A branch of mathematics concerned with questions of shape, size, relative position of figures, and the properties of space.

learn more… | top users | synonyms

1
vote
1answer
225 views

XY Location scaling with varying density screens

I have a phone with resolution H=1280,W=720,Density=2 I have a tablet with resolution H=1216,W=800,Density=1.331 I drew a rectangle on my phone with corners Left,Top (-1.6,1.55), Right,Bottom (1.6,-1....
1
vote
0answers
66 views

Blender: calculation of elevation and rotation angle from plane

I have a generic plane (any location, any rotation around every axis) with its normal axis passing by the center. Then I have a generic point and I need to find the elevation and the rotation angle ...
1
vote
3answers
207 views

Geometry problem for area of sight

My player have a line of sight and all objects between the white lines, turns red. To compute this, the following conditions are met: if the angle between the yellow line and the red line are small or ...
1
vote
0answers
294 views

How can I draw a model perpendicular to a sloped surface? [duplicate]

Possible Duplicate: How do I find rotation in 3D based on a vector/normal? My models are axis-aligned. I know the normal of the surface I want to draw them on. How do I compute the rotations ...
0
votes
1answer
426 views

enemy View Range , chase player

for 3D: Q1 : I want to make zone range for each enemy in the game , so that when the player in the view range he will be chased . Q2 :if I want to make enemy walk a little bit around his position (...
0
votes
1answer
1k views

Determining and culling non-visible vertices

Ahoy! After posting my previous question on tile maps, i've been tinkering with an implementation i'm rather pleased with so far but would like to gather some more information about submitting ...
0
votes
1answer
36 views

How to enforce touching within a ring shape?

I'd like to have the player moving the finger within the shaded ring: The game should be able to detect "out-of-boundary" events once the finger moves outside the ring. How can I accomplish this?
0
votes
1answer
88 views

What is the Z plane?

I am learning the basics of geometry shaders and I came across references to the "Z plane." It's pretty easy to visualize the X and Y planes, but where does the Z plane reside in Cartesian space? ...
0
votes
1answer
641 views

Issues with Sine Wave Generation and Rotation

I'm working on generating objects in sine wave that lets you specify parameters that are start x, end x, start y, and end y position. Below is the method that I used to generate the debris void ...
0
votes
1answer
73 views

What technique should I use to implement the following type of “diggable” terrain?

I'm trying to replicate a certain game mechanic from the game Diggles. This game takes place in a vertical cross-section of the earth and allows the player to dig tunnels and caves into the ...
0
votes
2answers
7k views

How to determine the point of intersection of two lines? [closed]

I have two lines say P1( 0, -1, 0, -1 ) and P2( -1, 0, 0, -1 ). Since I'm working in 2D, there is no Z component. The x,y,z components are normals and the w component is the distance from origin. I am ...
0
votes
2answers
108 views

Optimal way to find point D that lays at the perpendicular line between point A and line BC

I am trying to write a script in C# to find the position of point D in 2D space in a specific scenario. I know the (X,Y) position of point A, which never happens to be on the line that contains the ...
0
votes
4answers
2k views

How does atan2 work when getting angle of a vector?

I know that atan2 gives me the absolute angle of any vector. But it doesn't give a value from 0 to 360 degrees. Instead, it gives a value (if I'm not mistaken), between 0 and 180, or between 0 and -...
0
votes
2answers
559 views

Ways to define a curve

I'm trying to give shapes in my physics engine roundness/ curvature. I am aware of various methods for mathematically defining curves; such as bezier-cruves, ellipses, etc. However I am not sure ...
0
votes
1answer
48 views

Draw a square given 2 corners

I am at the moment trying to come up with a simple method to extract some data points, given two corners. A*************** **************** ***************B I tried to illustrate my situation above....
0
votes
1answer
370 views

Rotate Object Towards Direction in 2D

For my RTS game's physics engine, I'm trying to find out a clever way to make a unit face the direction it's moving in. Given a Vector2d direction of movement (its normalized velocity), how can I ...
0
votes
2answers
317 views

