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


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


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


BitmapClass::~BitmapClass()
{
}


bool BitmapClass::Initialize(ID3D11Device* device, ID3D11DeviceContext* deviceContext, int screenWidth, int screenHeight, int bitmapWidth, int bitmapHeight, char* textureFilename)
{
	bool result;


	// 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;

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

	// Initialize the vertex and index buffer that hold the geometry for the bitmap quad.
	result = InitializeBuffers(device);
	if(!result)
	{
		return false;
	}

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

	return true;
}


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

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

	return;
}


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;
}


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


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


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


	// 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;
	}

	// Set up the description of the dynamic 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 finally create the vertex buffer.
	result = device->CreateBuffer(&vertexBufferDesc, &vertexData, &m_vertexBuffer);
	if(FAILED(result))
	{
		return false;
	}

	// Set up the description of the 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;
}


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;
}


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


	// 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;
	}

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

	// 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;

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

	// Load the vertex array with data.
	// First triangle.
	vertices[0].position = XMFLOAT3(left, top, 0.0f);  // Top left.
	vertices[0].texture = XMFLOAT2(0.0f, 0.0f);

	vertices[1].position = XMFLOAT3(right, bottom, 0.0f);  // Bottom right.
	vertices[1].texture = XMFLOAT2(1.0f, 1.0f);

	vertices[2].position = XMFLOAT3(left, bottom, 0.0f);  // Bottom left.
	vertices[2].texture = XMFLOAT2(0.0f, 1.0f);

	// Second triangle.
	vertices[3].position = XMFLOAT3(left, top, 0.0f);  // Top left.
	vertices[3].texture = XMFLOAT2(0.0f, 0.0f);

	vertices[4].position = XMFLOAT3(right, top, 0.0f);  // Top right.
	vertices[4].texture = XMFLOAT2(1.0f, 0.0f);

	vertices[5].position = XMFLOAT3(right, bottom, 0.0f);  // Bottom right.
	vertices[5].texture = XMFLOAT2(1.0f, 1.0f);

	// Lock the vertex buffer.
	result = deviceContent->Map(m_vertexBuffer, 0, D3D11_MAP_WRITE_DISCARD, 0, &mappedResource);
	if(FAILED(result))
	{
		return false;
	}

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

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

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

	// Release the pointer reference.
	dataPtr = 0;

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

	return true;
}


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;
}


bool BitmapClass::LoadTexture(ID3D11Device* device, ID3D11DeviceContext* deviceContext, char* 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, deviceContext, filename);
	if(!result)
	{
		return false;
	}

	return true;
}


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

	return;
}