An educational piece aimed at informing the community what "glitching" is, how it happens and how to deal with it in the game.
by DeLeyt
1. The Basics To understand what a glitch is and why it occurs, we have to go back to the basics and break down the digital world we play in. This digital world (=cyberspace) consists of soldiers, trees, bushes, grasses, walls, rocks, hills, houses, fences, water and anything else you see while you are playing. We call each and every object in this world a model. A model is constructed of points which are placed at a certain position in three dimensional spaces (coordinates X, Y and Z = 3D). We call such a point a vertex. When these vertexes are in turn connected to each other by lines (also called vector or edge), we call it a wire-model. A wire-model gives a pretty good view of how the model's contours look like but it still looks transparent because the space between the connected lines is still not filled. To do this we have to create a closed set of lines so it can be filled in. The smallest amount of vertexes (or lines) needed to make a closed area is 3; a triangle. So when we fill the gap between a triangle, we have created a face. All those faces connected make up a renderable model that looks "solid".
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After all the faces are calculated, light rays are sent towards the faces which will highlight or darken them to give the model a sense of depth. Also textures are applied to the model to give the model his characteristic appearance (wood, grass, leather, cloth). Lighting and texturing have no influence on the part of glitching.
2. The Technical Stuff To Glitch Or Not To Glitch: A glitch is actually made up of a combination of at least two or sometimes three "errors": 1. A technique called face-normal 2. A technique called collision-check 3. Camera-placement (I call it "errors" but they are really no such thing. When combined, they become errors) Face-normal If you look at your graphics card’s specifications, you will notice that the fill rate is mentioned in triangles/second. The more triangles a graphics card can fill in a second the faster your card is, the faster your digital world is drawn and the smoother (and better looking) your game will run. Game graphics are developed in such a way that it takes the least amount of processor-time to get the maximum result. To do this, developers have invented a technique they call face-normal. What this technique actually does is decide if a face that is facing the camera, is important to draw or not. Take the cube in above picture for instance. You can see this cube because the render-program decided that the outside faces of the cube (where the face-normals are set) where important to draw to see the cube. What you don't see is that it also decided not to draw the inside of it (because the face-normals were not set there). This seems very logical to us but to a computer it takes effort and calculations to tell if a face is facing outward or inward. So, on a face we have two sides. A front side; this is the side we want to see and the computer has to draw, and a back side; this is the side the computer must not draw. We call the side which must be drawn the side with the face-normal. Don't confuse yourself that the face that is not drawn is gone. It's still there! It is merely not drawn by the computer. If we would move inside the cube we wouldn't see any cube because the face-normals are on the other side but the faces would still be there. This is the first important part of a glitch. Collision-check If you understand the basics and you understand face-normals, you understand that creating a model actually is nothing more but creating a shell. This applies to all models within the digital world. In the real world objects are physically there. If we roll a ball towards a wall it would bump into the wall and stay there or roll back because of the laws of physics. In a digital world objects are not physical but merely theoretical and there is no law that is affecting the model's behaviour. If a ball modelled in cyberspace would be moving towards a wall, it would go right through it because there is no physical restraint. To create this, game-developers have invented another technique called collision-check. It does nothing more but check if a part of a model collides with a part of another model. If so, certain properties are given to both models so the real-world "action-reaction" properties are simulated as close as possible. For instance; when you walk against a wall, properties are given to both models that the wall will stay in place and will not let you go through. You are restrained to move alongside the wall only. Second example; when you walk against another player, you will push the other player away because both model-properties are set in a way that you are able to push him. Your speed of movement will be reduced because you have more mass to shove around. If the other player would push back, you have equal force and nobody would move an inch. In this way the game-programmers try to approach the real-world physics as close as possible. What sometimes happens in Ghost Recon however (and also in other games) is that the collision-check is not working correctly or the collision-properties are not set properly. When that happens, there are no restraints and you are able to walk right into a wall or a rock. This is the second error of causing a glitch.
Camera-placement The third part of a glitch is the camera placement. The camera in Ghost Recon is actually the view by the player itself. The camera is placed exactly on the position of the player's eyes and the direction is set to the direction the head is looking in. By itself, this seems pretty harmless and it is the right way to simulate vision. It becomes part of a glitch though, when it is combined with face-normals and collision-check. Read on, my patient friend; it will all fall in place now.
