view docs/html/sdlsurface.html @ 1257:448a9a64537b

[PATCH] SDL_GetVideoMode() does not find best mode, part 2 Following commit 1.51, I come accross a problem when SDL must choose between several video modes that could suit the one asked. If I ask 320x240 with this list: 768x480 768x240 640x400 640x200 384x480 384x240 320x400 320x200 The smallest selectables modes are 384x240 and 320x400. And SDL choose the later in this list, but 384x240 is more suitable. So I added a check to compare the pixel count (surface) of modes, and select the one which has the smallest pixel count. In my example, 384x240 has 92160 pixels, and 320x400 has 128000 pixels. So now SDL will choose 384x240 for the asked 320x240 mode.
author Patrice Mandin <patmandin@gmail.com>
date Thu, 19 Jan 2006 21:28:52 +0000
parents 355632dca928
children
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<HTML
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>SDL_Surface</TITLE
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><H1
><A
NAME="SDLSURFACE"
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>SDL_Surface</H1
><DIV
CLASS="REFNAMEDIV"
><A
NAME="AEN3263"
></A
><H2
>Name</H2
>SDL_Surface&nbsp;--&nbsp;Graphical Surface Structure</DIV
><DIV
CLASS="REFSECT1"
><A
NAME="AEN3266"
></A
><H2
>Structure Definition</H2
><PRE
CLASS="PROGRAMLISTING"
>typedef struct SDL_Surface {
        Uint32 flags;                           /* Read-only */
        SDL_PixelFormat *format;                /* Read-only */
        int w, h;                               /* Read-only */
        Uint16 pitch;                           /* Read-only */
        void *pixels;                           /* Read-write */

        /* clipping information */
        SDL_Rect clip_rect;                     /* Read-only */

        /* Reference count -- used when freeing surface */
        int refcount;                           /* Read-mostly */

