How can I create an offset on a UIImageView - ios

I recently posted a question on here
Randomly generated tunnel walls that don't jump around from one to the next
That pretty much said I was getting a "drunken walk" tunnel instead of a correlated one due to a lack of an algorithm.
The answer works to an extent for what I'm attempting to create but I couldn't figure out how to implement the algorithm properly for my game.
I believe step one is to create the offsets for the pairs of walls. I want the images that appear (named: "Left1" and "Right1" , "Left2 and "Right2".... "Left41" and Right41") on each side of the screen to be "re-spawning" slightly offset to the left or right in succession of each other in order to create the illusion of a tunnel in appearance. I attempted to use the code provided to me in an answer to create an offset for a set of my walls but I get few errors when attempting to build. It was telling me first that a local declaration of 'Left1' hides instance variable, which I believe is because it's been declared already as a variable within my function? That came up twice.. Along with that I have an error that says Assigning to 'UIImageView *__strong' from incompatible type 'float'. How can I fix these? Or is it something I'm doing wrong elsewhere?
I'm kind of lost on this part since I don't know how to really rearrange it, due to the semantic issues.
I can answer any questions about the program to make it easier to assess the situation.
-(void) TunnelMovement{
CGFloat Left1 = 14;
for( int i = 0; i < 41; i++ ){
CGFloat offset = (CGFloat)arc4random_uniform(2*100) - 100;
Left1 += offset;
Right1 = Left1 + 14;
//...
}
}
This is what I have exactly in my code after trying to fill in the blanks from the answer given. Not sure if I put in all the necessities or what. Thank you.

[I can give you quick correction on that error message, but you are trying to run and you can't even walk yet, you can barely crawl.
Stack Overflow is a programming forum but it is not the place to learn or teach programming, people won't have the patience to teach basics.]
You can't assign the value of one thing to another if they are totally different things. In the line:
Right1 = Left1 + 14;
Right1 is a UIImageView and Left1 is a CGFloat, they are completely different things. Left1 is just a simple number, Right1 is a complex object.
You're trying to position UIImageView so you need to assign the value of Left1 + 14 to a part of the UIImageView that will position it and which is also a CGFloat.
So you need to assign it to something like the bounds or the frame or the center's x value, such as
Right1.center.x = Left1 + 14;
The warning is because you have two different things with the same name, you have UIImageView called Left1 but then you have a CGFloat also called Left1, you shouldn't give the same name to two different things - the CGFloat Left1 hides the UIImageView called Left1. You should have called it Left1X or LeftWallX or similar as it is in the answer to your other question.
That's just the error and warning, you're probably not ready to move on to the semantics of how to draw the maze if you were strugging with these two. In particular you will as a minimum need to know what the bounds, frame, center, x, y, CGPoint, CGRect, CGSize all are in order to fully understand what value to change and what effect changing those values will have on the position of the UIImageViews.
---- EDIT --- object programming 101
When you have an object like UIImageView it is like a having a house, the house can have a name and have lots of rooms in it, each with a name, within each room there are lots of things. You are trying to do the equivalent of replace the old television in one room with a new television.
So Right1 is like a house
Right1.center is like a room in a house
Right1.center.x is like the television in the room called center which is in the house called Right1.
Right1 = Left1 + 14;
is like trying to swap a new television for a house, instead of trying to swap it for a televsion within a room within a house.
Is that analogy too dumb?

