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0
votes
1answer
40 views

Image-Space coherence of the z-buffer algorithm

I'm reading Hierarchical z-Buffer Visibility by Ned Greene et al. and they state that traditional Z buffering makes reasonably good use of image-space coherence in the course of scan conversion. ...
5
votes
4answers
225 views

Creating force shields: the most efficient way of deforming/reshaping a simpler convex mesh so it envelopes a complex mesh?

So, the best way I can think of how to explain what I need is the following (images used here are just random images found trough google image search). What I am trying to create during run-time is ...
5
votes
2answers
99 views

How to find out the vertices of the polyhedron formed by the overlapping area of two rotated boxes?

What is the most efficient way for finding out the vertices of the polyhedron formed by the overlapping area of two rotated 3D boxes? If it is still confusing what I mean by "polyhedron formed ...
0
votes
0answers
197 views

Code sample on how to implement Lee's visibility graph

In my recent search, I've been amazed about how difficult it is to find code examples or information on how to build visibility graphs. Considering its importance on video-game development for AI ...
0
votes
0answers
37 views

Integer ops only 3D triangle-triangle collision detection

I've a need for 3D triangle-triangle collision detection using integer math only. Unfortunately, I'm not in a position where I can use 64-bit integers (only 32-bit) and my vertex values can be larger ...
0
votes
1answer
74 views

Generate Mesh of Shadow Volume

Given a mesh, I want to generate another mesh that is effectively a shadow volume of this mesh. I am looking for an algorithm/solution/implementation/reference that can do this under the following ...
12
votes
6answers
2k views

What's the fastest way checking if two moving AABBs intersect?

I have two AABBs that are moving, what's the fastest way to check if they will intersect under a frame? By moving I mean not just to check with the usual rectangle intersection method, I mean some ...
5
votes
1answer
611 views

How to construct the marching cubes tables algorithmically?

I want to implement the marching cubes algorithm from scratch, but I'm stuck at the polygon generation phase (building edge loops with correct orientation and triangulating them). Obviously, I should ...
-1
votes
1answer
154 views

how to turn (or solidify) water or fuild into solid material (Renderring Effect)

i want to implement an effect like this. for example, let's assume the clay are made of particles. liquids of clay flows for a while, then it becomes dry and rest.finally those particles becomes only ...
0
votes
0answers
96 views

Calculation technique for 2D inertia tensors?

Just wondering what the techniques are out there. It's only 2D so I figured there'd be a good chance for there to be a "one size fits all" solution out there that's essentially an analytical solution. ...
3
votes
3answers
6k views

How to calculate corner marks of a rotated rectangle?

I've got two elements, a 2D point and a rectangular area. The point represents the middle of that area. I also know the width and height of that area. And the area is tilted by 40° relative to the ...
2
votes
1answer
1k 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 ...
2
votes
1answer
1k 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
125 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
135 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
272 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
2k 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
548 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
150 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 ...
8
votes
1answer
2k 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
332 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 ...
2
votes
2answers
3k 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
727 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. ...
0
votes
1answer
234 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
885 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
929 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
1k 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 asegment and a cylinder? The segment is defined by ...
1
vote
6answers
1k 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
249 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, ...
4
votes
4answers
3k 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
487 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. ...
16
votes
1answer
1k 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
269 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 ...
17
votes
2answers
5k views

How do I test if a circle and concave polygon intersect?

I have a polygon (sometimes convex, but often concave), and a bunch of circles with different radii. How can I find out if a circle is intersecting/overlapping with the polygon? I could split my ...
4
votes
3answers
2k 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 ...