跟着cherno手搓游戏引擎【20】混合（blend）

抽象：

Renderer.h:

#pragma once
#include"RenderCommand.h"
#include "OrthographicCamera.h"
#include"Shader.h"
namespace YOTO {
 
	class Renderer {
	public:
 
 
		static void Init();
		static void BeginScene(OrthographicCamera& camera);
		static void EndScene();
		static void Submit(const Ref<Shader>& shader, const Ref<VertexArray>& vertexArray,const glm::mat4&transform = glm::mat4(1.0f));
		inline static RendererAPI::API GetAPI() {
			return RendererAPI::GetAPI();
		}
	private:
		struct SceneData {
			glm::mat4 ViewProjectionMatrix;
		};
		static SceneData* m_SceneData;
	};
 
}

Renderer.cpp:

#include"ytpch.h"
#include"Renderer.h"
#include <Platform/OpenGL/OpenGLShader.h>
namespace YOTO {
	Renderer::SceneData* Renderer::m_SceneData = new	Renderer::SceneData;
	void Renderer::Init()
	{
		RenderCommand::Init();
	}
	void Renderer::BeginScene(OrthographicCamera& camera)
	{
		m_SceneData->ViewProjectionMatrix = camera.GetViewProjectionMatrix();
	}
	void Renderer::EndScene()
	{
	}
	void Renderer::Submit(const Ref<Shader>& shader, const Ref<VertexArray>& vertexArray, const glm::mat4& transform)
	{
		shader->Bind();
		std::dynamic_pointer_cast<OpenGLShader>(shader)->UploadUniformMat4("u_ViewProjection", m_SceneData->ViewProjectionMatrix);
		std::dynamic_pointer_cast<OpenGLShader>(shader)->UploadUniformMat4("u_Transform", transform);
	/*	mi.Bind();*/
 
		vertexArray->Bind();
		RenderCommand::DrawIndexed(vertexArray);
	}
}

 RenderCommand.h:

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

 RendererAPI.h:

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

实现：

OpenGLRendererAPI.h

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

 OpenGLRendererAPI.h

#include "ytpch.h"
#include "OpenGLTexture.h"
#include<glad/glad.h>
#include"stb_image.h"
namespace YOTO {
	OpenGLTexture2D::OpenGLTexture2D(const std::string path)
		:m_Path(path)
	{
		int width, height, channels;
		stbi_set_flip_vertically_on_load(1);//翻转
		stbi_uc*data=stbi_load(path.c_str(),&width,&height,&channels,0);
		YT_CORE_ASSERT(data, "图片加载错误");
		m_Width = width;
		m_Height = height;
 
		GLenum internalFormat = 0,dataFormat=0;
		if (channels == 4) {
			internalFormat = GL_RGBA8;
			dataFormat = GL_RGBA;
		}
		else if (channels==3) {
			internalFormat = GL_RGB8;
			dataFormat = GL_RGB;
		}
		YT_CORE_ASSERT(internalFormat& dataFormat,"OpenGLTexture2D：不支持的颜色格式")
		//创建纹理
		glCreateTextures(GL_TEXTURE_2D, 1, &m_RendererID);
		///告诉OpenGLm_RendererID的纹理存储的是rbg8位，宽高的缓冲区
		glTextureStorage2D(m_RendererID, 1, internalFormat,m_Width,m_Height);
		//配置参数:纹理放大时用周围颜色的平均值过滤
		glTextureParameteri(m_RendererID,GL_TEXTURE_MIN_FILTER,GL_LINEAR);
		glTextureParameteri(m_RendererID, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
		glTextureSubImage2D(m_RendererID, 0, 0, 0, m_Width, m_Height, dataFormat,GL_UNSIGNED_BYTE,data);
		stbi_image_free(data);
	}
	OpenGLTexture2D::~OpenGLTexture2D()
	{
		glDeleteTextures(1,&m_RendererID);
	}
	void OpenGLTexture2D::Bind(uint32_t slot) const
	{
		glBindTextureUnit(slot, m_RendererID);
	}
}

