view src/video/dummy/SDL_nullrender.c @ 3473:7bdc10624cba

This is terrible, but the OpenGL standard says that lines are half open, which means that one endpoint is not covered so adjoining lines don't overlap. It also doesn't define which end is open, and indeed Mac OS X and Linux differ. Mac OS X seems to leave the second endpoint open, but Linux uses the right-most endpoint for x major lines and the bottom-most endpoint for y major lines.
author Sam Lantinga <slouken@libsdl.org>
date Sat, 21 Nov 2009 07:14:21 +0000
parents a65f7b3a2524
children 0267b8b1595c
line wrap: on
line source

/*
    SDL - Simple DirectMedia Layer
    Copyright (C) 1997-2009 Sam Lantinga

    This library is free software; you can redistribute it and/or
    modify it under the terms of the GNU Lesser General Public
    License as published by the Free Software Foundation; either
    version 2.1 of the License, or (at your option) any later version.

    This library is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
    Lesser General Public License for more details.

    You should have received a copy of the GNU Lesser General Public
    License along with this library; if not, write to the Free Software
    Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA

    Sam Lantinga
    slouken@libsdl.org
*/
#include "SDL_config.h"

#include "SDL_video.h"
#include "../SDL_sysvideo.h"
#include "../SDL_yuv_sw_c.h"
#include "../SDL_renderer_sw.h"


/* SDL surface based renderer implementation */

static SDL_Renderer *SDL_DUMMY_CreateRenderer(SDL_Window * window,
                                              Uint32 flags);
static int SDL_DUMMY_RenderPoint(SDL_Renderer * renderer, int x, int y);
static int SDL_DUMMY_RenderLine(SDL_Renderer * renderer, int x1, int y1,
                                int x2, int y2);
static int SDL_DUMMY_RenderFill(SDL_Renderer * renderer,
                                const SDL_Rect * rect);
static int SDL_DUMMY_RenderCopy(SDL_Renderer * renderer,
                                SDL_Texture * texture,
                                const SDL_Rect * srcrect,
                                const SDL_Rect * dstrect);
static int SDL_DUMMY_RenderReadPixels(SDL_Renderer * renderer,
                                      const SDL_Rect * rect,
                                      Uint32 format,
                                      void * pixels, int pitch);
static int SDL_DUMMY_RenderWritePixels(SDL_Renderer * renderer,
                                       const SDL_Rect * rect,
                                       Uint32 format,
                                       const void * pixels, int pitch);
static void SDL_DUMMY_RenderPresent(SDL_Renderer * renderer);
static void SDL_DUMMY_DestroyRenderer(SDL_Renderer * renderer);


SDL_RenderDriver SDL_DUMMY_RenderDriver = {
    SDL_DUMMY_CreateRenderer,
    {
     "dummy",
     (SDL_RENDERER_SINGLEBUFFER | SDL_RENDERER_PRESENTCOPY |
      SDL_RENDERER_PRESENTFLIP2 | SDL_RENDERER_PRESENTFLIP3 |
      SDL_RENDERER_PRESENTDISCARD),
     }
};

typedef struct
{
    int current_screen;
    SDL_Surface *screens[3];
} SDL_DUMMY_RenderData;

SDL_Renderer *
SDL_DUMMY_CreateRenderer(SDL_Window * window, Uint32 flags)
{
    SDL_VideoDisplay *display = SDL_GetDisplayFromWindow(window);
    SDL_DisplayMode *displayMode = &display->current_mode;
    SDL_Renderer *renderer;
    SDL_DUMMY_RenderData *data;
    int i, n;
    int bpp;
    Uint32 Rmask, Gmask, Bmask, Amask;

    if (!SDL_PixelFormatEnumToMasks
        (displayMode->format, &bpp, &Rmask, &Gmask, &Bmask, &Amask)) {
        SDL_SetError("Unknown display format");
        return NULL;
    }

    renderer = (SDL_Renderer *) SDL_calloc(1, sizeof(*renderer));
    if (!renderer) {
        SDL_OutOfMemory();
        return NULL;
    }

    data = (SDL_DUMMY_RenderData *) SDL_malloc(sizeof(*data));
    if (!data) {
        SDL_DUMMY_DestroyRenderer(renderer);
        SDL_OutOfMemory();
        return NULL;
    }
    SDL_zerop(data);

