vc5/src/io_device.cpp

#include "io_device.hpp"
#include <SDL2/SDL.h>
#include <SDL2/SDL_error.h>
#include <SDL2/SDL_render.h>
#include <SDL2/SDL_video.h>
#include <algorithm>
#include <array>
#include <cstdint>
#include <mutex>
#include <print>

using namespace vc5;

namespace {

bool sdl_is_initialized = false;

struct Char {
    explicit constexpr Char(char ch, uint64_t data)
        : ch(ch)
        , data(data)
    {
    }

    auto to_u64() const -> uint64_t
    {
        return data;
    }

    char ch;
    uint64_t data;
};

constexpr auto charset = std::array {
    Char(' ', 0x0000000000000000),
    Char('A', 0x66667E66667E1800),
    Char('B', 0x7C7E667C667E7800),
    Char('C', 0x3C7E6060607E3C00),
    Char('D', 0x7C7E6666667E7C00),
    Char('E', 0x7E7E607E607E7E00),
    Char('F', 0x60607878607E7E00),
    Char('G', 0x7E7E666E607E7E00),
    Char('H', 0x6666667E7E666600),
    Char('I', 0x7E7E1818187E7E00),
    Char('J', 0x3C7E6606067E7E00),
    Char('K', 0x666E7C7C6E666600),
    Char('L', 0x7E7E606060606000),
    Char('M', 0xC3C3C3C3DBFFE700),
    Char('N', 0x6666666E7E766600),
    Char('O', 0x3C66666666663C00),
    Char('P', 0x60607C7E667C7C00),
    Char('Q', 0x3F7E6E66667E3C00),
    Char('R', 0x666C7C7E667E7C00),
    Char('S', 0x3C66063C60663C00),
    Char('T', 0x18181818187E7E00),
    Char('U', 0x3C7E666666666600),
    Char('V', 0x183C7E6666666600),
    Char('W', 0xE7FFDBDBC3C3C300),
    Char('X', 0x6666663C3C666600),
    Char('Y', 0x181818183C666600),
    Char('Z', 0x7E7E30180C7E7E00),
};

}

auto IoDevice::create(int ch_size, int ch_width, int ch_height)
    -> std::expected<std::unique_ptr<IoDevice>, std::string>
{
    auto profile = ScreenProfile(ch_size, ch_width, ch_height);
    auto px_width= profile.px_width;
    auto px_height = profile.px_height;

    if (!sdl_is_initialized) {
        if (SDL_Init(SDL_INIT_VIDEO) != 0) {
            return std::unexpected(SDL_GetError());
        }
    }

    SDL_Window* window;
    SDL_Renderer* renderer;

    if (SDL_CreateWindowAndRenderer(px_width, px_height, 0, &window, &renderer)
        != 0) {
        return std::unexpected(SDL_GetError());
    }

    SDL_Texture* texture = SDL_CreateTexture(renderer,
        SDL_PIXELFORMAT_RGBA32,
        SDL_TEXTUREACCESS_STREAMING,
        px_width,
        px_height);

    if (texture == nullptr) {
        return std::unexpected(SDL_GetError());
    }

    SDL_RenderPresent(renderer);

    return std::make_unique<IoDevice>(profile, window, renderer, texture);
}

IoDevice::~IoDevice()
{
    auto lock = std::lock_guard(mx);

    SDL_DestroyTexture(m_texture);
    SDL_DestroyRenderer(m_renderer);
    SDL_DestroyWindow(m_window);

    if (sdl_is_initialized) {
        SDL_Quit();
    }
}

auto IoDevice::set_char(uint16_t offset, uint8_t value)
    -> std::expected<void, std::string>
{
    auto lock = std::lock_guard(mx);

    auto it = std::find_if(charset.begin(), charset.end(), [&](Char ch) {
        return ch.ch == value;
    });
    uint64_t char_data = it->to_u64();

    SDL_Color* buffer;
    int pitch;
    int res = SDL_LockTexture(m_texture, NULL, (void**)&buffer, &pitch);
    if (res != 0) {
        return std::unexpected(SDL_GetError());
    }

    auto [ch_size, ch_width, ch_height, px_width, px_height] = m_profile;
    std::println("ch_size = {}, ch_width = {}, ch_height = {}, px_width = {}, px_height = {}", ch_size, ch_width, ch_height, px_width, px_height);

    for (int ch_y = 0; ch_y < 8; ++ch_y) {
        for (int ch_x = 0; ch_x < 8; ++ch_x) {
            bool ch
                = char_data >> (ch_y * 8 + (8 - ch_x - 1))
                & 1;

            for (int px_y = 0; px_y < ch_size; ++px_y) {
                for (int px_x = 0; px_x < ch_size; ++px_x) {

                    int x = (offset % 4 * ch_size + ch_x) * 4
                        + px_x;
                    int y = (offset / 4 * ch_size + ch_y) * 4
                        + px_y;

                    buffer[y * px_width + x] = ch
                        ? SDL_Color { 0xff, 0xff, 0xff, 0xff }
                        : SDL_Color { 0x00, 0x00, 0x00, 0xff };
                }
            }
        }
    }

    SDL_UnlockTexture(m_texture);
    SDL_RenderCopy(m_renderer, m_texture, NULL, NULL);

    SDL_RenderPresent(m_renderer);

    return {};
}