  OpenGLRendererAPI.cpp

#include "ytpch.h"
#include "OpenGLRendererAPI.h"
#include <glad/glad.h>
namespace YOTO {
	void OpenGLRendererAPI::Init()
	{
		//启用混合
		glEnable(GL_BLEND);
		//设置混合函数
		glBlendFunc(GL_SRC_ALPHA,GL_ONE_MINUS_SRC_ALPHA);
	}
	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 Ref<VertexArray>& vertexArray)
	{
		glDrawElements(GL_TRIANGLES, vertexArray->GetIndexBuffer()->GetCount(), GL_UNSIGNED_INT, nullptr);
	}
}

调用：

Application.cpp:

#include"ytpch.h"
#include "Application.h"
 
#include"Log.h"
#include "YOTO/Renderer/Renderer.h"
#include"Input.h"
#include <GLFW/glfw3.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));
 
		m_Window->SetVSync(false);
 
		Renderer::Init();
 
		//new一个Layer，放在最后层进行渲染
		m_ImGuiLayer = new ImGuiLayer();
		PushOverlay(m_ImGuiLayer);	
	}
	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)
		{
			float time = (float)glfwGetTime();//window平台
			Timestep timestep = time - m_LastFrameTime;
			m_LastFrameTime = time;
 
 
			for (Layer* layer : m_LayerStack) {
				layer->OnUpdate(timestep);
			}
			//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();
	}
}

SandboxApp.cpp:

#include<YOTO.h>
#include "imgui/imgui.h"
#include<stdio.h>
#include <glm/gtc/matrix_transform.hpp>
#include <Platform/OpenGL/OpenGLShader.h>
#include <glm/gtc/type_ptr.hpp>
class ExampleLayer:public YOTO::Layer
{
public:
	ExampleLayer()
	:Layer("Example"),  m_Camera(-2.0f, 2.0f, -2.0f, 2.0f), m_CameraPosition(0){
		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(YOTO::VertexArray::Create());
 
 
		YOTO::Ref<YOTO::VertexBuffer> m_VertexBuffer;
		m_VertexBuffer.reset(YOTO::VertexBuffer::Create(vertices, sizeof(vertices)));
 
		{
			YOTO::BufferLayout setlayout = {
 
	{YOTO::ShaderDataType::Float3,"a_Position"},
		{YOTO::ShaderDataType::Float4,"a_Color"}
			};
			m_VertexBuffer->SetLayout(setlayout);
 
		}
 
		m_VertexArray->AddVertexBuffer(m_VertexBuffer);
 
 
		YOTO::Ref<YOTO::IndexBuffer>m_IndexBuffer;
		m_IndexBuffer.reset(YOTO::IndexBuffer::Create(indices, sizeof(indices) / sizeof(uint32_t)));
 
		m_VertexArray->AddIndexBuffer(m_IndexBuffer);
 
		std::string vertexSource = R"(
		#version 330 core
		layout(location = 0) in vec3 a_Position;
		layout(location = 1) in vec4 a_Color;
		uniform mat4 u_ViewProjection;
		uniform mat4 u_Transform;
		out vec3 v_Position;
		out vec4 v_Color;
		void main(){
		v_Position=a_Position;
		v_Color=a_Color;
		gl_Position =u_ViewProjection *u_Transform* vec4( a_Position,1.0);
		}
		)";
		//绘制颜色
		std::string fragmentSource = R"(
		#version 330 core
		layout(location = 0) out vec4 color;
		in vec3 v_Position;
		in vec4 v_Color;
		void main(){
		color=vec4(v_Color);
		}
		)";
		m_Shader.reset(YOTO::Shader::Create(vertexSource, fragmentSource));
 
		///测试/
 
		m_SquareVA.reset(YOTO::VertexArray::Create());
 
		float squareVertices[5 * 4] = {
			-0.5f,-0.5f,0.0f, 0.0f,0.0f,
			0.5f,-0.5f,0.0f,  1.0f,0.0f,
			0.5f,0.5f,0.0f,   1.0f,1.0f,
			-0.5f,0.5f,0.0f,  0.0f,1.0f,
		};
		YOTO::Ref<YOTO::VertexBuffer> squareVB;
		squareVB.reset(YOTO::VertexBuffer::Create(squareVertices, sizeof(squareVertices)));
		squareVB->SetLayout({
			{YOTO::ShaderDataType::Float3,"a_Position"},
				{YOTO::ShaderDataType::Float2,"a_TexCoord"}
			});
		m_SquareVA->AddVertexBuffer(squareVB);
		uint32_t squareIndices[6] = { 0,1,2,2,3,0 };
		YOTO::Ref<YOTO::IndexBuffer> squareIB;
 
		squareIB.reset((YOTO::IndexBuffer::Create(squareIndices, sizeof(squareIndices) / sizeof(uint32_t))));
 
		m_SquareVA->AddIndexBuffer(squareIB);
 