Related

Work out world coordinates relative to position and rotation of an object in lua

I am trying to make a new tool for the tabletop simulator community based on my "pack up bag". The Packup Bag is a tool that remembers world position and rotation of objects you place inside it, so you can then place them back in the same positions and rotations they came from when "unpacking the bag".
I have been trying to modify this so it spits things out in a relative position and rotation to the bag, instead of using hardcoded world coordinates. The idea here is that players can sit at any location at the table, pick the faction bag they wish to play.. drop it on a known spot marked for them and press the place and it will populate contents of the bag relative to its location.
Now I have gotten some of this worked out... I am able to get the bag to place relative in some ways .. but I am finding it beyond my maths skills to work out the modifications of the transforms.
Basically I have this part working..
The mod understands relative position to the bag
The mod understands relative rotation to the bag
BUT.. the mod dose not understand relative position AND rotation at the same time.... I need someway to modify the position data relative to the rotational data... but can not work out how.
See this video....
https://screencast-o-matic.com/watch/cFiOeYFsyi
As you can see as I move the bag around the object is placed relative to it.... but if I rotate the bag, the object has the correct rotation but I need math to work out the correct position IF it is rotated. You can see it is just getting placed in the same position it was as if there was no rotation... as I haven't worked out how to code it to do this.
Now I have heard of something called "matrix math" but I couldn't understand it. I'm a self taught programmer of only a few months after I started modding TTS.
You can kinda understand what I mean I hope.. In the video example, when I rotate the bag, the object should be placed with the correct rotation but the world position needs to be changed.
See this Example to see relative rotation ....
https://screencast-o-matic.com/watch/cFiOeZFsyq
My code dose this by remembering the self.getPostion() of the bag and the obj.Position() of the object getting packed up.. it then dose a self - obj and stores that value for the X and Y position. It also remembers if it is negative or position and then when placing it uses the self.postion() and adds or subtracts the adjustment value. Same for rotation.
Still I do not know what ot go from here.. I have been kinda hurting my head on this and thought maybe some of you math guys might have a better idea on how to do this.
: TL;DR :
So I have
bag.getPosition() and obj.getRotation()
bag.getRotation(0 and obj.getRotation()
These return (x,y,z}
What math can I use to find the relative position and rotation of the objects to the bag so if I rotate the bag. The objects come out of it in a relative way...
Preferably in LUA.. thank you!
I'd hope you've found the answer by now, but for anyone else finding this page:
The problem is much simpler than what you're suggesting - it's basic right triangle trigonometry.
Refer to this diagram. You have a right triangle with points A, B, and C, where C is the right angle. (For brevity, I'll use abbreviations opp, adj, and hyp.) The bag is at point A, you want the object at point B. You have the angle and distance (angle A and the length of the hyp, respectively), but you need the x,y coordinates of point B relative to point A.
The x coord is the length of adj, and y coord is the length of opp. As shown, the formulas to calculate these are:
cos(angle A) = adj/hyp
sin(angle A) = opp/hyp
solving for the unknowns:
adj = hyp * cos(angle A)
opp = hyp * sin(angle A)
For your specific use, and taking into account the shift in coordinate system x,y,z => x,z,y:
obj_x_offset = distance * math.cos(bag.getRotation().y)
obj_z_offset = distance * math.sin(bag.getRotation().y)
obj_x_position = bag.getPosition().x + obj_x_offset
obj_z_position = bag.getPosition().z + obj_z_offset
Diagram source:
https://www.khanacademy.org/math/geometry/hs-geo-trig/hs-geo-modeling-with-right-triangles/a/right-triangle-trigonometry-review

Endless scrolling over a 3d map

I have some experience with Metal and quite a bit with Unity and am familiar with setting up meshes, buffers, and the backing data for drawing; but not so much the math/shader side. What I'm struggling with is how to get an endless scrolling world. So if I pan far to the right side I can see the left side and keep going.
The application of this would be a seamless terrain that a player could scroll in any direction forever and have it just wrap.
I don't want to duplicate everything on draw and offset it, that seems horrendously inefficient. I am hoping for a way to either use some magic matrix math or some sort of shader to get things wrapping/drawing where they should when panning the map. I've searched all over for some sort of guide or explanation of how to get this working but haven't come up with anything.
I know a lot of old (dos) games did this somehow, is it still possible? Is there a reason why it seems the industry has migrated away from this type of scrolling (bounding to edges vs wrapping)?
I have created a simple example demonstrating what you're looking for (I think).
The basic idea of it is that you draw the map in a repeating grid, using the drawPrimitives(type:vertexStart:vertexCount:instanceCount:) method on MTLRenderCommandEncoder. As the instance count you want to pass in the number of identical maps you want to draw, extending it as far as needed to not see where it ends. In my example I used a simple 5x5 grid.
To not have the user see the edge of the map, we're gonna calculate their position modulo 1 (or whatever size your map is):
func didDrag(dx: CGFloat, dy: CGFloat) {
// Move user position on drag, adding 1 to not get below 0
x += Float(dx) * draggingSpeed + 1
z += Float(dy) * draggingSpeed + 1
x.formTruncatingRemainder(dividingBy: 1)
z.formTruncatingRemainder(dividingBy: 1)
}
This is how it looks:
Just a follow up on what I have actually implemented. First I essentially have an array of x,y points with altitude, terrain type and all that jazz. Using some simple % and additions/subtractions it is trivial to get the nodes around a point to generate triangles
On a draw I calculate the first showing point and the last showing point and calculate the groups of triangles shown between those points. The first/last point take into account wrapping, it is then pretty trivial to have an endless wrapping world. For each group a translation offset is passed via a uniform matrix for that group which will position that section where it should belong.
I set it via renderEncoder.setVertexBytes(&uniform, length:..., offset:...)

