跟着cherno手搓游戏引擎【15】DrawCall的封装

目标：

 Application.cpp:把渲染循环里的glad代码封装成自己的类：

#include"ytpch.h"
#include "Application.h"#include"Log.h"
#include "YOTO/Renderer/Renderer.h"
#include"Input.h"namespace YOTO {
#define BIND_EVENT_FN(x) std::bind(&x, this, std::placeholders::_1)Application* Application::s_Instance = nullptr;Application::Application() {YT_CORE_ASSERT(!s_Instance, "Application需要为空！")s_Instance = this;//智能指针m_Window = std::unique_ptr<Window>(Window::Creat());//设置回调函数m_Window->SetEventCallback(BIND_EVENT_FN(Application::OnEvent));//new一个Layer，放在最后层进行渲染m_ImGuiLayer = new ImGuiLayer();PushOverlay(m_ImGuiLayer);  //unsigned int id;//glGenBuffers(1, &id);uint32_t indices[3] = { 0,1,2 };float vertices[3 * 7] = {-0.5f,-0.5f,0.0f, 0.8f,0.2f,0.8f,1.0f,0.5f,-0.5f,0.0f,  0.2f,0.3f,0.8f,1.0f,0.0f,0.5f,0.0f,   0.8f,0.8f,0.2f,1.0f,};m_VertexArray.reset(VertexArray::Create());std::shared_ptr<VertexBuffer> m_VertexBuffer;m_VertexBuffer.reset(VertexBuffer::Create(vertices, sizeof(vertices)));{BufferLayout setlayout = {{ShaderDataType::Float3,"a_Position"},{ShaderDataType::Float4,"a_Color"}};m_VertexBuffer->SetLayout(setlayout);}m_VertexArray->AddVertexBuffer(m_VertexBuffer);std::shared_ptr<IndexBuffer>m_IndexBuffer;m_IndexBuffer.reset(IndexBuffer::Create(indices, sizeof(indices)/sizeof(uint32_t)));m_VertexArray->AddIndexBuffer(m_IndexBuffer);std::string vertexSource = R"(#version 330 corelayout(location = 0) in vec3 a_Position;layout(location = 1) in vec4 a_Color;out vec3 v_Position;out vec4 v_Color;void main(){v_Position=a_Position;v_Color=a_Color;gl_Position =vec4( a_Position+0.5,1.0);})";//绘制颜色std::string fragmentSource = R"(#version 330 corelayout(location = 0) out vec4 color;in vec3 v_Position;in vec4 v_Color;void main(){color=vec4(v_Color);})";m_Shader.reset(new Shader(vertexSource, fragmentSource));///测试/m_SquareVA.reset(VertexArray::Create());float squareVertices[3 * 4] = {-0.5f,-0.5f,0.0f,0.5f,-0.5f,0.0f, 0.5f,0.5f,0.0f,-0.5f,0.5f,0.0f};std::shared_ptr<VertexBuffer> squareVB;squareVB.reset(VertexBuffer::Create(squareVertices, sizeof(squareVertices)));squareVB->SetLayout({{ShaderDataType::Float3,"a_Position"}});m_SquareVA->AddVertexBuffer(squareVB);uint32_t squareIndices[6] = { 0,1,2,2,3,0 };std::shared_ptr<IndexBuffer> squareIB; squareIB.reset((IndexBuffer::Create(squareIndices, sizeof(squareIndices) / sizeof(uint32_t))));m_SquareVA->AddIndexBuffer(squareIB);//测试：std::string BlueShaderVertexSource = R"(#version 330 corelayout(location = 0) in vec3 a_Position;out vec3 v_Position;void main(){v_Position=a_Position;gl_Position =vec4( a_Position,1.0);})";//绘制颜色std::string BlueShaderFragmentSource = R"(#version 330 corelayout(location = 0) out vec4 color;in vec3 v_Position;void main(){color=vec4(0.2,0.3,0.8,1.0);})";m_BlueShader.reset(new Shader(BlueShaderVertexSource, BlueShaderFragmentSource));}Application::~Application() {}/// <summary>/// 所有的Window事件都会在这触发，作为参数e/// </summary>/// <param name="e"></param>void Application::OnEvent(Event& e) {//根据事件类型绑定对应事件EventDispatcher dispatcher(e);dispatcher.Dispatch<WindowCloseEvent>(BIND_EVENT_FN(Application::OnWindowClosed));//输出事件信息YT_CORE_INFO("Application：{0}",e);for (auto it = m_LayerStack.end(); it != m_LayerStack.begin();) {(*--it)->OnEvent(e);if (e.m_Handled)break;}}bool Application::OnWindowClosed(WindowCloseEvent& e) {m_Running = false;return true;}void Application::Run() {WindowResizeEvent e(1280, 720);if (e.IsInCategory(EventCategoryApplication)) {YT_CORE_TRACE(e);}if (e.IsInCategory(EventCategoryInput)) {YT_CORE_ERROR(e);}while (m_Running){/*	glClearColor(0.2f, 0.2f, 0.2f,1);glClear(GL_COLOR_BUFFER_BIT);*/RenderCommand::SetClearColor({0.2f, 0.2f, 0.2f, 1.0f});RenderCommand::Clear();Renderer::BeginScene();{m_BlueShader->Bind();Renderer::Submit(m_SquareVA);m_Shader->Bind();Renderer::Submit(m_VertexArray);Renderer::EndScene();}//m_BlueShader->Bind();//m_SquareVA->Bind();//glDrawElements(GL_TRIANGLES, m_SquareVA->GetIndexBuffer()->GetCount(), GL_UNSIGNED_INT, nullptr);glBindVertexArray(m_VertexArray);//m_Shader->Bind();//m_VertexArray->Bind();//glDrawElements(GL_TRIANGLES,m_VertexArray->GetIndexBuffer()->GetCount(),GL_UNSIGNED_INT,nullptr); for (Layer* layer : m_LayerStack) {layer->OnUpdate();}//将ImGui的刷新放到APP中，与Update分开m_ImGuiLayer->Begin();for (Layer* layer : m_LayerStack) {layer->OnImGuiRender();}m_ImGuiLayer->End();m_Window->OnUpdate();}}void Application::PushLayer(Layer* layer) {m_LayerStack.PushLayer(layer);layer->OnAttach();}void Application::PushOverlay(Layer* layer) {m_LayerStack.PushOverlay(layer);layer->OnAttach();}
}

