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

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4
votes
2answers
850 views

What is a good way to determine if a vector is between two other vectors?

I could operate with the angles, but I do not have the angles calculated yet (and would like to avoid having to do that). It would be possible to calculate and cache the local-coordinate-frame angles, ...
3
votes
1answer
94 views

Vertices shaking with large camera position values

Basicly when i set the position of my camera (my character in game) to a high value, the geometries seems to be shaking, the higher the position value, the more they shake. On low position values you ...
7
votes
2answers
1k views

Geometry System of Populous: The Beginning

I want to to develop a game like Populous: The Beginning with my friend. But we could not find out what type of geometry they have used for the world. We know that - all tiles have the same size - ...
22
votes
4answers
2k views

Is the Manhattan distance monotonic when used as heuristic function?

I have a square-based map. Only horizontal and vertical movement is allowed (no diagonals). Movement cost is always 1. I'm implementing an A* algorithm on that map, using the Manhattan distance as a ...
2
votes
2answers
137 views

Calculating specific coordinate along a path

Let's say I have a path comprised of a sequence of points that are connect by lines and arcs. The entire path has some specific length. Let's call that length 100. What would be the mechanism to ...
2
votes
1answer
369 views

Collision avoidance (AI)

Now my 3D model has complete AI behaviours, but my model has no collision avoidance while he is moving towards the player! Because of this, he gets stuck in front of 3D blocks sometimes. I think the ...
27
votes
6answers
2k views

Hexagon collision detection for fast moving objects?

A object has a position and a speed vector. Usually only the position is used to check if two objects collide, this is problematic for very fast moving objects as it can happen that the object moves ...
6
votes
1answer
463 views

Procedural Geometry Generation

I have recently been looking into SceneKit for OS X and noticed that there are several factory methods to create geometric shapes such as: Box, Capsule, Cone, Cylinder, Plane, Pyramid, Sphere, Torus ...
0
votes
1answer
180 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 ...
-1
votes
1answer
110 views

chasing , zone range

here is an image show what I am gonna to do in my XNA game , I want to check if the player is inside zone range and if yes then attack the player , I tried to do this using checking ray but it's odd ...
2
votes
1answer
454 views

How to calculate collision normal between two AxisAlignedBox's?

I'm writing a physics simulation in Ogre3D and I'm trying to figure out how to calculate the collision normal between two Ogre::AxisAlignedBox's. I am checking for collisions using the "intersects" ...
1
vote
0answers
47 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 ...
0
votes
1answer
157 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 ...
3
votes
2answers
156 views

What kind of projection is ScreenX=X/Z, ScreenY=Y/Z?

I have an existing class which transforms 3D vectors and projects them on a 2D plane (Camera). The code is all written in C without help from an external library. To project a single vector (X,Y,Z) ...
1
vote
1answer
125 views

A controlled trapezoid transformation with perspective projecton

I'm trying to implement a controlled trapezoid transformation in Adobe Flash's ActionScript using the built-in perspective projection facility. To give you an idea of how the effect looks like: ...
7
votes
4answers
1k views

Implementing 2D CSG (for collision shapes)?

Are there any simple (or well documented) algorithms for basic CSG operations on 2D polygons? I'm looking for a way to 'add' a number of overlapping 2D collision shapes. These may be convex or ...
1
vote
2answers
1k views

Wrong faces culled in OpenGL when drawing a rectangular prism

I'm trying to learn opengl. I did some code for building a rectangular prism. I don't want to draw back faces so I used glCullFace(GL_BACK), glEnable(GL_CULL_FACE);. But I keep getting back faces also ...
0
votes
0answers
91 views

Top down 2D camera in relation to keyboard commands

I have a basic 2D camera: transform = Matrix.CreateTranslation(-position.X, -position.Y, 0) * Matrix.CreateRotationZ(-rotation) * Matrix.CreateScale(new Vector3(zoom, zoom, 1)) * ...
1
vote
2answers
244 views

DirectX How to Gernerate Vertices for Diamond Shape and Render it?

How to generate vertices for 3D Diamond Shape in DirectX? EDIT: I am creating an application which receive DIAMETER, CROWN, GIRDLE and PAVILION as parameter and render a model of diamond according to ...
1
vote
3answers
178 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 ...
19
votes
3answers
1k views

Is there a 3D equivalent of hex tile maps?

Probably the biggest advantage of a hex-based versus square-based map tiling is that the center of each hex has the same distance to all its neighboring hexes. Is there a similar shape that tiles this ...
4
votes
2answers
531 views

Displaying (3D) objects' name above them

The Elder Scrolls: Morrowind has a rather interesting way to display each focused objects' name. It's all a bit fuzzy in my memory right now, but the most important part I remember perfectly: the ...
2
votes
0answers
130 views

How to trace contour of shapes with holes?

I am experimenting with the RVO2 library for collision avoidance in a 2D simulation. This library supports specifying arbitrary obstacles as a list of vertices. The obstacles must be full shapes, i.e. ...
7
votes
5answers
764 views

How do I calculate distance from a point to a rectangle?

I have a 2D rectangle with x, y position, height and width, and a randomly positioned point nearby. Is there a way to check if this point might collide with the rectangle if it is closer than a ...
0
votes
1answer
506 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 ...
24
votes
1answer
1k views

How do you turn a cube into a sphere?