10 Band Equaliser using NOVOCAINE

Im trying to build a 10 band Equaliser using NOVOCAINE.
I copied the Equaliser.mm's code in viewWillAppear, and added 9 more Sliders in the xib file, and changed IBAction code too this :
-(void)HPFSliderChanged:(UISlider *)sender {
PEQ[sender.tag - 1].centerFrequency = sender.value;
NSLog(#"%f",sender.value);
}
What I want to know is if I am doing this the right way or not ? and the what will be range of the Sliders ? Like in HPF example, the slider range is 2k to 8k. Need some guidance here.
Thanks.
EDIT: after your comment, I think it is clearer what you are asking.
Take the code to instantiate a NVPeakingEQFilter:
NVPeakingEQFilter* PEQ = [[NVPeakingEQFilter alloc] initWithSamplingRate:self.samplingRate];
PEQ.Q = QFactor;
PEQ.G = gain;
PEQ.centerFrequency = centerFrequencies;
you need define 3 parameters: Q, G, and centerFrequency. Both Q and centerFrequency are usually fixed (QFactor in my case is a constant equal to 2.0).
So, you have 10 sliders: each one corresponds to a fixed centerFrequency. I suggested iTunes values: 32Hz, 64Hz, 125Hz, 250Hz, 500Hz, 1KHz, 2KHz, 4KHz, 8KHz, 16KHz. You do not want to change those values when the slider value changes.
What you want to change when the slider value changes is the gain (G). At init time, G can be set to 0.0. This means "no amplification/attenuation".
When the slider moves, you change G, so actually you would do:
PEQ[sender.tag - 1].G = sender.value * kNominalGainRange;
where kNominalGainRange is 12.0, so if sender.value goes from -1.0 to +1.0, G goes from -12 to +12.
Hope this helps.
What I want to know is if I am doing this the right way or not ?
you do not show much code, but HPFSliderChanged seems correct. If you have any specific issue you should describe it and post more code.
and the what will be range of the Sliders ?
Actually, there is no rigid rule when it come to equalisers. iTunes goes from -12db to +12db, but you could use different ranges (with the only caveat being distortion).
Like in HPF example, the slider range is 2k to 8k. Need some guidance here.
again, you can take iTunes equaliser as an example (32Hz, 64Hz, 125Hz, 250Hz, 500Hz, 1KHz, 2KHz, 4KHz, 8KHz, 16KHz), or you can google for images of real equalisers and see which bands they use.

