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2
votes
1answer
155 views

OpenGL - have object follow mouse

I want to have an object follow around my mouse on the screen in OpenGL. (I am also using GLEW, GLFW, and GLM). The best idea I've come up with is: Get the coordinates within the window with ...
1
vote
1answer
103 views

Sphere-Sphere intersection and Circle-Sphere intersection

I have code for circle-circle intersection. But I need to expand it to 3-D. How do I calculate: Radius and center of the intersection circle of two spheres Points of the intersection of a sphere ...
3
votes
1answer
88 views

What is an axis aligned integer bounding box?

In this paper, in the Distance field computation section, it says that an axis aligned integer bounding box of a Prism has to be calculated. Can someone explain what an axis aligned integer bounding ...
3
votes
2answers
77 views

Reconstructing mesh from topological skeleton?

I have a topological skeleton of a 3d maze-like level (think Descent[I]/II). It looks like a tree where each node is a vertex in 3d-space. If it were on a 2d plain, I would "simply" use this to ...
4
votes
1answer
208 views

How can I test if an object will “fit” during pathfinding?

I'm tinkering around with a 2d game where obstacles are polygons of arbitrary shapes, sizes and locations, and movable entities (players/enemies) can also be of arbitrary sizes. What's a good general ...
4
votes
1answer
453 views

Quads Vs Triangles

I'm curious to know which is better for games? Quads or Triangles? Wouldn't quads be better for rendering performances and smoothing out tessellation?
4
votes
2answers
286 views

a flexible data structure for geometries

What data structure would you use to represent meshes that are to be altered (e.g. adding or removing new faces, vertices and edges), and that have to be "studied" in different ways (e.g. finding all ...
0
votes
0answers
91 views

Generate complex (non-convex) polyhedron UV mapping

I need to find an approach to the problem of generating texture maps for non-convex polyhedrons without using a design tool like Maya. Specifically, I am mapping simulation results data onto a 3D ...
0
votes
0answers
39 views

bounding box of objects reflected in a surface

I'm interested in a subset of ray-tracing functionality. Specifically, I have a mirror surface (specified as some bidimensional surface, as of yet with no specified implementation, maybe some ...
6
votes
1answer
615 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 ...
2
votes
2answers
148 views

How scanline rendering finds an intersection with an object

I'm a newbie with graphics and after I read many articles on the web I still don't understand how in rasterizing from a pixel coordinate like (0;0) on the screen the intersection with an object (let's ...
1
vote
2answers
1k views

How to create a walkable 3D terrain

I want to make a terrain for a RPG game that I'm developing. I started modeling the surface and implementing it to my game, but now I realized that i might be doing everything wrong. So I would like ...
0
votes
1answer
381 views

Fast software color interpolating triangle rasterization technique

I'm implementing a software renderer with this rasterization method, however, I was wondering if there is a possibility to improve it, or if there exists an alternative technique that is much faster. ...
3
votes
0answers
282 views

Annoying flickering of vertices and edges (possible z-fighting) [closed]

I'm trying to make a software z-buffer implementation (meaning no DirectX or OpenGL, only a 2D library, SDL to be precise), however, after I generate the z-buffer and proceed with the vertex culling, ...
0
votes
1answer
161 views

Scanline filling of polygons that share edges and vertices

In this picture (a perspective projection of an icosahedron), the scanline (red) intersects that vertex at the top. In an icosahedron each edge belongs to two triangles. From edge a, only one triangle ...
3
votes
2answers
512 views

Scan-Line Z-Buffering Dilemma

I have a set of vertices in 3D space, and for each I retain the following information: Its 3D coordinates (x, y, z). A list of pointers to some of the other vertices with which it's connected by ...
0
votes
1answer
544 views

Easy way to project point onto triangle (or plane)

I have a mesh of triangles (navigation mesh), and a point in 3d space. This point should be "over" one of the triangles all the times. I'm trying to determine which triangle is the one the point is ...
1
vote
2answers
705 views

Segment-Cylinder intersection

What is the complete code (C#, pseudo, does not matter) for calculating the resulting segment (or its absence) for the intersection of the segment and the cylinder? The segment is defined by ...
1
vote
6answers
425 views

Testing whether two cubes are touching in space

Does anyone have any clean ideas on testing whether two cubes in 3D space touch? By touch I mean, touch at corners or on a face or on an edge. Say that the cubes are axis aligned and there is no ...
1
vote
2answers
200 views

How do i calc what side the ball is of the rect?

I have this nice drawing: http://bildr.no/view/1085283 I know the ball's center and the rectangle's center, but how do I know (programming C#) what side of the rectangle the ball is? By my drawing, ...
3
votes
4answers
2k views

What is an efficient 2D line-segment-versus-triangle intersection test?

In a 2D plane, I have a line segment (P0 and P1) and a triangle, defined by three points (t0, t1 and t2). My goal is to test, as efficiently as possible ( in terms of computational time), whether the ...
2
votes
1answer
342 views

Determine the cut sections of a polygonal mesh

I have a polygonal mesh, defined by vertices $V$, edges $E$ and face $F$. One can view this as a real life 3D terrain. I want to obtain cut sections of this terrain, defined by vertical cut planes. ...
15
votes
1answer
750 views

How to resolve collisions of compound shapes using SAT?

SAT is a decent way to determine collisions between arbitrary convex polygons. You'll even get the vector that is needed to resolve a collision. To resolve collisions between complex (non-convex) ...
3
votes
2answers
242 views

How to generate slopes that meet the plane, is using collision detection a good idea?

I have a terrain, which is defined by mesh. And there are a lot of other polygonal faces scattered throughout the terrain, they can be located above, or below or cutting through the terrain. You can ...
14
votes
2answers
3k views

How to find if circle and concave polygon intersect?

I have a polygon (sometimes convex, but often concave), and a bunch of circles with different radius. How can I find out if a circle is intersecting/overlapping with the polygon? If it makes it ...
4
votes
3answers
1k views

Point line collision reaction

I am trying to program point line segment collision detection and reaction. I am doing this for fun and to learn. The point moves (it has a velocity, and can be controlled by the user), whilst the ...