DirectX11 Tutorial 19: 알파 매핑

원문: http://rastertek.com/dx11tut19.html

DirectX 11에서의 알파 매핑(Alpha mapping)은 두 텍스쳐를 혼합할 때 텍스쳐의 알파 레이어를 이용하여 각 픽셀이 어느 정도 혼합되어야 하는지를 계산하는 과정입니다.

이 과정을 시작하기에 앞서 아래 그림처럼 텍스쳐에 적용할 알파 레이어를 만듭니다.

각 픽셀은 두 텍스쳐를 얼마나 혼합할 것인지 지정할 수 있도록 0.0~1.0 사이의 값을 가집니다. 예를 들어 어떤 픽셀의 알파값이 0.3이라면 기본 텍스쳐 픽셀의 30%와 같이 섞을 텍스쳐 픽셀의 70%를 더할 것입니다. 이 튜토리얼에서는 아래 두 텍스쳐를 알파 맵으로 혼합할 것입니다.

그리고 그 결과는 다음과 같을 것입니다.

이 튜토리얼에서는 알파 맵을 따로 텍스쳐로 분리하여 사용할 것입니다. 이렇게 하면 같은 두 개의 이미지더라도 알파 맵을 여러 개 만들어 서로 다르게 혼합된 텍스쳐를 얻을 수 있습니다.

이 튜토리얼의 소스코드는 이전 튜토리얼에서 이어집니다.

알파 맵 정점 셰이더는 이전 라이트맵 세이더에서 이름만 바꾸었습니다.

////////////////////////////////////////////////////////////////////////////////
// Filename: alphamap.vs
////////////////////////////////////////////////////////////////////////////////


/////////////
// GLOBALS //
/////////////
cbuffer MatrixBuffer
{
    matrix worldMatrix;
    matrix viewMatrix;
    matrix projectionMatrix;
};


//////////////
// TYPEDEFS //
//////////////
struct VertexInputType
{
    float4 position : POSITION;
    float2 tex : TEXCOORD0;
};

struct PixelInputType
{
    float4 position : SV_POSITION;
    float2 tex : TEXCOORD0;
};


////////////////////////////////////////////////////////////////////////////////
// Vertex Shader
////////////////////////////////////////////////////////////////////////////////
PixelInputType AlphaMapVertexShader(VertexInputType input)
{
    PixelInputType output;
    

    // Change the position vector to be 4 units for proper matrix calculations.
    input.position.w = 1.0f;

    // Calculate the position of the vertex against the world, view, and projection matrices.
    output.position = mul(input.position, worldMatrix);
    output.position = mul(output.position, viewMatrix);
    output.position = mul(output.position, projectionMatrix);
    
    // Store the texture coordinates for the pixel shader.
    output.tex = input.tex;
    
    return output;
}

////////////////////////////////////////////////////////////////////////////////
// Filename: alphamap.ps
////////////////////////////////////////////////////////////////////////////////


/////////////
// GLOBALS //
/////////////

픽셀 셰이더의 첫번째 변화는 알파 맵 텍스쳐를 저장할 수 있도록 텍스쳐 배열의 크기를 증가시킨 것입니다.

Texture2D shaderTextures[3];
SamplerState SampleType;


//////////////
// TYPEDEFS //
//////////////
struct PixelInputType
{
    float4 position : SV_POSITION;
    float2 tex : TEXCOORD0;
};

알파 맵 픽셀 셰이더는 우선 각 텍스쳐의 픽셀과 알파 텍스쳐에서 픽셀 값을 샘플링합니다. 그리고 나서 기본 텍스쳐 픽셀에 해당 알파값을 곱합니다. 그리고 다른 텍스쳐 픽셀은 (1.0 - alpha)값을 곱합니다. 마지막으로 계산된 두 픽셀값을 더하고 0과 1사이의 숫자가 되도록 잘라내어 최종 결과를 얻어냅니다.

