Mercurial > sdl-ios-xcode
annotate docs/man3/SDL_CreateRGBSurface.3 @ 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> |
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date | Thu, 19 Jan 2006 21:28:52 +0000 |
parents | e5bc29de3f0a |
children | 546f7c1eb755 |
rev | line source |
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1 .TH "SDL_CreateRGBSurface" "3" "Tue 11 Sep 2001, 23:01" "SDL" "SDL API Reference" |
0 | 2 .SH "NAME" |
3 SDL_CreateRGBSurface\- Create an empty SDL_Surface | |
4 .SH "SYNOPSIS" | |
5 .PP | |
6 \fB#include "SDL\&.h" | |
7 .sp | |
8 \fBSDL_Surface *\fBSDL_CreateRGBSurface\fP\fR(\fBUint32 flags, int width, int height, int depth, Uint32 Rmask, Uint32 Gmask, Uint32 Bmask, Uint32 Amask\fR); | |
9 .SH "DESCRIPTION" | |
10 .PP | |
11 Allocate an empty surface (must be called after \fISDL_SetVideoMode\fR) | |
12 .PP | |
13 If \fBdepth\fR is 8 bits an empty palette is allocated for the surface, otherwise a \&'packed-pixel\&' \fI\fBSDL_PixelFormat\fR\fR is created using the \fB[RGBA]mask\fR\&'s provided (see \fI\fBSDL_PixelFormat\fR\fR)\&. The \fBflags\fR specifies the type of surface that should be created, it is an OR\&'d combination of the following possible values\&. | |
14 .TP 20 | |
15 \fBSDL_SWSURFACE\fP | |
16 SDL will create the surface in system memory\&. This improves the performance of pixel level access, however you may not be able to take advantage of some types of hardware blitting\&. | |
17 .TP 20 | |
18 \fBSDL_HWSURFACE\fP | |
19 SDL will attempt to create the surface in video memory\&. This will allow SDL to take advantage of Video->Video blits (which are often accelerated)\&. | |
20 .TP 20 | |
21 \fBSDL_SRCCOLORKEY\fP | |
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22 This flag turns on colourkeying for blits from this surface\&. If \fBSDL_HWSURFACE\fP is also specified and colourkeyed blits are hardware-accelerated, then SDL will attempt to place the surface in video memory\&. Use \fI\fBSDL_SetColorKey\fP\fR to set or clear this flag after surface creation\&. |
0 | 23 .TP 20 |
24 \fBSDL_SRCALPHA\fP | |
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25 This flag turns on alpha-blending for blits from this surface\&. If \fBSDL_HWSURFACE\fP is also specified and alpha-blending blits are hardware-accelerated, then the surface will be placed in video memory if possible\&. Use \fI\fBSDL_SetAlpha\fP\fR to set or clear this flag after surface creation\&. |
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26 .PP |
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27 .RS |
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28 \fBNote: |
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29 .PP |
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30 If an alpha-channel is specified (that is, if \fBAmask\fR is nonzero), then the \fBSDL_SRCALPHA\fP flag is automatically set\&. You may remove this flag by calling \fI\fBSDL_SetAlpha\fP\fR after surface creation\&. |
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31 .RE |
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32 .SH "RETURN VALUE" |
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33 .PP |
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34 Returns the created surface, or \fBNULL\fR upon error\&. |
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35 .SH "EXAMPLE" |
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36 .PP |
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37 .nf |
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38 \f(CW /* Create a 32-bit surface with the bytes of each pixel in R,G,B,A order, |
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39 as expected by OpenGL for textures */ |
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40 SDL_Surface *surface; |
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41 Uint32 rmask, gmask, bmask, amask; |
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42 |
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43 /* SDL interprets each pixel as a 32-bit number, so our masks must depend |
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44 on the endianness (byte order) of the machine */ |
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45 #if SDL_BYTEORDER == SDL_BIG_ENDIAN |
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46 rmask = 0xff000000; |
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47 gmask = 0x00ff0000; |
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48 bmask = 0x0000ff00; |
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49 amask = 0x000000ff; |
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50 #else |
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51 rmask = 0x000000ff; |
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52 gmask = 0x0000ff00; |
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53 bmask = 0x00ff0000; |
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54 amask = 0xff000000; |
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55 #endif |
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56 |
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57 surface = SDL_CreateRGBSurface(SDL_SWSURFACE, width, height, 32, |
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58 rmask, gmask, bmask, amask); |
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59 if(surface == NULL) { |
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60 fprintf(stderr, "CreateRGBSurface failed: %s |
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61 ", SDL_GetError()); |
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62 exit(1); |
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63 }\fR |
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64 .fi |
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65 .PP |
0 | 66 .SH "SEE ALSO" |
67 .PP | |
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68 \fI\fBSDL_CreateRGBSurfaceFrom\fP\fR, \fI\fBSDL_FreeSurface\fP\fR, \fI\fBSDL_SetVideoMode\fP\fR, \fI\fBSDL_LockSurface\fP\fR, \fI\fBSDL_PixelFormat\fR\fR, \fI\fBSDL_Surface\fR\fR \fI\fBSDL_SetAlpha\fP\fR \fI\fBSDL_SetColorKey\fP\fR |
181
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69 ...\" created by instant / docbook-to-man, Tue 11 Sep 2001, 23:01 |