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DirectX/10.0/Direct3D/2D 渲染

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能夠將 2D 影像渲染到螢幕上非常有用。例如，大多數使用者介面、精靈系統和文字引擎都是由 2D 影像組成的。DirectX 11 允許您透過將 2D 影像對映到多邊形，然後使用正交投影矩陣進行渲染來渲染 2D 影像。

2D 螢幕座標

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要將 2D 影像渲染到螢幕上，您需要計算螢幕 X 和 Y 座標。對於 DirectX，螢幕的中心是 0,0。從那裡，螢幕的左側和底部朝負方向移動。螢幕的右側和頂部朝正方向移動。例如，以 1024x768 解析度的螢幕為例，螢幕邊界的座標如下所示

因此請記住，您所有 2D 渲染都需要使用這些螢幕座標計算，並且您還需要使用者視窗/螢幕的大小才能正確放置 2D 影像。

在 DirectX 11 中停用 Z 緩衝區

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要進行 2D 繪製，您應該停用 Z 緩衝區。當 Z 緩衝區關閉時，它將在該畫素位置的任何內容之上寫入 2D 資料。確保使用畫家演算法，並從後到前繪製，以確保您獲得預期的渲染輸出。完成繪製 2D 圖形後，請再次啟用 Z 緩衝區，以便您可以正確地再次渲染 3D 物件。

要開啟和關閉 Z 緩衝區，您需要建立一個第二個深度模板狀態，與您的 3D 狀態相同，只是將 DepthEnable 設定為 false。然後，只需使用 OMSetDepthStencilState 在這兩種狀態之間切換即可開啟和關閉 Z 緩衝區。

動態頂點緩衝區

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另一個將要介紹的新概念是動態頂點緩衝區。到目前為止，我們在之前的教程中使用了靜態頂點緩衝區。靜態頂點緩衝區的問題是，您永遠無法更改緩衝區中的資料。另一方面，動態頂點緩衝區允許我們在需要時在每一幀內操作頂點緩衝區內部的資訊。這些緩衝區比靜態頂點緩衝區慢得多，但這是為了額外功能而付出的代價。

我們使用 2D 渲染的動態頂點緩衝區的原因是我們經常希望將 2D 影像移動到螢幕上的不同位置。一個很好的例子是滑鼠指標，它經常被移動，因此表示它在螢幕上的位置的頂點資料也需要經常更改。

兩點需要注意。除非絕對需要，否則不要使用動態頂點緩衝區，它們比靜態緩衝區慢得多。其次，不要在每一幀都銷燬和重新建立靜態頂點緩衝區，這會導致顯示卡完全鎖定（我在 ATI 上見過，但沒有在 Nvidia 上見過），並且與使用動態頂點緩衝區相比，整體效能要差得多。

DirectX 11 中的正交投影

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在 2D 中進行渲染所需的最後一個新概念是在正規的 3D 投影矩陣的基礎上使用正交投影矩陣。這將允許您渲染到 2D 螢幕座標。請記住，我們已經在 Direct3D 初始化程式碼中建立了此矩陣

	// Create an orthographic projection matrix for 2D rendering.
	D3DXMatrixOrthoLH(&m_orthoMatrix, (float)screenWidth, (float)screenHeight, screenNear, screenDepth);

框架

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本教程中的程式碼基於之前的教程。本教程的主要區別在於 ModelClass 已被 BitmapClass 替換，我們再次使用 TextureShaderClass 而不是 LightShaderClass。框架將如下所示

Bitmapclass.h

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BitmapClass 將用於表示需要渲染到螢幕上的單個 2D 影像。對於您擁有的每個 2D 影像，您都需要一個新的 BitmapClass。請注意，此類只是重新編寫的 ModelClass，用於處理 2D 影像而不是 3D 物件。

////////////////////////////////////////////////////////////////////////////////
// Filename: bitmapclass.h
////////////////////////////////////////////////////////////////////////////////
#ifndef _BITMAPCLASS_H_
#define _BITMAPCLASS_H_

//////////////
// INCLUDES //
//////////////
#include <d3d11.h>
#include <d3dx10math.h>

///////////////////////
// MY CLASS INCLUDES //
///////////////////////
#include "textureclass.h"

////////////////////////////////////////////////////////////////////////////////
// Class name: BitmapClass
////////////////////////////////////////////////////////////////////////////////
class BitmapClass
{
private:

每個點陣圖影像仍然是渲染類似於 3D 物件的多邊形物件。對於 2D 影像，我們只需要一個位置向量和紋理座標。

	struct VertexType
	{
		D3DXVECTOR3 position;
		D3DXVECTOR2 texture;
	};

public:
	BitmapClass();
	BitmapClass(const BitmapClass&);
	~BitmapClass();

	bool Initialize(ID3D11Device*, int, int, WCHAR*, int, int);
	void Shutdown();
	bool Render(ID3D11DeviceContext*, int, int);

	int GetIndexCount();
	ID3D11ShaderResourceView* GetTexture();

private:
	bool InitializeBuffers(ID3D11Device*);
	void ShutdownBuffers();
	bool UpdateBuffers(ID3D11DeviceContext*, int, int);
	void RenderBuffers(ID3D11DeviceContext*);

	bool LoadTexture(ID3D11Device*, WCHAR*);
	void ReleaseTexture();

private:
	ID3D11Buffer *m_vertexBuffer, *m_indexBuffer;
	int m_vertexCount, m_indexCount;
	TextureClass* m_Texture;

BitmapClass 需要維護 3D 模型不會維護的一些額外資訊，例如螢幕大小、點陣圖大小以及最後一次渲染的位置。我們在這裡添加了額外的私有變數來跟蹤這些額外資訊。

	int m_screenWidth, m_screenHeight;
	int m_bitmapWidth, m_bitmapHeight;
	int m_previousPosX, m_previousPosY;
};

#endif

Bitmapclass.cpp

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////////////////////////////////////////////////////////////////////////////////
// Filename: bitmapclass.cpp
////////////////////////////////////////////////////////////////////////////////
#include "bitmapclass.h"

類建構函式初始化類中的所有私有指標。

BitmapClass::BitmapClass()
{
	m_vertexBuffer = 0;
	m_indexBuffer = 0;
	m_Texture = 0;
}