抽象：

RendererAPI.h:渲染API的抽象，包括API实现的功能都封装一下：

#pragma once
#include<glm/glm.hpp>
#include "VertexArray.h"
namespace YOTO {class RendererAPI{public:enum class API {None = 0,OpenGL = 1};public:virtual void SetClearColor(const glm::vec4& color)=0;virtual void Clear() = 0;virtual void DrawIndexed(const std::shared_ptr<VertexArray>& vertexArray)=0;	inline static API GetAPI() { return s_API; }private:static API s_API;};
}

 RendererAPI.cpp:给当前API赋值：

#include "ytpch.h"
#include "RendererAPI.h"
namespace YOTO {RendererAPI::API RendererAPI::s_API = RendererAPI::API::OpenGL;
}

 实现：

OpenGLRendererAPI.h:实现接口，制定重写方法，在cpp中封账glad代码：

#pragma once
#include"YOTO/Renderer/RendererAPI.h"
namespace YOTO {class OpenGLRendererAPI:public RendererAPI{public:virtual void SetClearColor(const glm::vec4& color)override;virtual void Clear()override;virtual void DrawIndexed(const std::shared_ptr<VertexArray>& vertexArray) override;};
}

 OpenGLRendererAPI.cpp:

#include "ytpch.h"
#include "OpenGLRendererAPI.h"
#include <glad/glad.h>
namespace YOTO {void OpenGLRendererAPI::SetClearColor(const glm::vec4& color){glClearColor(color.r, color.g, color.b, color.a);}void OpenGLRendererAPI::Clear(){glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);}void OpenGLRendererAPI::DrawIndexed(const std::shared_ptr<VertexArray>& vertexArray){glDrawElements(GL_TRIANGLES, vertexArray->GetIndexBuffer()->GetCount(), GL_UNSIGNED_INT, nullptr);}
}

调用：

RenderCommand.h:根据当前API调用API的一些通用方法：

#pragma once
#include"RendererAPI.h"
namespace YOTO {class RenderCommand{public:inline static void SetClearColor(const glm::vec4& color) {s_RendererAPI->SetClearColor(color);}inline static void Clear() {s_RendererAPI->Clear();}inline static void DrawIndexed(const std::shared_ptr<VertexArray>& vertexArray) {s_RendererAPI->DrawIndexed(vertexArray);}private:static RendererAPI* s_RendererAPI;};}

 RenderCommand.cpp:（个人觉得应该在new的时候再给API的枚举赋值，在 RendererAPI

.cpp中导致可以new 其他API枚举选另一个API）（不知道后面会不会改）

#include "ytpch.h"
#include "RenderCommand.h"
#include"Platform/OpenGL/OpenGLRendererAPI.h"
namespace YOTO {RendererAPI* RenderCommand::s_RendererAPI = new OpenGLRendererAPI;
}

Renderer.h: 对command的一些方法进行进一步封装，并拓展出Begin和End方法：

#pragma once
#include"RenderCommand.h"
namespace YOTO {class Renderer {public:static void BeginScene();static void EndScene();static void Submit(const std::shared_ptr<VertexArray>& vertexArray);inline static RendererAPI::API GetAPI() {return RendererAPI::GetAPI();}};}

Renderer.cpp: 

#include"ytpch.h"
#include"Renderer.h"
namespace YOTO {void Renderer::BeginScene(){}void Renderer::EndScene(){}void Renderer::Submit(const std::shared_ptr<VertexArray>& vertexArray){vertexArray->Bind();RenderCommand::DrawIndexed(vertexArray);}
}

修改：

所有switch的枚举都改成这样（会报错，报了再改也行）

RendererAPI::API::OpenGL:

测试：

 原汁原味儿~能跑出来就对了！