C++小项目：directx11图形程序（五）：shadersclass

这个类是用来创建着色器并设置输入布局的。

这个类比较特殊，它创建的着色器与Effect文件有关，effect文件是用高级着色语言（hlsl）编写的。

shadersclass.h

#pragma once
#include <d3d11.h>
#include <d3dcompiler.h>
#include <D3DX11.h>
#include <xnamath.h>

#pragma comment(lib,"d3dx11.lib")
#pragma comment(lib,"d3d11.lib")
#pragma comment(lib,"d3dcompiler.lib")
class shaderclass
{
public:
    shaderclass();
    ~shaderclass();
    bool Initialize(ID3D11Device *device, ID3D11DeviceContext* context);
    void Shutdown();
private:
    bool CompileShaderFromFile(WCHAR* szFileName, LPCSTR szEntryPoint, LPCSTR szShaderModel, ID3DBlob** ppBlobOut);
private:
    ID3DBlob* m_vsblob,*m_psblob;
    ID3D11PixelShader *m_pixelshader;
    ID3D11VertexShader *m_vertexshader;
    ID3D11InputLayout *m_layout;
public:
    void GetShaders(ID3D11VertexShader*& vs, ID3D11PixelShader*& ps);
};

这个着色器类比较简单，只创建了顶点着色器和像素着色器，还设置了一个简单的输入布局，这些工作都由Initialize()函数来做，私有函数CompileShaderFromFile()函数则是用来将effect文件编译成二进制文件的，GetShaders()则是用来获取创建好的着色器对象的。

shaderclass.cpp

#include "shaderclass.h"


shaderclass::shaderclass()
{
}


shaderclass::~shaderclass()
{
}

bool shaderclass::Initialize(ID3D11Device *device,ID3D11DeviceContext* context)
{
    HRESULT hr = S_OK;
    bool result = CompileShaderFromFile(L"shader.fx", "VS", "vs_4_0", &m_vsblob);
    if (!result)
    {
        MessageBox(NULL,
            L"The FX file cannot be compiled.  Please run this executable from the directory that contains the FX file.", L"Error", MB_OK);
        return false;
    }
    
    hr = device->CreateVertexShader(m_vsblob->GetBufferPointer(), m_vsblob->GetBufferSize(), NULL, &m_vertexshader);
    if (FAILED(hr))
    {
        return false;
    }
    
    result = CompileShaderFromFile(L"shader.fx", "PS", "ps_4_0", &m_psblob);
    if (!result)
    {
        MessageBox(NULL,
            L"The FX file cannot be compiled.  Please run this executable from the directory that contains the FX file.", L"Error", MB_OK);
        return false;
    }
    
    hr = device->CreatePixelShader(m_psblob->GetBufferPointer(), m_psblob->GetBufferSize(), NULL, &m_pixelshader);
    if (FAILED(hr))
    {
        return false;
    }    
    D3D11_INPUT_ELEMENT_DESC layout[] =
    {
        { "POSITION", 0, DXGI_FORMAT_R32G32B32_FLOAT, 0, 0, D3D11_INPUT_PER_VERTEX_DATA, 0 },
        { "TEXCOORD", 0, DXGI_FORMAT_R32G32_FLOAT, 0, 12, D3D11_INPUT_PER_VERTEX_DATA, 0 },        
    };/////////////////
    UINT numElements = ARRAYSIZE(layout);    

    hr = device->CreateInputLayout(layout, numElements, m_vsblob->GetBufferPointer(),m_vsblob->GetBufferSize(), &m_layout);    
    if (FAILED(hr))
    {
        return false;
    }
    context->IASetInputLayout(m_layout);

    return true;
}
void shaderclass::Shutdown()
{
    if (m_layout)
    {
        m_layout->Release();
    }
    if (m_pixelshader)
    {
        m_pixelshader->Release();
    }
    if (m_psblob)
    {
        m_psblob->Release();
    }
    if (m_vertexshader)
    {
        m_vertexshader->Release();
    }
    if (m_vsblob)
    {
        m_vsblob->Release();
    }
}

bool shaderclass::CompileShaderFromFile(WCHAR* szFileName, LPCSTR szEntryPoint, LPCSTR szShaderModel, ID3DBlob** ppBlobOut)
{
    HRESULT hr = S_OK;

    DWORD dwShaderFlags = D3DCOMPILE_ENABLE_STRICTNESS;
#if defined( DEBUG ) || defined( _DEBUG )
    dwShaderFlags |= D3DCOMPILE_DEBUG;
#endif

    ID3DBlob* pErrorBlob=0;
    hr = D3DX11CompileFromFile(szFileName, NULL, NULL, szEntryPoint, szShaderModel,
        dwShaderFlags, 0, NULL, ppBlobOut, &pErrorBlob, NULL);

    if (FAILED(hr))
    {
        if (pErrorBlob != NULL)
            OutputDebugStringA((char*)pErrorBlob->GetBufferPointer());
        if (pErrorBlob) pErrorBlob->Release();
        return false;
    }
    if (pErrorBlob) 
        pErrorBlob->Release();
    
    return true;
}

void shaderclass::GetShaders(ID3D11VertexShader*& vs,ID3D11PixelShader*& ps)
{
    vs = m_vertexshader;
    ps = m_pixelshader;
}

Initialize()：

• 调用CompileShaderFromFile()函数编译effect文件里的顶点处理函数，得到二进制文件，根据二进制文件创建顶点着色器，CompileShaderFromFile()函数的第一个参数“shader.fx”就是effect文件
• 编译effect文件里的像素处理函数，得到二进制文件并创建像素着色器
• 填充输入布局描述数据结构，并创建输入布局，成功后设置输入布局

CompileShaderFromFile()： 里面只是单纯的调用dx11API D3DX11CompileFromFile()函数

整个类的编写非常简单，这只是因为我很简单的创建了两个着色器。如果要创建更复杂的着色器，还要学习很多。

另附上effect文件

shader.fx

Texture2D txDiffuse : register(t0);
SamplerState samLinear : register(s0);

cbuffer ConstantBuffer : register(b0)
{
    matrix World;
    matrix View;
    matrix Projection;
}


struct VS_INPUT
{
    float4 Pos : POSITION;
    float4 Tex : TEXCOORD0;
};
struct PS_INPUT
{
    float4 Pos : SV_POSITION;
    float2 Tex : TEXCOORD0;
};
//--------------------------------------------------------------------------------------
// Vertex Shader
//--------------------------------------------------------------------------------------
PS_INPUT VS(VS_INPUT input)
{
    PS_INPUT output = (PS_INPUT)0;
    output.Pos = mul(input.Pos, World);
    output.Pos = mul(output.Pos, View);
    output.Pos = mul(output.Pos, Projection);
    output.Tex = input.Tex;

    return output;
}
//--------------------------------------------------------------------------------------
// Pixel Shader
//--------------------------------------------------------------------------------------
float4 PS(PS_INPUT input) : SV_Target
{
    return txDiffuse.Sample(samLinear, input.Tex);
}