BitmapClass::BitmapClass(const BitmapClass& other)
{
}

BitmapClass::~BitmapClass()
{
}

bool BitmapClass::Initialize(ID3D11Device* device, int screenWidth, int screenHeight, WCHAR* textureFilename, int bitmapWidth, int bitmapHeight)
{
	bool result;

在 Initialize 函式中，螢幕大小和影像大小都被儲存。這些對於在渲染期間生成精確的頂點位置是必需的。請注意，影像的畫素不需要與使用的紋理完全相同，您可以將其設定為任何大小，並使用您想要的任何大小的紋理。

	// Store the screen size.
	m_screenWidth = screenWidth;
	m_screenHeight = screenHeight;

	// Store the size in pixels that this bitmap should be rendered at.
	m_bitmapWidth = bitmapWidth;
	m_bitmapHeight = bitmapHeight;

之前的渲染位置首先初始化為負一。這將是一個重要的變數，它將定位最後繪製此影像的位置。如果自上一幀以來影像位置沒有改變，那麼它不會修改動態頂點緩衝區，這將為我們節省一些週期。

	// Initialize the previous rendering position to negative one.
	m_previousPosX = -1;
	m_previousPosY = -1;

然後建立緩衝區，並載入此點陣圖影像的紋理。

	// Initialize the vertex and index buffers.
	result = InitializeBuffers(device);
	if(!result)
	{
		return false;
	}

	// Load the texture for this model.
	result = LoadTexture(device, textureFilename);
	if(!result)
	{
		return false;
	}

	return true;
}

Shutdown 函式將釋放頂點和索引緩衝區以及用於點陣圖影像的紋理。

void BitmapClass::Shutdown()
{
	// Release the model texture.
	ReleaseTexture();

	// Shutdown the vertex and index buffers.
	ShutdownBuffers();

	return;
}

Render 將 2D 影像的緩衝區放到顯示卡上。作為輸入，它獲取在螢幕上渲染影像的位置。UpdateBuffers 函式使用位置引數呼叫。如果自上一幀以來位置已更改，則它將更新動態頂點緩衝區中頂點的位置到新位置。如果沒有，它將跳過 UpdateBuffers 函式。之後，RenderBuffers 函式將為渲染準備最終的頂點/索引。

bool BitmapClass::Render(ID3D11DeviceContext* deviceContext, int positionX, int positionY)
{
	bool result;

	// Re-build the dynamic vertex buffer for rendering to possibly a different location on the screen.
	result = UpdateBuffers(deviceContext, positionX, positionY);
	if(!result)
	{
		return false;
	}

	// Put the vertex and index buffers on the graphics pipeline to prepare them for drawing.
	RenderBuffers(deviceContext);

	return true;
}

GetIndexCount 返回 2D 影像的索引數量。這幾乎總是六個。

int BitmapClass::GetIndexCount()
{
	return m_indexCount;
}

GetTexture 函式返回指向此 2D 影像的紋理資源的指標。著色器將呼叫此函式，以便它在繪製緩衝區時可以訪問影像。

ID3D11ShaderResourceView* BitmapClass::GetTexture()
{
	return m_Texture->GetTexture();
}

InitializeBuffers 是用於構建頂點和索引緩衝區的函式，這些緩衝區將用於繪製 2D 影像。

bool BitmapClass::InitializeBuffers(ID3D11Device* device)
{
	VertexType* vertices;
	unsigned long* indices;
	D3D11_BUFFER_DESC vertexBufferDesc, indexBufferDesc;
	D3D11_SUBRESOURCE_DATA vertexData, indexData;
	HRESULT result;
	int i;

我們將頂點設定為六個，因為我們正在用兩個三角形建立一個正方形，所以需要六個點。索引將相同。

	// Set the number of vertices in the vertex array.
	m_vertexCount = 6;

	// Set the number of indices in the index array.
	m_indexCount = m_vertexCount;

	// Create the vertex array.
	vertices = new VertexType[m_vertexCount];
	if(!vertices)
	{
		return false;
	}

	// Create the index array.
	indices = new unsigned long[m_indexCount];
	if(!indices)
	{
		return false;
	}

	// Initialize vertex array to zeros at first.
	memset(vertices, 0, (sizeof(VertexType) * m_vertexCount));

	// Load the index array with data.
	for(i=0; i<m_indexCount; i++)
	{
		indices[i] = i;
	}

以下是與 ModelClass 相比的重大變化。我們現在正在建立一個動態頂點緩衝區，以便我們可以在需要時在每一幀內修改頂點緩衝區內部的資料。為了使其動態，我們在描述中將 Usage 設定為 D3D11_USAGE_DYNAMIC，並將 CPUAccessFlags 設定為 D3D11_CPU_ACCESS_WRITE。

	// Set up the description of the static vertex buffer.
	vertexBufferDesc.Usage = D3D11_USAGE_DYNAMIC;
	vertexBufferDesc.ByteWidth = sizeof(VertexType) * m_vertexCount;
	vertexBufferDesc.BindFlags = D3D11_BIND_VERTEX_BUFFER;
	vertexBufferDesc.CPUAccessFlags = D3D11_CPU_ACCESS_WRITE;
	vertexBufferDesc.MiscFlags = 0;
	vertexBufferDesc.StructureByteStride = 0;

	// Give the subresource structure a pointer to the vertex data.
	vertexData.pSysMem = vertices;
	vertexData.SysMemPitch = 0;
	vertexData.SysMemSlicePitch = 0;

	// Now create the vertex buffer.
	result = device->CreateBuffer(&vertexBufferDesc, &vertexData, &m_vertexBuffer);
	if(FAILED(result))
	{
		return false;
	}

我們不需要使索引緩衝區動態，因為即使頂點的座標可能發生變化，六個索引也始終指向相同的六個頂點。

	// Set up the description of the static index buffer.
	indexBufferDesc.Usage = D3D11_USAGE_DEFAULT;
	indexBufferDesc.ByteWidth = sizeof(unsigned long) * m_indexCount;
	indexBufferDesc.BindFlags = D3D11_BIND_INDEX_BUFFER;
	indexBufferDesc.CPUAccessFlags = 0;
	indexBufferDesc.MiscFlags = 0;
	indexBufferDesc.StructureByteStride = 0;