Moving OBB vs. triangle intersection test

Requirements: to write a test function that, given a moving OBB (oriented bounding box) and a triangle, returns true whenever the OBB hits the triangle. The OBB is described by its half extents (h1, ...
0
votes
1answer
52 views

Geometry design and buffers

I'm making some tests with rendering stuff and I'm wondering how to design my Geometry class. For the moment, here is how I do: Init: Stock array with positions, array with colors, array with ...
0
votes
2answers
186 views

which quarter of a triangle the point is in

I've got a world made out of squares. The square are devided in four triangles like this: The corners have their heights stored in a 2D array and the center height is the average of the corners. To ...
0
votes
1answer
196 views

How to modify normal vectors with a tranformation matrix

Transformation is quite simple when it comes to Position or Color of the vertex, for Position just multiply matrix * vector and for color just don't do anything, but my question now is: How to handle ...
0
votes
1answer
154 views

“Walking” along a rotating surface in LimeJS

I'm trying to have a character walk along a plank (a long, thin rectangle) that works like a seesaw, being rotated around a central point by box2d physics (falling objects). I want the left and right ...
0
votes
1answer
998 views

Rotation of Rectangle along Y-axis transformed to parallelogram

After the rotation of a rectangular view along the Y-axis, about its center, transformed into parallelogram, how do I get the rotated parallelogram coordinates? By Y-axis, I mean perpendicular to the ...
0
votes
1answer
165 views

moving in the wrong direction

Solution: To move a unit forward: forward = Quaternion(0,0,0,1) rotation.normalize() # ocassionally ... pos += ((rotation * forward) * rotation.conjugated()).xyz().normalized() * speed I think the ...
0
votes
2answers
843 views

ray polygon intersection

Hi, I am looking for an elegant way to do ray and polygon intersections in 2d. I don't care about languages. Now what I'm doing is taking a line that lies on the ray (with a screen length) and ...
0
votes
1answer
548 views

Calculate path of laser beam?

Lets say we have a laser beam emitter that has a position and an angle (in a 2D world to simplify things). The laser emitted from that emitter will start at that position, and continue heading in the ...
0
votes
2answers
26 views

rough texturing on edges of mechanical parts

How do major studios fake the effect of "wear & tear" on the edges of guns and other things? I've always wondered this, but today it got to the point where I figured, why not just ask you guys. I"...
0
votes
1answer
35 views

Applying texture inside of an Icosphere?

I have implemented a code to generate an Icosphere procedurally in Unity 5.3.4f, which works pretty well. However, what I need to do know it tweak the code to make the sphere to receive texture only ...
0
votes
1answer
18 views

How to calculate the magnitude of the drag in Corona-sdk?

I'm making a game on Corona that launches a ball. The force is based on the magnitude of the drag: the larger is the drag -> the higher is the force. I'm having some trouble to do this, because I ...
0
votes
1answer
132 views

How could we use trigonometry for moving around a 3D World?

Well I have a question about geometry and 3-Dimensional player movement in general. I'm using Java, OpenGL and LWJGL. This is basically what I got: currentFrontSpeed: Is a float that contains the ...
0
votes
2answers
128 views

Rotate coordinates back after rotating game context (geometry)

To achieve something similar to the image below using HTML5 canvas one can simply write the following: var TO_RADIANS = 0.0174532925; context.translate(30, 20); context.rotate(30 * TO_RADIANS); ...
0
votes
2answers
69 views

Calculate land center on grid

I have a grid based game. The main map is 2d array with land ids, something like this (here are 2 lands on the map, one formed where the 1's are and one formed by where the 2's are): [ 1 , 2 , 2 ] [ ...
0
votes
1answer
93 views

Is there a way of moving the transform of an object relative to it's geometry

I have a number of objects (mostly prefabs) that have their transform origin in inconvienient places such as about 1 unit to the left of the actual geometry or somewhere inside an object where it's ...
0
votes
2answers
202 views

Outline of plane slice of arbitrary object

How would you extract the outline of a shape from slicing a plane through an arbitrary object? Note: This is related to my Unity Answers question, but not exactly the same.
0
votes
1answer
68 views

How can i calculate that normal lays in same part of plane with point?

