跟着cherno手搓游戏引擎【18】抽象Shader、项目小修改

抽象：

Shader.h:

#pragma once

#include

namespace YOTO {

class Shader {

public:

virtual~Shader()=default;

virtual void Bind()const=0;

virtual void UnBind()const=0;

static Shader* Create(const std::string& vertexSrc, const std::string& fragmentSrc);

}

;

}

Shader.cpp:

#include "ytpch.h"

#include "Shader.h"

#include"Renderer.h"

#include "Platform/OpenGL/OpenGLShader.h"

namespace YOTO {

Shader* Shader::Create(const std::string& vertexSrc, const std::string& fragmentSrc)

{

switch (Renderer::GetAPI())

{

case RendererAPI::API::None:

YT_CORE_ASSERT(false, "Buffer：API为None不支持");

return nullptr;

case RendererAPI::API::OpenGL:

return new OpenGLShader(vertexSrc, fragmentSrc);

}

YT_CORE_ASSERT(false, "Buffer：未知API");

return nullptr;

}

实现：

新建OpenGLShader类：

OpenGLShader.h

#pragma once

#include

#include "YOTO/Renderer/Shader.h"

#include

namespace YOTO {

class OpenGLShader:public Shader {

public:

OpenGLShader(const std::string& vertexSrc, const std::string& fragmentSrc);

~OpenGLShader();

void Bind()const override;

void UnBind()const override;

void UploadUniformMat4(const std::string& name, const glm::mat4& matrix);

void UploadUniformMat3(const std::string& name, const glm::mat3& matrix);

void UploadUniformFloat4(const std::string& name, const glm::vec4& values);

void UploadUniformFloat3(const std::string& name, const glm::vec3& values);

void UploadUniformFloat2(const std::string& name, const glm::vec2& values);

void UploadUniformFloat(const std::string& name, float values);

void UploadUniformInt(const std::string& name, int values);

private:

uint32_t m_RendererID;

}

;

}

OpenGLShader.cpp

#include "ytpch.h"

#include "OpenGLShader.h"

#include

namespace YOTO {

OpenGLShader::OpenGLShader(const std::string& vertexSrc, const std::string& fragmentSrc)

{

// 1.1.创建顶点着色器对象

GLuint vertexShader = glCreateShader(GL_VERTEX_SHADER);

// Send the vertex shader source code to GL

// Note that std::string's .c_str is NULL character terminated.

// 1.2.附加顶点着色器源码到顶点着色器对象中

const GLchar* source = vertexSrc.c_str();

glShaderSource(vertexShader, 1, &source, 0);

// 1.3.编译顶点着色器对象

glCompileShader(vertexShader);

// 1.4.检查是否编译成功

GLint isCompiled = 0;

glGetShaderiv(vertexShader, GL_COMPILE_STATUS, &isCompiled);

if (isCompiled == GL_FALSE) {

// 1.4.2编译失败可以打印报错信息

GLint maxLength = 0;

glGetShaderiv(vertexShader, GL_INFO_LOG_LENGTH, &maxLength);

// The maxLength includes the NULL character

std::vector infoLog(maxLength);

glGetShaderInfoLog(vertexShader, maxLength, &maxLength, &infoLog[0]);

// We don't need the shader anymore.

glDeleteShader(vertexShader);

YT_CORE_ERROR("{0}", infoLog.data());

YT_CORE_ASSERT(false, "Vertex shader compilation failure!");

return;

}

// 片段着色器一样

// 2.1.创建片段着色器对象

GLuint fragmentShader = glCreateShader(GL_FRAGMENT_SHADER);

// Send the fragment shader source code to GL

// Note that std::string's .c_str is NULL character terminated.

// 2.2.附加片段着色器源码到片段着色器对象中

source = fragmentSrc.c_str();

glShaderSource(fragmentShader, 1, &source, 0);

// 2.3.编译片段着色器对象

glCompileShader(fragmentShader);

// 2.4.检查是否编译成功

glGetShaderiv(fragmentShader, GL_COMPILE_STATUS, &isCompiled);

if (isCompiled == GL_FALSE) {

// 2.4.2编译失败可以打印报错信息

GLint maxLength = 0;

glGetShaderiv(fragmentShader, GL_INFO_LOG_LENGTH, &maxLength);

// The maxLength includes the NULL character

std::vector infoLog(maxLength);

glGetShaderInfoLog(fragmentShader, maxLength, &maxLength, &infoLog[0]);

// We don't need the shader anymore.

glDeleteShader(fragmentShader);

// Either of them. Don't leak shaders.

glDeleteShader(vertexShader);

YT_CORE_ERROR("{0}", infoLog.data());

YT_CORE_ASSERT(false, "Fragment shader compilation failure!");

return;

}

// Vertex and fragment shaders are successfully compiled.

// Now time to link them together into a program.

// Get a program object.

// 3.1创建着色器程序对象

m_RendererID = glCreateProgram();

GLuint program = m_RendererID;

// 3.2附加着色器对象给着色器程序对象

glAttachShader(program, vertexShader);

glAttachShader(program, fragmentShader);

// 3.3链接着色器程序对象

glLinkProgram(program);

// 3.4可以检查链接是否成功

// Note the different functions here: glGetProgram* instead of glGetShader*.

GLint isLinked = 0;

glGetProgramiv(program, GL_LINK_STATUS, (int*)&isLinked);

if (isLinked == GL_FALSE) {

GLint maxLength = 0;

glGetProgramiv(program, GL_INFO_LOG_LENGTH, &maxLength);

// The maxLength includes the NULL character

std::vector infoLog(maxLength);

glGetProgramInfoLog(program, maxLength, &maxLength, &infoLog[0]);

// We don't need the program anymore.

glDeleteProgram(program);

// Don't leak shaders either.

glDeleteShader(vertexShader);

glDeleteShader(fragmentShader);

YT_CORE_ERROR("{0}", infoLog.data());

YT_CORE_ASSERT(false, "Shader link failure!");

return;

}

// 4.删除着色器对象

// Always detach shaders after a successful link.

glDetachShader(program, vertexShader);

glDetachShader(program, fragmentShader);

}

OpenGLShader::~OpenGLShader()

{

glDeleteProgram(m_RendererID);

}

void OpenGLShader::Bind() const

{

glUseProgram(m_RendererID);

}

void OpenGLShader::UnBind() const

{

glUseProgram(0);

}

void OpenGLShader::UploadUniformMat4(const std::string& name, const glm::mat4& matrix)

{