	// Give the subresource structure a pointer to the index data.
	indexData.pSysMem = indices;
	indexData.SysMemPitch = 0;
	indexData.SysMemSlicePitch = 0;

	// Create the index buffer.
	result = device->CreateBuffer(&indexBufferDesc, &indexData, &m_indexBuffer);
	if(FAILED(result))
	{
		return false;
	}

	// Release the arrays now that the vertex and index buffers have been created and loaded.
	delete [] vertices;
	vertices = 0;

	delete [] indices;
	indices = 0;

	return true;
}

ShutdownBuffers 釋放頂點和索引緩衝區。

void BitmapClass::ShutdownBuffers()
{
	// Release the index buffer.
	if(m_indexBuffer)
	{
		m_indexBuffer->Release();
		m_indexBuffer = 0;
	}

	// Release the vertex buffer.
	if(m_vertexBuffer)
	{
		m_vertexBuffer->Release();
		m_vertexBuffer = 0;
	}

	return;
}

UpdateBuffers 函式在每一幀中呼叫，以更新動態頂點緩衝區的內容，以便根據需要重新定位螢幕上的 2D 點陣圖影像。

bool BitmapClass::UpdateBuffers(ID3D11DeviceContext* deviceContext, int positionX, int positionY)
{
	float left, right, top, bottom;
	VertexType* vertices;
	D3D11_MAPPED_SUBRESOURCE mappedResource;
	VertexType* verticesPtr;
	HRESULT result;

我們檢查渲染此影像的位置是否已更改。如果它沒有改變，那麼我們只需退出，因為頂點緩衝區不需要為這一幀進行任何更改。此檢查可以為我們節省很多處理時間。

	// If the position we are rendering this bitmap to has not changed then don't update the vertex buffer since it
	// currently has the correct parameters.
	if((positionX == m_previousPosX) && (positionY == m_previousPosY))
	{
		return true;
	}

如果渲染此影像的位置已更改，則我們記錄新位置，以便下次呼叫此函式時可以使用。

	// If it has changed then update the position it is being rendered to.
	m_previousPosX = positionX;
	m_previousPosY = positionY;

需要計算影像的四條邊。請參閱教程頂部的圖表以瞭解完整說明。

	// Calculate the screen coordinates of the left side of the bitmap.
	left = (float)((m_screenWidth / 2) * -1) + (float)positionX;

	// Calculate the screen coordinates of the right side of the bitmap.
	right = left + (float)m_bitmapWidth;

	// Calculate the screen coordinates of the top of the bitmap.
	top = (float)(m_screenHeight / 2) - (float)positionY;

	// Calculate the screen coordinates of the bottom of the bitmap.
	bottom = top - (float)m_bitmapHeight;

現在座標已計算完畢，建立一個臨時頂點陣列，並用新的六個頂點填充它。

	// Create the vertex array.
	vertices = new VertexType[m_vertexCount];
	if(!vertices)
	{
		return false;
	}

	// Load the vertex array with data.
	// First triangle.
	vertices[0].position = D3DXVECTOR3(left, top, 0.0f);  // Top left.
	vertices[0].texture = D3DXVECTOR2(0.0f, 0.0f);

	vertices[1].position = D3DXVECTOR3(right, bottom, 0.0f);  // Bottom right.
	vertices[1].texture = D3DXVECTOR2(1.0f, 1.0f);

	vertices[2].position = D3DXVECTOR3(left, bottom, 0.0f);  // Bottom left.
	vertices[2].texture = D3DXVECTOR2(0.0f, 1.0f);

	// Second triangle.
	vertices[3].position = D3DXVECTOR3(left, top, 0.0f);  // Top left.
	vertices[3].texture = D3DXVECTOR2(0.0f, 0.0f);

	vertices[4].position = D3DXVECTOR3(right, top, 0.0f);  // Top right.
	vertices[4].texture = D3DXVECTOR2(1.0f, 0.0f);

	vertices[5].position = D3DXVECTOR3(right, bottom, 0.0f);  // Bottom right.
	vertices[5].texture = D3DXVECTOR2(1.0f, 1.0f);

現在使用 Map 和 memcpy 函式將頂點陣列的內容複製到頂點緩衝區中。

	// Lock the vertex buffer so it can be written to.
	result = deviceContext->Map(m_vertexBuffer, 0, D3D11_MAP_WRITE_DISCARD, 0, &mappedResource);
	if(FAILED(result))
	{
		return false;
	}

	// Get a pointer to the data in the vertex buffer.
	verticesPtr = (VertexType*)mappedResource.pData;

	// Copy the data into the vertex buffer.
	memcpy(verticesPtr, (void*)vertices, (sizeof(VertexType) * m_vertexCount));

	// Unlock the vertex buffer.
	deviceContext->Unmap(m_vertexBuffer, 0);

	// Release the vertex array as it is no longer needed.
	delete [] vertices;
	vertices = 0;

	return true;
}

RenderBuffers 函式設定 GPU 上的頂點和索引緩衝區，以便著色器進行繪製。

void BitmapClass::RenderBuffers(ID3D11DeviceContext* deviceContext)
{
	unsigned int stride;
	unsigned int offset;

	// Set vertex buffer stride and offset.
	stride = sizeof(VertexType); 
	offset = 0;
    
	// Set the vertex buffer to active in the input assembler so it can be rendered.
	deviceContext->IASetVertexBuffers(0, 1, &m_vertexBuffer, &stride, &offset);

	// Set the index buffer to active in the input assembler so it can be rendered.
	deviceContext->IASetIndexBuffer(m_indexBuffer, DXGI_FORMAT_R32_UINT, 0);

	// Set the type of primitive that should be rendered from this vertex buffer, in this case triangles.
	deviceContext->IASetPrimitiveTopology(D3D11_PRIMITIVE_TOPOLOGY_TRIANGLELIST);

	return;
}

以下函式載入用於繪製 2D 影像的紋理。

bool BitmapClass::LoadTexture(ID3D11Device* device, WCHAR* filename)
{
	bool result;

	// Create the texture object.
	m_Texture = new TextureClass;
	if(!m_Texture)
	{
		return false;
	}

