2d

问题 I want to get the angle between two lines with respect to direction of the line. A normal dot product of the 2 vectors of the lines always returns the lowest angle between the two lines, which is not what I'm looking for. Example image: Blue lines: The lines I have Red lines: indication of the direction Green lines: failed attempt at a curving line that indicates the direction of the rotation I want. p0~p3: the x, y coordinates of the points of the lines. a: The angle I am looking to get. I

问题 I want to get the angle between two lines with respect to direction of the line. A normal dot product of the 2 vectors of the lines always returns the lowest angle between the two lines, which is not what I'm looking for. Example image: Blue lines: The lines I have Red lines: indication of the direction Green lines: failed attempt at a curving line that indicates the direction of the rotation I want. p0~p3: the x, y coordinates of the points of the lines. a: The angle I am looking to get. I

问题 I'm in no way a professional programmer so, pls don't expect a sophisticated approach or language here. I'll however appreciate your advice and recommendations to materialize an algorithm which, at a later stage, I could programmatically add to my project... Here is the problem: Imagine an arbitrary point (Point X) in space with the following properties: has coordinates lies on a 2D-surface is stationary belongs to a single area (boundary coordinates of which are also known) at any given time

问题 title_list = [['determined', 'by', 'saturation', 'transfer', '31P', 'NMR'], ['Interactions', 'of', 'the', 'F1', 'ATPase', 'subunits', 'from', 'Escherichia', 'coli', 'detected', 'by', 'the', 'yeast', 'two', 'hybrid', 'system']] pc_title_list = [[]] print(title_list[1][0].isalpha() == True) for i in range(len(title_list)): for j in range(len(title_list[i])): if (title_list[i][j].isalpha() == True): pc_title_list[i].append(title_list[i][j].lower()) And now i going to stucking in this (IndexError

问题 I create Aliment struct. And i have an array of Aliment. struct Aliment { let name: String let vitamineARetinol: Float let vitaminC: Float let vitaminD: Float let calories: Float let grammage: Float } let ListAlimentsBrut = [ Aliment(name: "Orange", vitamineARetinol: 0.5, vitaminC: 57, vitaminD: 0.98, calories: 140, grammage: 100), Aliment(name: "Pomme", vitamineARetinol: 0.2, vitaminC: 6.25, vitaminD: 0.38, calories: 120, grammage: 100), Aliment(name: "Poire", vitamineARetinol: 0.1, vitaminC

问题 my problem is that I need to save the things that I draw with java graphics as independent objects, to later recolor them, erase them indepently... Here is my eclipse project for you to import. (The main class is the Paint class) This is the method I use to draw: protected void paintComponent(Graphics g) { if (imagen == null) { imagen = createImage(getSize().width, getSize().height); graficos = (Graphics2D) imagen.getGraphics(); graficos.setRenderingHint(RenderingHints.KEY_ANTIALIASING,

问题 How do I remove a specific row from a matrix, keeping the same order? Example: 1 1 1 2 2 2 3 3 3 Let's say I need to remove the row with all even elements, so after deleting it should look like: 1 1 1 3 3 3 I tried writing code myself, (condition not the same as i mentioned above!) but it doesn't actually work properly: for (i = 0 ; i < no_of_rows ; i++) { if (abs(prosjeci[i] - prosjek) < 0.1) { /* condition */ for (k = i ; k < no_of_rows - 1 ; k++) { for (j = 0 ; j < no_of_columns ; j++) {

问题 What I have: A projectile in Unity 5 2D, affected by gravity, that I want to move from point A to point B with initial impulse on a parabolic path What I know: The 2D coordinates of a random starting position (A) The 2D coordinates of a random target position (B) The time (X) I want the body to reach the target position after What I want to know: The initial impulse (as in unity applyforce with forcemode impulse) that I have to apply to the body onetime in order for it to reach the desired

问题 i have the following geometrical issue in 2D: i have a point from which i cast an infinite angle (2D-cone) which is given by a direction and an angle. (the point and the direction form a vector and to each side half of the angle forms the 2D-cone) now i want to check if another point in 2D is inside this cone or outside. how can this be achieved? thanks! 回答1: Calculate the vector from the center of the cone to the query point. Normalize the vector to be of length 1, Take the center vector of

问题 It's difficult to tell what is being asked here. This question is ambiguous, vague, incomplete, overly broad, or rhetorical and cannot be reasonably answered in its current form. For help clarifying this question so that it can be reopened, visit the help center. Closed 7 years ago . I'm trying to plot 3D points onto a 2D surface (I'm currently working with SDL.NET as my 'game engine'). The surface will be 800x400 pixels in size and the 3d coordinates will range from -4000 to 4000. My view