I'm trying to make a quad sphere based on an article, which shows results like this: I can generate a cube correctly: But when I convert all the points according to this formula (from the page ...
-5
votes
3answers
297 views

in the shadow of a sphere [duplicate]

(Related, but somewhat different, to my previous question) How can I determine in a fragment shader if a fragment is in the shadow of a sphere? That is, if it is occluded by the sphere and is past ...
1
vote
1answer
66 views

Build a Cube/Prism from other varied Cubes/Prisms [closed]

I'm wondering, are there any algorithms or theories in existence (that aren't patented/proprietary/protected) that would take a series of 3d rectangular prisms (or cubes but a cube is a prism) and ...
3
votes
1answer
356 views

How do I render a filled and stroked path using OpenGL?

I want to render a 2-dimensional geometric path consisting of B├ęzier curves and straight lines. Paths can be concave. What is the most efficient way to draw this using modern OpenGL? Can I do this ...
1
vote
2answers
2k views

Voronoi regions of a (convex) polygon

I'm looking to add circle-polygon collisions to my Separating Axis Theorem collision detection. The metanet software tutorial (http://www.metanetsoftware.com/technique/tutorialA.html#section3) on ...
0
votes
2answers
381 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 ...
2
votes
2answers
811 views

How can I transform a point from world space to object space?

If I have an object space described by transformation matrix that should be applied to object to transform it to world space, what I have to do to transform point (world space) to that object space. ...
0
votes
1answer
38 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 ...
1
vote
1answer
90 views

How to linearly “blend” between multiple 3D points?

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 ...
5
votes
4answers
268 views

Would like some help in understanding rendering geometry vs textures

So I was just pondering whether it is more taxing on the GPU to render geometry or a texture. What I'm trying to see is whether there is a huge difference in rendering two scenes with the same setup: ...
6
votes
3answers
526 views

Transforming a primitive tetrahedron into a primitive icosahedron?

I've created a tetrahedron by creating a BoundingBox and building the faces of the tetrahedron within the bounding box as follows (see image as well): VertexPositionNormalTexture[] vertices = new ...
2
votes
2answers
106 views

Splitting Graph into distinct polygons in O(E) complexity

If you have seen my last question: trapped inside a Graph : Find paths along edges that do not cross any edges How do you split an entire graph into distinct shapes 'trapped' inside the graph(like ...
4
votes
1answer
2k views

Morph a sphere to a cube and a cube to a sphere with GLSL

I'm getting started with GLSL with quartz composer. I have a patch with a particle system in which each particle is mapped into a sphere with a blend value. With blend=0 particles are in random ...
1
vote
2answers
2k views

Rotate an object given only by its points?

I was recently writing a simple 3D maze FPP game. Once I was done fiddling with planes in OpenGL, I wanted to add support for importing Blender objects. The approach I used was triangulization of the ...
5
votes
1answer
124 views

trapped inside a Graph : Find paths along edges that do not cross any edges

This is a graph based platformer level and the round shapes are creatures. I am looking for a path traveling along edges that does not cross other edges(To simulate the creature crawling on the ...
6
votes
3answers
2k views

2D isometric: screen to tile coordinates

I'm writing an isometric 2D game and I'm having difficulty figuring precisely on which tile the cursor is. Here's a drawing: where xs and ys are screen coordinates (pixels), xt and yt are tile ...
2
votes
1answer
141 views

Finding the normals of an oriented bounding box?

Here is my problem. I'm working on the physics for my 2D game. All objects are oriented bounding boxes (OBB) based on the separate axis theorem. In order to do collision resolution, I need to be ...
18
votes
5answers
598 views

Moving CW or CCW?

Lets say we have a jagged shape: And two creatures moving along it's outline. Then we smooth the shape completely by pulling the corners out. We get this: It is easy to see now that Orange is ...
0
votes
1answer
755 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> ...
4
votes
3answers
297 views

How to get distance from point to line with distinction between side of line?

I'm making a 2d racing game. I'm taking the nice standard approach of having a set of points defining the center of the track and detecting whether the car is off the track by detecting its distance ...
10
votes
2answers
1k views

Arbitrary Rotation about a Sphere

I'm coding a mechanic which allows a user to move around the surface of a sphere. The position on the sphere is currently stored as theta and phi, where theta is the angle between the z-axis and the ...
10
votes
2answers
516 views

How to limit click'n'drag movement to an area?

I apologize for the somewhat generic title. I'm really don't have much clue about how to accomplish what I'm trying to do, which is making it harder even to research a possible solution. I'm trying ...
1
vote
2answers
154 views

The distance to a line from a point, find the constant values?

I have 3 points, (x1, y1), (x2, y2), (x3, y3) I should find the AH height. For this i must use: How can i find each "a", "b" and "c" values?
1
vote
2answers
111 views

ricocheting off a wall

I have a capsule (sphere sweep) that I've computed the collision on a mesh with. I know the point of impact and normal of the face it collides with. My moving object - I'm using a capsule to ...
9
votes
1answer
3k views

Circle-Line Collision Detection Problem

I am currently developing a breakout clone and I have hit a roadblock in getting collision detection between a ball (circle) and a brick (convex polygon) working correctly. I am using a Circle-Line ...