annotate docs/man3/SDL_MouseMotionEvent.3 @ 1544:ab1e4c41ab71

Fixed bug #33 Mike Frysinger wrote: > with libsdl-1.2.9, some games (like bomberclone) started > segfaulting in Gentoo [...snip...] > the last change in the last hunk: [...snip...] > if i change the statement to read: > (table[which].blit_features & GetBlitFeatures()) == GetBlitFeatures() > bomberclone no longer segfaults on my box Alex Volkov wrote: > The test "(table[which].blit_features & GetBlitFeatures()) == > table[which].blit_features)" is correct, and the previous > "(table[which].cpu_mmx == SDL_HasMMX())" was actually broken. I think there is potentially a slightly different cause of the above problem. During the introduction of the Altivec code, the blit_table struct field 'alpha' got changed from a straightforward enum to a bitmask, which makes perfect sense by itself. However, now the table driven blitter selection code in SDL_CalculateBlitN() can choose the wrong blitters when searching for a NO_ALPHA blitter because of the following code: int a_need = 0; ... (a_need & table[which].alpha) == a_need && When searching through the normal_blit_2[] table, a SET_ALPHA blitter (like Blit_RGB565_ARGB8888) can now be selected instead of a NO_ALPHA one, causing alpha channel bits to appear in a non-alpha destination surface. I suppose this could theoretically be an indirect cause of the segfault mentioned above. I *think* this can be fixed by changing to int a_need = NO_ALPHA;
author Sam Lantinga <slouken@libsdl.org>
date Wed, 15 Mar 2006 15:47:49 +0000
parents e5bc29de3f0a
children 546f7c1eb755
rev   line source
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e5bc29de3f0a Updated from the SDL Documentation Project
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1 .TH "SDL_MouseMotionEvent" "3" "Tue 11 Sep 2001, 22:59" "SDL" "SDL API Reference"
0
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2 .SH "NAME"
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3 SDL_MouseMotionEvent\- Mouse motion event structure
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4 .SH "STRUCTURE DEFINITION"
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5 .PP
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6 .nf
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7 \f(CWtypedef struct{
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8 Uint8 type;
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9 Uint8 state;
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10 Uint16 x, y;
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11 Sint16 xrel, yrel;
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12 } SDL_MouseMotionEvent;\fR
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13 .fi
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14 .PP
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15 .SH "STRUCTURE DATA"
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16 .TP 20
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17 \fBtype\fR
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18 \fBSDL_MOUSEMOTION\fP
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19 .TP 20
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20 \fBstate\fR
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21 The current button state
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22 .TP 20
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23 \fBx\fR, \fBy\fR
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24 The X/Y coordinates of the mouse
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25 .TP 20
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26 \fBxrel\fR, \fByrel\fR
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27 Relative motion in the X/Y direction
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28 .SH "DESCRIPTION"
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29 .PP
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30 \fBSDL_MouseMotionEvent\fR is a member of the \fI\fBSDL_Event\fR\fR union and is used when an event of type \fBSDL_MOUSEMOTION\fP is reported\&.
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31 .PP
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32 Simply put, a \fBSDL_MOUSEMOTION\fP type event occurs when a user moves the mouse within the application window or when \fI\fBSDL_WarpMouse\fP\fR is called\&. Both the absolute (\fBx\fR and \fBy\fR) and relative (\fBxrel\fR and \fByrel\fR) coordinates are reported along with the current button states (\fBstate\fR)\&. The button state can be interpreted using the \fBSDL_BUTTON\fP macro (see \fI\fBSDL_GetMouseState\fP\fR)\&.
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33 .PP
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34 If the cursor is hidden (\fI\fBSDL_ShowCursor\fP(0)\fR) and the input is grabbed (\fI\fBSDL_WM_GrabInput\fP(SDL_GRAB_ON)\fR), then the mouse will give relative motion events even when the cursor reaches the edge fo the screen\&. This is currently only implemented on Windows and Linux/Unix-a-likes\&.
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35 .SH "SEE ALSO"
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36 .PP
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37 \fI\fBSDL_Event\fR\fR, \fI\fBSDL_MouseButtonEvent\fR\fR
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38 ...\" created by instant / docbook-to-man, Tue 11 Sep 2001, 22:59