    renderer->RenderPoint = SDL_DUMMY_RenderPoint;
    renderer->RenderLine = SDL_DUMMY_RenderLine;
    renderer->RenderFill = SDL_DUMMY_RenderFill;
    renderer->RenderCopy = SDL_DUMMY_RenderCopy;
    renderer->RenderReadPixels = SDL_DUMMY_RenderReadPixels;
    renderer->RenderWritePixels = SDL_DUMMY_RenderWritePixels;
    renderer->RenderPresent = SDL_DUMMY_RenderPresent;
    renderer->DestroyRenderer = SDL_DUMMY_DestroyRenderer;
    renderer->info.name = SDL_DUMMY_RenderDriver.info.name;
    renderer->info.flags = 0;
    renderer->window = window->id;
    renderer->driverdata = data;
    Setup_SoftwareRenderer(renderer);

    if (flags & SDL_RENDERER_PRESENTFLIP2) {
        renderer->info.flags |= SDL_RENDERER_PRESENTFLIP2;
        n = 2;
    } else if (flags & SDL_RENDERER_PRESENTFLIP3) {
        renderer->info.flags |= SDL_RENDERER_PRESENTFLIP3;
        n = 3;
    } else {
        renderer->info.flags |= SDL_RENDERER_PRESENTCOPY;
        n = 1;
    }
    for (i = 0; i < n; ++i) {
        data->screens[i] =
            SDL_CreateRGBSurface(0, window->w, window->h, bpp, Rmask, Gmask,
                                 Bmask, Amask);
        if (!data->screens[i]) {
            SDL_DUMMY_DestroyRenderer(renderer);
            return NULL;
        }
        SDL_SetSurfacePalette(data->screens[i], display->palette);
    }
    data->current_screen = 0;

    return renderer;
}

static int
SDL_DUMMY_RenderPoint(SDL_Renderer * renderer, int x, int y)
{
    SDL_DUMMY_RenderData *data =
        (SDL_DUMMY_RenderData *) renderer->driverdata;
    SDL_Surface *target = data->screens[data->current_screen];
    int status;

    if (renderer->blendMode == SDL_BLENDMODE_NONE ||
        renderer->blendMode == SDL_BLENDMODE_MASK) {
        Uint32 color =
            SDL_MapRGBA(target->format, renderer->r, renderer->g, renderer->b,
                        renderer->a);

        status = SDL_DrawPoint(target, x, y, color);
    } else {
        status =
            SDL_BlendPoint(target, x, y, renderer->blendMode, renderer->r,
                           renderer->g, renderer->b, renderer->a);
    }
    return status;
}

static int
SDL_DUMMY_RenderLine(SDL_Renderer * renderer, int x1, int y1, int x2, int y2)
{
    SDL_DUMMY_RenderData *data =
        (SDL_DUMMY_RenderData *) renderer->driverdata;
    SDL_Surface *target = data->screens[data->current_screen];
    int status;

    if (renderer->blendMode == SDL_BLENDMODE_NONE ||
        renderer->blendMode == SDL_BLENDMODE_MASK) {
        Uint32 color =
            SDL_MapRGBA(target->format, renderer->r, renderer->g, renderer->b,
                        renderer->a);

        status = SDL_DrawLine(target, x1, y1, x2, y2, color);
    } else {
        status =
            SDL_BlendLine(target, x1, y1, x2, y2, renderer->blendMode,
                          renderer->r, renderer->g, renderer->b, renderer->a);
    }
    return status;
}

static int
SDL_DUMMY_RenderFill(SDL_Renderer * renderer, const SDL_Rect * rect)
{
    SDL_DUMMY_RenderData *data =
        (SDL_DUMMY_RenderData *) renderer->driverdata;
    SDL_Surface *target = data->screens[data->current_screen];
    SDL_Rect real_rect = *rect;
    int status;

    if (renderer->blendMode == SDL_BLENDMODE_NONE) {
        Uint32 color =
            SDL_MapRGBA(target->format, renderer->r, renderer->g, renderer->b,
                        renderer->a);

        status = SDL_FillRect(target, &real_rect, color);
    } else {
        status =
            SDL_BlendRect(target, &real_rect, renderer->blendMode,
                          renderer->r, renderer->g, renderer->b, renderer->a);
    }
    return status;
}

static int
SDL_DUMMY_RenderCopy(SDL_Renderer * renderer, SDL_Texture * texture,
                     const SDL_Rect * srcrect, const SDL_Rect * dstrect)
{
    SDL_DUMMY_RenderData *data =
        (SDL_DUMMY_RenderData *) renderer->driverdata;
    SDL_Window *window = SDL_GetWindowFromID(renderer->window);
    SDL_VideoDisplay *display = SDL_GetDisplayFromWindow(window);