	// Initialize the texture object.
	result = m_Texture->Initialize(device, filename);
	if(!result)
	{
		return false;
	}

	return true;
}

此 ReleaseTexture 函式釋放已載入的紋理。

void BitmapClass::ReleaseTexture()
{
	// Release the texture object.
	if(m_Texture)
	{
		m_Texture->Shutdown();
		delete m_Texture;
		m_Texture = 0;
	}

	return;
}

D3dclass.h

[編輯 | 編輯原始碼]

D3DClass 已修改為處理啟用和停用 Z 緩衝區。

////////////////////////////////////////////////////////////////////////////////
// Filename: d3dclass.h
////////////////////////////////////////////////////////////////////////////////
#ifndef _D3DCLASS_H_
#define _D3DCLASS_H_

/////////////
// LINKING //
/////////////
#pragma comment(lib, "dxgi.lib")
#pragma comment(lib, "d3d11.lib")
#pragma comment(lib, "d3dx11.lib")
#pragma comment(lib, "d3dx10.lib")

//////////////
// INCLUDES //
//////////////
#include <dxgi.h>
#include <d3dcommon.h>
#include <d3d11.h>
#include <d3dx10math.h>

////////////////////////////////////////////////////////////////////////////////
// Class name: D3DClass
////////////////////////////////////////////////////////////////////////////////
class D3DClass
{
public:
	D3DClass();
	D3DClass(const D3DClass&);
	~D3DClass();

	bool Initialize(int, int, bool, HWND, bool, float, float);
	void Shutdown();
	
	void BeginScene(float, float, float, float);
	void EndScene();

	ID3D11Device* GetDevice();
	ID3D11DeviceContext* GetDeviceContext();

	void GetProjectionMatrix(D3DXMATRIX&);
	void GetWorldMatrix(D3DXMATRIX&);
	void GetOrthoMatrix(D3DXMATRIX&);

	void GetVideoCardInfo(char*, int&);

我們現在在 D3DClass 中新增了兩個函式，用於在渲染 2D 影像時開啟和關閉 Z 緩衝區。

	void TurnZBufferOn();
	void TurnZBufferOff();
 
private:
	bool m_vsync_enabled;
	int m_videoCardMemory;
	char m_videoCardDescription[128];
	IDXGISwapChain* m_swapChain;
	ID3D11Device* m_device;
	ID3D11DeviceContext* m_deviceContext;
	ID3D11RenderTargetView* m_renderTargetView;
	ID3D11Texture2D* m_depthStencilBuffer;
	ID3D11DepthStencilState* m_depthStencilState;
	ID3D11DepthStencilView* m_depthStencilView;
	ID3D11RasterizerState* m_rasterState;
	D3DXMATRIX m_projectionMatrix;
	D3DXMATRIX m_worldMatrix;
	D3DXMATRIX m_orthoMatrix;

還有一種用於 2D 繪製的深度模板狀態。

	ID3D11DepthStencilState* m_depthDisabledStencilState;
 
};

#endif

D3dclass.cpp

[編輯 | 編輯原始碼]

我們將只介紹自紋理教程以來在此類中更改的功能。

////////////////////////////////////////////////////////////////////////////////
// Filename: d3dclass.cpp
////////////////////////////////////////////////////////////////////////////////
#include "d3dclass.h"

D3DClass::D3DClass()
{
	m_swapChain = 0;
	m_device = 0;
	m_deviceContext = 0;
	m_renderTargetView = 0;
	m_depthStencilBuffer = 0;
	m_depthStencilState = 0;
	m_depthStencilView = 0;
	m_rasterState = 0;

在類建構函式中將新的深度模板狀態初始化為 null。

	m_depthDisabledStencilState = 0;
 
}

D3DClass::D3DClass(const D3DClass& other)
{
}

D3DClass::~D3DClass()
{
}

bool D3DClass::Initialize(int screenWidth, int screenHeight, bool vsync, HWND hwnd, bool fullscreen, float screenDepth, float screenNear)
{
	HRESULT result;
	IDXGIFactory* factory;
	IDXGIAdapter* adapter;
	IDXGIOutput* adapterOutput;
	unsigned int numModes, i, numerator, denominator, stringLength;
	DXGI_MODE_DESC* displayModeList;
	DXGI_ADAPTER_DESC adapterDesc;
	int error;
	DXGI_SWAP_CHAIN_DESC swapChainDesc;
	D3D_FEATURE_LEVEL featureLevel;
	ID3D11Texture2D* backBufferPtr;
	D3D11_TEXTURE2D_DESC depthBufferDesc;
	D3D11_DEPTH_STENCIL_DESC depthStencilDesc;
	D3D11_DEPTH_STENCIL_VIEW_DESC depthStencilViewDesc;
	D3D11_RASTERIZER_DESC rasterDesc;
	D3D11_VIEWPORT viewport;
	float fieldOfView, screenAspect;

我們有一個新的深度模板描述變數用於設定新的深度模板。

	D3D11_DEPTH_STENCIL_DESC depthDisabledStencilDesc;
 
	// Store the vsync setting.
	m_vsync_enabled = vsync;

	// Create a DirectX graphics interface factory.
	result = CreateDXGIFactory(__uuidof(IDXGIFactory), (void**)&factory);
	if(FAILED(result))
	{
		return false;
	}

	// Use the factory to create an adapter for the primary graphics interface (video card).
	result = factory->EnumAdapters(0, &adapter);
	if(FAILED(result))
	{
		return false;
	}

	// Enumerate the primary adapter output (monitor).
	result = adapter->EnumOutputs(0, &adapterOutput);
	if(FAILED(result))
	{
		return false;
	}

	// Get the number of modes that fit the DXGI_FORMAT_R8G8B8A8_UNORM display format for the adapter output (monitor).
	result = adapterOutput->GetDisplayModeList(DXGI_FORMAT_R8G8B8A8_UNORM, DXGI_ENUM_MODES_INTERLACED, &numModes, NULL);
	if(FAILED(result))
	{
		return false;
	}

	// Create a list to hold all the possible display modes for this monitor/video card combination.
	displayModeList = new DXGI_MODE_DESC[numModes];
	if(!displayModeList)
	{
		return false;
	}

