shader.cpp

#include "shader.h"

Shader::Shader(){};
Shader::Shader(const GLchar* vertexPath, const GLchar* fragmentPath)
{
    this->setup(vertexPath, fragmentPath);
}

void Shader::setup(const GLchar* vertexPath, const GLchar* fragmentPath)
{
    // 1. 从文件路径中获取顶点/片段着色器
    std::string vertexCode;
    std::string fragmentCode;
    std::ifstream vShaderFile;
    std::ifstream fShaderFile;
    // 保证ifstream对象可以抛出异常：
    vShaderFile.exceptions (std::ifstream::failbit | std::ifstream::badbit);
    fShaderFile.exceptions (std::ifstream::failbit | std::ifstream::badbit);
    try 
    {
        // 打开文件
        vShaderFile.open(vertexPath);
        fShaderFile.open(fragmentPath);
        std::stringstream vShaderStream, fShaderStream;
        // 读取文件的缓冲内容到数据流中
        vShaderStream << vShaderFile.rdbuf();
        fShaderStream << fShaderFile.rdbuf();       
        // 关闭文件处理器
        vShaderFile.close();
        fShaderFile.close();
        // 转换数据流到string
        vertexCode   = vShaderStream.str();
        fragmentCode = fShaderStream.str();     
    }
    catch(std::ifstream::failure e)
    {
        std::cout << "ERROR::SHADER::FILE_NOT_SUCCESFULLY_READ" << std::endl;
    }
    const char* vShaderCode = vertexCode.c_str();
    const char* fShaderCode = fragmentCode.c_str();

    // 2. 编译着色器
    unsigned int vertex, fragment;
    int success;
    char infoLog[512];

    // 顶点着色器
    vertex = glCreateShader(GL_VERTEX_SHADER);
    glShaderSource(vertex, 1, &vShaderCode, NULL);
    glCompileShader(vertex);
    // 打印编译错误（如果有的话）
    glGetShaderiv(vertex, GL_COMPILE_STATUS, &success);
    if(!success)
    {
        glGetShaderInfoLog(vertex, 512, NULL, infoLog);
        std::cout << "ERROR::SHADER::VERTEX::COMPILATION_FAILED\n" << infoLog << std::endl;
    };

    // 片段着色器
    fragment = glCreateShader(GL_FRAGMENT_SHADER);
    glShaderSource(fragment, 1, &fShaderCode, NULL);
    glCompileShader(fragment);
    // 打印编译错误（如果有的话）
    glGetShaderiv(fragment, GL_COMPILE_STATUS, &success);
    if(!success)
    {
        glGetShaderInfoLog(fragment, 512, NULL, infoLog);
        std::cout << "ERROR::SHADER::FRAGMENT::COMPILATION_FAILED\n" << infoLog << std::endl;
    };

    // 着色器程序
    ID = glCreateProgram();
    glAttachShader(ID, vertex);
    glAttachShader(ID, fragment);
    glLinkProgram(ID);
    // 打印连接错误（如果有的话）
    glGetProgramiv(ID, GL_LINK_STATUS, &success);
    if(!success)
    {
        glGetProgramInfoLog(ID, 512, NULL, infoLog);
        std::cout << "ERROR::SHADER::PROGRAM::LINKING_FAILED\n" << infoLog << std::endl;
    }

    // 删除着色器，它们已经链接到我们的程序中了，已经不再需要了
    glDeleteShader(vertex);
    glDeleteShader(fragment);
}

void Shader::use()
{
    glUseProgram(ID);
}

void Shader::setInt(const std::string &name, int value) const
{
    glUniform1i(glGetUniformLocation(ID, name.c_str()), value);
}

void Shader::setBool(const std::string &name, bool value) const
{
    glUniform1i(glGetUniformLocation(ID, name.c_str()), (int)value);
}

void Shader::setFloat(const std::string &name, float value) const
{
    glUniform1f(glGetUniformLocation(ID, name.c_str()), value);
}

void Shader::setTexture(const std::string &name, int unit) const
{
    setInt(name.c_str(), unit);
}

void Shader::setMat4(const std::string &name, glm::mat4 transform) const
{
    unsigned int transformLoc = glGetUniformLocation(ID, name.c_str());
    glUniformMatrix4fv(transformLoc, 1, GL_FALSE, glm::value_ptr(transform));
}

void Shader::setVec3(const std::string &name, float vx, float vy, float vz) const
{
    unsigned int vecLoc = glGetUniformLocation(ID, name.c_str());
    glUniform3fv(vecLoc, 1, glm::value_ptr(glm::vec3(vx, vy, vz)));
}

void Shader::setVec3(const std::string &name, glm::vec3 vec3) const
{
    unsigned int vecLoc = glGetUniformLocation(ID, name.c_str());
    glUniform3fv(vecLoc, 1, glm::value_ptr(vec3));
}