1
vote
2answers
74 views

Find closest point from an origin, in a mesh

I want to do something similar to a raycast. With a raycast, you can set an origin and a destiny, and check where the ray collides with something but only with a line. What I want to do, is given an ...
0
votes
1answer
51 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 ...
2
votes
1answer
152 views

Why is there high performance hit with many meshes?

I am currently reading upon Geometry Instancing, as I want to render a lot of animatable objects on the screen. However I have come to a more fundamental question first: Why do I even need to use it? ...
7
votes
3answers
526 views

How do I target a tank turret with an offset barrel?

I have a tank model consisting of multiple parts, a body, a turret and the barrel of the gun. The turret is offset from the body origin and can rotate around the Y axis(up). The barrel is connected to ...
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 ...
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 ...
4
votes
2answers
534 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 ...
1
vote
1answer
127 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: ...
1
vote
1answer
201 views

Moving an object toward another object on sphere knowing their quaternions

I have a sphere centered in world origin. On the sphere surface I have two objects and I know their quaternions (rotation around sphere). Currently my movement works on Vector2 inputs (cannot change ...
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 ...
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 ...
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 ...
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: ...
11
votes
3answers
413 views

Are the first three values that describe a 3D plane actually a 3D vector?

A 3d plane is typically defined as a,b,c,d. Are a,b,c actually the x,y,z coordinates of a 3d vector, with d defining the rotation of the plane, something like axis-angle rotation data?
3
votes
3answers
864 views

Textureing subdivided Icosahedron in XNA, seam problem

*Look below for the updated source code* I have started to to make some different types of objects and create them by code in XNA. Right now I have finished the code for creating a Icosahedron. And ...
1
vote
2answers
966 views

Render a polyline with rounded joints

I have a list of points (3D) and want to draw a line connecting all points with a specified width. The line should be rendered in OpenGL (using OSG) as triangles. The real challenge of this task is to ...
4
votes
2answers
534 views

Repairing back-facing triangles without user input

My 3D application works with user-imported 3D models. Frequently, those models have a few vertices facing into the wrong direction. (For example, there is a 3D roof and a few triangles of that roof ...
4
votes
1answer
341 views

Running geometry shader only once

(Unfortunately couldn't find the answer myself) Does a neat way to cache the geometry shader results in Direct3D10 or OpenGL exist? (preferably Direct3D10). I'm building my geometry based on texture ...
0
votes
0answers
93 views

Drawbacks for using only quads for model geometry [duplicate]

Possible Duplicate: Why do game engines convert models to triangles compared to keeping it as four side polygon What are the main drawbacks for using "only" quads for model geometry? Does ...
4
votes
1answer
5k views

How to calculate a 3x3 rotation matrix from 2 direction vectors?

I've got 2 direction vectors, for the X axis and the Y axis of the object. How do I calculate the rotation matrix of the object using these?
4
votes
2answers
445 views

OpenGL, Offset and Camera Space

I was reading chapter 4 of the Arcsyntesis OpenGL tutorial when I came across this line in the GLSL shader. vec4 cameraPos = position + vec4(offset.x, offset.y, 0.0, 0.0); About it, the tutorial ...
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 - ...
6
votes
2answers
520 views

Perspective in early pseudo-3d games

Please take a look at the screenshot below, from the old classic Space Harrier. My question regards the curved perspective on the chequerboard 'ground'. It's got a strangely curved geometry (I ...
1
vote
2answers
458 views

Rotating coordinate system

Lets say that you want to rotate simple cube around fixed point in center. Is it possible to use such coordinate system, that you need to use only sine and cosine in order to rotate? I have done ...