	// Now fill the display mode list structures.
	result = adapterOutput->GetDisplayModeList(DXGI_FORMAT_R8G8B8A8_UNORM, DXGI_ENUM_MODES_INTERLACED, &numModes, displayModeList);
	if(FAILED(result))
	{
		return false;
	}

	// Now go through all the display modes and find the one that matches the screen width and height.
	// When a match is found store the numerator and denominator of the refresh rate for that monitor.
	for(i=0; i<numModes; i++)
	{
		if(displayModeList[i].Width == (unsigned int)screenWidth)
		{
			if(displayModeList[i].Height == (unsigned int)screenHeight)
			{
				numerator = displayModeList[i].RefreshRate.Numerator;
				denominator = displayModeList[i].RefreshRate.Denominator;
			}
		}
	}

	// Get the adapter (video card) description.
	result = adapter->GetDesc(&adapterDesc);
	if(FAILED(result))
	{
		return false;
	}

	// Store the dedicated video card memory in megabytes.
	m_videoCardMemory = (int)(adapterDesc.DedicatedVideoMemory / 1024 / 1024);

	// Convert the name of the video card to a character array and store it.
	error = wcstombs_s(&stringLength, m_videoCardDescription, 128, adapterDesc.Description, 128);
	if(error != 0)
	{
		return false;
	}

	// Release the display mode list.
	delete [] displayModeList;
	displayModeList = 0;

	// Release the adapter output.
	adapterOutput->Release();
	adapterOutput = 0;

	// Release the adapter.
	adapter->Release();
	adapter = 0;

	// Release the factory.
	factory->Release();
	factory = 0;

	// Initialize the swap chain description.
	ZeroMemory(&swapChainDesc, sizeof(swapChainDesc));

	// Set to a single back buffer.
	swapChainDesc.BufferCount = 1;

	// Set the width and height of the back buffer.
	swapChainDesc.BufferDesc.Width = screenWidth;
	swapChainDesc.BufferDesc.Height = screenHeight;

	// Set regular 32-bit surface for the back buffer.
	swapChainDesc.BufferDesc.Format = DXGI_FORMAT_R8G8B8A8_UNORM;

	// Set the refresh rate of the back buffer.
	if(m_vsync_enabled)
	{
		swapChainDesc.BufferDesc.RefreshRate.Numerator = numerator;
		swapChainDesc.BufferDesc.RefreshRate.Denominator = denominator;
	}
	else
	{
		swapChainDesc.BufferDesc.RefreshRate.Numerator = 0;
		swapChainDesc.BufferDesc.RefreshRate.Denominator = 1;
	}

	// Set the usage of the back buffer.
	swapChainDesc.BufferUsage = DXGI_USAGE_RENDER_TARGET_OUTPUT;

	// Set the handle for the window to render to.
	swapChainDesc.OutputWindow = hwnd;

	// Turn multisampling off.
	swapChainDesc.SampleDesc.Count = 1;
	swapChainDesc.SampleDesc.Quality = 0;

	// Set to full screen or windowed mode.
	if(fullscreen)
	{
		swapChainDesc.Windowed = false;
	}
	else
	{
		swapChainDesc.Windowed = true;
	}

	// Set the scan line ordering and scaling to unspecified.
	swapChainDesc.BufferDesc.ScanlineOrdering = DXGI_MODE_SCANLINE_ORDER_UNSPECIFIED;
	swapChainDesc.BufferDesc.Scaling = DXGI_MODE_SCALING_UNSPECIFIED;

	// Discard the back buffer contents after presenting.
	swapChainDesc.SwapEffect = DXGI_SWAP_EFFECT_DISCARD;

	// Don't set the advanced flags.
	swapChainDesc.Flags = 0;

	// Set the feature level to DirectX 11.
	featureLevel = D3D_FEATURE_LEVEL_11_0;

	// Create the swap chain, Direct3D device, and Direct3D device context.
	result = D3D11CreateDeviceAndSwapChain(NULL, D3D_DRIVER_TYPE_HARDWARE, NULL, 0, &featureLevel, 1, D3D11_SDK_VERSION, &swapChainDesc, &m_swapChain, 
					       &m_device, NULL, &m_deviceContext);
	if(FAILED(result))
	{
		return false;
	}

	// Get the pointer to the back buffer.
	result = m_swapChain->GetBuffer(0, __uuidof(ID3D11Texture2D), (LPVOID*)&backBufferPtr);
	if(FAILED(result))
	{
		return false;
	}

	// Create the render target view with the back buffer pointer.
	result = m_device->CreateRenderTargetView(backBufferPtr, NULL, &m_renderTargetView);
	if(FAILED(result))
	{
		return false;
	}

	// Release pointer to the back buffer as we no longer need it.
	backBufferPtr->Release();
	backBufferPtr = 0;

	// Initialize the description of the depth buffer.
	ZeroMemory(&depthBufferDesc, sizeof(depthBufferDesc));

	// Set up the description of the depth buffer.
	depthBufferDesc.Width = screenWidth;
	depthBufferDesc.Height = screenHeight;
	depthBufferDesc.MipLevels = 1;
	depthBufferDesc.ArraySize = 1;
	depthBufferDesc.Format = DXGI_FORMAT_D24_UNORM_S8_UINT;
	depthBufferDesc.SampleDesc.Count = 1;
	depthBufferDesc.SampleDesc.Quality = 0;
	depthBufferDesc.Usage = D3D11_USAGE_DEFAULT;
	depthBufferDesc.BindFlags = D3D11_BIND_DEPTH_STENCIL;
	depthBufferDesc.CPUAccessFlags = 0;
	depthBufferDesc.MiscFlags = 0;

	// Create the texture for the depth buffer using the filled out description.
	result = m_device->CreateTexture2D(&depthBufferDesc, NULL, &m_depthStencilBuffer);
	if(FAILED(result))
	{
		return false;
	}

	// Initialize the description of the stencil state.
	ZeroMemory(&depthStencilDesc, sizeof(depthStencilDesc));

	// Set up the description of the stencil state.
	depthStencilDesc.DepthEnable = true;
	depthStencilDesc.DepthWriteMask = D3D11_DEPTH_WRITE_MASK_ALL;
	depthStencilDesc.DepthFunc = D3D11_COMPARISON_LESS;

	depthStencilDesc.StencilEnable = true;
	depthStencilDesc.StencilReadMask = 0xFF;
	depthStencilDesc.StencilWriteMask = 0xFF;

