light/Engine/src/Platform/GraphicsAPI/DirectX/dxBuffers.cpp

#include "dxBuffers.h"
#include "dxSharedContext.h"

namespace Light {

	//======================================== CONSTANT_BUFFER ========================================//
	dxConstantBuffer::dxConstantBuffer(ConstantBufferIndex index, unsigned int size, Ref<dxSharedContext> sharedContext)
		: m_Context(sharedContext),
		  m_Buffer(nullptr),
		  m_Map{},
		  m_Index(static_cast<int>(index))
	{
		D3D11_BUFFER_DESC bDesc = {};
		
		bDesc.ByteWidth = size;
		bDesc.Usage = D3D11_USAGE_DYNAMIC;
		bDesc.BindFlags = D3D11_BIND_CONSTANT_BUFFER;
		bDesc.CPUAccessFlags = D3D11_CPU_ACCESS_WRITE;

		HRESULT hr;
		DXC(m_Context->GetDevice()->CreateBuffer(&bDesc, nullptr, &m_Buffer));
		m_Context->GetDeviceContext()->VSSetConstantBuffers(m_Index, 1u, m_Buffer.GetAddressOf());
	}

	void dxConstantBuffer::Bind()
	{
		m_Context->GetDeviceContext()->VSSetConstantBuffers(m_Index, 1u, m_Buffer.GetAddressOf());
	}

	void* dxConstantBuffer::Map()
	{
		m_Context->GetDeviceContext()->VSSetConstantBuffers(m_Index, 1u, m_Buffer.GetAddressOf());
		m_Context->GetDeviceContext()->Map(m_Buffer.Get(), NULL, D3D11_MAP_WRITE_DISCARD, NULL, &m_Map);
		return m_Map.pData;
	}

	void dxConstantBuffer::UnMap()
	{
		m_Context->GetDeviceContext()->Unmap(m_Buffer.Get(), NULL);
	}
	//======================================== CONSTANT_BUFFER ========================================//

	//================================================== VERTEX_BUFFER ==================================================//
	dxVertexBuffer::dxVertexBuffer(float* vertices, unsigned int stride, unsigned int count, Ref<dxSharedContext> sharedContext)
		: m_Context(sharedContext),
		  m_Buffer(nullptr),
		  m_Map{},
		  m_Stride(stride)
	{
		// buffer desc
		D3D11_BUFFER_DESC bDesc = {};

		bDesc.BindFlags = D3D11_BIND_VERTEX_BUFFER;
		bDesc.Usage = D3D11_USAGE_DYNAMIC;
		bDesc.CPUAccessFlags = D3D11_CPU_ACCESS_WRITE;

		bDesc.ByteWidth = count * stride;
		bDesc.StructureByteStride = stride;

		// create buffer
		HRESULT hr;
		DXC(m_Context->GetDevice()->CreateBuffer(&bDesc, nullptr, &m_Buffer));
	}

	dxVertexBuffer::~dxVertexBuffer()
	{
		UnBind();
	}

	void* dxVertexBuffer::Map()
	{
		m_Context->GetDeviceContext()->Map(m_Buffer.Get(), NULL, D3D11_MAP_WRITE_DISCARD, NULL, &m_Map);
		return m_Map.pData;
	}

	void dxVertexBuffer::UnMap()
	{
		m_Context->GetDeviceContext()->Unmap(m_Buffer.Get(), NULL);
	}

	void dxVertexBuffer::Bind()
	{
		static const unsigned int offset = 0u;
		m_Context->GetDeviceContext()->IASetVertexBuffers(0u, 1u, m_Buffer.GetAddressOf(), &m_Stride, &offset);
	}

	void dxVertexBuffer::UnBind()
	{
		static const unsigned int offset = 0u;
		static ID3D11Buffer* buffer = nullptr;

		m_Context->GetDeviceContext()->IASetVertexBuffers(0u, 1u, &buffer, &m_Stride, &offset);
	}
	//================================================== VERTEX_BUFFER ==================================================//

	//======================================== INDEX_BUFFER ========================================//
	dxIndexBuffer::dxIndexBuffer(unsigned int* indices, unsigned int count, Ref<dxSharedContext> sharedContext)
		: m_Context(sharedContext),
		  m_Buffer(nullptr)
	{
		// generate indices if not provided
		bool hasIndices = !!indices;
		if (!hasIndices)
		{
			// check
			if (count % 6 != 0)
			{
				LT_ENGINE_WARN("dxIndexBuffer::dxIndexBuffer: 'indices' can only be null if count is multiple of 6");
				LT_ENGINE_WARN("dxIndexBuffer::dxIndexBuffer: adding {} to 'count' -> {}", (6 - (count % 6)), count + (6 - (count % 6)));
				count = count + (6 - (count % 6));
			}

			// create indices
			indices = new unsigned int[count];
			unsigned int offset = 0;
			for (unsigned int i = 0; i < count; i += 6)
			{
				indices[i + 0] = offset + 0u;
				indices[i + 1] = offset + 3u;
				indices[i + 2] = offset + 2u;

				indices[i + 3] = offset + 2u;
				indices[i + 4] = offset + 1u;
				indices[i + 5] = offset + 0u;

				offset += 4u;
			}
		}

		// buffer desc
		D3D11_BUFFER_DESC bDesc = {};
		bDesc.BindFlags = D3D11_BIND_INDEX_BUFFER;
		bDesc.Usage = D3D11_USAGE_DEFAULT;

		bDesc.ByteWidth = count * sizeof(unsigned int);
		bDesc.StructureByteStride = sizeof(unsigned int);

		// subresource data
		D3D11_SUBRESOURCE_DATA sDesc = {};
		sDesc.pSysMem = indices;

		// create buffer
		HRESULT hr;
		DXC(m_Context->GetDevice()->CreateBuffer(&bDesc, &sDesc, &m_Buffer));

		// delete indices
		if (!hasIndices)
			delete[] indices;
	}

	dxIndexBuffer::~dxIndexBuffer()
	{
		UnBind();
	}

	void dxIndexBuffer::Bind()
	{
		m_Context->GetDeviceContext()->IASetIndexBuffer(m_Buffer.Get(), DXGI_FORMAT_R32_UINT, 0u);
	}

	void dxIndexBuffer::UnBind()
	{
		static const unsigned int offset = 0u;
		static ID3D11Buffer* buffer = nullptr;

		m_Context->GetDeviceContext()->IASetIndexBuffer(buffer, DXGI_FORMAT_R32_UINT, offset);
	}
	//======================================== INDEX_BUFFER ========================================//

}