Rock Paper Scissors

Probability

Rock Paper Scissors (RPS) uses the function _determineRPSResult which has three possible outcomes: 1, 2 and 3.

randomActions[i] = uint8(randomWords[i] % 3);
outcomes[i] = _determineRPSResult(game.action, randomActions[i]);

Player outcome	Probability
Rock	33.3%
Paper	33.3%
Scissors	33.3%

House Edge and Multiplier

A 2% fee is taken off the payout by multiplying with 1.98 on a win and can be found in the RockPaperScissors contract:

payout += (game.wager * 198) / 100;
payouts[i] = (game.wager * 198) / 100;

A 1% fee is taken off the wager by multiplying with 0.99 on a draw:

payout += (game.wager * 99) / 100;
payouts[i] = (game.wager * 99) / 100;

No fee is taken on a loss.

Player outcome	Fee	Multiplier
Win	2%	1.98x
Draw	1%	0.99x
Loss	0%	0x

Therefor, the house edge for RPS is 1% ((2+1+0)/3).

Odds

With the above in mind, the odds for RPS are:

Odds	Outcome
Decimal odds	0.99
Return to Player	99%
Probability odds	49.5%