////////////////////////////////////////////////////////////////////////////////
// Pixel Shader
////////////////////////////////////////////////////////////////////////////////
float4 AlphaMapPixelShader(PixelInputType input) : SV_TARGET
{
    float4 color1;
    float4 color2;
    float4 alphaValue;
    float4 blendColor;


    // Get the pixel color from the first texture.
    color1 = shaderTextures[0].Sample(SampleType, input.tex);

    // Get the pixel color from the second texture.
    color2 = shaderTextures[1].Sample(SampleType, input.tex);

    // Get the alpha value from the alpha map texture.
    alphaValue = shaderTextures[2].Sample(SampleType, input.tex);
	
    // Combine the two textures based on the alpha value.
    blendColor = (alphaValue * color1) + ((1.0 - alphaValue) * color2);
    
    // Saturate the final color value.
    blendColor = saturate(blendColor);

    return blendColor;
}

AlphaMapShaderClass 클래스는 이전 튜토리얼의 LightMapShaderClass를 조금 수정한 것입니다.

////////////////////////////////////////////////////////////////////////////////
// Filename: alphamapshaderclass.h
////////////////////////////////////////////////////////////////////////////////
#ifndef _ALPHAMAPSHADERCLASS_H_
#define _ALPHAMAPSHADERCLASS_H_


//////////////
// INCLUDES //
//////////////
#include <d3d11.h>
#include <d3dx10math.h>
#include <d3dx11async.h>
#include <fstream>
using namespace std;


////////////////////////////////////////////////////////////////////////////////
// Class name: AlphaMapShaderClass
////////////////////////////////////////////////////////////////////////////////
class AlphaMapShaderClass
{
private:
	struct MatrixBufferType
	{
		D3DXMATRIX world;
		D3DXMATRIX view;
		D3DXMATRIX projection;
	};

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

	bool Initialize(ID3D11Device*, HWND);
	void Shutdown();
	bool Render(ID3D11DeviceContext*, int, D3DXMATRIX, D3DXMATRIX, D3DXMATRIX, ID3D11ShaderResourceView**);

private:
	bool InitializeShader(ID3D11Device*, HWND, WCHAR*, WCHAR*);
	void ShutdownShader();
	void OutputShaderErrorMessage(ID3D10Blob*, HWND, WCHAR*);

	bool SetShaderParameters(ID3D11DeviceContext*, D3DXMATRIX, D3DXMATRIX, D3DXMATRIX, ID3D11ShaderResourceView**);
	void RenderShader(ID3D11DeviceContext*, int);

private:
	ID3D11VertexShader* m_vertexShader;
	ID3D11PixelShader* m_pixelShader;
	ID3D11InputLayout* m_layout;
	ID3D11Buffer* m_matrixBuffer;
	ID3D11SamplerState* m_sampleState;
};

#endif

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


AlphaMapShaderClass::AlphaMapShaderClass()
{
	m_vertexShader = 0;
	m_pixelShader = 0;
	m_layout = 0;
	m_matrixBuffer = 0;
	m_sampleState = 0;
}


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


AlphaMapShaderClass::~AlphaMapShaderClass()
{
}


bool AlphaMapShaderClass::Initialize(ID3D11Device* device, HWND hwnd)
{
	bool result;

alphamap.vs와 alphamap.ps 두 셰이더 파일을 불러옵니다.

	// Initialize the vertex and pixel shaders.
	result = InitializeShader(device, hwnd, L"../Engine/alphamap.vs", L"../Engine/alphamap.ps");
	if(!result)
	{
		return false;
	}

	return true;
}


void AlphaMapShaderClass::Shutdown()
{
	// Shutdown the vertex and pixel shaders as well as the related objects.
	ShutdownShader();

	return;
}


bool AlphaMapShaderClass::Render(ID3D11DeviceContext* deviceContext, int indexCount, D3DXMATRIX worldMatrix,
				 D3DXMATRIX viewMatrix, D3DXMATRIX projectionMatrix, ID3D11ShaderResourceView** textureArray)
{
	bool result;


	// Set the shader parameters that it will use for rendering.
	result = SetShaderParameters(deviceContext, worldMatrix, viewMatrix, projectionMatrix, textureArray);
	if(!result)
	{
		return false;
	}