		//测试：
		std::string BlueShaderVertexSource = R"(
		#version 330 core
		layout(location = 0) in vec3 a_Position;
		uniform mat4 u_ViewProjection;
		uniform mat4 u_Transform;
		out vec3 v_Position;
		void main(){
		v_Position=a_Position;
		gl_Position =u_ViewProjection*u_Transform*vec4( a_Position,1.0);
		}
		)";
		//绘制颜色
		std::string BlueShaderFragmentSource = R"(
		#version 330 core
		layout(location = 0) out vec4 color;
		in vec3 v_Position;
		uniform vec3 u_Color;
		void main(){
		color=vec4(u_Color,1.0);
		}
		)";
		m_BlueShader.reset(YOTO::Shader::Create(BlueShaderVertexSource, BlueShaderFragmentSource));
		std::string textureVertexSource = R"(
		#version 330 core
		layout(location = 0) in vec3 a_Position;
		layout(location = 1) in vec2 a_TexCoord;
		uniform mat4 u_ViewProjection;
		uniform mat4 u_Transform;
		
		out vec2 v_TexCoord;
		out vec3 v_Position;
		void main(){
		v_TexCoord=a_TexCoord;
		v_Position=a_Position;
		gl_Position =u_ViewProjection*u_Transform*vec4( a_Position,1.0);
		}
		)";
		//绘制颜色
		std::string textureFragmentSource = R"(
		#version 330 core
		layout(location = 0) out vec4 color;
		in vec3 v_Position;
		in vec2 v_TexCoord;
		uniform sampler2D u_Texture ;
		void main(){
		color = texture(u_Texture, v_TexCoord);	
	//	color = vec4(v_TexCoord, 0.0f, 1.0f);	
		}
		)";
		m_TextureShader.reset(YOTO::Shader::Create(textureVertexSource, textureFragmentSource));
		m_Texture=YOTO::Texture2D::Create("assets/textures/Checkerboard.png");
		m_ChernoLogo= YOTO::Texture2D::Create("assets/textures/ChernoLogo.png");
		std::dynamic_pointer_cast<YOTO::OpenGLShader>(m_TextureShader)->Bind();
		std::dynamic_pointer_cast<YOTO::OpenGLShader>(m_TextureShader)->UploadUniformInt("u_Texture", 0);
	}
	void OnImGuiRender() override {
		ImGui::Begin("设置");
		ImGui::ColorEdit3("正方形颜色", glm::value_ptr(m_SquareColor));
		ImGui::End();
	}
	void OnUpdate(YOTO::Timestep ts)override {
		//YT_CLIENT_TRACE("delta time {0}s ({1}ms)", ts.GetSeconds(), ts.GetMilliseconds());
	
 
		if (YOTO::Input::IsKeyPressed(YT_KEY_LEFT)) {
			m_CameraPosition.x -= m_CameraMoveSpeed* ts;
		}
		else if (YOTO::Input::IsKeyPressed(YT_KEY_RIGHT)) {
			m_CameraPosition.x += m_CameraMoveSpeed * ts;
		}
		if (YOTO::Input::IsKeyPressed(YT_KEY_DOWN)) {
			m_CameraPosition.y -= m_CameraMoveSpeed * ts;
		}
		else if (YOTO::Input::IsKeyPressed(YT_KEY_UP)) {
			m_CameraPosition.y += m_CameraMoveSpeed * ts;
		}
		if (YOTO::Input::IsKeyPressed(YT_KEY_A)) {
			m_CameraRotation += m_CameraRotationSpeed * ts;
		}else if (YOTO::Input::IsKeyPressed(YT_KEY_D)) {
			m_CameraRotation -= m_CameraRotationSpeed * ts;
		}
 
