b_engine/src/ShaderProgram.cpp

//
// Created by lbmas on 4/29/2026.
//

#include "ShaderProgram.h"

#include <fstream>
#include <string>
#include <sstream>

#include "glad/gl.h"
#include "spdlog/spdlog.h"

void log_shader_compile_errors(GLuint shader, std::string_view shaderType);
void log_program_compile_errors(GLuint program);

std::shared_ptr<ShaderProgram> ShaderProgram::load(std::string_view vertexPath, std::string_view fragmentPath)
{
    std::string vertexSource;
    std::string fragmentSource;

    std::ifstream vertexFile {};
    std::ifstream fragmentFile {};

    try
    {
        std::stringstream ss;
        vertexFile.open(vertexPath.data());
        fragmentFile.open(fragmentPath.data());

        ss << vertexFile.rdbuf();
        vertexSource = ss.str();
        ss.clear();
        ss << fragmentFile.rdbuf();
        fragmentSource = ss.str();

        vertexFile.close();
        fragmentFile.close();
    } catch (std::ifstream::failure& e) {
        spdlog::error("Failed to load shader program {}, {}: {}", vertexPath, fragmentPath, std::string(e.what()).c_str());
        return nullptr;
    }

    unsigned int vertex;
    unsigned int fragment;

    vertex = glCreateShader(GL_VERTEX_SHADER);
    glShaderSource(vertex, 1, reinterpret_cast<const GLchar* const*>(vertexSource.data()), NULL);
    glCompileShader(vertex);
    log_shader_compile_errors(vertex, "vertex");

    fragment = glCreateShader(GL_FRAGMENT_SHADER);
    glShaderSource(fragment, 1, reinterpret_cast<const GLchar* const*>(fragmentSource.data()), NULL);
    glCompileShader(fragment);
    log_shader_compile_errors(fragment, "fragment");

    ShaderProgram program;
    program.id = glCreateProgram();

    glAttachShader(program.id, vertex);
    glAttachShader(program.id, fragment);
    glLinkProgram(program.id);
    log_program_compile_errors(program.id);

    glDeleteShader(vertex);
    glDeleteShader(fragment);

    return std::make_shared<ShaderProgram>(program);
}

void ShaderProgram::bind()
{
    glUseProgram(id);
}

void ShaderProgram::unbind()
{
    glUseProgram(0);
}

void ShaderProgram::setFloat(std::string_view name, float value) const
{

}

void ShaderProgram::setVec2(std::string_view name, const glm::vec2& value) const
{

}

void ShaderProgram::setVec3(std::string_view name, const glm::vec3& value) const
{

}

void ShaderProgram::setVec4(std::string_view name, const glm::vec4& value) const
{

}

void ShaderProgram::setMat4(std::string_view name, const glm::mat4& value) const
{

}

void log_shader_compile_errors(GLuint shader, std::string_view shaderType)
{
    GLint success;
    GLchar infoLog[1024];
    glGetShaderiv(shader, GL_COMPILE_STATUS, &success);
    if (!success)
    {
        glGetShaderInfoLog(shader, 1024, NULL, infoLog);
        spdlog::error("Failed to compile {} shader: {}", shaderType, infoLog);
    }
}

void log_program_compile_errors(GLuint program)
{
    GLint success;
    GLchar infoLog[1024];
    glGetProgramiv(program, GL_COMPILE_STATUS, &success);
    if (!success)
    {
        glGetShaderInfoLog(program, 1024, NULL, infoLog);
        spdlog::error("Failed to compile program: {}", infoLog);
    }
}