6847_sdl2.c

/*
 *	6847 driver raster output for SDL2
 *
 *	There are lots of variants of this device that have subtle differences
 *	including NTSC and PAL versions.
 */

#include <stdio.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>
#include <SDL2/SDL.h>

#include "6847.h"
#include "6847_render.h"

extern int sdl_live;

/*
 * The 6847 set up is odd - there are 8 colours in the encoding plus black
 * which has a life of its own and we keep in slot 8 
 *
 * Ignore colour artifacting for the moment
 *
 * These colours seem to be very subjective and system dependent and
 * in reality also shift a bit by mode and PAL/NTSC.
 */

static uint32_t vdp_ctab[9] = {
    0xFF30D200,		/* Green */
    0xFFC1E500,		/* Yellow */
    0xFF4C3AB4,		/* Blue */
    0xFF9A3236,		/* Red */
    0xFFBFC8AD,		/* "Buff" */
    0xFF41AF71,		/* Cyan */
    0xFFC84EF0,		/* Magenta */
    0xFFD47F00,		/* Orange/Brown */
    0xFF263016,		/* Black */
};

struct m6847_renderer {
    struct m6847 *vdp;
    SDL_Renderer *render;
    SDL_Texture *texture;
    SDL_Window *window;
};
    

void m6847_render(struct m6847_renderer *render)
{
    SDL_Rect sr;

    sr.x = 0;
    sr.y = 0;
    sr.w = 256;
    sr.h = 192;

    SDL_UpdateTexture(render->texture, NULL, m6847_get_raster(render->vdp), 1024);
    SDL_RenderClear(render->render);
    SDL_RenderCopy(render->render, render->texture, NULL, &sr);
    SDL_RenderPresent(render->render);
}

void m6847_renderer_free(struct m6847_renderer *render)
{
    if (render->texture)
        SDL_DestroyTexture(render->texture);
}


struct m6847_renderer *m6847_renderer_create(struct m6847 *vdp)
{
    struct m6847_renderer *render;

    /* We will need a nicer way to do this once we have multiple SDL using
       devices */
    if (sdl_live == 0) {
        sdl_live = 1;
        if (SDL_Init(SDL_INIT_EVERYTHING) < 0) {
            fprintf(stderr, "SDL init failed: %s.\n", SDL_GetError());
            exit(1);
        }
        atexit(SDL_Quit);
    }

    render = malloc(sizeof(struct m6847_renderer));
    if (render == NULL) {
        fprintf(stderr, "Out of memory.\n");
        exit(1);
    }
    memset(render, 0, sizeof(struct m6847_renderer));
    render->vdp = vdp;
    m6847_set_colourmap(vdp, vdp_ctab);
    render->window = SDL_CreateWindow("6847",
        SDL_WINDOWPOS_UNDEFINED,
        SDL_WINDOWPOS_UNDEFINED,
        512, 384,
        SDL_WINDOW_RESIZABLE);
    if (render->window == NULL) {
        fprintf(stderr, "Unable to create window: %s.\n", SDL_GetError());
        exit(1);
    }
    render->render = SDL_CreateRenderer(render->window, -1, SDL_RENDERER_ACCELERATED);
    if (render->render == NULL) {
        fprintf(stderr, "Unable to create renderer: %s.\n", SDL_GetError());
        exit(1);
    }
    SDL_SetHint(SDL_HINT_RENDER_SCALE_QUALITY, "linear");
    SDL_RenderSetLogicalSize(render->render, 256, 192);

    render->texture = SDL_CreateTexture(render->render,
                        SDL_PIXELFORMAT_ARGB8888,
                        SDL_TEXTUREACCESS_STREAMING,
                        256, 192);
    if (render->render == NULL) {
        fprintf(stderr, "Unable to create renderer: %s.\n", SDL_GetError());
        exit(1);
    }
    SDL_SetRenderDrawColor(render->render, 0, 0, 0, 255);
    SDL_RenderClear(render->render);
    SDL_RenderPresent(render->render);
    return render;
}