R.C. Pro-Am II/Game Mechanics - Revision history

Ktwo: /* RAM addresses */

2023-06-11T10:55:46Z

‎RAM addresses

Ktwo: /* RAM addresses */

2023-06-11T10:04:30Z

‎RAM addresses

Ktwo: /* Letters */

2023-06-11T10:01:27Z

‎Letters

Ktwo: /* Letters */

2022-10-10T15:42:36Z

‎Letters

Ktwo: /* RNG */

2022-10-10T15:41:36Z

‎RNG

Ktwo: /* RNG */

2022-10-10T15:38:17Z

‎RNG

Ktwo: /* RAM addresses */

2022-10-10T15:26:50Z

‎RAM addresses

Ktwo: /* RAM addresses */

2018-09-10T19:56:15Z

‎RAM addresses

Ktwo: /* Letters */

2018-05-09T18:29:20Z

‎Letters

Ktwo: /* Max speeds */

2018-05-09T18:27:24Z

‎Max speeds

@@ Line 604: / Line 604: @@
 * 05B2 - Zipper boost
 * 0748 - Nitros
-* 0626 - Nitro boost (see section about nitros)
+* 0626/061E/0622 - Nitro boost/phase/counter (see section about nitros)
-* 061E - Nitro phase (see section about nitros)
-* 0622 - Nitro counter (see section about nitros)
 * 043C - Frame counter giving input to the RNG (letters/line-up/traffic light)
 * 0756-0759 - RNG-addresses
@@ Line 614: / Line 612: @@
 * 0704 - Tyre type (0-4, where 0 is the standard tires and 4 is the Scoopers tires)
 * 0710 - Car upgrade (0-2, where 0 is standard and 2 is the 2nd car upgrade)
-* 075B - Small money address. Value multiplied by 10.
+* 05F2/05F6 - Big/Small money earned/collected during a race. The decimal value is multiplied by 10 for a player's earnings during the race.
-* 075F - Big money address. Value multiplied by 2560.
+* 075F/075B - Big/Small money (total). The decimal value is multiplied by 10 for the player's total cash (added up after each race).
 * 07A1 - Letters collected. P is worth 64, R 32, O 16, A 8, M 4, the first I 2 and the second I is worth 1. This adds up to 127 (or 01111111 in binary). When you enter the shop with a value of 127, you'll get the first upgrade and the value changes to 128 (or 10000000 in binary). Once you reach 255 (128+127), you'll get the second car upgrade and the value is set to 253 for the rest of the game.
 * 0728/072C/0730/0734/0738/073C/0740/0744 - Buckshots/Missiles/Bombs/Lazers/Freezes/Mega Pulses/Shields/Slicks

@@ Line 600: / Line 600: @@
 ==RAM addresses==
-For player-specific stats, the neighboring addresses contain the corresponding stats of the opponents.
+All player-specific stats are for P1. The next three addresses contain the corresponding stats of the other cars.
 * 0596 - Car speed
 * 05B2 - Zipper boost

@@ Line 166: / Line 166: @@
 The six letter addresses depend on the different cars in the following way:
-* 01CD - The XOR operation will be based on car 1's letters (red, address 0741)
+* 01CD - The XOR operation will be based on car 1's letters (red, address 07A1)
-* 01CE - Car 2's letters (blue, address 0742)
+* 01CE - Car 2's letters (blue, address 07A2)
-* 01CF - Car 3's letters (green, address, 0743)
+* 01CF - Car 3's letters (green, address, 07A3)
-* 01D0 - Car 4's letters (yellow, address 0744)
+* 01D0 - Car 4's letters (yellow, address 07A4)
 * 01D1 - Car letters depending on the race. In race 1, it's car 1's letters, in race 2, car 2's etc. Note that the bonus stages count as well. So race 9 will depend on car 2's letters.
 * 01D2 - Random car (= depends on the RNG-addresses and therefore not predictable)

@@ Line 153: / Line 153: @@
 Each individual letter item (to avoid any possible confusion, it's the white boxes with a black letter) is linked to one of six letter addresses (01CD-01D2). These links are static and are described further down. Each letter address is recalculated at the start of every race, regardless of if it's going to be used or not. The letter generation process is as follows:
 #Update RNG-addresses 0756-0759. The detailed calculation with comments is described in http://tasvideos.org/forum/viewtopic.php?t=9164
-#Perform an XOR on the "letters collected" address of one of the cars (07A1-07A4) and $FF. Since each letter collected is a binary 1 in the corresponding byte, the result will contain 1 for the bits corresponding to letters <u>not</u> collected by that car.
+#Perform an XOR on the "letters collected" address of one of the cars (07A1-07A4) and 0xFF. Since each letter collected is a binary 1 in the corresponding byte, the result will contain 1 for the bits corresponding to letters <u>not</u> collected by that car.
 #Perform an AND on the result in 2 with 0756. The AND-operation is performed from left to right and stops as soon as it results in a 1.
 #The position of the resulting 1 determines the letter in the order P, R, O, A and M, with the rest always resulting in an I. Write the corresponding result to the letter address.