3. Putting it all together Types of glitches: When you put all three parts together, you are likely to encounter a glitch (of the third kind ?). There are several types of glitches which can be categorized into 2 sections: 1. Wall- and Rock-glitch (W/R-glitch) 2. Crater- or Ditch-glitch (C/D-glitch) W/R-glitch A picture says a thousand words, so take a look at the picture below. You will notice that the prison gate is clearly visible by the player (me, in this case). If you look at a section of the map that is inserted on the bottom left however, you will notice that it should be impossible to see that gate and the enemies in front of it because I'm lying behind the tower in a corner. What happened here is that we have a combination of two "errors": face-normal and collision-check. The collision-check failed and let me go through the face of the wall. At the same time the backside of the faces on the other side of the wall do not have a face-normal. This means that the face is not drawn and you are able to look right through it. The face is there however and you are not able to shoot the enemies from that position. The bullets will simply ricochet of the wall.
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C/D-glitch Explaining this glitch is much easier now because you know the basics. This glitch is a combination of all three "errors": face-normals, collision-check and camera-placement. Case: A player is lying down in a crater (natural shelter). Another one is standing outside the crater a few meters back from the rim. He sees the head of the guy inside the crater sticking out over the rim just enough to get a shot. He shoots and he seems to miss. He shoots again, this time focusing on the aim and the bullet seems to ricochet of the rim again. He fires a whole clip empty on a head sticking out that just seems to be invincible.
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The guy inside the crater sees and hears the gunfire and focuses on the source. He has his enemy clear in sight, takes one shot and the player is dead. This is a scenario that happens a lot in Ghost Recon today. What happened here? Let's focus on the guy in the crater first: because the collision-check is a bit faulty, his head is actually sticking inside the rim (camera-placement). The face-normal of the rim is on the other side so the player looks right through the rim on to his enemy. Because the starting point of the bullet is somewhat further then the rim, the bullet can be fired and the enemy is killed. Now focus on the guy outside the crater again: the player that is trying to hit the guy inside the crater can see the head but it's mostly covered by the invisible faces that lie just on top of the rim. He does not see the faces but they are there and it stops the bullet from hitting the head that he so clearly sees. This is a typical case of glitching! So why doesn't the player in the crater stop doing that? The answer is very simple: he has no idea that he IS glitching! To him it's just as if he is just looking over the edge of the crater-rim and takes the shot when he sees his opponent. This is the hard part of the C/D-glitch: it's very hard to tell if you are doing it unless the opponent says you are because you stick out and he is unable to shoot you.
Here are some other examples of a C/D glitch:
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4. How to prevent it There are a few easy rules for preventing glitching: * Cover with sharp edges (like a crater-rim) is likely to harbour a collision-error in them. Avoiding crawling up to these kinds of edges is wise. When your ready to see over the rim, use the crouch or upright stance. The same applies for a ditch. * Try to avoid running backwards into walls or rocks. It seems that you are more likely to go through a collision-check backwards then moving forward or sideways. * Lying down tight against a wall and peeking at the same time can cause you to look beyond the walls boundaries. Of course these errors are part of the game. Sometimes it happens by accident. Sometimes you have no choice but to seek shelter in a crater or a ditch. So don't see this information as a "must do" but more as a "gentleman's understanding". If you are aware that you are glitching then try to undo it.
5.How to deal with it in-game? I have played a lot of games on servers with Ghost Recon and my experience is that you have two kinds of players: 1. Players that think they are very good and do nothing but complain about glitching although they have no idea how it is caused. Therefore they are not able to figure out that it might be an accident or that the other player is just not aware about the fact that he is glitching. These players just scream "FIRE!" at every little puff of smoke they see. 2. Players that just accept the fact that sometimes glitching occurs although it is not intended. These players are usually the nicest players to share a game with. There is nothing more annoying today during a game then to hear people screaming that another guy is glitching. Some players even can't get enough of it and accuse every single player every time they miss a shot. Remember that it's just possible that you missed because your rifle-accuracy isn't that good or even your aim is off. of course accusing someone can be a tactic too. I know that there are players out there that just say you are glitching, so you won't hide in the craters and ditches anymore, making it easier for him to kill you. Some players even say it to prove to the rest of the players that he got killed because someone else was glitching.
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Thank you for your attention DeLeyt
Special thanks to Deleyt for creating this very informative piece and for allowing us to make it part of our site. And }Skorpn--7 for the screen shots.
