cube-bench-classic

A new benchmark for Classic Macintosh Computers

Cube Bench Classic is a very simple benchmark involving a cube designed for Classic Mac OS System 7. Requires Color QuickDraw.

I wanted something a bit more relatable than a bar chart or flashing patterned rectangles to get a feel for performance differences between classic Macs (LC III, etc.). So for #Marchintosh 2024, I wrote my own benchmark with the classic spinning cube(s).

Cube Bench Classic is designed to stress the CPU, FPU, and memory bus. Being a System 7 application, software rendering is pretty much the only game in town. Cube Bench Classic uses floating point arithmetic for pretty much everything to stress the CPU (or FPU if present). Particularly, the cube is rotated using transcendentals (i.e., trigonometric functions).

Drawing on the screen is done using QuickDraw lines and filled polygons. Every QuickDraw call seems to force a screen refresh so something had to be done to avoid flickering. There's no way to flip buffers in QuickDraw that I could find, so the usual double-buffering wasn't an option. Instead, rendering is done on an Offscreen Graphics World (back buffer) before copying to the Onscreen Graphics World (front buffer). This stresses the memory bus.

Compilation

Developed with Symantec C++ for Macintosh 7.0, using a mix of real hardware, working in Symantec C++ in BasiliskII or VS Code. Probably an even split BasiliskII.

To compile, open the Project Manager and create a new Mac Application Project. Add the contents of cubes/ folder and then add a few libraries:

• ANSI++
• CPlusLib
• MacTraps (this should be there by default)

You may want to set Symantec C++ and THINK C options (Compiler Settings) to make use of your hardware FPU if present:

• Generate 68881 instructions
• Use 881 for transcendental

Line endings

This repository currently is set to use CRLF line endings via .gitattributes file so that files are somewhat readable no matter what operating system they are read on.

Classic Mac OS expects CR line endings, so opening the files as is will show a square character. To remove these, convert the files using the dos2unix and unix2mac tools from the dos2unix package.

Convert to CR line endings:

find . -type f -a \( -name '*.cpp' -o -name '*.h' \) | xargs dos2unix
find . -type f -a \( -name '*.cpp' -o -name '*.h' \) | xargs unix2mac

Convert back to CRLF line endings:

find . -type f -a \( -name '*.cpp' -o -name '*.h' \) | xargs mac2unix
find . -type f -a \( -name '*.cpp' -o -name '*.h' \) | xargs unix2dos

Configuration

Program configuration options are stored in config.h. Resolutions can be tweaked with the SHRINK setting here, changing how much smaller the window is than screen resolution. LONG_STATS defines the number of frames that make up the benchmark, and changing it will change the length of the benchmark.

Versioning

Program version is kept in CUBE_VERSION defined in version.h. This can be updated automatically upon a git commit with a .git/hooks/post-commit script containing

#!/bin/bash
COMMIT_HASH=$(git rev-parse --short HEAD)
VERSION_FILE="cubes/version.h"
echo "Updating version.h to $COMMIT_HASH"
sed -i "s/[0-9a-f]\{7\}/$COMMIT_HASH/" $VERSION_FILE

Partition size

If your Mac has as resolution higher than 640x480 at 256 colours, you will need to increase the partition size in order to run the application. This can either be done using Get Info (⌘I) in the Finder and entering a larger 'Preferred size', or during compilation going to the 'Project' menu, selecting 'Set Project Type...', and entering a larger value in the 'Partition (K)' field.

A 512 K partition size is fine for 800x600 at 256 colours.

Usage

Command-R to run from within Symantec C++. To quit, click anywhere outside the window, press return, or press escape.

There are a lot of keyboard commands, check out the section below for details, or press the h key to bring up on screen help. More cubes can be shown on screen and the cube moved, or set to bounce.

Press the b key to begin a benchmark. This will render the same 1800 frames. This would take 30 seconds at 60 FPS, but will probably take more like 5-10 minutes. Pressing any key while the benchmark is running will cancel the benchmark. The final result is shown as a frame time stat (see below). Once the benchmark has run the cubes will stop moving. At this point you may screenshot using shift-p or export to a text file using shift-t. Any other keys will clear the result.

Performance is displayed a few different ways:

• First is a per-frame measure of TPF, or ticks per frame. One tick corresponds to one screen refresh, generally about 1/60th of a second.
• Second, a more traditional FPS or frames per second is displayed. This is a mean taken over a 30 frame rolling average plus or minus the standard deviation.
• Third is FT or frame time, which is the time taken to generate each frame in milliseconds. This is inversely proportional to FPS and is also displayed as a 30 frame mean plus or minus the standard deviation.
• Fourth is the benchmark result as mean frame time plus or minus the standard deviation over the entire benchmark run.

The 95th percentile FPS will be approximately the mean minus two standard deviations, and the 99th percentile will be approximately the mean minus three standard deviations.

Tested under System 7.5.3 on an LC, LC II, LC II, LC 475, and BasiliskII 1.0.0_p20240224. Tested under System 7.1 on a Macintosh SE with a Radius Accelerator 25.

Key bindings

Capital keys accessed using caps lock or shift plus key, for example P is shift-p.

Key	Action
`	Quit
ret	Quit
esc	Quit
b/B	Run benchmark
c/C	Clear (erase) canvas
f/F	Toggle filled cube faces
h/H	On screen help message
m/M	Toggle movement
n/N	Toggle rotation
x/X	Toggle cubes bouncing
P	Save a screenshot to a BMP image
T	Save benchmark results to a text file
r	reset all active cubes
R	randomise all active cubes
v/V	Toggle invert background colour
spc	Toggle rotation & movement
-/+	-/+ (decrease/increase) current cube size
0-9	select & toggle the current cube 0 to 9
j/l	-/+ x-rotate current cube
i/k	-/+ y-rotate current cube
u/o	-/+ z-rotate current cube
J/L	-/+ x-rotation speed of current cube
I/K	-/+ y-rotation speed of current cube
U/O	-/+ z-rotation speed of current cube
a/d	-/+ x-move current cube
w/s	-/+ y-move current cube
q/e	-/+ z-move current cube
A/D	-/+ x-velocity of current cube
W/S	-/+ y-velocity of current cube
Q/E	-/+ z-velocity of current cube

The default current cube is cube 1. Press other number keys to turn on more cubes and increase benchmark difficulty.

Clicking outside the window will quit.

Known issues

Immediately quits

• This will happen if either Cube Bench Classic has been compiled to use a FPU and one is not detected (1 beep) or if System version is less than 7 (2 beeps).

Multiple screens, maybe?

• Window size is determined from screenBits, which documentation suggests doesn't acknowledge the existence of multiple screens. If you have two screens, the window may span across multiple screens.

1-bit colour

• Only so much you can do with black and white, but that aside there may be some instances where things disappear due to not calling ForeColor(whiteColor). File an issue please.

Saving screenshots

• Sometimes the background looks a bit pink. Are you in 16-bit ("Thousands of Colors") mode? 16-bit bitmaps are scuffed, with missing green precision, due to Motorola 68000 CPUs being big-endian and BMP needing little-endian (as written at least). What image editors do with the left over bits varies. Try opening in another image editor, e.g., the GNU Image Manipulation Program.

• Sometimes there's some garbage along the left and right edges of the screenshot. This is expected and happens when the buffer we are saving a copy of is larger than what is displayed on screen due to Apple memory aligning the for faster copies. You may safely ignore these parts of the image.

• One beep during saving a screenshot indicates an issue selecting the save file.

• Two beeps during saving a screenshot indicate an issue writing the image data.