Cv1/tricks - Revision history

SBDWolf at 13:12, 1 November 2023

2023-11-01T13:12:33Z

SBDWolf: Score mechanics in relation to lag

2023-10-03T19:23:23Z

Score mechanics in relation to lag

SBDWolf: RNG write-up

2023-10-03T12:36:38Z

RNG write-up

SBDWolf: fix typo

2023-05-05T13:15:41Z

fix typo

KidCharlemagneReturns: /* Scroll Glitch */

2022-08-11T21:51:35Z

‎Scroll Glitch

SBDWolf at 16:25, 7 May 2021

2021-05-07T16:25:24Z

SBDWolf at 15:13, 7 May 2021

2021-05-07T15:13:37Z

SBDWolf at 23:52, 26 April 2021

2021-04-26T23:52:00Z

SBDWolf at 00:10, 6 April 2021

2021-04-06T00:10:13Z

SBDWolf: /* Movement */

2021-03-31T21:37:44Z

‎Movement

@@ Line 182: / Line 182: @@
 On one hand, the fact that the RNG algorithm is placed in the idle loop can make it very hard to manipulate its value, because the length of this loop will be affected by how many things the game has already processed on that frames, where in the loop the NMI interrupt happened on the previous frame (since it will resume exactly where it left off on the next frame), as well as CPU/PPU sync (which is deterministic on most emulators but random on a real console).<br />
-On the other hand, this RNG algorithm is extremely prone to getting stuck on either a single value, or a very limited set of values. In other words, the idle loop will pretty much always loop over a limited set of value. There are even values from the BonusTable array that are never going to get picked.<br />
+On the other hand, this RNG algorithm is extremely prone to getting stuck on either a single value, or a very limited set of values. In other words, the idle loop will pretty much always loop over a limited set of values. There are even values from the BonusTable array that are never going to get picked.<br />
 On top of that, the RNG value will always reset every 16 frames (to value 0x7A). This gives the value that the RNG will assume a degree of predictability.

@@ Line 233: / Line 233: @@
 For a practical example, with the standard strat of entering Dracula's room without losing any frames, Dracula's pattern will be determined with the frame counter reading 0xC7.<br />
 On this frame, the possible values are either 0x87 or 0x7A. If it reads 0x87, this will make Dracula do the fast fireball pattern, while if it reads 0x7A, this will make Dracula do the slow fireball pattern. This essentially makes either pattern a 50% chance that is impossible to control in an RTA setting.
 === Additional Links ===
 *[http://tasvideos.org/GameResources/NES/Castlevania.html TASVideos tricks page]

@@ Line 155: / Line 155: @@
 *Stage 14-2
-=== Enemy Patterns ===
+=== RNG ===
-A lot of enemy patterns are only a function of how many frames have elapsed since the start of the screen and Simon's current position on screen. This allows for pattern manipulation on enemies such as the Bat Boss, Birds, and the Mummies.
+==== In Summary ====
-White Skeletons are also affected by RNG on top of the factors mentioned above. Notably, they have a set amount of patterns (sometimes a single possible pattern) depending on those two factors. The exact pattern gets chosen at random. This allows for a smaller extent of manipulation.
+Some enemy patterns are only a function of how many frames have elapsed since the start of the screen and Simon's current position on screen. This allows for pattern manipulation on enemies such as the Bat Boss and the Mummies.
 === Additional Links ===
 *[http://tasvideos.org/GameResources/NES/Castlevania.html TASVideos tricks page]

@@ Line 4: / Line 4: @@
 Simon moves at a consistent 1 pixel per frame. Walking is the same speed as jumping. While traveling on stairs, he moves more slowly.
 A damage boost has Simon travel at 1 pixel per frame, but loses 23 (22? needs confirmation) frames to hit and recovery frames.
-Whipping or using a subweapon takes 23 frames on the gorund or 22 frames while in the air. If landing with an attack, Simon will not be able to move until the attack animation is over.<br />
+Whipping or using a subweapon takes 23 frames on the ground or 22 frames while in the air. If landing with an attack, Simon will not be able to move until the attack animation is over.<br />
 If falling or jumping off of a 4-block height or higher, Simon goes into a clunk animation which loses 16 frames. This can be prevent by whipping on landing (can only be done off of a jump), as the whip animation takes precedence over the clunk. The earlier the whip, the less frames Simon has to spend locked on the ground on landing. With a perfect whip, zero frames can be lost from the landing.<br />
 Falling off a small height loses 2 frames. This can be avoided by simply jumping over it.

