I need to apply different border thicknesses in a transformation. That is, the left side could be 10dp and the top 8dp, etc. for each cell in a GridView.
I have a Transformation with local variables for the thicknesses which I apply in transform using Canvas drawing primitives. This all works and the drawing is happening.
My question: because each transformation has different parameters it means I have to create a new transformation for each cell (in my adapter), set its properties and pass it to the Picasso builder.
I read elsewhere that transformations should not be created multiple times and they can be re-used. But thats not really possible in my scenario since each transformation has different state.
Am I doing this right and/or whats the best way to achieve what I'm trying to do?
Thanks.
If the values are truly dynamic you will have to create a new instance for every call. It's not the end of the world to do this, it's only a single, small allocation. Most transformers are completely stateless and it makes sense to re-use the same instance.
You could also pool these objects, but it's needlessly complicated. You have to deal with request joining, canceling, and the asynchronous nature of how they're used. Unless it becomes a problem, just pay the cost of the allocation.
If the range of values is limited or you are using the same values over and over you could cache those instances in a map.
Related
I want to create the feature as mentioned below in Picture. The number tells the touch order in the screen and dot tells the position. I want to create as same effect.
We can do this using normal drawing index primitive method. But I want to know whether Is it possible to create this effect using MTKMesh ? Please suggest/give some ideas to perform this in better way ?
You probably shouldn't use a MTKMesh in this case. After all, if you have all of the vertex and index data, you can just place it directly in one or more MTLBuffer objects and use those to draw. Using MetalKit means you'll need to create all kinds of intermediate objects (a MDLVertexDescriptor, a MTKMeshBufferAllocator, one or more mesh buffers, a submesh, and an MDLMesh) only to turn around and iterate all of those superfluous objects to get back to the underlying Metal buffers. MTKMesh exists to make it easy to import 3D content from model files via Model I/O.
I am needing a way to test out some heavy mathematical functionality in my code and have come to the point where I need to verify that such code is working properly. I would like to be able to create a path based on an array of points and use this path for testing without a graphics context.
As an example, Java has various classes such as the Path2D class that is completely independent on any kind of context or view unless you need to display the information in some kind of graphics context.
It looks like that Apple doesn't provide any methods that allow you to create, manipulate and change arbitrary geometric shapes but I wanted to come here and make sure.
CGPath and UIBezierPath can both be created without having a current context. But it depends what you want to do as to how much use they will be because their purpose is really for drawing. As such it isn't really easy to get the points back from the path once added.
At first I think my question should have been asked before, but I didn't find what I want.
One element of this iOS app I'm developing is break a 8x8 grid into Tetris pieces (every piece is made of 4 blocks). Two particular question I have are:
what is the best way to represent a Tetris piece in objective-C?
what algorithm to present the grid into random Tetris pieces (and later on how to check if two pieces fits together).
Edition on 01/28
#livingtech, I think I implemented pretty much what you say, except the point of "having a hole". My code works with no hole at simple stage when Tetris block is two blocks only (yes, two squares, connected either horizontally or vertically), but at 3-square Tetris block, I would get holes. I just tested and out of 1000 running, I would get one without a hole. So definitely I need some mechanism to check if next square will be a singleton.
I been trying to do the same thing for my game. Though I am a total beginner, and I'm using XNA and C#.
But the way I'm trying to go about it is: 4x6 grid array
--y123456
X1-000000
X2-000000
X3-000000
X4-000000
Here,
0 signifies no block
1 defines a block
Algorithm
Start by taking the very first 0 in the array ( top left corner )
and randomly pick a 0 or a 1.
Randomly choose the coordinates based on x1/x2-y1/y2, decide 1 or 0.
If it is 1, then decide coordinated based on where that 1 was put.
If it was 1 on x2 y1, then decide if a 1 should go on next touching
coordinate.
If you just have to code in what coordinates touch and which don't,
and the logic will roll through.
I have mine set up bit different. But this is the basic foundation of my random Tetris engine.
I also found that making it like that really helps to have a whiteboard and make a drawing of the grid and label with your coordinates.
since ur board is 8*8, i think u can use a int64 to represent the board. each bit of the int64 represents whether the specific grid is filled or not.
Implementing Tetris is a hobby of mine. First implemented it in Windows/C. Then in Perl/Tk! Last implementation I did in Obj-C/Cocoa (Mac). In all cases, the game logic is the same. Only the UI stuff changes. I treat every little box separately and have a two-dimensional array which contains the presence (and color) of every "set" box on the board. Standard board size I use is 10 boxes wide by 20 boxes high.
Separately I keep track of the "dropping" piece: it's location and what kind of piece it is. Based on a timer, try to make the piece drop. If any of the boxes where the "dropping" piece would drop is already set, then stop dropping the piece and add the piece boxes to the "set" part of the board. Create a new piece, and start over.
