OpenGL/Shader.cpp at master · AmandeepMandal1077/OpenGL · GitHub

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#include "Shader.h"
#include "Renderer.h"
Shader::Shader(const std::string& filepath)
	:m_RendererID(0), m_filePath(filepath)
{
    sourceShader source = parseShader(filepath);
    m_RendererID = createShader(source.vertexShader, source.fragmentShader);
}

Shader::~Shader()
{
    GLCall(glDeleteProgram(m_RendererID));
}


sourceShader Shader::parseShader(const std::string& filePath)
{
    enum class shaderType
    {
        NONE = -1, VERTEX = 0, FRAGMENT = 1
    };

    std::ifstream file(filePath);
    std::stringstream ss[2];
    std::string line;

    shaderType type = shaderType::NONE;

    while (getline(file, line))
    {
        if (line.find("#Shader") != std::string::npos)
        {
            if (line.find("Vertex") != std::string::npos)
                type = shaderType::VERTEX;
            else
                type = shaderType::FRAGMENT;
        }
        else
            ss[int(type)] << line << '\n';
    }

    return { ss[0].str(), ss[1].str() };

}
unsigned int Shader::compileShader(unsigned int type, const std::string& source)
{
    GLCall(unsigned int id = glCreateShader(type));
    const char* src = source.c_str();
    GLCall(glShaderSource(id, 1, &src, NULL));
    GLCall(glCompileShader(id));

    int result;
    GLCall(glGetShaderiv(id, GL_COMPILE_STATUS, &result));
    if (result == 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") << std::endl;
        std::cout << message << std::endl;

        GLCall(glDeleteShader(id));
        return 0;
    }


    return id;
}

unsigned int Shader::createShader(const std::string& vertexShader, const std::string& fragmentShader)
{
    GLCall(unsigned int program = glCreateProgram());
    unsigned int vs = compileShader(GL_VERTEX_SHADER, vertexShader);
    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::Bind() const
{
    GLCall(glUseProgram(m_RendererID));
}

void Shader::Unbind() const
{
    GLCall(glUseProgram(0));
}

void Shader::setUniform1f(const std::string& name, float value)
{
    GLCall(glUniform1f(getUniformLocation(name), value));
}

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::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: " << name << " doesn't exist" << std::endl;

    m_UniformLocationCache[name] = location;
    return location;
}