2d

问题 I have a python (NumPy) function which creates a uniform random quaternion. I would like to get two quaternion multiplication as 2-dimensional returned array from the same or an another function. The formula of quaternion multiplication in my recent case is Q1*Q2 and Q2*Q1. Here, Q1=(w0, x0, y0, z0) and Q2=(w1, x1, y1, z1) are two quaternions. The expected two quaternion multiplication output (as 2-d returned array) should be return([-x1*x0 - y1*y0 - z1*z0 + w1*w0, x1*w0 + y1*z0 - z1*y0 + w1

问题 Is there a way to combine multiple draw operations to a 2d canvas rendering context in such a way that they their combined result is composed onto the previous content of the canvas, as opposed to each drawing operation being composed by itself? One application: I'd like to draw a translucent line with an arrow head, and I'd like to avoid increased opacity in those areas where the line and the arrow head overlap. Many other rendering models support such features. SVG has a group opacity

问题 Im trying to get all my small images like grass, water and asphalt and so on, into one bitmap. I have an Array that goes like this: public int Array[]={3, 1, 3, 3, 1, 1, 3, 3, 3, 3, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1 ,1 ,1, 1, 1 ,1 ,1 ,7 ,7 ,7, 7, 7 ,7, 7 ,7 ,7, 7 ,7 ,7 ,7 ,7, 7 ,7, 7 ,7 ,7 ,7 ,7 ,7 ,7 ,7, 7, 7, 7, 7 ,7 ,7 ,7 ,7 ,7 ,7, 7, 7 ,7 ,7 ,7 ,7 ,7 ,7 ,7 ,7, 7, 7, 7 ,7 ,7, 7 ,6, 6, 6, 6, 6 ,6 ,6, 6, 6 ,6 ,6, 6, 6 ,6, 6, 6 ,6, 6 ,6 ,6 }; So basicly this is a 10*10 Every number is

问题 I have made a simple program that has a 2D String array storing lots of data. I have searched a lot of places for how to store and retrieve 2D arrays. I want to save the data in my array at the end of the program and have this data retrieved upon the start of the program. I have tried: ObjectOutputStream toFile = new ObjectOutputStream(new FileWriter("array.DATA")); toFile.writeObject(array); This came up with the error: incompatible types: FileWriter cannot be converted to OutputStream I

问题 Please take a moment to understand my situation. If it is not comprehendable, please tell me in a comment. I have an ArrayList of Waypoints. These waypoints are not in any order. A waypoint has the following properties: {int type, float z, float y, float x, float rotation} This applies to a 3 dimensional world, but since my pathfinding should not care about height (and thus treat the world as a 2 dimensional one), the y value is ignored. Rotation is not of importance for this question. In

问题 Question is simple so, no codes! If someone knows Box2D and SDL2, then, please tell me how to wrap SDL_Rect with b2body. Ofcourse, it requires to know the conversion of metre to pixel and vice versa. This is because Box2D measures distance in metres. Can you give me a simple expression or function to convert metres(of Box2D) to pixels or pixels to metres(of Box2D)? 回答1: Can you give me a simple expression or function to convert metres(of Box2D) to pixels or pixels to metres(of Box2D)?

问题 is there a nice way to calculate the position of a path (CGPath or UIBezierPath) at a given time (from 0 to 1)? Using CAShapeLayer for example, one can create an animated stroke end. I want to know the position of that stroke end at arbitrary times. Thanks in advance, Adrian 回答1: You can definitely base your approach on the CADisplayLink and a tracking layer. However, if you don't mind doing a little bit of math on your own, the solution is not too complicated. Plus, you wont have to depend

问题 I'm working on a little 2D platformer/fighting game with C++ and SDL, and I'm having quite a bit of trouble with the collision detection. The levels are made up of an array of tiles, and I use a for loop to go through each one (I know it may not be the best way to do it, and I may need help with that too). For each side of the character, I move it one pixel in that direction and check for a collision (I also check to see if the character is moving in that direction). If there is a collision,

问题 Firstly, here is my code http://pastebin.com/BxpE7aFA. Now. I want to read a text file which looks like this http://pastebin.com/d3PWqSTV and put all those integers into an array, called level. level has a size of 100x25, which is declared at the top. My only problem now is where you see the ???. How do I get the char from the file, and put that into level[i][j]? 回答1: Check the code of initialization of a matrix, it should be int level[HEIGHT][WIDTH]; not int level[WIDTH][HEIGHT]; also, your

问题 Firstly, here is my code http://pastebin.com/BxpE7aFA. Now. I want to read a text file which looks like this http://pastebin.com/d3PWqSTV and put all those integers into an array, called level. level has a size of 100x25, which is declared at the top. My only problem now is where you see the ???. How do I get the char from the file, and put that into level[i][j]? 回答1: Check the code of initialization of a matrix, it should be int level[HEIGHT][WIDTH]; not int level[WIDTH][HEIGHT]; also, your