Glimmer Portal Glitch

Sheep · Jul 28, 2013 8:21 PM

I found a new glitch while playing on my PSP a short while ago. (This is recorden on a pc emulator)

Start a new game, go through the level, talk to everyone and get the orbs. (I'm not exactly sure what makes it work) Then get a rock and go to the portal. Positon yourself just outside the range where the portal's sky appears. Spit the rock at the portal, and the portal rises towards the sky.

Both the PSP port of the game and the version I played with the emulator are NTSC, so I don't know what happens in the PAL version.

Hwd45 · Jul 28, 2013 9:58 PM

That's hilarious, I need to try that and find out if it works in PAL xD

ccrogers15 · Jul 28, 2013 11:22 PM

Oh my god! It works!

Pure out lol.

Stormy · Jul 28, 2013 11:22 PM

Wow, interesting, I wonder what makes it do that. XD It's especially weird that there's a different result when you replay the level.

36IStillLikeSpyro36 · Jul 28, 2013 11:53 PM

the fact that smoke appears underneath where the portal's arches are suggests that this was an intentional thing in the game, doesn't it, since they wouldn't have bothered to add it otherwise?

by the way, i have to try this now. with the moonjump Gameshark code on, of course.

Sheep · Jul 29, 2013 7:20 AM

36IStillLikeSpyro36 wrote:

the fact that smoke appears underneath where the portal's arches are suggests that this was an intentional thing in the game, doesn't it, since they wouldn't have bothered to add it otherwise?
by the way, i have to try this now. with the moonjump Gameshark code on, of course.

The portal rising and the smoke were both intentional, but only for when the portal rises from the ground when you receive the Talisman. Somehow, the rock made the portal go back to the state of rising O.o

I'm guessing that when the rock hits the portal, it "believes" the portal to be a lizard, and tries to set the "lizard's" state to a value that means 'dying', while for the portal, this value means it should rise.

Gekoncze · Jul 29, 2013 9:19 AM

Wow that's cool big_smile ^.^ I have to try it.
Btw the colors of spyro seems a bit inaccurate. I had this problem on one epsxe opengl plugin and fixed it by enabling advanced blending I think.

Sheep · Jul 29, 2013 9:49 AM

Blako wrote:

Wow that's cool ^.^ I have to try it.
Btw the colors of spyro seems a bit inaccurate. I had this problem on one epsxe opengl plugin and fixed it by enabling advanced blending I think.

Wow, thanks, that did the trick big_smile

Breaking Bad · Feb 01, 2014 2:40 AM

Interesting theory, Sheep. It also might just be as simple as the fact that the Physics system isn't up to par. For instance, notice how the model's faces hit each other, and cause texture issues? The collision boxes seem to not be that great, either. It could just be for the fact that the PlayStation wasn't a powerful console, but also Spyro didn't have a very long development time, either. Either Way, it's a great game, and we'll always find funny issues. bentley

Flapjacks · Feb 01, 2014 2:45 AM

I don't think it's much of a 'physics system' so much as it's 'collision detection.'

Breaking Bad · Feb 01, 2014 3:19 AM

Collision Detection is the most basic, and fundamental part of physics.

Stormy · Feb 01, 2014 3:53 AM

This is the first I've heard of collision detection being considered "physics," but I know next to nothing about game development, so I'm not exactly someone you'd want to ask. Somehow, though, I think physics is more about how things move and fall than deciding whether or not two things are touching.

Breaking Bad · Feb 01, 2014 3:56 AM

Hate to use Wiki, but...

"A physics engine is computer software that provides an approximate simulation of certain physical systems, such as rigid body dynamics (including collision detection), soft body dynamics, and fluid dynamics, of use in the domains of computer graphics, video games and film."
Source: http://en.wikipedia.org/wiki/Physics_engine

36IStillLikeSpyro36 · Feb 01, 2014 4:38 AM

oh yeah, if anyone's wondering, i tried it with moonjump, but missed the portal.

my guess is it's still fully functional, just inaccessible.

i had a spam post here before, i meant to post it in CTRL + V, so yeah.

Last edited by 36IStillLikeSpyro36 (Feb 01, 2014 4:39 AM)

Breaking Bad · Feb 01, 2014 5:35 AM

Could you show a video of you attempting?

