferUploadHeap, 0, 0, 1, &vertexData);

// transition the vertex buffer data from copy destination state to vertex buffer state
commandList->ResourceBarrier(1, &CD3DX12_RESOURCE_BARRIER::Transition(vertexBuffer, D3D12_RESOURCE_STATE_COPY_DEST, D3D12_RESOURCE_STATE_VERTEX_AND_CONSTANT_BUFFER));

// Create index buffer

// a quad (2 triangles)
DWORD iList[] = {
// first quad (blue)
0, 1, 2, // first triangle
0, 3, 1, // second triangle
    };

int iBufferSize = sizeof(iList);

// create default heap to hold index buffer
device->CreateCommittedResource(
&CD3DX12_HEAP_PROPERTIES(D3D12_HEAP_TYPE_DEFAULT), // a default heap
D3D12_HEAP_FLAG_NONE, // no flags
&CD3DX12_RESOURCE_DESC::Buffer(iBufferSize), // resource description for a buffer
D3D12_RESOURCE_STATE_COPY_DEST, // start in the copy destination state
nullptr, // optimized clear value must be null for this type of resource
IID_PPV_ARGS(&indexBuffer));

// we can give resource heaps a name so when we debug with the graphics debugger we know what resource we are looking at
vertexBuffer->SetName(L"Index Buffer Resource Heap");

// create upload heap to upload index buffer
ID3D12Resource* iBufferUploadHeap;
device->CreateCommittedResource(
&CD3DX12_HEAP_PROPERTIES(D3D12_HEAP_TYPE_UPLOAD), // upload heap
D3D12_HEAP_FLAG_NONE, // no flags
&CD3DX12_RESOURCE_DESC::Buffer(vBufferSize), // resource description for a buffer
D3D12_RESOURCE_STATE_GENERIC_READ, // GPU will read from this buffer and copy its contents to the default heap
nullptr,
IID_PPV_ARGS(&iBufferUploadHeap));
vBufferUploadHeap->SetName(L"Index Buffer Upload Resource Heap");

// store vertex buffer in upload heap
D3D12_SUBRESOURCE_DATA indexData = {};
indexData.pData = reinterpret_cast<BYTE*>(iList); // pointer to our index array
indexData.RowPitch = iBufferSize; // size of all our index buffer
indexData.SlicePitch = iBufferSize; // also the size of our index buffer

// we are now creating a command with the command list to copy the data from
// the upload heap to the default heap
UpdateSubresources(commandList, indexBuffer, iBufferUploadHeap, 0, 0, 1, &indexData);

// transition the vertex buffer data from copy destination state to vertex buffer state
commandList->ResourceBarrier(1, &CD3DX12_RESOURCE_BARRIER::Transition(indexBuffer, D3D12_RESOURCE_STATE_COPY_DEST, D3D12_RESOURCE_STATE_VERTEX_AND_CONSTANT_BUFFER));

// Create the depth/stencil buffer

// create a depth stencil descriptor heap so we can get a pointer to the depth stencil buffer
D3D12_DESCRIPTOR_HEAP_DESC dsvHeapDesc = {};
dsvHeapDesc.NumDescriptors = 1;
dsvHeapDesc.Type = D3D12_DESCRIPTOR_HEAP_TYPE_DSV;
dsvHeapDesc.Flags = D3D12_DESCRIPTOR_HEAP_FLAG_NONE;
hr = device->CreateDescriptorHeap(&dsvHeapDesc, IID_PPV_ARGS(&dsDescriptorHeap));
if (FAILED(hr))
    {
Running = false;
    }

D3D12_DEPTH_STENCIL_VIEW_DESC depthStencilDesc = {};
depthStencilDesc.Format = DXGI_FORMAT_D32_FLOAT;
depthStencilDesc.ViewDimension = D3D12_DSV_DIMENSION_TEXTURE2D;
depthStencilDesc.Flags = D3D12_DSV_FLAG_NONE;

D3D12_CLEAR_VALUE depthOptimizedClearValue = {};
depthOptimizedClearValue.Format = DXGI_FORMAT_D32_FLOAT;
depthOptimizedClearValue.DepthStencil.Depth = 1.0f;
depthOptimizedClearValue.DepthStencil.Stencil = 0;

device->CreateCommittedResource(
&CD3DX12_HEAP_PROPERTIES(D3D12_HEAP_TYPE_DEFAULT),
D3D12_HEAP_FLAG_NONE,
&CD3DX12_RESOURCE_DESC::Tex2D(DXGI_FORMAT_D32_FLOAT, Width, Height, 1, 0, 1, 0, D3D12_RESOURCE_FLAG_ALLOW_DEPTH_STENCIL),
D3D12_RESOURCE_STATE_DEPTH_WRITE,
&depthOptimizedClearValue,
IID_PPV_ARGS(&depthStencilBuffer)
        );
hr = device->CreateDescriptorHeap(&dsvHeapDesc, IID_PPV_ARGS(&dsDescriptorHeap));
if (FAILED(hr))
    {
Running = false;
    }
dsDescriptorHeap->SetName(L"Depth/Stencil Resource Heap");

device->CreateDepthStencilView(depthStencilBuffer, &depthStencilDesc, dsDescriptorHeap->GetCPUDescriptorHandleForHeapStart());