	// Stencil operations if pixel is front-facing.
	depthStencilDesc.FrontFace.StencilFailOp = D3D11_STENCIL_OP_KEEP;
	depthStencilDesc.FrontFace.StencilDepthFailOp = D3D11_STENCIL_OP_INCR;
	depthStencilDesc.FrontFace.StencilPassOp = D3D11_STENCIL_OP_KEEP;
	depthStencilDesc.FrontFace.StencilFunc = D3D11_COMPARISON_ALWAYS;

	// Stencil operations if pixel is back-facing.
	depthStencilDesc.BackFace.StencilFailOp = D3D11_STENCIL_OP_KEEP;
	depthStencilDesc.BackFace.StencilDepthFailOp = D3D11_STENCIL_OP_DECR;
	depthStencilDesc.BackFace.StencilPassOp = D3D11_STENCIL_OP_KEEP;
	depthStencilDesc.BackFace.StencilFunc = D3D11_COMPARISON_ALWAYS;

	// Create the depth stencil state.
	result = m_device->CreateDepthStencilState(&depthStencilDesc, &m_depthStencilState);
	if(FAILED(result))
	{
		return false;
	}

	// Set the depth stencil state.
	m_deviceContext->OMSetDepthStencilState(m_depthStencilState, 1);

	// Initialize the depth stencil view.
	ZeroMemory(&depthStencilViewDesc, sizeof(depthStencilViewDesc));

	// Set up the depth stencil view description.
	depthStencilViewDesc.Format = DXGI_FORMAT_D24_UNORM_S8_UINT;
	depthStencilViewDesc.ViewDimension = D3D11_DSV_DIMENSION_TEXTURE2D;
	depthStencilViewDesc.Texture2D.MipSlice = 0;

	// Create the depth stencil view.
	result = m_device->CreateDepthStencilView(m_depthStencilBuffer, &depthStencilViewDesc, &m_depthStencilView);
	if(FAILED(result))
	{
		return false;
	}

	// Bind the render target view and depth stencil buffer to the output render pipeline.
	m_deviceContext->OMSetRenderTargets(1, &m_renderTargetView, m_depthStencilView);

	// Setup the raster description which will determine how and what polygons will be drawn.
	rasterDesc.AntialiasedLineEnable = false;
	rasterDesc.CullMode = D3D11_CULL_BACK;
	rasterDesc.DepthBias = 0;
	rasterDesc.DepthBiasClamp = 0.0f;
	rasterDesc.DepthClipEnable = true;
	rasterDesc.FillMode = D3D11_FILL_SOLID;
	rasterDesc.FrontCounterClockwise = false;
	rasterDesc.MultisampleEnable = false;
	rasterDesc.ScissorEnable = false;
	rasterDesc.SlopeScaledDepthBias = 0.0f;

	// Create the rasterizer state from the description we just filled out.
	result = m_device->CreateRasterizerState(&rasterDesc, &m_rasterState);
	if(FAILED(result))
	{
		return false;
	}

	// Now set the rasterizer state.
	m_deviceContext->RSSetState(m_rasterState);
	
	// Setup the viewport for rendering.
	viewport.Width = (float)screenWidth;
	viewport.Height = (float)screenHeight;
	viewport.MinDepth = 0.0f;
	viewport.MaxDepth = 1.0f;
	viewport.TopLeftX = 0.0f;
	viewport.TopLeftY = 0.0f;

	// Create the viewport.
	m_deviceContext->RSSetViewports(1, &viewport);

	// Setup the projection matrix.
	fieldOfView = (float)D3DX_PI / 4.0f;
	screenAspect = (float)screenWidth / (float)screenHeight;

	// Create the projection matrix for 3D rendering.
	D3DXMatrixPerspectiveFovLH(&m_projectionMatrix, fieldOfView, screenAspect, screenNear, screenDepth);

	// Initialize the world matrix to the identity matrix.
	D3DXMatrixIdentity(&m_worldMatrix);

	// Create an orthographic projection matrix for 2D rendering.
	D3DXMatrixOrthoLH(&m_orthoMatrix, (float)screenWidth, (float)screenHeight, screenNear, screenDepth);

在這裡我們設定深度模板的描述。注意，這個新的深度模板與舊的深度模板唯一的區別在於，這裡將 DepthEnable 設定為 false 以進行 2D 繪製。

	// Clear the second depth stencil state before setting the parameters.
	ZeroMemory(&depthDisabledStencilDesc, sizeof(depthDisabledStencilDesc));

	// Now create a second depth stencil state which turns off the Z buffer for 2D rendering.  The only difference is 
	// that DepthEnable is set to false, all other parameters are the same as the other depth stencil state.
	depthDisabledStencilDesc.DepthEnable = false;
	depthDisabledStencilDesc.DepthWriteMask = D3D11_DEPTH_WRITE_MASK_ALL;
	depthDisabledStencilDesc.DepthFunc = D3D11_COMPARISON_LESS;
	depthDisabledStencilDesc.StencilEnable = true;
	depthDisabledStencilDesc.StencilReadMask = 0xFF;
	depthDisabledStencilDesc.StencilWriteMask = 0xFF;
	depthDisabledStencilDesc.FrontFace.StencilFailOp = D3D11_STENCIL_OP_KEEP;
	depthDisabledStencilDesc.FrontFace.StencilDepthFailOp = D3D11_STENCIL_OP_INCR;
	depthDisabledStencilDesc.FrontFace.StencilPassOp = D3D11_STENCIL_OP_KEEP;
	depthDisabledStencilDesc.FrontFace.StencilFunc = D3D11_COMPARISON_ALWAYS;
	depthDisabledStencilDesc.BackFace.StencilFailOp = D3D11_STENCIL_OP_KEEP;
	depthDisabledStencilDesc.BackFace.StencilDepthFailOp = D3D11_STENCIL_OP_DECR;
	depthDisabledStencilDesc.BackFace.StencilPassOp = D3D11_STENCIL_OP_KEEP;
	depthDisabledStencilDesc.BackFace.StencilFunc = D3D11_COMPARISON_ALWAYS;