Maybe if somebody could edit the map, they could add stairs to reach that spot.

36IStillLikeSpyro36 · Feb 01, 2014 5:44 AM

i could do it again, but it was enough of a bother to get the glitch to work the first time. i missed the portal, like i said. nothing really interesting happened, it just kept going up and i completely lost sight of it.

Sheep · Feb 01, 2014 10:49 AM

Breaking Bad wrote:

Interesting theory, Sheep. It also might just be as simple as the fact that the Physics system isn't up to par. For instance, notice how the model's faces hit each other, and cause texture issues? The collision boxes seem to not be that great, either. It could just be for the fact that the PlayStation wasn't a powerful console, but also Spyro didn't have a very long development time, either. Either Way, it's a great game, and we'll always find funny issues.

The texture issues is rather interesting(nothing to do with physics, nor collision detection, though). Because of how the PS1 renders 3d models, with flat, depth sorted(distance from triangle center to camera) triangles rather than a depth buffer, they overlap each other incorrectly because the center of one triangle is closer to the camera than the center of a triangle that is in front of the first one. (This also means that the PS1 can't correctly render triangles that are going through each other.) A cause of this would for example be that parts of Spyro would be obscured by the ground below his feet, unless the developers had not countered it by giving Spyro and several other objects(or the individual triangles of these objects) an offset to the depth value to make the sorting algorithm think they are closer to the camera. This again causes issues like in this video: https://www.youtube.com/watch?v=CboOloU … e=youtu.be
My theory is this:
They wanted to make sure that the triangles of the portal frame that were behind the actual portal triangles(those displaying the skybox), didn't obscure the latter, but couldn't give the portal(not frame) a depth offset because that would make Spyro obscured by it if he was too close. As you can see in this image http://s13.postimg.org/emvd8gf1z/portaldepth.png, Spyro, sitting on the ground behind the portal, is visible through the portal because he has a depth offset, while the portal doesn't. The solution would be to make the frame triangles behind the portal have an opposite depth offset, making them appear to the sorting algorithm as being further away from the camera. If you look closely at the graphical glitch in the video, you can see that the it is the triangles of the roof hole structure that hide certain of the portal frame triangles, as if the game thinks they are closer to the camera than those specific frame triangles.

Anyway, "the fact that the Physics system isn't up to par" is a rather vague explanation tongue

Spyro's collision box is obviously a sphere(anything more complex would probably be too slow, and definitely unnecessary), and the rock probably is too(either that, a capsule, to simulate the rock's position between frames, or some kind volume ray casting), but possibly slightly enlarged to forgive bad aiming. But the portal's collision "box" is actually the full polygon model, or a very slightly optimized one.

We can see that the rock does correctly detect collision with the portal(collides when it should, and narrowly slips by when it should), and it doesn't need to have any physical reaction to the collision, because when detecting a collision, it creates some particles and stop existing. No physics. It does however cause reactions to a few of the game objects: Start the death animation/state of lizards and ladybugs, break baskets and vases, and cause the banner next to the portal to shake like when Spyro charges it. Most or all of these reactions would involve changing one or more of the hit object's variables.

A flaw in the general physics/collision system that randomly sets a variable of one of the objects would be very strange, as the code would only need to deal with physics related variables. In the code of the rock object, on the other hand, we know that it sets particular variables of particular objects.

There might be something funny with the system that controls the spit-able object's interaction with various game objects, though. If you aim next to characters, enemies, gem containers, etc., the spitting direction is automatically corrected to help the player hit directly on target. This also applies to the portal. I tested this with some other objects, like the gem lamps and flying powerup. When I aimed near the base of the lamps(or the end that sticks into the ceiling for the lamps in the cave), the aim was corrected to hit the base. When I aimed near center of the base of the powerup, the aim was corrected, and the rock even collided with something invisible when I spat from a certain distance.

Breaking Bad · Feb 01, 2014 9:18 PM

Sheep is the man.

Are you currently studying Graphical Programming?

Sheep · Feb 01, 2014 10:55 PM

No, but in my free time, I try to make games with GameMaker. I want to make 3d platform games like Crash and Spyro, but because GameMaker's 3d support is rather limited, I've had to make my own 3d polygonal collision detection/reaction system. The PS1 style 3d model rendering and depth sorting issues, I learned about when trying to make a similar 3d rendering system for a javascript/HTML5 canvas2d 3d platform game.

