c++ - 使用 SpriteFont 类绘制文本时出现的问题

Question

我正在使用 SpriteFont/SpriteBatch 类将文本渲染到我的游戏中，因为坦率地说，我厌倦了使用 Direct2D 和 DirectWrite...但是每次我使用 SpriteFont 绘制文本时，我都会在屏幕上显示文本，但是它写在黑色背景上...黑色背景挡住了我游戏的整个场景..有什么办法可以去除黑色背景只保留文字吗？

下面是我对 SpriteFont 的实现..

void RenderText(int FPS)
{

std::unique_ptr<DirectX::SpriteFont> Sprite_Font(new DirectX::SpriteFont(device, L"myfile.spritefont"));

std::unique_ptr<DirectX::SpriteBatch> Sprite_Batch(new DirectX::SpriteBatch(DevContext));

Sprite_Batch->Begin();

Sprite_Font->DrawString(Sprite_Batch.get(), L"FPS: ", DirectX::XMFLOAT2(200,200));

Sprite_Batch->End();


}

在我看来，黑色背景是由于我在函数 ClearRenderTargetView() 中指定的值而绘制的。

float BackgroundColor[4] = { 0.0f, 0.0f, 0.0f, 0.0f };

DevContext->ClearRenderTargetView(RenderTarget, BackgroundColor); //This is where the black background gets drawn over my entire scene

每次我将 BackgroundColor[4] 更改为不同的值时，背景颜色也会相应地发生变化。如何从我的游戏中删除黑色背景并只包含文本？

这是我的全部代码。

#include <Windows.h>
#include <SpriteFont.h>
#include <SpriteBatch.h>
#include <d3dcompiler.h>
#include <SimpleMath.h>

#pragma comment (lib, "dinput8.lib")
#pragma comment (lib, "D3D11.lib")
#pragma comment (lib, "d3dcompiler.lib")

LRESULT CALLBACK WindowProcedure(HWND, unsigned int, WPARAM, LPARAM);
void Create_Window(HINSTANCE&);
void Initialize_Direct3D11(HINSTANCE);
void Initialize_Rendering_Pipeline();
void Initialize_Sprites();
void Render_Frame();
void Render_Text();
void Create_Vertex_Buffer_for_triangle();

HWND MainWindow;
IDXGISwapChain * SwapChain;
ID3D11Device * device;
ID3D11DeviceContext * DevContext;
ID3D11RenderTargetView * RenderTarget;
ID3D11Buffer * VertexBuffer;
ID3D10Blob * VertexShader;
ID3D10Blob * PixelShader;
ID3D11VertexShader * VS;
ID3D11PixelShader * PS;
ID3D11InputLayout * inputLayout;
std::unique_ptr<DirectX::SpriteFont> Sprite_Font;
std::unique_ptr<DirectX::SpriteBatch> Sprite_Batch;
DirectX::SimpleMath::Vector2 m_fontPos;
const wchar_t* output = L"Hello World";


struct Vertex_Buffer
{
 float Positions[3];


Vertex_Buffer(float x, float y, float z)
{
    Positions[0] = x;
    Positions[1] = y;
    Positions[2] = z;
};

};


int WINAPI WinMain(HINSTANCE CurrentInstance, HINSTANCE PrevInstance, LPSTR ignore, int WindowShow)
{
MSG message;
HRESULT status;

Create_Window(CurrentInstance);
Initialize_Direct3D11(CurrentInstance);
Initialize_Sprites();
Initialize_Rendering_Pipeline();
Create_Vertex_Buffer_for_triangle();


while (true)
{
    if (PeekMessage(&message, MainWindow, 0, 0, PM_REMOVE))
    {
        TranslateMessage(&message);
        DispatchMessage(&message);

    }

    else
    {   
        Render_Frame();
        Render_Text();
        SwapChain->Present(0, 0);
    }

}

}

void Initialize_Sprites()
{
Sprite_Font.reset(new DirectX::SpriteFont(device, L"myfile.spritefont"));
Sprite_Batch.reset(new DirectX::SpriteBatch(DevContext));

m_fontPos.x = 200;
m_fontPos.y = 200;

}

void Create_Window(HINSTANCE &CurrentInstance)
{
WNDCLASSEX windowclass;                                 