現在建立新的深度模板。

	// Create the state using the device.
	result = m_device->CreateDepthStencilState(&depthDisabledStencilDesc, &m_depthDisabledStencilState);
	if(FAILED(result))
	{
		return false;
	}
 
	return true;
}

void D3DClass::Shutdown()
{
	// Before shutting down set to windowed mode or when you release the swap chain it will throw an exception.
	if(m_swapChain)
	{
		m_swapChain->SetFullscreenState(false, NULL);
	}

這裡我們在 Shutdown 函式中釋放新的深度模板。

	if(m_depthDisabledStencilState)
	{
		m_depthDisabledStencilState->Release();
		m_depthDisabledStencilState = 0;
	}
 
	if(m_rasterState)
	{
		m_rasterState->Release();
		m_rasterState = 0;
	}

	if(m_depthStencilView)
	{
		m_depthStencilView->Release();
		m_depthStencilView = 0;
	}

	if(m_depthStencilState)
	{
		m_depthStencilState->Release();
		m_depthStencilState = 0;
	}

	if(m_depthStencilBuffer)
	{
		m_depthStencilBuffer->Release();
		m_depthStencilBuffer = 0;
	}

	if(m_renderTargetView)
	{
		m_renderTargetView->Release();
		m_renderTargetView = 0;
	}

	if(m_deviceContext)
	{
		m_deviceContext->Release();
		m_deviceContext = 0;
	}

	if(m_device)
	{
		m_device->Release();
		m_device = 0;
	}

	if(m_swapChain)
	{
		m_swapChain->Release();
		m_swapChain = 0;
	}

	return;
}

void D3DClass::BeginScene(float red, float green, float blue, float alpha)
{
	float color[4];

	// Setup the color to clear the buffer to.
	color[0] = red;
	color[1] = green;
	color[2] = blue;
	color[3] = alpha;

	// Clear the back buffer.
	m_deviceContext->ClearRenderTargetView(m_renderTargetView, color);
    
	// Clear the depth buffer.
	m_deviceContext->ClearDepthStencilView(m_depthStencilView, D3D11_CLEAR_DEPTH, 1.0f, 0);

	return;
}

void D3DClass::EndScene()
{
	// Present the back buffer to the screen since rendering is complete.
	if(m_vsync_enabled)
	{
		// Lock to screen refresh rate.
		m_swapChain->Present(1, 0);
	}
	else
	{
		// Present as fast as possible.
		m_swapChain->Present(0, 0);
	}

	return;
}

ID3D11Device* D3DClass::GetDevice()
{
	return m_device;
}

ID3D11DeviceContext* D3DClass::GetDeviceContext()
{
	return m_deviceContext;
}

void D3DClass::GetProjectionMatrix(D3DXMATRIX& projectionMatrix)
{
	projectionMatrix = m_projectionMatrix;
	return;
}

void D3DClass::GetWorldMatrix(D3DXMATRIX& worldMatrix)
{
	worldMatrix = m_worldMatrix;
	return;
}

void D3DClass::GetOrthoMatrix(D3DXMATRIX& orthoMatrix)
{
	orthoMatrix = m_orthoMatrix;
	return;
}

void D3DClass::GetVideoCardInfo(char* cardName, int& memory)
{
	strcpy_s(cardName, 128, m_videoCardDescription);
	memory = m_videoCardMemory;
	return;
}

這些是啟用和停用 Z 緩衝區的新函式。要開啟 Z 緩衝區，我們設定原始的深度模板。要關閉 Z 緩衝區，我們設定新的深度模板，該模板將 depthEnable 設定為 false。通常，使用這些函式的最佳方法是先進行所有 3D 渲染，然後關閉 Z 緩衝區並進行 2D 渲染，然後再次開啟 Z 緩衝區。

void D3DClass::TurnZBufferOn()
{
	m_deviceContext->OMSetDepthStencilState(m_depthStencilState, 1);
	return;
}

void D3DClass::TurnZBufferOff()
{
	m_deviceContext->OMSetDepthStencilState(m_depthDisabledStencilState, 1);
	return;
}

Graphicsclass.h

[編輯 | 編輯原始碼]
////////////////////////////////////////////////////////////////////////////////
// Filename: graphicsclass.h
////////////////////////////////////////////////////////////////////////////////
#ifndef _GRAPHICSCLASS_H_
#define _GRAPHICSCLASS_H_

///////////////////////
// MY CLASS INCLUDES //
///////////////////////
#include "d3dclass.h"
#include "cameraclass.h"
#include "textureshaderclass.h"

這裡我們包含新的 BitmapClass 標頭檔案。

#include "bitmapclass.h"
 
/////////////
// GLOBALS //
/////////////
const bool FULL_SCREEN = true;
const bool VSYNC_ENABLED = true;
const float SCREEN_DEPTH = 1000.0f;
const float SCREEN_NEAR = 0.1f;

////////////////////////////////////////////////////////////////////////////////
// Class name: GraphicsClass
////////////////////////////////////////////////////////////////////////////////
class GraphicsClass
{
public:
	GraphicsClass();
	GraphicsClass(const GraphicsClass&);
	~GraphicsClass();

	bool Initialize(int, int, HWND);
	void Shutdown();
	bool Frame();

private:
	bool Render(float);

private:
	D3DClass* m_D3D;
	CameraClass* m_Camera;
	TextureShaderClass* m_TextureShader;

我們在這裡建立一個新的私有 BitmapClass 物件。

	BitmapClass* m_Bitmap;
 
};

#endif

Graphicsclass.cpp

[編輯 | 編輯原始碼]
////////////////////////////////////////////////////////////////////////////////
// Filename: graphicsclass.cpp
////////////////////////////////////////////////////////////////////////////////
#include "graphicsclass.h"

GraphicsClass::GraphicsClass()
{
	m_D3D = 0;
	m_Camera = 0;
	m_TextureShader = 0;

我們在類建構函式中將新的點陣圖物件初始化為 null。

	m_Bitmap = 0;
 
}

GraphicsClass::GraphicsClass(const GraphicsClass& other)
{
}

GraphicsClass::~GraphicsClass()
{
}

bool GraphicsClass::Initialize(int screenWidth, int screenHeight, HWND hwnd)
{
	bool result;