    if (SDL_ISPIXELFORMAT_FOURCC(texture->format)) {
        SDL_Surface *target = data->screens[data->current_screen];
        void *pixels =
            (Uint8 *) target->pixels + dstrect->y * target->pitch +
            dstrect->x * target->format->BytesPerPixel;
        return SDL_SW_CopyYUVToRGB((SDL_SW_YUVTexture *) texture->driverdata,
                                   srcrect, display->current_mode.format,
                                   dstrect->w, dstrect->h, pixels,
                                   target->pitch);
    } else {
        SDL_Surface *surface = (SDL_Surface *) texture->driverdata;
        SDL_Surface *target = data->screens[data->current_screen];
        SDL_Rect real_srcrect = *srcrect;
        SDL_Rect real_dstrect = *dstrect;

        return SDL_LowerBlit(surface, &real_srcrect, target, &real_dstrect);
    }
}

static int
SDL_DUMMY_RenderReadPixels(SDL_Renderer * renderer, const SDL_Rect * rect,
                           Uint32 format, void * pixels, int pitch)
{
    SDL_DUMMY_RenderData *data =
        (SDL_DUMMY_RenderData *) renderer->driverdata;
    SDL_Window *window = SDL_GetWindowFromID(renderer->window);
    SDL_VideoDisplay *display = SDL_GetDisplayFromWindow(window);
    SDL_Surface *screen = data->screens[data->current_screen];
    Uint32 screen_format = display->current_mode.format;
    Uint8 *screen_pixels = (Uint8 *) screen->pixels +
                            rect->y * screen->pitch +
                            rect->x * screen->format->BytesPerPixel;
    int screen_pitch = screen->pitch;

    return SDL_ConvertPixels(rect->w, rect->h,
                             screen_format, screen_pixels, screen_pitch,
                             format, pixels, pitch);
}

static int
SDL_DUMMY_RenderWritePixels(SDL_Renderer * renderer, const SDL_Rect * rect,
                            Uint32 format, const void * pixels, int pitch)
{
    SDL_DUMMY_RenderData *data =
        (SDL_DUMMY_RenderData *) renderer->driverdata;
    SDL_Window *window = SDL_GetWindowFromID(renderer->window);
    SDL_VideoDisplay *display = SDL_GetDisplayFromWindow(window);
    SDL_Surface *screen = data->screens[data->current_screen];
    Uint32 screen_format = display->current_mode.format;
    Uint8 *screen_pixels = (Uint8 *) screen->pixels +
                            rect->y * screen->pitch +
                            rect->x * screen->format->BytesPerPixel;
    int screen_pitch = screen->pitch;

    return SDL_ConvertPixels(rect->w, rect->h,
                             format, pixels, pitch,
                             screen_format, screen_pixels, screen_pitch);
}

static void
SDL_DUMMY_RenderPresent(SDL_Renderer * renderer)
{
    static int frame_number;
    SDL_DUMMY_RenderData *data =
        (SDL_DUMMY_RenderData *) renderer->driverdata;

    /* Send the data to the display */
    if (SDL_getenv("SDL_VIDEO_DUMMY_SAVE_FRAMES")) {
        char file[128];
        SDL_snprintf(file, sizeof(file), "SDL_window%d-%8.8d.bmp",
                     renderer->window, ++frame_number);
        SDL_SaveBMP(data->screens[data->current_screen], file);
    }

    /* Update the flipping chain, if any */
    if (renderer->info.flags & SDL_RENDERER_PRESENTFLIP2) {
        data->current_screen = (data->current_screen + 1) % 2;
    } else if (renderer->info.flags & SDL_RENDERER_PRESENTFLIP3) {
        data->current_screen = (data->current_screen + 1) % 3;
    }
}

static void
SDL_DUMMY_DestroyRenderer(SDL_Renderer * renderer)
{
    SDL_DUMMY_RenderData *data =
        (SDL_DUMMY_RenderData *) renderer->driverdata;
    int i;

    if (data) {
        for (i = 0; i < SDL_arraysize(data->screens); ++i) {
            if (data->screens[i]) {
                SDL_FreeSurface(data->screens[i]);
            }
        }
        SDL_free(data);
    }
    SDL_free(renderer);
}

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