GLTypes.h

//
//  GLTypes.h
//  avara3d
//
//  Created by Morgan Davis on 12/31/25.
//  Copyright © 2026 Morgan K Davis. All rights reserved.
//
 
#ifndef AVARA3D_RENDER_BACKEND_OPENGL_GLTYPES_H
#define AVARA3D_RENDER_BACKEND_OPENGL_GLTYPES_H
 
#include <cstdint>
#include <cstddef> // std::ptrdiff_t
 
namespace a3d::gl {
 
using enum_t     = std::uint32_t;   // GLenum
using uint_t     = std::uint32_t;   // GLuint
using int_t      = std::int32_t;    // GLint
using sizei_t    = std::int32_t;    // GLsizei
using boolean_t  = std::uint8_t;    // GLboolean
using bitfield_t = std::uint32_t;   // GLbitfield
 
using sizeiptr_t = std::ptrdiff_t;  // GLsizeiptr
using intptr_t   = std::ptrdiff_t;  // GLintptr
 
using char_t   = char;            // GLchar
using float_t  = float;           // GLfloat
using double_t = double;          // GLdouble
 
using int64_t  = std::int64_t;    // GLint64
using uint64_t = std::uint64_t;   // GLuint64
 
namespace value {
 
    constexpr enum_t false_ = 0u;
    constexpr enum_t true_  = 1u;
 
    constexpr enum_t unsigned_byte  = 0x1401u; // GL_UNSIGNED_BYTE
    constexpr enum_t unsigned_short = 0x1403u; // GL_UNSIGNED_SHORT
    constexpr enum_t unsigned_int   = 0x1405u; // GL_UNSIGNED_INT
    constexpr enum_t float32        = 0x1406u; // GL_FLOAT
 
    constexpr enum_t invalid_index = 0xFFFFFFFFu; // GL_INVALID_INDEX
    constexpr uint_t null_handle   = 0u;          // “0” object name
 
} // namespace value
 
enum class index_type : enum_t {
    u8  = value::unsigned_byte,
    u16 = value::unsigned_short,
    u32 = value::unsigned_int,
};
 
// helpers
template<class E>
constexpr enum_t raw(E e) noexcept {
    return static_cast<enum_t>(e);
}
 
constexpr boolean_t gl_bool(bool b) noexcept {
    return b ? static_cast<boolean_t>(value::true_) : static_cast<boolean_t>(value::false_);
}
 
// strong-typed handles (zero-cost)
template<class Tag>
struct handle {
    uint_t             id = value::null_handle;
 
    constexpr explicit operator bool() const noexcept {
        return id != value::null_handle;
    }
 
    friend constexpr bool operator==(handle, handle) = default;
};
 
struct buffer_tag {};
 
struct texture_tag {};
 
struct vao_tag {};
 
struct program_tag {};
 
struct shader_tag {};
 
struct framebuffer_tag {};
 
using buffer      = handle<buffer_tag>;
using texture     = handle<texture_tag>;
using vao         = handle<vao_tag>;
using program     = handle<program_tag>;
using shader      = handle<shader_tag>;
using framebuffer = handle<framebuffer_tag>;
 
} // namespace a3d::gl
 
#endif // AVARA3D_RENDER_BACKEND_OPENGL_GLTYPES_H