	// Now render the prepared buffers with the shader.
	RenderShader(deviceContext, indexCount);

	return true;
}


bool AlphaMapShaderClass::InitializeShader(ID3D11Device* device, HWND hwnd, WCHAR* vsFilename, WCHAR* psFilename)
{
	HRESULT result;
	ID3D10Blob* errorMessage;
	ID3D10Blob* vertexShaderBuffer;
	ID3D10Blob* pixelShaderBuffer;
	D3D11_INPUT_ELEMENT_DESC polygonLayout[2];
	unsigned int numElements;
	D3D11_BUFFER_DESC matrixBufferDesc;
	D3D11_SAMPLER_DESC samplerDesc;


	// Initialize the pointers this function will use to null.
	errorMessage = 0;
	vertexShaderBuffer = 0;
	pixelShaderBuffer = 0;

알파 맵 정점 셰이더를 로드합니다.

	// Compile the vertex shader code.
	result = D3DX11CompileFromFile(vsFilename, NULL, NULL, "AlphaMapVertexShader", "vs_5_0", D3D10_SHADER_ENABLE_STRICTNESS, 
				       0, NULL, &vertexShaderBuffer, &errorMessage, NULL);
	if(FAILED(result))
	{
		// If the shader failed to compile it should have writen something to the error message.
		if(errorMessage)
		{
			OutputShaderErrorMessage(errorMessage, hwnd, vsFilename);
		}
		// If there was  nothing in the error message then it simply could not find the shader file itself.
		else
		{
			MessageBox(hwnd, vsFilename, L"Missing Shader File", MB_OK);
		}

		return false;
	}

알파 맵 픽셀 셰이더를 로드합니다.

	// Compile the pixel shader code.
	result = D3DX11CompileFromFile(psFilename, NULL, NULL, "AlphaMapPixelShader", "ps_5_0", D3D10_SHADER_ENABLE_STRICTNESS, 
				       0, NULL, &pixelShaderBuffer, &errorMessage, NULL);
	if(FAILED(result))
	{
		// If the shader failed to compile it should have writen something to the error message.
		if(errorMessage)
		{
			OutputShaderErrorMessage(errorMessage, hwnd, psFilename);
		}
		// If there was  nothing in the error message then it simply could not find the file itself.
		else
		{
			MessageBox(hwnd, psFilename, L"Missing Shader File", MB_OK);
		}

		return false;
	}

	// Create the vertex shader from the buffer.
	result = device->CreateVertexShader(vertexShaderBuffer->GetBufferPointer(), vertexShaderBuffer->GetBufferSize(), NULL, 
					    &m_vertexShader);
	if(FAILED(result))
	{
		return false;
	}

	// Create the vertex shader from the buffer.
	result = device->CreatePixelShader(pixelShaderBuffer->GetBufferPointer(), pixelShaderBuffer->GetBufferSize(), NULL, 
					   &m_pixelShader);
	if(FAILED(result))
	{
		return false;
	}

	// Create the vertex input layout description.
	// This setup needs to match the VertexType stucture in the ModelClass and in the shader.
	polygonLayout[0].SemanticName = "POSITION";
	polygonLayout[0].SemanticIndex = 0;
	polygonLayout[0].Format = DXGI_FORMAT_R32G32B32_FLOAT;
	polygonLayout[0].InputSlot = 0;
	polygonLayout[0].AlignedByteOffset = 0;
	polygonLayout[0].InputSlotClass = D3D11_INPUT_PER_VERTEX_DATA;
	polygonLayout[0].InstanceDataStepRate = 0;

	polygonLayout[1].SemanticName = "TEXCOORD";
	polygonLayout[1].SemanticIndex = 0;
	polygonLayout[1].Format = DXGI_FORMAT_R32G32_FLOAT;
	polygonLayout[1].InputSlot = 0;
	polygonLayout[1].AlignedByteOffset = D3D11_APPEND_ALIGNED_ELEMENT;
	polygonLayout[1].InputSlotClass = D3D11_INPUT_PER_VERTEX_DATA;
	polygonLayout[1].InstanceDataStepRate = 0;

	// Get a count of the elements in the layout.
	numElements = sizeof(polygonLayout) / sizeof(polygonLayout[0]);

	// Create the vertex input layout.
	result = device->CreateInputLayout(polygonLayout, numElements, vertexShaderBuffer->GetBufferPointer(), 
					   vertexShaderBuffer->GetBufferSize(), &m_layout);
	if(FAILED(result))
	{
		return false;
	}

