138 lines
2.8 KiB
Plaintext
138 lines
2.8 KiB
Plaintext
.TH EMU 2
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.SH NAME
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initemu, regkeyfn, flushmouse, flushscreen, flushaudio, screenwipe \- graphical emulator-like software scaffolding
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.SH SYNOPSIS
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.nf
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.ft L
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#include <u.h>
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#include <libc.h>
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#include <emu.h>
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.PP
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.ta +\w'\fLvoid fP'u
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.B
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void flushmouse(int discard);
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.PP
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.B
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void flushscreen(void);
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.PP
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.B
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void flushaudio(int (*fn)(void));
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.PP
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.B
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void regkeyfn(Rune r, void (*fn)(void));
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.PP
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.B
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void regkey(char *joyk, Rune r, int k);
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.PP
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.B
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void initemu(int dx, int dy, int bpp, ulong chan,
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.B
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int dokey, void(*kproc)(void*));
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.SH DESCRIPTION
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.I Libemu
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implements common user interfaces for programs controlled
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with a joypad or a limited number of keys.
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.PP
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.B initemu
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initializes the display for the given internal screen size
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.B dx
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by
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.B dy
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and
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.B bpp
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bit depth.
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.B Chan
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is an
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.B Image
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pixel format descriptor to be used for an internal framebuffer (see
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.IR draw (2)).
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.PP
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If
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.B dokey
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is true,
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a keyboard process is started which sets a 64-bit wide bit vector for input keys.
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.PP
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Keys are set via
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.B regkey.
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Pressing the key corresponding to the
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.B r
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rune, or writing
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.B joyk
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to standard in will
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.L OR
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.B k
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with the key bit vector.
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.PP
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.B Regkeyfn
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registers an additional rune and a callback for the keyboard process.
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.PP
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Normally, a joypad process is also started, and parses standard input for key presses.
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If
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.B dokey
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is false, only the joypad process will be started.
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If
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.B kproc
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is a valid function pointer,
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it will be used for keyboard processing instead of the library-provided one,
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and no joypad process will be started.
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.PP
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.IP
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.EX
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.ta 6n
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uchar *pic;
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.EE
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.PP
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Once
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.B initemu
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is called, a framebuffer of the specifized size is allocated,
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and may be accessed via
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.BR pic .
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.L Libemu
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scales the framebuffer to fit the greatest multiple of the framebuffer's
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width in the window.
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The scaling is horizontal only and needs to be taken into account for drawing
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within the program.
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.PP
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Typically, mouse event handling is followed by drawing the final image from the
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internal framebuffer render and writing a constant amount of audio samples,
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thereby synchronizing the program's framerate to the audio writes.
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.IP
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.EX
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.ta 6n
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Mouse m;
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extern Mousectl *mc;
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flushmouse(0);
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while(nbrecv(mc->c, &m) > 0){
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...
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}
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flushscreen();
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flushaudio(audioout);
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.EE
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.PP
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Besides window resizing, mouse events are discarded by default.
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If
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.B discard
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is false
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.B flushmouse
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will let the user program handle mouse events prior to flushing the screen (see
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.BR event (2)).
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.PP
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.B Flushscreen
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handles re-scaling and re-allocating the buffers used, as well as drawing to
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the screen, either directly, or by duplicating pre-scaled scanlines.
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.SH SOURCE
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.B /sys/src/libemu
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.SH "SEE ALSO"
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.IR draw (2),
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.IR event (2)
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.SH BUGS
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The semantics for
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.B initemu
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input selection are confusing.
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.PP
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A greater effort should be made to simplify automatic scaling for user programs.
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.SH HISTORY
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.I Libemu
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first appeared in 9front in May, 2018.
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