		YOTO::RenderCommand::SetClearColor({ 0.2f, 0.2f, 0.2f, 1.0f });
		YOTO::RenderCommand::Clear();
		m_Camera.SetPosition(m_CameraPosition);
		m_Camera.SetRotation(m_CameraRotation);
		YOTO::Renderer::BeginScene(m_Camera);
		{
			static glm::mat4 scale = glm::scale(glm::mat4(1.0f), glm::vec3(0.1f)); 
			glm::vec4  redColor(0.8f, 0.3f, 0.3f, 1.0f);
			glm::vec4  blueColor(0.2f, 0.3f, 0.8f, 1.0f);
 
	/*		YOTO::MaterialRef material = new YOTO::MaterialRef(m_FlatColorShader);
			YOTO::MaterialInstaceRef mi = new YOTO::MaterialInstaceRef(material);
			mi.setValue("u_Color",redColor);
			mi.setTexture("u_AlbedoMap", texture);
			squreMesh->SetMaterial(mi);*/
 
			std::dynamic_pointer_cast<YOTO::OpenGLShader>(m_BlueShader)->Bind();
			std::dynamic_pointer_cast<YOTO::OpenGLShader>(m_BlueShader)->UploadUniformFloat3("u_Color",m_SquareColor);
			for (int y = 0; y < 20; y++) {
				for (int x = 0; x <20; x++)
				{
 
					glm::vec3 pos(x * 0.105f,y* 0.105f, 0.0);
					glm::mat4 transform = glm::translate(glm::mat4(1.0f), pos) * scale;
					/*if (x % 2 == 0) {
						m_BlueShader->UploadUniformFloat4("u_Color", redColor);
					}
					else {
						m_BlueShader->UploadUniformFloat4("u_Color", blueColor);
					}*/
		
 
					YOTO::Renderer::Submit(m_BlueShader, m_SquareVA, transform);
				}
			}
			
			m_Texture->Bind();
			YOTO::Renderer::Submit(m_TextureShader, m_SquareVA, glm::scale(glm::mat4(1.0f), glm::vec3(1.5f)));
			m_ChernoLogo->Bind();
			YOTO::Renderer::Submit(m_TextureShader, m_SquareVA, glm::scale(glm::mat4(1.0f), glm::vec3(1.5f)));
 
			//YOTO::Renderer::Submit(m_Shader, m_VertexArray);
 
 
			YOTO::Renderer::EndScene();
		}
 
	}
	void OnEvent(YOTO::Event& event)override {
		/*if (event.GetEventType() == YOTO::EventType::KeyPressed) {
		YOTO:: KeyPressedEvent& e = (YOTO::KeyPressedEvent&)event;
		YT_CLIENT_TRACE("ExampleLayer:{0}",(char)e.GetKeyCode());
		if (e.GetKeyCode()==YT_KEY_TAB) {
			YT_CLIENT_INFO("ExampleLayerOnEvent:TAB按下了");
		}}*/
		//YT_CLIENT_TRACE("SandBoxApp:测试event{0}", event);
 
 
 
 
	}
 
 
private:
	YOTO::Ref<YOTO::Shader> m_Shader;
	YOTO::Ref<YOTO::VertexArray> m_VertexArray;
 
 
	YOTO::Ref<YOTO::Shader> m_BlueShader,m_TextureShader;
	YOTO::Ref<YOTO::VertexArray> m_SquareVA;
	
	YOTO::Ref<YOTO::Texture2D> m_Texture,m_ChernoLogo;
 
	YOTO::OrthographicCamera m_Camera;
	glm::vec3 m_CameraPosition;
	float m_CameraMoveSpeed = 5.0f;
 
	float m_CameraRotation = 0;
	float m_CameraRotationSpeed = 180.0f;
 
	glm::vec3 m_SquareColor = { 0.2f,0.3f,0.7f };
 
};
 
 
class Sandbox:public YOTO::Application
{
public:
	Sandbox(){
		PushLayer(new ExampleLayer());
		//PushLayer(new YOTO::ImGuiLayer());
	}
	~Sandbox() {
 
	}
 
private:
 
};
 
YOTO::Application* YOTO::CreateApplication() {
	printf("helloworld");
	return new Sandbox();
}

加了个init涉及了好几个类，小改动，为了方便观察，我把整个类都复制下来了。