	// Release the vertex shader buffer and pixel shader buffer since they are no longer needed.
	vertexShaderBuffer->Release();
	vertexShaderBuffer = 0;

	pixelShaderBuffer->Release();
	pixelShaderBuffer = 0;

	// Setup the description of the matrix dynamic constant buffer that is in the vertex shader.
	matrixBufferDesc.Usage = D3D11_USAGE_DYNAMIC;
	matrixBufferDesc.ByteWidth = sizeof(MatrixBufferType);
	matrixBufferDesc.BindFlags = D3D11_BIND_CONSTANT_BUFFER;
	matrixBufferDesc.CPUAccessFlags = D3D11_CPU_ACCESS_WRITE;
	matrixBufferDesc.MiscFlags = 0;
	matrixBufferDesc.StructureByteStride = 0;

	// Create the matrix constant buffer pointer so we can access the vertex shader constant buffer from within this class.
	result = device->CreateBuffer(&matrixBufferDesc, NULL, &m_matrixBuffer);
	if(FAILED(result))
	{
		return false;
	}

	// Create a texture sampler state description.
	samplerDesc.Filter = D3D11_FILTER_MIN_MAG_MIP_LINEAR;
	samplerDesc.AddressU = D3D11_TEXTURE_ADDRESS_WRAP;
	samplerDesc.AddressV = D3D11_TEXTURE_ADDRESS_WRAP;
	samplerDesc.AddressW = D3D11_TEXTURE_ADDRESS_WRAP;
	samplerDesc.MipLODBias = 0.0f;
	samplerDesc.MaxAnisotropy = 1;
	samplerDesc.ComparisonFunc = D3D11_COMPARISON_ALWAYS;
	samplerDesc.BorderColor[0] = 0;
	samplerDesc.BorderColor[1] = 0;
	samplerDesc.BorderColor[2] = 0;
	samplerDesc.BorderColor[3] = 0;
	samplerDesc.MinLOD = 0;
	samplerDesc.MaxLOD = D3D11_FLOAT32_MAX;

	// Create the texture sampler state.
	result = device->CreateSamplerState(&samplerDesc, &m_sampleState);
	if(FAILED(result))
	{
		return false;
	}

	return true;
}


void AlphaMapShaderClass::ShutdownShader()
{
	// Release the sampler state.
	if(m_sampleState)
	{
		m_sampleState->Release();
		m_sampleState = 0;
	}

	// Release the matrix constant buffer.
	if(m_matrixBuffer)
	{
		m_matrixBuffer->Release();
		m_matrixBuffer = 0;
	}

	// Release the layout.
	if(m_layout)
	{
		m_layout->Release();
		m_layout = 0;
	}

	// Release the pixel shader.
	if(m_pixelShader)
	{
		m_pixelShader->Release();
		m_pixelShader = 0;
	}

	// Release the vertex shader.
	if(m_vertexShader)
	{
		m_vertexShader->Release();
		m_vertexShader = 0;
	}

	return;
}


void AlphaMapShaderClass::OutputShaderErrorMessage(ID3D10Blob* errorMessage, HWND hwnd, WCHAR* shaderFilename)
{
	char* compileErrors;
	unsigned long bufferSize, i;
	ofstream fout;


	// Get a pointer to the error message text buffer.
	compileErrors = (char*)(errorMessage->GetBufferPointer());

	// Get the length of the message.
	bufferSize = errorMessage->GetBufferSize();

	// Open a file to write the error message to.
	fout.open("shader-error.txt");

	// Write out the error message.
	for(i=0; i<bufferSize; i++)
	{
		fout << compileErrors[i];
	}

	// Close the file.
	fout.close();

	// Release the error message.
	errorMessage->Release();
	errorMessage = 0;

	// Pop a message up on the screen to notify the user to check the text file for compile errors.
	MessageBox(hwnd, L"Error compiling shader.  Check shader-error.txt for message.", shaderFilename, MB_OK);

	return;
}


bool AlphaMapShaderClass::SetShaderParameters(ID3D11DeviceContext* deviceContext, D3DXMATRIX worldMatrix,
					      D3DXMATRIX viewMatrix, D3DXMATRIX projectionMatrix, 
					      ID3D11ShaderResourceView** textureArray)
{
	HRESULT result;
	D3D11_MAPPED_SUBRESOURCE mappedResource;
	MatrixBufferType* dataPtr;
	unsigned int bufferNumber;