	// Create the Direct3D object.
	m_D3D = new D3DClass;
	if(!m_D3D)
	{
		return false;
	}

	// Initialize the Direct3D object.
	result = m_D3D->Initialize(screenWidth, screenHeight, VSYNC_ENABLED, hwnd, FULL_SCREEN, SCREEN_DEPTH, SCREEN_NEAR);
	if(!result)
	{
		MessageBox(hwnd, L"Could not initialize Direct3D.", L"Error", MB_OK);
		return false;
	}

	// Create the camera object.
	m_Camera = new CameraClass;
	if(!m_Camera)
	{
		return false;
	}

	// Set the initial position of the camera.
	m_Camera->SetPosition(0.0f, 0.0f, -10.0f);
	
	// Create the texture shader object.
	m_TextureShader = new TextureShaderClass;
	if(!m_TextureShader)
	{
		return false;
	}

	// Initialize the texture shader object.
	result = m_TextureShader->Initialize(m_D3D->GetDevice(), hwnd);
	if(!result)
	{
		MessageBox(hwnd, L"Could not initialize the texture shader object.", L"Error", MB_OK);
		return false;
	}

這裡我們建立並初始化新的 BitmapClass 物件。它使用 seafloor.dds 作為紋理，我將大小設定為 256x256。您可以將此大小更改為您喜歡的任何大小，因為它不需要反映紋理的精確大小。

	// Create the bitmap object.
	m_Bitmap = new BitmapClass;
	if(!m_Bitmap)
	{
		return false;
	}

	// Initialize the bitmap object.
	result = m_Bitmap->Initialize(m_D3D->GetDevice(), screenWidth, screenHeight, L"../Engine/data/seafloor.dds", 256, 256);
	if(!result)
	{
		MessageBox(hwnd, L"Could not initialize the bitmap object.", L"Error", MB_OK);
		return false;
	}
 
	return true;
}

void GraphicsClass::Shutdown()
{

BitmapClass 物件在 Shutdown 函式中被釋放。

	// Release the bitmap object.
	if(m_Bitmap)
	{
		m_Bitmap->Shutdown();
		delete m_Bitmap;
		m_Bitmap = 0;
	}
 
	// Release the texture shader object.
	if(m_TextureShader)
	{
		m_TextureShader->Shutdown();
		delete m_TextureShader;
		m_TextureShader = 0;
	}

	// Release the camera object.
	if(m_Camera)
	{
		delete m_Camera;
		m_Camera = 0;
	}

	// Release the D3D object.
	if(m_D3D)
	{
		m_D3D->Shutdown();
		delete m_D3D;
		m_D3D = 0;
	}

	return;
}

bool GraphicsClass::Frame()
{
	bool result;
	static float rotation = 0.0f;

	// Update the rotation variable each frame.
	rotation += (float)D3DX_PI * 0.005f;
	if(rotation > 360.0f)
	{
		rotation -= 360.0f;
	}
	
	// Render the graphics scene.
	result = Render(rotation);
	if(!result)
	{
		return false;
	}

	return true;
}

bool GraphicsClass::Render(float rotation)
{
	D3DXMATRIX worldMatrix, viewMatrix, projectionMatrix, orthoMatrix;
 
	bool result;

	// Clear the buffers to begin the scene.
	m_D3D->BeginScene(0.0f, 0.0f, 0.0f, 1.0f);

	// Generate the view matrix based on the camera's position.
	m_Camera->Render();

	// Get the world, view, projection, and ortho matrices from the camera and d3d objects.
	m_Camera->GetViewMatrix(viewMatrix);
	m_D3D->GetWorldMatrix(worldMatrix);
	m_D3D->GetProjectionMatrix(projectionMatrix);

我們現在還從 D3DClass 獲取正交矩陣以進行 2D 渲染。我們將傳入此矩陣而不是投影矩陣。

	m_D3D->GetOrthoMatrix(orthoMatrix);

在進行任何 2D 渲染之前，Z 緩衝區將被關閉。

	// Turn off the Z buffer to begin all 2D rendering.
	m_D3D->TurnZBufferOff();

然後我們將點陣圖渲染到螢幕上的 100, 100 位置。您可以將其更改為要渲染的任何位置。

	// Put the bitmap vertex and index buffers on the graphics pipeline to prepare them for drawing.
	result = m_Bitmap->Render(m_D3D->GetDeviceContext(), 100, 100);
	if(!result)
	{
		return false;
	}

一旦頂點/索引緩衝區準備好，我們使用紋理著色器繪製它們。請注意，我們在渲染 2D 時傳入 orthoMatrix 而不是 projectionMatrix。另請注意，如果您的檢視矩陣正在發生變化，您將需要為 2D 渲染建立一個預設的檢視矩陣，並使用它而不是常規的檢視矩陣。在本教程中，使用常規的檢視矩陣是可以的，因為本教程中的相機是靜止的。

	// Render the bitmap with the texture shader.
	result = m_TextureShader->Render(m_D3D->GetDeviceContext(), m_Bitmap->GetIndexCount(), worldMatrix, viewMatrix, orthoMatrix, m_Bitmap->GetTexture());
	if(!result)
	{
		return false;
	}

完成所有 2D 渲染後，我們將開啟 Z 緩衝區以進行下一輪 3D 渲染。

	// Turn the Z buffer back on now that all 2D rendering has completed.
	m_D3D->TurnZBufferOn();
 
	// Present the rendered scene to the screen.
	m_D3D->EndScene();

	return true;
}

總結

[編輯 | 編輯原始碼]

有了這些新概念，我們現在可以將 2D 影像渲染到螢幕上。這為渲染使用者介面和字體系統打開了大門。

待辦事項

[編輯 | 編輯原始碼]

1. 重新編譯程式碼，並確保您在螢幕上的 100, 100 位置繪製了 2D 影像。

2. 更改螢幕上影像繪製的位置。

3. 更改 GraphicsClass 中 m_Bitmap->Initialize 函式呼叫中的影像大小。

4. 更改用於 2D 影像的紋理。

檢索自 "https://wikibook.tw/w/index.php?title=DirectX/10.0/Direct3D/2D_Rendering&oldid=3372359"
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