AppleWin/source/frontends/sdl

SA2: Apple ][ Emulator for Linux based on SDL2

This file only lists options not already described in -h.

The default frontend uses SDL2 + ImGui and requires an OpenGL ES2.0 implementation. It is possible to use plain SDL2 and select the renderer (pass --no-imgui and look at -h).

Configuration

The configuration GUI only works with ImGui: otherwise either manually edit the configuration file ~/.applewin/applewin.conf or use qapple and run sa2 --qt-ini. The format of the configuration file is the same as the Windows Registry of AppleWin.

Drag & drop works for floppy disks. With ImGui it is possible to select which drive they are dropped into (D&D). If the filename ends with .yaml, it will be loaded as a State file.

Individual options can be passed via arguments too: -c Configuration.Printer_FileName=Printer.txt.

If you have a modern gamepad where the axes (LEFTX and LEFTY) move in a circle, the emulator will automatically map to a square: use --no-squaring to avoid this.

Dear ImGui

The rendering is performed with Dear ImGui.

On a Raspberry Pi, a KMS driver is mandatory and best results are obtained on a Pi4 with FullKMS (full screen via F6).

Output mentions the Dear ImGui version, e.g.: IMGUI_VERSION: 1.81 WIP.

Some of the configuration options are exposed in the Settings menu. This is not a modal dialog and options are applied immediately. You might need to Restart the emulator manually.

Hotkeys

F2, F5, F6, F9, F11, F12 and Pause have the same meaning as in AppleWin.

Left Alt and Right Alt emulate the Open and Solid Apple key.

Shift-Insert pastes the clipboard to the input key buffer.

Ctrl-Insert copies the text screen (in AppleWin this is Ctrl-PrintScreen).

Audio

Audio works reasonably well, using AppleWin adaptive algorithm.

Use F1 during emulation to have an idea of the size of the audio queue

Channels: 1, buffer: 32768, SDL:  8804, queue: 0.47 s
Channels: 2, buffer: 45000, SDL: 65536, queue: 0.63 s

(1) is the speaker, (2) the Mockingboard.

Speed diagnostic

At the end of the run, it will print stats about timings:

Video refresh rate: 60 Hz, 16.67 ms
Global:  total =    7789.16 ms, mean =    7789.16 ms, std =       0.00 ms, n =      1
Events:  total =      22.42 ms, mean =       0.05 ms, std =       0.17 ms, n =    471
Texture: total =     113.32 ms, mean =       0.24 ms, std =       0.06 ms, n =    471
Screen:  total =    7624.87 ms, mean =      16.19 ms, std =       1.66 ms, n =    471
CPU:     total =     647.21 ms, mean =       1.34 ms, std =       0.48 ms, n =    484
Expected clock: 1020484.45 Hz, 7.74 s
Actual clock:   1014560.11 Hz, 7.79 s

• events: SDL events and audio
• texture: SDL_UpdateTexture
• screen: SDL_RenderCopyEx and SDL_RenderPresent (this includes vsync)
• cpu: AW's code

The clock shows expected vs actual speed.

Debugging

For debugging and profiling (valgrind), it is best to switch off adaptive speed, as otherwise it enters a feedback loop and seems to hang.

Use --fixed-speed.