Mercurial > sdl-ios-xcode
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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181
e5bc29de3f0a
Updated from the SDL Documentation Project
Sam Lantinga <slouken@libsdl.org>
parents:
55
diff
changeset
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1 .TH "SDL_MouseMotionEvent" "3" "Tue 11 Sep 2001, 22:59" "SDL" "SDL API Reference" |
0 | 2 .SH "NAME" |
3 SDL_MouseMotionEvent\- Mouse motion event structure | |
4 .SH "STRUCTURE DEFINITION" | |
5 .PP | |
6 .nf | |
7 \f(CWtypedef struct{ | |
8 Uint8 type; | |
9 Uint8 state; | |
10 Uint16 x, y; | |
11 Sint16 xrel, yrel; | |
12 } SDL_MouseMotionEvent;\fR | |
13 .fi | |
14 .PP | |
15 .SH "STRUCTURE DATA" | |
16 .TP 20 | |
17 \fBtype\fR | |
18 \fBSDL_MOUSEMOTION\fP | |
19 .TP 20 | |
20 \fBstate\fR | |
21 The current button state | |
22 .TP 20 | |
23 \fBx\fR, \fBy\fR | |
24 The X/Y coordinates of the mouse | |
25 .TP 20 | |
26 \fBxrel\fR, \fByrel\fR | |
27 Relative motion in the X/Y direction | |
28 .SH "DESCRIPTION" | |
29 .PP | |
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\&. | |
31 .PP | |
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)\&. | |
33 .PP | |
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\&. | |
35 .SH "SEE ALSO" | |
36 .PP | |
37 \fI\fBSDL_Event\fR\fR, \fI\fBSDL_MouseButtonEvent\fR\fR | |
181
e5bc29de3f0a
Updated from the SDL Documentation Project
Sam Lantinga <slouken@libsdl.org>
parents:
55
diff
changeset
|
38 ...\" created by instant / docbook-to-man, Tue 11 Sep 2001, 22:59 |