Breaking Bad · Feb 02, 2014 1:59 AM

Couldn't you just use a library, like OpenGL or Direct3D, Framework like LWJGL or LOVE, or even an engine like Unity?

Gekoncze · Feb 02, 2014 12:06 PM

Unity is too... big I think and LWJGL is java. And of course you need love for every project to be good ^.^
also you can't do all the tricky stuff with already created engines, you are always limited in some way

Stormy · Feb 02, 2014 4:20 PM

This is getting off-topic. Why don't you guys start a game development topic or something if you want to continue this?

Sheep · Feb 02, 2014 5:12 PM

Yeah, I agree about Unity. I tried to use it, but was put off by the amount of different things all over, that I probably wasn't ever going to use, and the "hidden" stuff doing everything for me in the background. The advanced stuff being so abstracted does of course make it easier to use and to make advanced things, but I didn't feel comfortable not understanding what exactly was going on.
Most likely, I gave up too quickly, but it was more fun to try to push the limits of GM. Recently, GM has got lots of improvements; export modules to various devices, shaders, a compiler(usually, GM is interpreted), so my incentive to stay with it it just got stronger:P
I did an attempt at C++, but wasted several days trying to get Direct3D and OpenGL to work(I need to play with something graphical to be able to stand learning a new language), with no success, so I just went back to GM again:P
When it comes to frameworks, I haven't really looked at them, so I don't know what I'm missing xD

Anyway, more related to the topic, I have tried to do the same in other levels(Magma Cone and Skelos Badlands) with the lava balls, but I got no strange results.

Giganoto · Feb 02, 2014 6:56 PM

Sheep wrote:

I found a new glitch while playing on my PSP a short while ago. (This is recorden on a pc emulator)
Start a new game, go through the level, talk to everyone and get the orbs. (I'm not exactly sure what makes it work) Then get a rock and go to the portal. Positon yourself just outside the range where the portal's sky appears. Spit the rock at the portal, and the portal rises towards the sky.
Both the PSP port of the game and the version I played with the emulator are NTSC, so I don't know what happens in the PAL version.

This is probably the best spyro glitch i have seen so far

Portal: My people need me *whimsical opera plays in background as it floats away*

36IStillLikeSpyro36 · Feb 03, 2014 3:45 AM

i wonder if the portal is under the ground *before* it rises up to the main ground.

in Spyro 3, you can swim under certain portals and get into the worlds even though they're technically not unlocked. (not enough eggs, not enough gems, need to do something, etc.) because the portals are still there under the area.

i wonder if the same applies to the return home portals in Spyro 2. i never thought to check.

#1 Jul 28, 2013 8:21 PM

Glimmer Portal Glitch

#2 Jul 28, 2013 9:58 PM

Re: Glimmer Portal Glitch

#3 Jul 28, 2013 11:22 PM

Re: Glimmer Portal Glitch

#4 Jul 28, 2013 11:22 PM

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#5 Jul 28, 2013 11:53 PM

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#6 Jul 29, 2013 7:20 AM

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#7 Jul 29, 2013 9:19 AM

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#8 Jul 29, 2013 9:49 AM

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#9 Feb 01, 2014 2:40 AM

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#10 Feb 01, 2014 2:45 AM

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#11 Feb 01, 2014 3:19 AM

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#12 Feb 01, 2014 3:53 AM

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#13 Feb 01, 2014 3:56 AM

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#14 Feb 01, 2014 4:38 AM

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#15 Feb 01, 2014 5:35 AM

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#16 Feb 01, 2014 5:44 AM

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#17 Feb 01, 2014 10:49 AM

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#18 Feb 01, 2014 9:18 PM

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#19 Feb 01, 2014 10:55 PM

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#20 Feb 02, 2014 1:59 AM

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#21 Feb 02, 2014 12:06 PM

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#22 Feb 02, 2014 4:20 PM

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#23 Feb 02, 2014 5:12 PM

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#24 Feb 02, 2014 6:56 PM

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#25 Feb 03, 2014 3:45 AM

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