Water Ripple effect from Scratch 1.x

NoMod-Programming

I decided to delve back into the old 1.x days of Scratch (back when it ran on Squeak), and thought about looking into the “Water Ripple” effect and why it didn't work. According to the Scratch Wiki:

Scratch Wiki wrote:
There was also a water ripple effect, which crashed Scratch due to the system not having enough memory

Well, looking into the source, I noticed that out of bounds reads and writes were occurring within the following lines of code:

	for (q = 0; q <= (width * height); q += 1) {
		temp = bArray[q];
		bArray[q] = (aArray[q]);
		aArray[q] = temp;
	}

If you didn't notice the issue, it's the <= comparison used for checking that the variable “q” is between 0 and (width * height). Because arrays bArray and aArray are 0-indexed, though, the last element, at width * height, doesn't exist. So the code crashed every time it tried looping over the final element. The fix to this, therefore, was to replace the <= comparison with the < operator, such as in the following snippet:

	for (q = 0; q < (width * height); q += 1) {
		temp = bArray[q];
		bArray[q] = (aArray[q]);
		aArray[q] = temp;
	}

That one character fix gets the “water ripple” effect working (after recompiling the plugin), and it can be seen in the following gif:

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Maximouse

Interesting! Someone should correct the wiki article then.

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Jeffalo

imagine how different scratch might have been if they didn't mess that up.

for compatibility i'm guessing they would keep the water ripple effect… which might have changed a lot of things. we might have had more advanced effects and stuff. wow!

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CatsUnited

Jeffalo wrote:
imagine how different scratch might have been if they didn't mess that up.

I could see a lot of people using this in their projects as cool glitch effect woah

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Bacteria999

bump

FunE552

i found a project called instant scratch crasher that contains a block that is an effect set that has the option chosen for water ripple effect, it does nothing but is a cool relic and i put it in my backpack so i always have id

ps: i am not lying go there right now

ninjaMAR

Cool! I hope the ST sees this and re-adds it

Raihan142857

ninjaMAR wrote:
Cool! I hope the ST sees this and re-adds it

Haha, the ST never adds anything. Also why did @FunE552 necropost thats not cool

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CatsUnited

Raihan142857 wrote:
Also why did @FunE552 necropost thats not cool

because it is cool?

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nekoender

I'm using the system browser thing in 1.x to fix it. where is this line of code?

	for (q = 0; q <= (width * height); q += 1) {
		temp = bArray[q];
		bArray[q] = (aArray[q]);
		aArray[q] = temp;
	}

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yeah idk what else to put here lol

Maximouse

nekoender wrote:
I'm using the system browser thing in 1.x to fix it. where is this line of code?
	for (q = 0; q <= (width * height); q += 1) {
		temp = bArray[q];
		bArray[q] = (aArray[q]);
		aArray[q] = temp;
	}

It's in a plugin, so you can't change it in the editor itself.

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flyingtrain322

Is there any way to use the plugin file or does it do it automatically?

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RSITYTScratch

flyingtrain322 wrote:
Is there any way to use the plugin file or does it do it automatically?

Don't necropost.

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CST1229

RSITYTScratch wrote:
(#13)
flyingtrain322 wrote:
Is there any way to use the plugin file or does it do it automatically?
Don't necropost.

I wouldn't call that a necropost because it is related to the topic and is not spam or anything like that.

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ScratchCatHELLO

RSITYTScratch wrote:
flyingtrain322 wrote:
Is there any way to use the plugin file or does it do it automatically?
Don't necropost.

I don’t think it’s possible to necropost in Advanced Topics.

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Andricxa

new effects

change [water ripple v] effect by (25)

change [blur v] effect by (25)

tyson4621

set [WWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWW v] effect to (WWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWw)

just use that

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