@@ Line 146: / Line 146: @@
 * Line-up at the start line
 <br />
-All three are determined by a set of RNG-addresses (0756-0759) and a frame counter (043C) when pressing start in the shop. The RNG-algorithm is triggered a few times during the start of a race and can also occasionally be called during a race. The frame counter is reset between every race, which in theory could provide a method for manipulating the RNG. There are ways to determine the RNG-seed in race 1 (by looking at the car order at line-up and which letter is in the letter box). One could technically learn a few neighboring RNG-seeds that follow in race 2, depending on how long the frame counter was left to run during the shop menu. But the possibilities quickly branch out and it will in practice be difficult to memorize all possible branches. This means real-time manipulation is likely going to be limited. There is one exception and that is race 1, which always starts from the same seed and therefore only depends on the frame counter.
+All three are determined by a set of RNG-addresses (0756-0759) and a frame counter (043C) when pressing start in the shop. The RNG-algorithm is recursive with the frame counter acting as enthropy. It's triggered a few times during the start of a race and can also occasionally be called during a race. The frame counter is reset between every race, which in theory could provide a method for manipulating the RNG. There are ways to determine the RNG-seed in race 1 (by looking at the car order at line-up and which letter is in the letter box). One could technically learn a few neighboring RNG-seeds that follow in race 2, depending on how long the frame counter was left to run during the shop menu. But the possibilities quickly multiply and it will in practice be difficult to memorize all possible branches. This means real-time manipulation is likely going to be limited. There is one exception and that is race 1, which always starts from the same seed and therefore only depends on the frame counter.
 ===Letters===
@@ Line 152: / Line 152: @@
 Each individual letter item (to avoid any possible confusion, it's the white boxes with a black letter) is linked to one of six letter addresses (01CD-01D2). These links are static and are described further down. Each letter address is recalculated at the start of every race, regardless of if it's going to be used or not. The letter generation process is as follows:
-#Update RNG-addresses 0756-0759 through a series of calculations with input from 043C (frame counter) used as entropy. The detailed calculation with comments is described in http://tasvideos.org/forum/viewtopic.php?t=9164
+#Update RNG-addresses 0756-0759. The detailed calculation with comments is described in http://tasvideos.org/forum/viewtopic.php?t=9164
 #Perform an XOR on the "letters collected" address of one of the cars (07A1-07A4) and $FF. Since each letter collected is a binary 1 in the corresponding byte, the result will contain 1 for the bits corresponding to letters <u>not</u> collected by that car.
 #Perform an AND on the result in 2 with 0756. The AND-operation is performed from left to right and stops as soon as it results in a 1.

@@ Line 621: / Line 621: @@
 * 0531/052C - Big/Small x-position of the car (with reference to the screen). Positive to the right.
 * 053B/0536 - Big/Small y-position of the car (with reference to the screen). Positive down.
 More addresses are listed in http://tasvideos.org/forum/viewtopic.php?t=9164

@@ Line 159: / Line 159: @@
 Observations:
-* Only letters <u>not</u> collected by the determining car are possible
+* Only letters <u>not</u> collected by the determining car are possible (except I, which is <u>always</u> possible)
 * Assuming the RNG-generation algorithm is accurate (which appears to be the case), the probability of possible letters drops by roughly half each step and finally the rest going into I. E.g. if a car has collected the letters P, R and M, the probabilities become O - 50%, A - 25% and I - 25%.
 * A letter can never have a probability of >50%, except for I, which can actually be 100% determined if that's the only letter missing.

@@ Line 14: / Line 14: @@
 ===Max speeds===
-The below table shows how the max speeds increase with the upgrades. The numbers in the motor rows correspond to their additional speed boost.
+The below table shows how the max speed increases with the upgrades. The numbers in the motor rows correspond to their additional speed boost.
 {| class="wikitable"
+|