	// Transpose the matrices to prepare them for the shader.
	D3DXMatrixTranspose(&worldMatrix, &worldMatrix);
	D3DXMatrixTranspose(&viewMatrix, &viewMatrix);
	D3DXMatrixTranspose(&projectionMatrix, &projectionMatrix);

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

	// Get a pointer to the data in the constant buffer.
	dataPtr = (MatrixBufferType*)mappedResource.pData;

	// Copy the matrices into the constant buffer.
	dataPtr->world = worldMatrix;
	dataPtr->view = viewMatrix;
	dataPtr->projection = projectionMatrix;

	// Unlock the matrix constant buffer.
	deviceContext->Unmap(m_matrixBuffer, 0);

	// Set the position of the matrix constant buffer in the vertex shader.
	bufferNumber = 0;

	// Now set the matrix constant buffer in the vertex shader with the updated values.
	deviceContext->VSSetConstantBuffers(bufferNumber, 1, &m_matrixBuffer);

이전 튜토리얼에 두 개의 텍스쳐를 설정했던 것처럼 이번에는 세 개의 텍스쳐를 할당합니다.

	// Set shader texture array resource in the pixel shader.
	deviceContext->PSSetShaderResources(0, 3, textureArray);

	return true;
}


void AlphaMapShaderClass::RenderShader(ID3D11DeviceContext* deviceContext, int indexCount)
{
	// Set the vertex input layout.
	deviceContext->IASetInputLayout(m_layout);

	// Set the vertex and pixel shaders that will be used to render this triangle.
	deviceContext->VSSetShader(m_vertexShader, NULL, 0);
	deviceContext->PSSetShader(m_pixelShader, NULL, 0);

	// Set the sampler state in the pixel shader.
	deviceContext->PSSetSamplers(0, 1, &m_sampleState);

	// Render the triangles.
	deviceContext->DrawIndexed(indexCount, 0, 0);

	return;
}

TextureArrayClass 클래스도 세 개의 텍스쳐를 다루도록 바뀌었습니다.

////////////////////////////////////////////////////////////////////////////////
// Filename: texturearrayclass.h
////////////////////////////////////////////////////////////////////////////////
#ifndef _TEXTUREARRAYCLASS_H_
#define _TEXTUREARRAYCLASS_H_


//////////////
// INCLUDES //
//////////////
#include <d3d11.h>
#include <d3dx11tex.h>


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

	bool Initialize(ID3D11Device*, WCHAR*, WCHAR*, WCHAR*);
	void Shutdown();

	ID3D11ShaderResourceView** GetTextureArray();

private:

텍스쳐 배열의 요소 수를 3개로 바꿉니다.

	ID3D11ShaderResourceView* m_textures[3];
};

#endif

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

TextureArrayClass::TextureArrayClass()
{
	m_textures[0] = 0;
	m_textures[1] = 0;
	m_textures[2] = 0;
}


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


TextureArrayClass::~TextureArrayClass()
{
}

Initialize 함수는 텍스쳐 배열에 텍스쳐 세 개를 로드합니다.

bool TextureArrayClass::Initialize(ID3D11Device* device, WCHAR* filename1, WCHAR* filename2, WCHAR* filename3)
{
	HRESULT result;


	// Load the first texture in.
	result = D3DX11CreateShaderResourceViewFromFile(device, filename1, NULL, NULL, &m_textures[0], NULL);
	if(FAILED(result))
	{
		return false;
	}

	// Load the second texture in.
	result = D3DX11CreateShaderResourceViewFromFile(device, filename2, NULL, NULL, &m_textures[1], NULL);
	if(FAILED(result))
	{
		return false;
	}

	// Load the third texture in.
	result = D3DX11CreateShaderResourceViewFromFile(device, filename3, NULL, NULL, &m_textures[2], NULL);
	if(FAILED(result))
	{
		return false;
	}

	return true;
}

Shutdown 함수도 세 텍스쳐를 해제합니다.

