erc-c/include/vm_screen.h

#ifndef _VM_SCREEN_H_
#define _VM_SCREEN_H_

#include <SDL.h>
#include <stdbool.h>
#include <sys/time.h>

#include "vm_area.h"
#include "vm_bits.h"

typedef struct {
    /*
     * Red, green, blue
     */
    vm_8bit r, g, b;

    /*
     * This is alpha, which would be the degree of transparency of the
     * graphics. This is here only if needed--for example, the Apple II
     * doesn't have any alpha channel.
     */
    vm_8bit a;
} vm_color;

typedef struct {
    /*
     * This is the window in SDL that we're displaying. It's fine for a
     * screen to be headless; that is, not to have a window. Screen
     * functions which deal with SDL will simply not run that code if
     * headless.
     */
    SDL_Window *window;

    /*
     * In SDL, the renderer is comparable to the old SDL_Surface type
     * (which is still there!). A renderer is a little more stateful; it
     * contains its own color information to be used when rendering
     * shapes, for example.
     */
    SDL_Renderer *render;

    /*
     * These are the x and y coordinates of the window we're creating.
     * FIXME: this should probably be renamed to width and height...
     */
    int xcoords;
    int ycoords;

    /*
     * This is the time we last refreshed the screen.
     */
    struct timeval reftime;

    /*
     * This field is the number of microseconds we have to wait until we
     * are ready to redraw the frame. It cannot be greater than 1000000,
     * which is the number of microseconds within a second.
     */
    int usec_until_refresh;

    /*
     * Hang onto the last key pressed and the status of whether a key
     * is pressed right now or not.
     */
    vm_8bit last_key;
    bool key_pressed;

    /*
     * Is the screen dirty? That is to say, has something about it
     * changed that now requires we redraw the screen?
     */
    bool dirty;

    /*
     * Should we exit (the next chance we get)?
     */
    bool should_exit;

} vm_screen;

extern bool vm_screen_active(vm_screen *);
extern bool vm_screen_dirty(vm_screen *);
extern bool vm_screen_key_pressed(vm_screen *);
extern bool vm_screen_needs_frame(vm_screen *);
extern char vm_screen_last_key(vm_screen *);
extern int vm_screen_add_window(vm_screen *, int, int);
extern int vm_screen_init();
extern int vm_screen_xcoords(vm_screen *);
extern int vm_screen_ycoords(vm_screen *);
extern vm_screen *vm_screen_create();
extern void vm_screen_draw_rect(vm_screen *, vm_area *);
extern void vm_screen_finish();
extern void vm_screen_free(vm_screen *);
extern void vm_screen_prepare(vm_screen *);
extern void vm_screen_refresh(vm_screen *);
extern void vm_screen_set_color(vm_screen *, vm_color);
extern void vm_screen_set_logical_coords(vm_screen *, int, int);

#endif