I.e. n0 for A and n1 for B. Plane divided by plane CD.
0
votes
1answer
265 views

Formula to measure uv-mapping distortion

Does anyone know a simple way of calculating (offline) the amount a texture is distorted when mapped to a triangle like the following? Vertex Position UV Coordinates A (Ax, Ay, Az) (...
0
votes
1answer
115 views

How to calculate “real” distance between cursor and away object?

I don't really know how to formulate the title, but the problem is the following: I'm using a scripting language called "SQF" which has been created by a company named "Bohemia Interactive" (no, I do ...
0
votes
1answer
64 views

Picking a local origin as the centroid of given three points in 3D

Given three points non-collinear P, Q, R in 3D, I need a generic method to generate x', y', z' unit vectors that behave like origin of local coordinate system. x' and y' vectos should be on the plane ...
0
votes
1answer
106 views

Best method for selecting points from a point set - path distance

having a big set of points and a polygonal path what is the best way to select a set of points that are at a certain distance or smaller from the path? Or do I need to iterate thru all points on each ...
0
votes
1answer
55 views

How to linearly blend between multiple points, deviating from a default point?

I have a set of 3D points that I need to "blend" between. Lets say I have points [A,B,C] and I have the amount I want to blend each as [0.5, 0.2, 0.8], how can I blend between these points with the ...
0
votes
1answer
3k views

“LNK2001: unresolved external symbol” when trying to build my program

I get the following error(s) on my program that captures the mouse and then draws a line. Errors: 1>------ Build started: Project: Capture_Mouse_Line, Configuration: Debug Win32 ------ 1> main....
0
votes
1answer
59 views

applying rotation and speed to move user

My player has a position (vec3), rotation (quaternion) and speed. I have a fixed time step. At each tick, I work out from key-state etc what rotation and speed adjustments to make. How do I now ...
0
votes
1answer
286 views

Minimap Around Perimeter of Screen, Code Provided

What I'm essentially trying to do is what a lot of FPS's nowadays do in regards to their HUD. When an objective is off-screen, a small icon / symbol is shown on the perimeter of the screen, basically ...
0
votes
2answers
384 views

Partial recalculation of visibility on a 2D uniform grid

Problem Imagine that we have a 2D uniform grid of dimensions N x N. For this grid we have also pre-computed a visibility look-up table, e.g. with DDA, which answers the boolean query is cell X visible ...
0
votes
1answer
349 views

How do I rotate a segment + normal so that the normal is (0,-1) and the segment is now axis aligned

I have an arbitrary line segment, which may or may not be axis aligned along with its normal eg: Segment(Coord(-1,-1), Coord(1,1), Coord(-1, 1).normalize) which represents a line segment with a 45 ...
0
votes
3answers
310 views

exact point on a rotating sphere

I have a sphere that represents the Earth textured with real pictures. It's rotating around the x axis, and when user click down it has to show me the exact place he clicked on. For example if he ...
0
votes
0answers
20 views

Rotating a UI arrow according to the change in camera's rotation

I have been trying different alternatives to do what is a very basic thing but I couldn't have any success. What I want to do is this. I have a 2D UI sprite at the screen, formed by 2 triangles, with ...
0
votes
0answers
25 views

Finding minimum horizontal offset to disjoin two objects in 3D

This is an extension of sorts of the question asked here: Allowing a player to walk up and down slopes without resistance I am using the Separating Axis Theorem to determine the minimum translation ...
0
votes
0answers
28 views

How to convert Non-Axis Aligned Bounding Boxes to AABB

I'm trying to write a raytracer to render boxes (cubes) that are arbitrarily rotated, i.e. not necessarily axis aligned. While I'm reasonably comfortable ray-tracing an axis-aligned cube, I don't know ...
0
votes
1answer
59 views

Normal to an edge of a polygon, from a point inside the polygon

Suppose that I have a closed boundary that is represented by n points. Using these n points I construct a polygon with n sides. I have a point P(x,y) that lays inside the polygon. I want to draw the ...
0
votes
0answers
33 views

How to find visible planes in a world of boxes

I have a world where each object is a box: Each box has position x, y=0, z, dimensions width, height, depth. The boxes are never rotated. Each box is composed of 5 planes (left, right, front, back ...