Boardgame-Map with crossroads etc

I have a little logical problem over here.
As the title says, I try to build a boardgame as a computer-program (maybe with internet-support, but thats another story)
As for now, I have a map, which has some crossroads in it, hence I cannot simply define the fields as '1, 2, 3, 4, ...' because if there is a crossroad at field 10, I would have more than one field which has to be labeled 11 (Because then there is a field left and right of field 10, for example.)
So the problem is, if I cannot define the Board in numbers then I cannot simply get the possible positions a player can take when he rolls 2d6-dices with calculating 'Field-Nr. + RandomRange(1,6) + RandomRange(1,6)'
Does anybody have an idea, how to define a Map like this on another way, where I still can calculate the possible new-fields for Player X with a 2d6-dice-roll?
Thanks in advance.
If i understand well... (i don't thing so) this might help you. Just use dynamic arrays for your boardgame field and change your actions after the dimensions x,y .... Look at this "type Name = array of {array of ...} Base type; // Dynamic array"
It sounds like you have a graph of connected vertices. When a player is at a particular vertex of N edges, assuming N < 12, the new Field will be reached from traversing edge number N % ( rand(6) + rand(6) ).
You could also just do rand(12), but that would have an even distribution, unlike 2d6.
Instead of dynamic arrays, I would recommend using a linked-list of records to describe the surrounding cells, and traverse the player's location and possible moves using that linked-list.
First, define a record that describes each cell in your board's playable grid (the cells on the grid can be four-sided like a chessboard, or hexagonal like in Civilization V) ... each cell record should contain info such as coordinates, which players are also in that cell, any rewards/hazards/etc that would affect gameplay, etc. (you get the idea).
Finally, the linked-list joins all of these cells, effectively pointing to any connected cells. That way, all you'd need is the cell location of Player X and calculate possible moves over n amount of cells (determined by the dice roll), traversing the adjoining cells (that don't have hazards, for example).
If all you want is to track the possible roads, you can also use this approach to identify possible paths (instead of cells) Player X can travel on.

Repeating 2d world

How to make a 2d world with fixed size, which would repeat itself when reached any side of the map?
When you reach a side of a map you see the opposite side of the map which merged togeather with this one. The idea is that if you didn't have a minimap you would not even notice the transition of map repeating itself.
I have a few ideas how to make it:
1) Keeping total of 3x3 world like these all the time which are exactly the same and updated the same way, just the players exists in only one of them.
2) Another way would be to seperate the map into smaller peaces and add them to required place when asked.
Either way it can be complicated to complete it. I remember that more thatn 10 years ago i played some game like that with soldiers following each other in a repeating wold shooting other AI soldiers.
Mostly waned to hear your thoughts about the idea and how it could be achieved. I'm coding in XNA(C#).
Another alternative is to generate noise using libnoise libraries. The beauty of this is that you can generate noise over a theoretical infinite amount of space.
Take a look at the following:
http://libnoise.sourceforge.net/tutorials/tutorial3.html#tile
There is also an XNA port of the above at: http://bigblackblock.com/tools/libnoisexna
If you end up using the XNA port, you can do something like this:
Perlin perlin = new Perlin();
perlin.Frequency = 0.5f; //height
perlin.Lacunarity = 2f; //frequency increase between octaves
perlin.OctaveCount = 5; //Number of passes
perlin.Persistence = 0.45f; //
perlin.Quality = QualityMode.High;
perlin.Seed = 8;
//Create our 2d map
Noise2D _map = new Noise2D(CHUNKSIZE_WIDTH, CHUNKSIZE_HEIGHT, perlin);
//Get a section
_map.GeneratePlanar(left, right, top, down);
GeneratePlanar is the function to call to get the sections in each direction that will connect seamlessly with the rest of your world.
If the game is tile based I think what you should do is:
Keep only one array for the game area.
Determine the visible area using modulo arithmetics over the size of the game area mod w and h where these are the width and height of the table.
E.g. if the table is 80x100 (0,0) top left coordinates with a width of 80 and height of 100 and the rect of the viewport is at (70,90) with a width of 40 and height of 20 you index with [70-79][0-29] for the x coordinate and [90-99][0-9] for the y. This can be achieved by calculating the index with the following formula:
idx = (n+i)%80 (or%100) where n is the top coordinate(x or y) for the rect and i is in the range for the width/height of the viewport.
This assumes that one step of movement moves the camera with non fractional coordinates.
So this is your second alternative in a little bit more detailed way. If you only want to repeat the terrain, you should separate the contents of the tile. In this case the contents will most likely be generated on the fly since you don't store them.
Hope this helped.

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