RenderShadows.cpp

#include "Defines.h"
#include "RenderShadows.h"

RenderShadows::RenderShadows(ID3D11Device* device) :matrixBuffer(nullptr), vertexShader(nullptr)
{
	CreateBuffer(device, matrixBuffer, sizeof(XMFLOAT4X4));

	std::string shaderData;
	std::ifstream reader;
	// VERTEX SHADER
	reader.open(vsPath, std::ios::binary | std::ios::ate);
	if (!reader.is_open())
	{
		std::cerr << "Could not open VS file!" << std::endl;
		return;
	}

	reader.seekg(0, std::ios::end);
	shaderData.reserve(static_cast<unsigned int>(reader.tellg()));
	reader.seekg(0, std::ios::beg);

	shaderData.assign((std::istreambuf_iterator<char>(reader)), std::istreambuf_iterator<char>());

	if (FAILED(device->CreateVertexShader(shaderData.c_str(), shaderData.length(), nullptr, &vertexShader)))
	{
		std::cerr << "Failed to create pixel shader!" << std::endl;
		return;
	}

	shaderData.clear();
	reader.close();

}

void RenderShadows::Render(ID3D11DeviceContext* context, Model* model)
{
	// Shadows use an positions only input layout to determine the position of each pixel
	context->IASetInputLayout(Shaders::positionOnlyLayout);
	context->VSSetShader(vertexShader, NULL, 0);							// VS containing a position 
	context->PSSetShader(NULL, NULL, 0);									// not using a pixelshader since the shadow does not need it
	context->IASetPrimitiveTopology(D3D11_PRIMITIVE_TOPOLOGY_TRIANGLELIST); // Trianglelist
	context->GSSetShader(NULL, NULL, 0);									// Not using a GS for the shadowpass

	// ShaderData::lightMatrix has got the dirLight.GetMatrix() with the matrix = XMMatrixTranspose(viewMatrix * ortographicMatrix) from DirectionalLight 

	XMFLOAT4X4 WVP1;
	XMMATRIX WVP = Shaders::lightingMatrix * XMMatrixTranspose(model->GetWorldMatrix());	// Worldspace -> viewspace -> clipspace (lights clipspace)
	// WVP1 is the address at which to store the data from WVP, WVP is the matrix contining the data that we want to store 
	XMStoreFloat4x4(&WVP1, WVP);
	UpdateBuffer(context, matrixBuffer, WVP1); // Update the buffer containing the models TRANSPOSED worldmatrix, To write out column-major data it requires the XMMATRIX be transposed
	context->VSSetConstantBuffers(0, 1, &matrixBuffer); // Set the CB for the VS
	context->IASetVertexBuffers(0, 1, model->GetPositionsBuffer(), &stride, &offset); // Set the VB with the vertex position data from the vector in model.h
	context->Draw(model->GetVertexCount(), 0); // draw the model for the shadow pass
}



void RenderShadows::ShutDown()
{
	matrixBuffer->Release();
	vertexShader->Release();
}