void TextureArrayClass::Shutdown()
{
	// Release the texture resources.
	if(m_textures[0])
	{
		m_textures[0]->Release();
		m_textures[0] = 0;
	}

	if(m_textures[1])
	{
		m_textures[1]->Release();
		m_textures[1] = 0;
	}

	if(m_textures[2])
	{
		m_textures[2]->Release();
		m_textures[2] = 0;
	}

	return;
}


ID3D11ShaderResourceView** TextureArrayClass::GetTextureArray()
{
	return m_textures;
}

ModelClass 클래스도 세 개의 텍스쳐를 다루도록 수정되었습니다.

////////////////////////////////////////////////////////////////////////////////
// Filename: modelclass.h
////////////////////////////////////////////////////////////////////////////////
#ifndef _MODELCLASS_H_
#define _MODELCLASS_H_


//////////////
// INCLUDES //
//////////////
#include <d3d11.h>
#include <d3dx10math.h>
#include <fstream>
using namespace std;


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


////////////////////////////////////////////////////////////////////////////////
// Class name: ModelClass
////////////////////////////////////////////////////////////////////////////////
class ModelClass
{
private:
	struct VertexType
	{
		D3DXVECTOR3 position;
		D3DXVECTOR2 texture;
	};

	struct ModelType
	{
		float x, y, z;
		float tu, tv;
		float nx, ny, nz;
	};

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

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

	int GetIndexCount();
	ID3D11ShaderResourceView** GetTextureArray();

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

	bool LoadTextures(ID3D11Device*, WCHAR*, WCHAR*, WCHAR*);
	void ReleaseTextures();

	bool LoadModel(char*);
	void ReleaseModel();

private:
	ID3D11Buffer *m_vertexBuffer, *m_indexBuffer;
	int m_vertexCount, m_indexCount;
	ModelType* m_model;
	TextureArrayClass* m_TextureArray;
};

#endif

설명은 이전 튜토리얼에서 달라진 부분을 위주로 다루겠습니다.

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

Initialize 함수는 텍스쳐 파일 이름 세 개를 받습니다. 처음 두 개는 혼합할 텍스쳐이고 세 번째는 알파 텍스쳐입니다.

bool ModelClass::Initialize(ID3D11Device* device, char* modelFilename, WCHAR* textureFilename1, WCHAR* textureFilename2, 
			    WCHAR* textureFilename3)
{
	bool result;


	// Load in the model data,
	result = LoadModel(modelFilename);
	if(!result)
	{
		return false;
	}

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

LoadTextures 함수는 입력으로 세 개의 텍스쳐 파일 이름을 받습니다.

	// Load the textures for this model.
	result = LoadTextures(device, textureFilename1, textureFilename2, textureFilename3);
	if(!result)
	{
		return false;
	}

	return true;
}

LoadTextures 함수는 세 개의 텍스쳐 파일 이름을 받아 생성한 텍스쳐 배열에 불러옵니다. 다시 설명하자면, 처음 두 텍스쳐는 혼합할 텍스쳐이고 세 번째는 알파 텍스쳐입니다.

bool ModelClass::LoadTextures(ID3D11Device* device, WCHAR* filename1, WCHAR* filename2, WCHAR* filename3)
{
	bool result;


	// Create the texture array object.
	m_TextureArray = new TextureArrayClass;
	if(!m_TextureArray)
	{
		return false;
	}

	// Initialize the texture array object.
	result = m_TextureArray->Initialize(device, filename1, filename2, filename3);
	if(!result)
	{
		return false;
	}

	return true;
}

////////////////////////////////////////////////////////////////////////////////
// Filename: graphicsclass.h
////////////////////////////////////////////////////////////////////////////////
#ifndef _GRAPHICSCLASS_H_
#define _GRAPHICSCLASS_H_


/////////////
// GLOBALS //
/////////////
const bool FULL_SCREEN = true;
const bool VSYNC_ENABLED = true;
const float SCREEN_DEPTH = 1000.0f;
const float SCREEN_NEAR = 0.1f;


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

GraphicsClass 헤더 파일에 AlphaMapShaderClass 헤더를 추가합니다.