ZeroMemory(&windowclass, sizeof(WNDCLASSEX));
windowclass.cbSize = sizeof(WNDCLASSEX);                
windowclass.lpszClassName = L"Window Class";        
windowclass.hInstance = CurrentInstance;                
windowclass.lpfnWndProc = WindowProcedure;              
windowclass.hIcon = LoadIcon(NULL, IDI_WINLOGO);        
windowclass.hCursor = LoadCursor(NULL, IDC_ARROW);      


RegisterClassEx(&windowclass);


MainWindow = CreateWindowEx(
    0,                                                  
    L"Window Class",                                    
    L"The Empire of Anatoria",                          
    WS_OVERLAPPEDWINDOW,                                
    CW_USEDEFAULT,                                      
    CW_USEDEFAULT,                                      
    800,                                                
    600,                                                
    NULL,                                               
    NULL,                                               
    CurrentInstance,                                    
    NULL                                                
    );


ShowWindow(MainWindow, SW_SHOW);
}

void Render_Text()
{
DirectX::SimpleMath::Vector2 origin = Sprite_Font->MeasureString(output);

Sprite_Batch->Begin();
Sprite_Font->DrawString(Sprite_Batch.get(), output,
    m_fontPos, DirectX::Colors::White, 0.f, origin);
Sprite_Batch->End();

}

void Initialize_Direct3D11(HINSTANCE instance) 
{
DXGI_MODE_DESC BackBufferDesc;
DXGI_SWAP_CHAIN_DESC SwapChainDesc;



ZeroMemory(&BackBufferDesc, sizeof(DXGI_MODE_DESC));
BackBufferDesc.Width = 400;                         
BackBufferDesc.Height = 400;                         
BackBufferDesc.RefreshRate.Numerator = 60;          
BackBufferDesc.RefreshRate.Denominator = 1;         
BackBufferDesc.Format = DXGI_FORMAT_R8G8B8A8_UNORM; 


ZeroMemory(&SwapChainDesc, sizeof(DXGI_SWAP_CHAIN_DESC));
SwapChainDesc.BufferDesc = BackBufferDesc;      
SwapChainDesc.BufferCount = 1;                          
SwapChainDesc.BufferUsage = DXGI_USAGE_RENDER_TARGET_OUTPUT;
SwapChainDesc.SampleDesc.Count = 1;                     
SwapChainDesc.SampleDesc.Quality = 0;                   
SwapChainDesc.OutputWindow = MainWindow;            
SwapChainDesc.Windowed = TRUE;                          
SwapChainDesc.SwapEffect = DXGI_SWAP_EFFECT_DISCARD;    



D3D11CreateDeviceAndSwapChain(NULL,                      
    D3D_DRIVER_TYPE_HARDWARE,   
    NULL,                        
    NULL,                       
    NULL,                   
    NULL,                        
    D3D11_SDK_VERSION,       
    &SwapChainDesc,          
    &SwapChain,             
    &device,                    
    NULL,                       
    &DevContext             
    );



ID3D11Texture2D * BackBuffer;
SwapChain->GetBuffer(0, __uuidof(ID3D11Texture2D), (void**)&BackBuffer);
device->CreateRenderTargetView(BackBuffer, NULL, &RenderTarget);
DevContext->OMSetRenderTargets(
            1,                            
            &RenderTarget,                  
            NULL                            
            );
BackBuffer->Release();

DevContext->IASetPrimitiveTopology(D3D11_PRIMITIVE_TOPOLOGY_TRIANGLELIST);

}

void Initialize_Rendering_Pipeline()
{
D3DCompileFromFile(L"VertexShader.hlsl", 0, 0, "main", "vs_5_0", 0, 0, &VertexShader, 0);
D3DCompileFromFile(L"VertexShader.hlsl", 0, 0, "Pixel_Shader", "ps_5_0", 0, 0, &PixelShader, 0);

device->CreateVertexShader(VertexShader->GetBufferPointer(), VertexShader->GetBufferSize(), NULL, &VS);
device->CreatePixelShader(PixelShader->GetBufferPointer(), PixelShader->GetBufferSize(), NULL, &PS);

