crocparty/sdl_host/main.c

#include <stdio.h>
#include <stdbool.h>

// don't use sdl's redefinition of main
#define SDL_MAIN_HANDLED
#include "sdl/include/SDL.h"
#include "device/device.h"
#include "game/game.h"

void sdl_host_suggest_dimensions(uint32_t* window_w, uint32_t* window_h);
void sdl_host_loop();
void sdl_host_handle_keyboard_event(SDL_KeyboardEvent event);

SDL_Window* sdl_host_window;
SDL_Renderer* sdl_host_renderer;
SDL_Texture* sdl_host_target;

int main(int argc, char** argv) {
    int result = 0;
    if (SDL_Init(SDL_INIT_VIDEO | SDL_INIT_TIMER)) {
        printf("could not initialize SDL! sdl error: %s\n", SDL_GetError());
        result = 1;
        goto sdl_done;
    }

    uint32_t window_w, window_h;
    sdl_host_suggest_dimensions(&window_w, &window_h);

    // create window
    sdl_host_window = SDL_CreateWindow(
        game_title(),
        SDL_WINDOWPOS_CENTERED,
        SDL_WINDOWPOS_CENTERED,
        (int) window_w, (int) window_h,
        SDL_WINDOW_SHOWN
    );

    if (sdl_host_window == NULL) {
        printf("could not create window! sdl error: %s\n", SDL_GetError());
        result = 1;
        goto window_done;
    }

    // create renderer
    sdl_host_renderer = SDL_CreateRenderer(sdl_host_window, -1, 0);
    if (sdl_host_renderer == NULL) {
        printf("could not create renderer! sdl error: %s\n", SDL_GetError());
        result = 1;
        goto renderer_done;
    }

    // create target
    sdl_host_target = SDL_CreateTexture(
        sdl_host_renderer,
        SDL_PIXELFORMAT_RGBA8888,
        SDL_TEXTUREACCESS_STREAMING,
        DEVICE_W, DEVICE_H
    );

    if (sdl_host_target == NULL) {
        printf("could not create target texture! sdl error: %s\n", SDL_GetError());
        result = 1;
        goto target_done;
    }

    sdl_host_loop();

    // target_cleanup:
    SDL_DestroyTexture(sdl_host_target);
    sdl_host_target = NULL;
    target_done: ;

    // renderer_cleanup:
    SDL_DestroyRenderer(sdl_host_renderer);
    sdl_host_renderer = NULL;
    renderer_done: ;

    // window_cleanup:
    SDL_DestroyWindow(sdl_host_window);
    sdl_host_window = NULL;
    window_done: ;

    // sdl_cleanup:
    SDL_Quit();
    sdl_done: ;

    return result;
}

void sdl_host_suggest_dimensions(uint32_t* window_w, uint32_t* window_h) {
    SDL_DisplayMode dm;
    if (SDL_GetCurrentDisplayMode(0, &dm) != 0) {
        printf("could not get current display mode: %s\n", SDL_GetError());
        dm.w = 0;
        dm.h = 0;
    }

    for (int scalar = 4; scalar >= 1; scalar--) {
        uint32_t w = DEVICE_W * scalar;
        uint32_t h = DEVICE_H * scalar;
        if (w <= dm.w && h <= dm.h) {
            *window_w = w;
            *window_h = h;
            return;
        }
    }

    for (int scalar = 1; scalar <= 5; scalar++) {
        uint32_t w = DEVICE_W / scalar;
        uint32_t h = DEVICE_H / scalar;
        if (w <= dm.w && h <= dm.h) {
            *window_w = w;
            *window_h = h;
            return;
        }
    }

    *window_w = DEVICE_W;
    *window_h = DEVICE_H;
}

void sdl_host_loop() {
    uint32_t ticks_per_frame = 1000/60;
    uint32_t real_pixels[DEVICE_H][DEVICE_W];

    game_init();
    while (true) {
        uint32_t frame_start = SDL_GetTicks();
        uint32_t next_frame_start = frame_start + ticks_per_frame;

        SDL_Event e;
        while (SDL_PollEvent(&e)) {
            if (e.type == SDL_QUIT) { goto quit; }
            if (e.type == SDL_KEYDOWN || e.type == SDL_KEYUP) {
                sdl_host_handle_keyboard_event(e.key);
            }
        }

        // trigger game logic
        game_update();
        game_draw();

        for (int x = 0; x < DEVICE_W; x++) {
            for (int y = 0; y < DEVICE_H; y++) {
                real_pixels[y][x] = device_palette[device_pixels[y][x]];
            }
        }

        SDL_UpdateTexture(sdl_host_target, NULL, &real_pixels, sizeof(real_pixels[0]));
        SDL_RenderClear(sdl_host_renderer);
        SDL_RenderCopy(sdl_host_renderer, sdl_host_target, NULL, NULL);
        SDL_RenderPresent(sdl_host_renderer);

        // hold off until next frame
        while (SDL_GetTicks() < next_frame_start) {
            SDL_Delay(1);
        }
    }
    quit: ;
}

void sdl_host_handle_keyboard_event(SDL_KeyboardEvent event) {
    bool is_down;
    switch (event.type) {
        case SDL_KEYDOWN: is_down = true; break;
        case SDL_KEYUP: is_down = false; break;
        default: return;
    }

    if (event.repeat) {
        return;
    }

    DeviceButton db;

    switch (event.keysym.sym) {
        case SDLK_LEFT: db = DEVICE_BUTTON_L; break;
        case SDLK_RIGHT: db = DEVICE_BUTTON_R; break;
        case SDLK_UP: db = DEVICE_BUTTON_U; break;
        case SDLK_DOWN: db = DEVICE_BUTTON_D; break;
        case SDLK_z: db = DEVICE_BUTTON_0; break;
        case SDLK_x: db = DEVICE_BUTTON_1; break;
        case SDLK_c: db = DEVICE_BUTTON_2; break;
        case SDLK_v: db = DEVICE_BUTTON_3; break;
        default: return;
    }

    device_buttons[db] = is_down;
}