@@ Line 37: / Line 37: @@
 Attempts to load the blocks will continue until Simon is close enough to them. Usually this requires the user to perform 20+ 1-frame movements on the correct frames, which is unfeasible in a Real Time setting.
 There is another exploit to this mechanic though: if, on the frame a tileset would normally load, Simon moves BACK instead of forward, the block will fail to load, and no further attempts will be made to load it until 8 more frames of movement on "loading frames", at which point another turnaround will be needed. Usually two or three turnarounds are needed to permanently prevent a tileset from being loaded. This method is feasible in Real Time and leads to a number of skips.
 ----

@@ Line 34: / Line 34: @@
 === Scroll Glitch ===
+This glitch is related to Castlevania's way of loading tilesets offscreen. Blocks may only be loaded every 2 frames, and only while Simon is moving. This means that by moving only on frames when blocks are not being updated, they will fail to load properly and instead leave on screen a predetermined, consistent "garbage" tileset.
+Attempts to load the blocks will continue until Simon is close enough to them. Usually this requires the user to perform 20+ 1-frame movements on the correct frames, which is unfeasible in a Real Time setting.
 ----

@@ Line 1: / Line 1: @@
 === Movement ===
 Simon moves at a consistent 1 pixel per frame. Walking is the same speed as jumping. While traveling on stairs, he moves more slowly.
@@ Line 30: / Line 32: @@
 === Clips ===
 If Simon gets hit just below a standable platform during the ascent of his jump, he will clip through it.

@@ Line 133: / Line 133: @@
 === Framerules ===
 A Framerule is a mechanic that only allows the player to progress in increments of x amount of frames. Imagine a bus stop, where every bus leaves every x amount of frames: it doesn't matter whether you arrive early, or just before the bus leaves, you will always catch the same bus and leave the bus stop at always the same time. That is, unless you miss the bus and have to wait for the next one to arrive. This means that to get a perfect time you don't need to play perfectly, but just well enough to catch the same bus as someone who played perfectly.<br />
-Screens that end with a door are affected by a 16-frame Framerule. Note that any other screen in NOT affected by Framerules, nor does it influence the screens that are. Screens that are affected by Framerules have their own timer that stars from the last black screen transition, and those rooms and those rooms alone can only be completed in increments of 16 frames. Any frames gained or lost in other rooms are truly gained or lost.<br />
+Screens that end with Simon transitioning through a door are affected by a 16-frame Framerule. Note that any other screen in NOT affected by Framerules, nor does it influence the screens that are. Screens that are affected by Framerules have their own timer that stars from the last black screen transition, and those rooms and those rooms alone can only be completed in increments of 16 frames. Any frames gained or lost in other rooms are truly gained or lost.<br />
 The way the game slows down the player to wait for the next Framerule is by holding the door semi-open until the moment the metaphorical bus arrives. This means that the door will open very quickly if a framerule has just been barely caught, and it will open very slowly if a framerule has barely been missed.<br />
 Lag frames are truly lost and don't count towards the Framerule timer.

@@ Line 126: / Line 126: @@
 If a title screen demo gets an item drop, this will advance the current slot and carry over to the main game. It is recommended to reset the game before every run to prevent the demos from affecting gameplay.<br />
 Enemies may also drop other items such as Small Hearts (2 frames before an Item Drop) or Big Hearts (Hunchbacks and Axe Knights). These are unrelated to the item chart.
 === Framerules ===