// Now we execute the command list to upload the initial assets (triangle data)
commandList->Close();
ID3D12CommandList* ppCommandLists[] = { commandList };
commandQueue->ExecuteCommandLists(_countof(ppCommandLists), ppCommandLists);

// increment the fence value now, otherwise the buffer might not be uploaded by the time we start drawing
fenceValue[frameIndex]++;
hr = commandQueue->Signal(fence[frameIndex], fenceValue[frameIndex]);
if (FAILED(hr))
    {
Running = false;
    }

// create a vertex buffer view for the triangle. We get the GPU memory address to the vertex pointer using the GetGPUVirtualAddress() method
vertexBufferView.BufferLocation = vertexBuffer->GetGPUVirtualAddress();
vertexBufferView.StrideInBytes = sizeof(Vertex);
vertexBufferView.SizeInBytes = vBufferSize;

// create a vertex buffer view for the triangle. We get the GPU memory address to the vertex pointer using the GetGPUVirtualAddress() method
indexBufferView.BufferLocation = indexBuffer->GetGPUVirtualAddress();
indexBufferView.Format = DXGI_FORMAT_R32_UINT; // 32-bit unsigned integer (this is what a dword is, double word, a word is 2 bytes)
indexBufferView.SizeInBytes = iBufferSize;

// Fill out the Viewport
viewport.TopLeftX = 0;
viewport.TopLeftY = 0;
viewport.Width = Width;
viewport.Height = Height;
viewport.MinDepth = 0.0f;
viewport.MaxDepth = 1.0f;

// Fill out a scissor rect
scissorRect.left = 0;
scissorRect.top = 0;
scissorRect.right = Width;
scissorRect.bottom = Height;

return true;
}

void Update()
{
// update app logic, such as moving the camera or figuring out what objects are in view
}

void UpdatePipeline()
{
HRESULT hr;

// We have to wait for the gpu to finish with the command allocator before we reset it
WaitForPreviousFrame();

// we can only reset an allocator once the gpu is done with it
// resetting an allocator frees the memory that the command list was stored in
hr = commandAllocator[frameIndex]->Reset();
if (FAILED(hr))
    {
Running = false;
    }

// reset the command list. by resetting the command list we are putting it into
// a recording state so we can start recording commands into the command allocator.
// the command allocator that we reference here may have multiple command lists
// associated with it, but only one can be recording at any time. Make sure
// that any other command lists associated to this command allocator are in
// the closed state (not recording).
// Here you will pass an initial pipeline state object as the second parameter,
// but in this tutorial we are only clearing the rtv, and do not actually need
// anything but an initial default pipeline, which is what we get by setting
// the second parameter to NULL
hr = commandList->Reset(commandAllocator[frameIndex], pipelineStateObject);
if (FAILED(hr))
    {
Running = false;
    }

// here we start recording commands into the commandList (which all the commands will be stored in the commandAllocator)

// transition the "frameIndex" render target from the present state to the render target state so the command list draws to it starting from here
commandList->ResourceBarrier(1, &CD3DX12_RESOURCE_BARRIER::Transition(renderTargets[frameIndex], D3D12_RESOURCE_STATE_PRESENT, D3D12_RESOURCE_STATE_RENDER_TARGET));

// here we again get the handle to our current render target view so we can set it as the render target in the output merger stage of the pipeline
CD3DX12_CPU_DESCRIPTOR_HANDLE rtvHandle(rtvDescriptorHeap->GetCPUDescriptorHandleForHeapStart(), frameIndex, rtvDescriptorSize);

// get a handle to the depth/stencil buffer
CD3DX12_CPU_DESCRIPTOR_HANDLE dsvHandle(dsDescriptorHeap->GetCPUDescriptorHandleForHeapStart());

// set the render target for the output merger stage (the output of the pipeline)
commandList->OMSetRenderTargets(1, &rtvHandle, FALSE, &dsvHandle);

// Clear the render target by using the ClearRenderTargetView command
const float clearColor[] = { 0.0f, 0.2f, 0.4f, 1.0f };
commandList->ClearRenderTargetView(rtvHandle, clearColor, 0, nullptr);

// clear the depth/stencil buffer
commandList->ClearDepthStencilView(dsDescriptorHeap->GetCPUDescriptorHandleForHeapStart(), D3D12_CLEAR_FLAG_DEPTH, 1.0f, 0, 0, nullptr);

// draw triangle
commandList->SetGraphicsRootSignature(rootSignature); // set the root signature
commandList->RSSetViewports(1, &viewport); // set the viewports
commandList->RSSetScissorRects(1, &scissorRect); // set the scissor rects
commandList->IASetPrimitiveTopology(D3D_PRIMITIVE_TOPOLOGY_TRIANGLELIST); // set the primitive topology
commandList->IASetVertexBuffers(0, 1, &vertexBufferView); // set the vertex buffer (using the vertex buffer view)
commandList->IASetIndexBuffer(&indexBufferView);
commandList->DrawIndexedInstanced(6, 1, 0, 0, 0); // draw first quad
commandList->DrawIndexedInstanced(6, 1, 0, 4, 0); // draw second quad