It may not be the best way to implement it, but it makes sense in my head. From a pure OO perspective, each shape of a dropping piece could be a subclass of a generic shape class. Override functions that check whether the shape can drop, the offsets of the individual boxes in the shape, etc.
I don't think anybody has taken a stab at your question #2 yet here, so I'm going to outline what I would do.
Setup:
You'll need to represent your grid as an array of some kind. At the very least, you'll want some kind of boolean values, to denote whether each coordinate in the grid is "occupied".
You'll need to keep track of the pieces on your grid. This could be another array, this time holding references to the four coordinates for each piece.
You'll need a variable or variables to keep track of a coordinate in your grid where you'll start filling in pieces, (I would probably populate these with a corner to start).
Set up a "pool" of all possible Tetris pieces and rotations. (You'll want to keep track of which ones you've already checked on every iteration outlined below.)
Iterate:
Get a random piece from your pool that will fit into your starting coordinate. (If you want to get fancy, you could be smart about which ones you choose, or you could just go totally random. As pieces don't fit, mark them checked, so you don't keep checking randomly forever. If you get to a point where you've checked all the pieces, you have a solution that doesn't work, either back up an iteration, or start over.)
Make sure the Tetris piece you selected didn't leave a "hole", or empty space with less than 4 squares. (I don't know your requirements for solving this problem, so I can't say whether you should focus on speed or ease of coding, but you may be able to skip this step if you want, and "brute force" the solution.)
"Place" the piece, by writing it to your piece array and marking the coordinates filled.
Check for "finished" condition, in which all your spaces are filled.
Pick a new coordinate in your grid and repeat #1. (I would pick an empty one next to the previous coordinate.)
If this actual yet, I wrote test tetris app on Objective-C few months ago https://github.com/SonnyBlack/Test-Demo-Tetris . I think my algorithm not very well, but it working. =)
let's say I want to display a customizable (2D, cartoon-like) character, where some properties e.g. eye color, hair style, clothing etc can be chosen from a predefined set of options. Now I want to animate the character. What's the best way to deal with the customization?
1) For example, I could make a sprite sheet for each combination of properties. That's not very memory efficient and not very flexible, but probably gives the best performance.
2) I could compose the character from various layers, where each property only affects one layer. Thus, I could make a sprite-sheet for the body, a collection of sprite-sheets for the eyes (one for each eye color) etc.
2a) In that case, I could merge the selected sprite-sheets in order to generate a single sprite-sheet containing the animation of the customized character.
2b) Alternatively, I could keep the sprite-sheets separate and try to animate them simultaneously as layers. I fear, that this might become a problem performance-wise.
3) I could try to modify the layers programmatically, e.g. use a sprite-sheet for the eyes as a mask and map some texture on it before merging it down to a single sprite-sheet. I would think this is a very flexible approach when it comes to simple properties like eye colors, but might become difficult for things like hair-style. I am aware that this depends much on the character and probably a general answer is difficult.
I assume that my problem is not new, so there is probably a standard approach to it.
Concerning the platform, I'm particularly interested in iOS and try to avoid OpenGL (well, I'm open-minded). Maybe there is a nice framework that can help me here?
Thanks!
Depending on what your working on, you might want to animate part/all of the animations outside in another tool, such as flash. It is much easier to work with a visual environment.
Then there are tools that take swf files, and create sprite sheets that you would then animate in cocos2d.
That is a common game creation workflow.
You problably want to take a look on how to create sprites at cocos2d.
Cocos2d comes with a set of tools that help you to animate single parts and offers abstractions to compose parts (like CCBatchNode or CCNode). Also, it comes with tools that helps you to pack sprites into sprite sheets (e.g Texture Packer) and develop levels (e.g Level Helper).
Cocos2d is an open source framework and it is widely used. You also have cocos3d but I never used it :).
I'm currently in the process of building a game using the MVC pattern. I am also using full blitting for the first time and have come to a cross roads in my code. I'm questioning where the data for the blitting should go (ie spritesheet, rectangle data etc). I feel like it should be part of the Model but it seems a bit clumsy, when drawing the pixel data in the View, to keep referring to the model for everything (ie model.canvas.copyPixels(model.spriteSheet, model.rectsArray[model.index], model.point) ).
Has anyone had any experience setting up MVC for use with blitting? Would this be the best set up?
One the one hand, graphics data should clearly go in the view. However, it's often also important for things like bounds checking, collision shapes, etc. Therefore I advise to encapsulate the graphics data in a class/module with two interfaces.
One interface provides access to just the graphics in can be given to the view.
The other provides access to the data derived from the graphics and can be given to the model.