#include "pch.h"
#include "Effect.h"


Effect::Effect(D2D_SIZE_U inputSize, ID3D11RenderTargetView* output, ID3D11SamplerState* linearSampler, D2D1_VECTOR_2F scale) : _output(output), _linearSampler(linearSampler) {
	_d3dDevice = Env::$instance->GetD3DDevice();
	_d3dDC = Env::$instance->GetD3DDC();

	ComPtr<ID3D11Resource> outputResource;
	output->GetResource(&outputResource);
	ComPtr<ID3D11Texture2D> outputTexture;
	outputResource.As<ID3D11Texture2D>(&outputTexture);
	D3D11_TEXTURE2D_DESC desc;
	outputTexture->GetDesc(&desc);
	D2D1_SIZE_U outputTextureSize = { desc.Width, desc.Height };

	_vp.Width = (float)outputTextureSize.width;
	_vp.Height = (float)outputTextureSize.height;
	_vp.MinDepth = 0.0f;
	_vp.MaxDepth = 1.0f;

	// 编译顶点着色器
	ComPtr<ID3DBlob> blob = nullptr;
	Debug::ThrowIfComFailed(
		_CompileShaderFromFile(L"shaders\\Lanczos6.hlsl", "VS", "vs_5_0", &blob),
		L""
	);

	Debug::ThrowIfComFailed(
		_d3dDevice->CreateVertexShader(blob->GetBufferPointer(), blob->GetBufferSize(), nullptr, &_vsShader),
		L""
	);

	// 创建输入布局
	D3D11_INPUT_ELEMENT_DESC layout[] = {
		{ "POSITION", 0, DXGI_FORMAT_R32G32B32_FLOAT, 0, 0, D3D11_INPUT_PER_VERTEX_DATA, 0 },
		{ "TEXCOORD", 0, DXGI_FORMAT_R32G32B32A32_FLOAT, 0, sizeof(XMFLOAT3), D3D11_INPUT_PER_VERTEX_DATA, 0 },
	};
	UINT numElements = ARRAYSIZE(layout);
	Debug::ThrowIfComFailed(
		_d3dDevice->CreateInputLayout(layout, numElements, blob->GetBufferPointer(),
			blob->GetBufferSize(), &_vtxLayout),
		L""
	);

	// 编译像素着色器
	Debug::ThrowIfComFailed(
		_CompileShaderFromFile(L"shaders\\Lanczos6.hlsl", "PS", "ps_5_0", &blob),
		L""
	);
	Debug::ThrowIfComFailed(
		_d3dDevice->CreatePixelShader(blob->GetBufferPointer(), blob->GetBufferSize(), nullptr, &_psShader),
		L""
	);


	// 创建顶点缓冲区
	D2D1_SIZE_U outputSize = {
		(UINT32)lroundf(inputSize.width * scale.x),
		(UINT32)lroundf(inputSize.height * scale.y)
	};

	float outputLeft, outputTop, outputRight, outputBottom;
	if (outputTextureSize.width == outputSize.width && outputTextureSize.height == outputSize.height) {
		outputLeft = outputBottom = -1;
		outputRight = outputTop = 1;
	} else {
		outputLeft = std::floorf(((float)outputTextureSize.width - outputSize.width) / 2) * 2 / outputTextureSize.width - 1;
		outputTop = 1 - std::ceilf(((float)outputTextureSize.height - outputSize.height) / 2) * 2 / outputTextureSize.height;
		outputRight = outputLeft + 2 * outputSize.width / (float)outputTextureSize.width;
		outputBottom = outputTop - 2 * outputSize.height / (float)outputTextureSize.height;
	}

	float pixelWidth = 1.0f / inputSize.width;
	float pixelHeight = 1.0f / inputSize.height;
	SimpleVertex vertices[] = {
		{ XMFLOAT3(outputLeft, outputTop, 0.5f), XMFLOAT4(0.0f, 0.0f, pixelWidth, pixelHeight) },
		{ XMFLOAT3(outputRight, outputTop, 0.5f), XMFLOAT4(1.0f, 0.0f, pixelWidth, pixelHeight) },
		{ XMFLOAT3(outputLeft, outputBottom, 0.5f), XMFLOAT4(0.0f, 1.0f, pixelWidth, pixelHeight) },
		{ XMFLOAT3(outputRight, outputBottom, 0.5f), XMFLOAT4(1.0f, 1.0f, pixelWidth, pixelHeight) }
	};
	D3D11_BUFFER_DESC bd = {};
	bd.Usage = D3D11_USAGE_DEFAULT;
	bd.ByteWidth = sizeof(vertices);
	bd.BindFlags = D3D11_BIND_VERTEX_BUFFER;

	D3D11_SUBRESOURCE_DATA InitData = {};
	InitData.pSysMem = vertices;
	Debug::ThrowIfComFailed(
		_d3dDevice->CreateBuffer(&bd, &InitData, &_vtxBuffer),
		L""
	);
}

void Effect::Draw() {
}
/*
void Apply(ID3D11ShaderResourceView* input) {
	_d3dDC->RSSetViewports(1, &_vp);
	_d3dDC->OMSetRenderTargets(1, &_output, nullptr);

	_d3dDC->IASetInputLayout(_vtxLayout.Get());

	UINT stride = sizeof(SimpleVertex);
	UINT offset = 0;
	auto t = _vtxBuffer.Get();
	_d3dDC->IASetVertexBuffers(0, 1, &t, &stride, &offset);

	_d3dDC->VSSetShader(_vsShader.Get(), nullptr, 0);

	_d3dDC->PSSetShader(_psShader.Get(), nullptr, 0);
	_d3dDC->PSSetSamplers(0, 1, &_linearSampler);
	_d3dDC->PSSetShaderResources(0, 1, &input);
	
	_d3dDC->Draw(4, 0);
}*/



HRESULT Effect::_CompileShaderFromFile(const WCHAR* szFileName, LPCSTR szEntryPoint, LPCSTR szShaderModel, ID3DBlob** ppBlobOut) {
	DWORD dwShaderFlags = D3DCOMPILE_ENABLE_STRICTNESS;
#ifdef _DEBUG
	// Set the D3DCOMPILE_DEBUG flag to embed debug information in the shaders.
	// Setting this flag improves the shader debugging experience, but still allows 
	// the shaders to be optimized and to run exactly the way they will run in 
	// the release configuration of this program.
	dwShaderFlags |= D3DCOMPILE_DEBUG;

	// Disable optimizations to further improve shader debugging
	dwShaderFlags |= D3DCOMPILE_SKIP_OPTIMIZATION;
#endif

	ComPtr<ID3DBlob> pErrorBlob = nullptr;
	HRESULT hr = D3DCompileFromFile(szFileName, nullptr, nullptr, szEntryPoint, szShaderModel,
		dwShaderFlags, 0, ppBlobOut, &pErrorBlob);
	if (FAILED(hr)) {
		if (pErrorBlob) {
			OutputDebugStringA(reinterpret_cast<const char*>(pErrorBlob->GetBufferPointer()));
		}
		return hr;
	}

	return S_OK;
}