Shader.cpp

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#include "Shader.h"
#include "Renderer.h"
 
Shader::Shader(const std::string& filepath) :
    m_FilePath(filepath), m_RendererID(0)
{
    ShaderProgramSource source = ParseShader(filepath);
    m_RendererID = CreateShader(source.VertexSource, source.FragmentSource);
}
 
Shader::~Shader()
{
    GLCall(glDeleteProgram(m_RendererID));
}
 
void Shader::Bind() const
{
    GLCall(glUseProgram(m_RendererID));
}
 
void Shader::Unbind() const
{
    GLCall(glUseProgram(0));
}
 
ShaderProgramSource Shader::ParseShader(const std::string& filepath)
{
    std::ifstream stream(filepath);
 
    enum class ShaderType
    {
        NONE = -1,
        VERTEX = 0,
        FRAGMENT = 1
    };
 
    std::string line;
    std::stringstream ss[2];
    ShaderType type = ShaderType::NONE;
    if (stream.is_open())
    {
        while (getline(stream, line))
        {
            if (line.find("#shader") != std::string::npos)
            {
                if (line.find("vertex") != std::string::npos)
                {
                    type = ShaderType::VERTEX;
                }
                else if (line.find("fragment") != std::string::npos)
                {
                    type = ShaderType::FRAGMENT;
                }
            }
            else
            {
                ss[(int)type] << line << '\n';
            }
        }
 
        return {ss[0].str(), ss[1].str()};
    }
    else
    {
        std::cout << "No Shaders File Found!!!" << std::endl;
        throw "No Shaders File Found!!!";
    }
}
 
unsigned int Shader::CompileShader(unsigned int type, const std::string& source)
{
    unsigned int id = glCreateShader(type);
    const char* src = source.c_str();
    GLCall(glShaderSource(id, 1, &src, nullptr));
    GLCall(glCompileShader(id));
 
    int result;
    GLCall(glGetShaderiv(id, GL_COMPILE_STATUS, &result));
 
    if (result == GL_FALSE)
    {
        int length;
        GLCall(glGetShaderiv(id, GL_INFO_LOG_LENGTH, &length));
        char* message = (char*)alloca(length * sizeof(char));
        GLCall(glGetShaderInfoLog(id, length, &length, message));
        std::cout << "Failed to compile " << (type == GL_VERTEX_SHADER ? "vertex" : "fragment") << " shader" << std::endl;
        std::cout << message << std::endl;
 
        GLCall(glDeleteShader(id));
        return 0;
    }
 
    return id;
}
 
unsigned int Shader::CreateShader(const std::string& verxterShader, const std::string& fragmentShader)
{
    unsigned int program = glCreateProgram();
    unsigned int vs = CompileShader(GL_VERTEX_SHADER, verxterShader);
    unsigned int fs = CompileShader(GL_FRAGMENT_SHADER, fragmentShader);
 
    GLCall(glAttachShader(program, vs));
    GLCall(glAttachShader(program, fs));
 
    GLCall(glLinkProgram(program));
    GLCall(glValidateProgram(program));
 
    GLCall(glDeleteShader(vs));
    GLCall(glDeleteShader(fs));
 
    return program;
}
 
void Shader::SetUniform1i(const std::string& name, int value)
{
    GLCall(glUniform1i(GetUniformLocation(name), value));
}
 
void Shader::SetUniform4f(const std::string& name, float v0, float v1, float v2, float v3)
{
    GLCall(glUniform4f(GetUniformLocation(name), v0, v1, v2, v3));
}
 
void Shader::SetUniform2f(const std::string& name, float v0, float v1)
{
    GLCall(glUniform2f(GetUniformLocation(name), v0, v1));
}
 
void Shader::SetUniform1f(const std::string& name, float value)
{
    GLCall(glUniform1f(GetUniformLocation(name), value));
}
 
void Shader::SetUniformMat4f(const std::string& name, glm::mat4& matrix)
{
    GLCall(glUniformMatrix4fv(GetUniformLocation(name), 1, GL_FALSE, &matrix[0][0]));
}
 
int Shader::GetUniformLocation(const std::string& name)
{
    if (m_UniformLocationCache.find(name) != m_UniformLocationCache.end())
    {
        return m_UniformLocationCache[name];
    }
    GLCall(int location = glGetUniformLocation(m_RendererID, name.c_str()));
    if (location == -1)
        std::cout << "Warning: uniform '" << name << "' doesn't exist!!" << std::endl;
 
    m_UniformLocationCache[name] = location;
 
    return location;
}