// transition the "frameIndex" render target from the render target state to the present state. If the debug layer is enabled, you will receive a
// warning if present is called on the render target when it's not in the present state
commandList->ResourceBarrier(1, &CD3DX12_RESOURCE_BARRIER::Transition(renderTargets[frameIndex], D3D12_RESOURCE_STATE_RENDER_TARGET, D3D12_RESOURCE_STATE_PRESENT));

hr = commandList->Close();
if (FAILED(hr))
    {
Running = false;
    }
}

void Render()
{
HRESULT hr;

UpdatePipeline(); // update the pipeline by sending commands to the commandqueue

// create an array of command lists (only one command list here)
ID3D12CommandList* ppCommandLists[] = { commandList };

// execute the array of command lists
commandQueue->ExecuteCommandLists(_countof(ppCommandLists), ppCommandLists);

// this command goes in at the end of our command queue. we will know when our command queue 
// has finished because the fence value will be set to "fenceValue" from the GPU since the command
// queue is being executed on the GPU
hr = commandQueue->Signal(fence[frameIndex], fenceValue[frameIndex]);
if (FAILED(hr))
    {
Running = false;
    }

// present the current backbuffer
hr = swapChain->Present(0, 0);
if (FAILED(hr))
    {
Running = false;
    }
}

void Cleanup()
{
// wait for the gpu to finish all frames
for (int i = 0; i < frameBufferCount; ++i)
    {
frameIndex = i;
WaitForPreviousFrame();
    }

// get swapchain out of full screen before exiting
BOOL fs = false;
if (swapChain->GetFullscreenState(&fs, NULL))
swapChain->SetFullscreenState(false, NULL);

SAFE_RELEASE(device);
SAFE_RELEASE(swapChain);
SAFE_RELEASE(commandQueue);
SAFE_RELEASE(rtvDescriptorHeap);
SAFE_RELEASE(commandList);

for (int i = 0; i < frameBufferCount; ++i)
    {
SAFE_RELEASE(renderTargets[i]);
SAFE_RELEASE(commandAllocator[i]);
SAFE_RELEASE(fence[i]);
    };

SAFE_RELEASE(pipelineStateObject);
SAFE_RELEASE(rootSignature);
SAFE_RELEASE(vertexBuffer);
SAFE_RELEASE(indexBuffer);

SAFE_RELEASE(depthStencilBuffer);
SAFE_RELEASE(dsDescriptorHeap);
}

void WaitForPreviousFrame()
{
HRESULT hr;

// swap the current rtv buffer index so we draw on the correct buffer
frameIndex = swapChain->GetCurrentBackBufferIndex();

// if the current fence value is still less than "fenceValue", then we know the GPU has not finished executing
// the command queue since it has not reached the "commandQueue->Signal(fence, fenceValue)" command
if (fence[frameIndex]->GetCompletedValue() < fenceValue[frameIndex])
    {
// we have the fence create an event which is signaled once the fence's current value is "fenceValue"
hr = fence[frameIndex]->SetEventOnCompletion(fenceValue[frameIndex], fenceEvent);
if (FAILED(hr))
        {
Running = false;
        }

// We will wait until the fence has triggered the event that it's current value has reached "fenceValue". once it's value
// has reached "fenceValue", we know the command queue has finished executing
WaitForSingleObject(fenceEvent, INFINITE);
    }

// increment fenceValue for next frame
fenceValue[frameIndex]++;
}

参考链接：

1. 1. 
      
2. ​​​https://docs.microsoft.com/en-us/windows/win32/direct3d12/directx-12-programming-guide​​​
3. ​​​http://www.d3dcoder.net/​​​
4. ​​​https://www.braynzarsoft.net/viewtutorial/q16390-04-directx-12-braynzar-soft-tutorials​​​
5. ​​​https://developer.nvidia.com/dx12-dos-and-donts​​​
6. ​​​https://www.3dgep.com/learning-directx-12-1/​​​
7. ​​​https://gpuopen.com/learn/lets-learn-directx12/​​​
8. ​​​https://alain.xyz/blog/raw-directx12​​​
9. ​​​https://www.rastertek.com/tutdx12.html​​​
10. ​​​https://digitalerr0r.net/2015/08/19/quickstart-directx-12-programming/​​​
11. ​​​https://walbourn.github.io/getting-started-with-direct3d-12/​​​
12. ​​​https://docs.aws.amazon.com/lumberyard/latest/userguide/graphics-rendering-directx.html​​​
13. ​​​http://diligentgraphics.com/diligent-engine/samples/​​​
14. ​​​https://www.programmersought.com/article/2904113865/​​​
15. ​​​https://www.tutorialspoint.com/directx/directx_first_hlsl.htm​​​
16. ​​​http://rbwhitaker.wikidot.com/hlsl-tutorials​​​
17. ​​​https://digitalerr0r.net/2015/08/19/quickstart-directx-12-programming/​​​
18. ​​​https://www.ronja-tutorials.com/post/002-hlsl/​​​
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