#include "alphamapshaderclass.h"


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

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

private:
	D3DClass* m_D3D;
	CameraClass* m_Camera;
	ModelClass* m_Model;

AlphaMapShaderClass 객체를 선언합니다.

	AlphaMapShaderClass* m_AlphaMapShader;
};

#endif

설명은 이전 튜토리얼과 달라진 부분을 위주로 다루겠습니다.

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


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

생성자에서 AlphaMapShaderClass 객체를 null로 초기화합니다.

	m_AlphaMapShader = 0;
}


bool GraphicsClass::Initialize(int screenWidth, int screenHeight, HWND hwnd)
{
	bool result;
	D3DXMATRIX baseViewMatrix;

		
	// 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;
	}

	// Initialize a base view matrix with the camera for 2D user interface rendering.
	m_Camera->SetPosition(0.0f, 0.0f, -1.0f);
	m_Camera->Render();
	m_Camera->GetViewMatrix(baseViewMatrix);

	// Create the model object.
	m_Model = new ModelClass;
	if(!m_Model)
	{
		return false;
	}

세 개의 텍스쳐와 함께 ModelClass 객체를 초기화합니다. 처음 두 텍스쳐는 색상이 있는 텍스쳐입니다. 세 번째 입력으로 들어가는 텍스쳐는 두 텍스쳐를 혼합하는 데 사용할 알파 텍스쳐입니다.

	// Initialize the model object.
	result = m_Model->Initialize(m_D3D->GetDevice(), "../Engine/data/square.txt", L"../Engine/data/stone01.dds", 
				     L"../Engine/data/dirt01.dds", L"../Engine/data/alpha01.dds");
	if(!result)
	{
		MessageBox(hwnd, L"Could not initialize the model object.", L"Error", MB_OK);
		return false;
	}

AlphaMapShaderClass 객체를 생성하고 초기화합니다.

	// Create the alpha map shader object.
	m_AlphaMapShader = new AlphaMapShaderClass;
	if(!m_AlphaMapShader)
	{
		return false;
	}

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

	return true;
}


void GraphicsClass::Shutdown()
{

AlphaMapShaderClass 객체를 이 함수에서 해제합니다.

	// Release the alpha map shader object.
	if(m_AlphaMapShader)
	{
		m_AlphaMapShader->Shutdown();
		delete m_AlphaMapShader;
		m_AlphaMapShader = 0;
	}

	// Release the model object.
	if(m_Model)
	{
		m_Model->Shutdown();
		delete m_Model;
		m_Model = 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::Render()
{
	D3DXMATRIX worldMatrix, viewMatrix, projectionMatrix, orthoMatrix;


	// 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_D3D->GetWorldMatrix(worldMatrix);
	m_Camera->GetViewMatrix(viewMatrix);
	m_D3D->GetProjectionMatrix(projectionMatrix);
	m_D3D->GetOrthoMatrix(orthoMatrix);

	// Put the model vertex and index buffers on the graphics pipeline to prepare them for drawing.
	m_Model->Render(m_D3D->GetDeviceContext());

AlphaMapShaderClass 객체를 사용하여 모델 객체를 알파 블렌딩으로 그려냅니다.

	// Render the model using the alpha map shader.
	m_AlphaMapShader->Render(m_D3D->GetDeviceContext(), m_Model->GetIndexCount(), worldMatrix, viewMatrix, projectionMatrix,
				 m_Model->GetTextureArray());

	// Present the rendered scene to the screen.
	m_D3D->EndScene();

	return true;
}

알파 매핑을 통해 여러 텍스쳐를 쉽게 혼합할 수 있습니다. 많은 지형 기반 어플리케이션들은 매우 넓은 지역을 그릴 때 알파 매핑을 통해 서로 다른 텍스쳐들을 부드럽게 연결시킵니다.

1. 이 프로그램을 다시 컴파일하고 실행하여 알파 매핑의 결과를 확인해 보십시오. esc키를 눌러 종료합니다.

2. 여러분만의 알파 맵을 만들어 다른 효과의 텍스쳐 혼합을 해 보십시오.

Visual Studio 2008 프로젝트: dx11tut19.zip

소스 코드: dx11src19.zip

실행 파일: dx11exe19.zip