DevContext->VSSetShader(VS, 0, 0);
DevContext->PSSetShader(PS, 0, 0);


D3D11_VIEWPORT Raster;

ZeroMemory(&Raster, sizeof(D3D11_VIEWPORT));
Raster.MinDepth = 0.0f;
Raster.MaxDepth = 1.0f;
Raster.Width = 400;
Raster.Height = 400;
DevContext->RSSetViewports(1, &Raster);



D3D11_INPUT_ELEMENT_DESC InputLayout[1];

ZeroMemory(&InputLayout[0], sizeof(D3D11_INPUT_ELEMENT_DESC));
InputLayout[0].SemanticName = "POSITION";
InputLayout[0].Format = DXGI_FORMAT_R32G32B32_FLOAT;
InputLayout[0].InputSlot = 0;
InputLayout[0].AlignedByteOffset = 0;
InputLayout[0].InputSlotClass = D3D11_INPUT_PER_VERTEX_DATA;

device->CreateInputLayout(
    InputLayout,
    1,
    VertexShader->GetBufferPointer(),
    VertexShader->GetBufferSize(),
    &inputLayout
    );
DevContext->IASetInputLayout(inputLayout);
}

void Render_Frame()
{
float BackgroundColor[4] = {0.0f, 0.0f, 0.0f, 1.0f};

DevContext->ClearRenderTargetView(RenderTarget, BackgroundColor);

DevContext->Draw(3, 0);

}

void Create_Vertex_Buffer_for_triangle()
{
D3D11_BUFFER_DESC VertexBufferDesc;
D3D11_SUBRESOURCE_DATA VertexData;
UINT stride = sizeof(Vertex_Buffer);
UINT offset = 0;

ZeroMemory(&VertexBufferDesc, sizeof(D3D11_BUFFER_DESC));
VertexBufferDesc.Usage = D3D11_USAGE_DEFAULT;
VertexBufferDesc.BindFlags = D3D11_BIND_VERTEX_BUFFER;
VertexBufferDesc.CPUAccessFlags = 0;
VertexBufferDesc.ByteWidth = sizeof(Vertex_Buffer) * 3;


Vertex_Buffer VerticesData[] =
{
    Vertex_Buffer(0.0f, 0.5f, 0.5f),
    Vertex_Buffer(0.5f, -0.5f, 0.5f),
    Vertex_Buffer(-0.5f, -0.5f, 0.5f)
};


ZeroMemory(&VertexData, sizeof(D3D11_SUBRESOURCE_DATA));
VertexData.pSysMem = VerticesData;

device->CreateBuffer(
    &VertexBufferDesc,
    &VertexData,
    &VertexBuffer);

DevContext->IASetVertexBuffers(
    0,
    1,
    &VertexBuffer,
    &stride,
    &offset
    );

}

LRESULT CALLBACK WindowProcedure(HWND handle, unsigned int message, WPARAM ignore1, LPARAM ignore2)
{
switch (message)
{

case WM_CREATE:
    return 0;


case WM_CLOSE:
    DestroyWindow(handle);
    return 0;


default:
    return DefWindowProc(handle, message, ignore1, ignore2);
}


}

这是 VertexShader.hlsl 文件

float4 main( float4 pos : POSITION ) : SV_POSITION
{
return pos;
}

float4 Pixel_Shader() : SV_TARGET
{
return float4(1.0f, 0.0f, 0.0f, 1.0f);
}

Answer 1

首先，如果您的代码片段是准确的，您不应该在每一帧都创建SpriteFont 和SpriteBatch 实例。您只需在设备更改时创建它们。

默认情况下，SpriteFont 使用预乘 alpha 混合模式进行绘制，因此，如果您获得的是完全“背景色”图像，那么您的管道状态中存在其他问题。很可能您在 clear 和 RenderText 之间的渲染中保留了一些有效状态，这会影响您应该重置的 SpriteBatch 渲染器。

它也可能是您用于透明背景的颜色，其 alpha 设置为 0 而不是 1。尝试使用:

float BackgroundColor[4] = { 0.0f, 0.0f, 0.0f, 1.0f };

Try working through a few of the DirectX Tool Kit tutorials to make sure things are working in isolation and so you understand how the classes work, specifically Drawing text.