	/* This structure also contains private fields not shown here */
} SDL_Surface;</PRE
></DIV
><DIV
CLASS="REFSECT1"
><A
NAME="AEN3269"
></A
><H2
>Structure Data</H2
><DIV
CLASS="INFORMALTABLE"
><A
NAME="AEN3271"
></A
><P
></P
><TABLE
BORDER="0"
CLASS="CALSTABLE"
><TBODY
><TR
><TD
ALIGN="LEFT"
VALIGN="TOP"
><TT
CLASS="STRUCTFIELD"
><I
>flags</I
></TT
></TD
><TD
ALIGN="LEFT"
VALIGN="TOP"
>Surface flags</TD
></TR
><TR
><TD
ALIGN="LEFT"
VALIGN="TOP"
><TT
CLASS="STRUCTFIELD"
><I
>format</I
></TT
></TD
><TD
ALIGN="LEFT"
VALIGN="TOP"
>Pixel <A
HREF="sdlpixelformat.html"
>format</A
></TD
></TR
><TR
><TD
ALIGN="LEFT"
VALIGN="TOP"
><TT
CLASS="STRUCTFIELD"
><I
>w, h</I
></TT
></TD
><TD
ALIGN="LEFT"
VALIGN="TOP"
>Width and height of the surface</TD
></TR
><TR
><TD
ALIGN="LEFT"
VALIGN="TOP"
><TT
CLASS="STRUCTFIELD"
><I
>pitch</I
></TT
></TD
><TD
ALIGN="LEFT"
VALIGN="TOP"
>Length of a surface scanline in bytes</TD
></TR
><TR
><TD
ALIGN="LEFT"
VALIGN="TOP"
><TT
CLASS="STRUCTFIELD"
><I
>pixels</I
></TT
></TD
><TD
ALIGN="LEFT"
VALIGN="TOP"
>Pointer to the actual pixel data</TD
></TR
><TR
><TD
ALIGN="LEFT"
VALIGN="TOP"
><TT
CLASS="STRUCTFIELD"
><I
>clip_rect</I
></TT
></TD
><TD
ALIGN="LEFT"
VALIGN="TOP"
>surface clip <A
HREF="sdlrect.html"
>rectangle</A
></TD
></TR
></TBODY
></TABLE
><P
></P
></DIV
></DIV
><DIV
CLASS="REFSECT1"
><A
NAME="AEN3300"
></A
><H2
>Description</H2
><P
><SPAN
CLASS="STRUCTNAME"
>SDL_Surface</SPAN
>'s represent areas of "graphical"
memory, memory that can be drawn to. The video framebuffer is returned
as a <SPAN
CLASS="STRUCTNAME"
>SDL_Surface</SPAN
> by
<A
HREF="sdlsetvideomode.html"
><TT
CLASS="FUNCTION"
>SDL_SetVideoMode</TT
></A
>
and <A
HREF="sdlgetvideosurface.html"
><TT
CLASS="FUNCTION"
>SDL_GetVideoSurface</TT
></A
>.
Most of the fields should be pretty obvious.
<TT
CLASS="STRUCTFIELD"
><I
>w</I
></TT
> and <TT
CLASS="STRUCTFIELD"
><I
>h</I
></TT
> are the
width and height of the surface in pixels.
<TT
CLASS="STRUCTFIELD"
><I
>pixels</I
></TT
> is a pointer to the actual pixel data,
the surface should be <A
HREF="sdllocksurface.html"
>locked</A
>
before accessing this field. The <TT
CLASS="STRUCTFIELD"
><I
>clip_rect</I
></TT
> field
is the clipping rectangle as set by
<A
HREF="sdlsetcliprect.html"
><TT
CLASS="FUNCTION"
>SDL_SetClipRect</TT
></A
>.</P
><P
>The following are supported in the
<TT
CLASS="STRUCTFIELD"
><I
>flags</I
></TT
> field.</P
><DIV
CLASS="INFORMALTABLE"
><A
NAME="AEN3318"
></A
><P
></P
><TABLE
BORDER="1"
CLASS="CALSTABLE"
><TBODY
><TR
><TD
ALIGN="LEFT"
VALIGN="TOP"
><TT
CLASS="LITERAL"
>SDL_SWSURFACE</TT
></TD
><TD
ALIGN="LEFT"
VALIGN="TOP"
>Surface is stored in system memory</TD
></TR
><TR
><TD
ALIGN="LEFT"
VALIGN="TOP"
><TT
CLASS="LITERAL"
>SDL_HWSURFACE</TT
></TD
><TD
ALIGN="LEFT"
VALIGN="TOP"
>Surface is stored in video memory</TD
></TR
><TR
><TD
ALIGN="LEFT"
VALIGN="TOP"
><TT
CLASS="LITERAL"
>SDL_ASYNCBLIT</TT
></TD
><TD
ALIGN="LEFT"
VALIGN="TOP"
>Surface uses asynchronous blits if possible</TD
></TR
><TR
><TD
ALIGN="LEFT"
VALIGN="TOP"
><TT
CLASS="LITERAL"
>SDL_ANYFORMAT</TT
></TD
><TD
ALIGN="LEFT"
VALIGN="TOP"
>Allows any pixel-format (Display surface)</TD
></TR
><TR
><TD
ALIGN="LEFT"
VALIGN="TOP"
><TT
CLASS="LITERAL"
>SDL_HWPALETTE</TT
></TD
><TD
ALIGN="LEFT"
VALIGN="TOP"
>Surface has exclusive palette</TD
></TR
><TR
><TD
ALIGN="LEFT"
VALIGN="TOP"
><TT
CLASS="LITERAL"
>SDL_DOUBLEBUF</TT
></TD
><TD
ALIGN="LEFT"
VALIGN="TOP"
>Surface is double buffered (Display surface)</TD
></TR
><TR
><TD
ALIGN="LEFT"
VALIGN="TOP"
><TT
CLASS="LITERAL"
>SDL_FULLSCREEN</TT
></TD
><TD
ALIGN="LEFT"
VALIGN="TOP"
>Surface is full screen (Display Surface)</TD
></TR
><TR
><TD
ALIGN="LEFT"
VALIGN="TOP"
><TT
CLASS="LITERAL"
>SDL_OPENGL</TT
></TD
><TD
ALIGN="LEFT"
VALIGN="TOP"
>Surface has an OpenGL context (Display Surface)</TD
></TR
><TR
><TD
ALIGN="LEFT"
VALIGN="TOP"
><TT
CLASS="LITERAL"
>SDL_OPENGLBLIT</TT
></TD
><TD
ALIGN="LEFT"
VALIGN="TOP"
>Surface supports OpenGL blitting (Display Surface)</TD
></TR
><TR
><TD
ALIGN="LEFT"
VALIGN="TOP"
><TT
CLASS="LITERAL"
>SDL_RESIZABLE</TT
></TD
><TD
ALIGN="LEFT"
VALIGN="TOP"
>Surface is resizable (Display Surface)</TD
></TR
><TR
><TD
ALIGN="LEFT"
VALIGN="TOP"
><TT
CLASS="LITERAL"
>SDL_HWACCEL</TT
></TD
><TD
ALIGN="LEFT"
VALIGN="TOP"
>Surface blit uses hardware acceleration</TD
></TR
><TR
><TD
ALIGN="LEFT"
VALIGN="TOP"
><TT
CLASS="LITERAL"
>SDL_SRCCOLORKEY</TT
></TD
><TD
ALIGN="LEFT"
VALIGN="TOP"
>Surface use colorkey blitting</TD
></TR
><TR
><TD
ALIGN="LEFT"
VALIGN="TOP"
><TT
CLASS="LITERAL"
>SDL_RLEACCEL</TT
></TD
><TD
ALIGN="LEFT"
VALIGN="TOP"
>Colorkey blitting is accelerated with RLE</TD
></TR
><TR
><TD
ALIGN="LEFT"
VALIGN="TOP"
><TT
CLASS="LITERAL"
>SDL_SRCALPHA</TT
></TD
><TD
ALIGN="LEFT"
VALIGN="TOP"
>Surface blit uses alpha blending</TD
></TR
><TR
><TD
ALIGN="LEFT"
VALIGN="TOP"
><TT
CLASS="LITERAL"
>SDL_PREALLOC</TT
></TD
><TD
ALIGN="LEFT"
VALIGN="TOP"
>Surface uses preallocated memory</TD
></TR
></TBODY
></TABLE
><P
></P
></DIV
></DIV
><DIV
CLASS="REFSECT1"
><A
NAME="AEN3381"
></A
><H2
>See Also</H2
><P
><A
HREF="sdlpixelformat.html"
><SPAN
CLASS="STRUCTNAME"
>SDL_PixelFormat</SPAN
></A
></P
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