SDL_os4framebuffer.c

/*
  Simple DirectMedia Layer
  Copyright (C) 1997-2023 Sam Lantinga <slouken@libsdl.org>

  This software is provided 'as-is', without any express or implied
  warranty.  In no event will the authors be held liable for any damages
  arising from the use of this software.

  Permission is granted to anyone to use this software for any purpose,
  including commercial applications, and to alter it and redistribute it
  freely, subject to the following restrictions:

  1. The origin of this software must not be misrepresented; you must not
     claim that you wrote the original software. If you use this software
     in a product, an acknowledgment in the product documentation would be
     appreciated but is not required.
  2. Altered source versions must be plainly marked as such, and must not be
     misrepresented as being the original software.
  3. This notice may not be removed or altered from any source distribution.
*/
#include "SDL_internal.h"

#if SDL_VIDEO_DRIVER_AMIGAOS4

#include <proto/layers.h>
#include <proto/graphics.h>

#include "SDL_os4video.h"
#include "SDL_os4framebuffer.h"
#include "SDL_os4window.h"

#include "../../main/amigaos4/SDL_os4debug.h"

int
OS4_CreateWindowFramebuffer(SDL_VideoDevice *_this, SDL_Window * window, Uint32 * format, void ** pixels, int * pitch)
{
    APTR lock;
    APTR base_address;
    uint32 bytes_per_row;
    uint32 depth;
    PIX_FMT pixf;

    SDL_WindowData *data = window->driverdata;

    if (data->bitmap) {
        dprintf("Freeing old bitmap %p\n", data->bitmap);
        IGraphics->FreeBitMap(data->bitmap);
    }

    if (!data->syswin) {
        dprintf("No system window\n");
        return SDL_SetError("No system window");
    }

    // Hardcode pixel format. It seems that SDL2 doesn't support all pixel formats
    // AmigaOS may use (for example PIXF_R5G6B5PC)
    pixf = PIXF_A8R8G8B8;
    depth = 32;

    *format = SDL_PIXELFORMAT_ARGB8888;

    dprintf("Native format %d, SDL format %d (%s)\n", pixf, *format, SDL_GetPixelFormatName(*format));
    dprintf("Allocating %d*%d*%d bitmap)\n", window->w, window->h, depth);

    data->bitmap = IGraphics->AllocBitMapTags(
        window->w,
        window->h,
        depth,
        BMATags_Clear, TRUE,
        BMATags_UserPrivate, TRUE,
        //BMATags_Friend, data->syswin->RPort->BitMap,
        BMATags_PixelFormat, pixf,
        TAG_DONE);

    if (data->bitmap) {
        /* Fill with zeroes, similar to SW renderer surface creation */
        struct RastPort rp;
        IGraphics->InitRastPort(&rp);
        rp.BitMap = data->bitmap;

        IGraphics->RectFillColor(
            &rp,
            0,
            0,
            window->w - 1,
            window->h - 1,
            0x00000000); // graphics.lib v54!
    } else {
        dprintf("Failed to allocate bitmap\n");
        return SDL_SetError("Failed to allocate bitmap for framebuffer");
    }

    /* Lock the bitmap to get details. Since it's user private,
    it should be safe to cache address and pitch. */
    lock = IGraphics->LockBitMapTags(
        data->bitmap,
        LBM_BaseAddress, &base_address,
        LBM_BytesPerRow, &bytes_per_row,
        TAG_DONE);

    if (lock) {
        *pixels = base_address;
        *pitch = bytes_per_row;

        IGraphics->UnlockBitMap(lock);
    } else {
        dprintf("Failed to lock bitmap\n");

        IGraphics->FreeBitMap(data->bitmap);
        data->bitmap = NULL;

        return SDL_SetError("Failed to lock framebuffer bitmap");
    }

    return 0;
}

static int
min(int a, int b)
{
    return (a < b) ? a : b;
}

int
OS4_UpdateWindowFramebuffer(SDL_VideoDevice *_this, SDL_Window * window, const SDL_Rect * rects, int numrects)
{
    SDL_WindowData * data = window->driverdata;
    int32 ret = -1;

    //dprintf("Called\n");

    if (data->bitmap && data->syswin) {
        int i;

        struct Window *syswin = data->syswin;

        const struct IBox windowBox = {
            syswin->BorderLeft,
            syswin->BorderTop,
            syswin->Width - syswin->BorderLeft - syswin->BorderRight,
            syswin->Height - syswin->BorderTop - syswin->BorderBottom };

        //dprintf("blit box %d*%d\n", windowBox.Width, windowBox.Height);

        ILayers->LockLayer(0, syswin->WLayer);

        for (i = 0; i < numrects; ++i) {
            const SDL_Rect * r = &rects[i];

            ret = IGraphics->BltBitMapTags(
                BLITA_Source, data->bitmap,
                //BLITA_SrcType, BLITT_BITMAP,
                BLITA_Dest, syswin->RPort,
                BLITA_DestType, BLITT_RASTPORT,
                BLITA_SrcX, r->x,
                BLITA_SrcY, r->y,
                BLITA_DestX, r->x + windowBox.Left,
                BLITA_DestY, r->y + windowBox.Top,
                BLITA_Width, min(r->w, windowBox.Width),
                BLITA_Height, min(r->h, windowBox.Height),
                TAG_DONE);

            if (ret != -1) {
                dprintf("BltBitMapTags() returned %d\n", ret);
            }
        }

        ILayers->UnlockLayer(syswin->WLayer);
    }

    if (ret != -1) {
        return SDL_SetError("BltBitMapTags failed");
    }

    return 0;
}

void
OS4_DestroyWindowFramebuffer(SDL_VideoDevice *_this, SDL_Window * window)
{
    SDL_WindowData *data = window->driverdata;

    if (data->bitmap) {
        dprintf("Freeing bitmap %p\n", data->bitmap);

        IGraphics->FreeBitMap(data->bitmap);
        data->bitmap = NULL;
    }
}

#endif /* SDL_VIDEO_DRIVER_AMIGAOS4 */

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