Opengl sphere to cylinder

Posted on 15.04.2021 Comments

Or as a function of 3 space coordinates x,y,zall the points satisfying the following lie on a sphere of radius r centered at the origin.

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For a sphere centered at a point x o ,y o ,z o the equation is simply. If the expression on the left is less than r 2 then the point x,y,z is on the interior of the sphere, if greater than r 2 it is on the exterior of the sphere. Lines through a sphere A line can intersect a sphere at one point in which case it is called a tangent.

It can not intersect the sphere at all or it can intersect the sphere at two points, the entry and exit points. For the mathematics for the intersection point s of a line or line segment and a sphere see this. A line that passes through the center of a sphere has two intersection points, these are called antipodal points. A plane can intersect a sphere at one point in which case it is called a tangent plane. Otherwise if a plane intersects a sphere the "cut" is a circle.

Lines of latitude are examples of planes that intersect the Earth sphere. Great Circles A great circle is the intersection a plane and a sphere where the plane also passes through the center of the sphere. Lines of longitude and the equator of the Earth are examples of great circles. Two points on a sphere that are not antipodal define a unique great circle, it traces the shortest path between the two points. If the points are antipodal there are an infinite number of great circles that pass through them, for example, the antipodal points of the north and south pole of Earth there are of course infinitely many others.

Great circles define geodesics for a sphere. A geodesic is the closest path between two points on any surface. Lune A lune is the area between two great circles who share antipodal points.

Spinning Cylinder - OpenGL & GLSL

If the angle between the planes defining the great circle is A, then the area of a lune on a sphere of radius r is. A triangle on a sphere is defined as the intersecting area of three great circles. Unlike a plane where the interior angles of a triangle sum to pi radians degreeson a sphere the interior angles sum to more than pi. As the sphere becomes large compared to the triangle then the the sum of the internal angles approach pi.

Calculating Centre Two lines can be formed through 2 pairs of the three points, the first passes through the first two points P 1 and P 2.Please be more specific — what books or online articles have you looked at? Posting your code always is a good start. It is quite difficult to answer such a broad question — maybe looking at how to do an animation itself may help so see Post That post shows a rotating cube, to get a rotating cylinder the code is modifed to use GLUquadricObj as follows.

Please guide me, any valuable answer is appreciated.

opengl sphere to cylinder

There is a nice image loading library called DevIL that is cross platform. To use it see a previous post from earlier today at Post After you load the image like the post, you simply need to add two lines of code in the Display function before you start drawing the gluCylinder ….

Compile: gcc cc1. This is what gives you texture coordinates. Now if you have a. The above code is working fine without any error messages.

opengl sphere to cylinder

Notice how the first argument it expects is a pointer to a GLUquadric. And reading further this pointer is defined by a very specific function, gluNewQuadric. The question about multiple textures on a single cylinder is more involved question. Do you have to do multiple textures or simply make a single texture in some drawing program that has the effect of multiple decals? The second approach easily maps to the code you already have.

But if you have to do the first approach — A quick google search lead to multitexturing tutorial that may help you get started. Also see Post I believe with this you will have to start using the openGL extensions — you can get setup to use them with the GLEW library. To use it read Glew basic usage. And note the compile command is.

Regarding multitexturing, the code which is in above link is in shading language is it same for C. Sorry for asking simple question.

It shows how to do multitexturing in c but on a QUAD instead of a cylinder. I realized my previous post could use the older blending capabilities instead … see chapter06 in Redbook. Heres some alternative code that reads two textures Logo. The changes mostly occure in the Display function. What code are you referring exactly? I have lost track. Also did you see the Post and compile and run it — that I think is a better example of multitexturing.The definition of a cylinder is a 3D closed surface that has 2 parallel circular bases at the ends and connected by a curved surface side.

Similarly, a prism is a 3D closed surface that has 2 parallel polygonal bases connected by flat surfaces. Since we cannot draw a perfect circular base and curved side of the cylinder, we only sample a limited amount of points by dividing the base by sectors slices. Therefore, it is technically constructing a prism by connecting these sampled points together. As the number of samples increases, the geometry is closer to a cylinder.

Suppose a cylinder is centered at the origin and its radius is r and the height is h.

opengl sphere to cylinder

The range of sector angles is from 0 to degrees. The sector angle for each step can be calculated by the following. It also creates other vertex attributes; surface normals and texture coordinates.

In order to reduce multiple computations of sine and cosine, we compute the vertices of a unit circle on XY plane only once, and then re-use these points multiple times by scaling with the base radius. These are also used for the normal vectors of the side faces of the cylinder.

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The constructor also takes additional parameters to construct various shapes of a cylinder, similar to OpenGL gluCylinder function. For instance, if the base radius is 0, it becomes a cone shape. For more details, please refer to Cylinder. In order to draw the surface of a cylinder in OpenGL, you must triangulate adjacent vertices counterclockwise to form polygons.

Each sector on the side surface requires 2 triangles. And the number of triangles for the base or top surface is the same as the number of sectors.

Download: cylinder. This example constructs cylinders with 36 sectors and 8 stacks, but with different shadings; flat, smooth or textured. You could also pass the custom parameters to the constructor, similar to gluCylinder. Press the space key to change the number of sectors and stacks of the cylinders.

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Or, download cylinderShader. Triangular Prism 3. Rectangluar Prism 4. Octagonal Prism 8.

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Hexadecagonal Prism A vertex coordinate on a cylinder.By using our site, you acknowledge that you have read and understand our Cookie PolicyPrivacy Policyand our Terms of Service. The dark mode beta is finally here. Change your preferences any time. Stack Overflow for Teams is a private, secure spot for you and your coworkers to find and share information.

I would like to form a shape between two updating points in 3D space using pyqtgraph and OpenGL. However, I would like to have an oval or cylinder form connected between the points, but I cannot seem to find a way to use the integrated MeshData sphere and cylinder, without jumping into complicated mathematics, rotation matrices and trigonometry.

And if you prefer linear algebra rather than trigonometry, that's not too bad either, although a bit more verbose:. Learn more. How to connect an oval or cylinder formed shape between two updating 3D points using pyqtgraph and OpenGL?

Ask Question. Asked 6 days ago. Active today. Viewed 68 times. Illustration of what I have right now, and what I would like to have instead: Sample code: from pyqtgraph. Qt import QtCore, QtGui import pyqtgraph as pg import pyqtgraph.

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Feedback on Q2 Community Roadmap. Technical site integration observational experiment live on Stack Overflow. Dark Mode Beta - help us root out low-contrast and un-converted bits.The OpenGL library GL is designed for low-level operations, both streamlined and accessible to hardware acceleration. Some of the GLU operations are covered in other chapters.

The use of gluPickMatrix is explained in Chapter Only two GLU topics remain: polygon tessellators and quadric surfaces, and those topics are discussed in this chapter.

To optimize performance, the basic OpenGL only renders convex polygons, but the GLU contains routines to tessellate concave polygons into convex ones, which the basic OpenGL can handle. Where the basic OpenGL operates upon simple primitives, such as points, lines, and filled polygons, the GLU can create higher-level objects, such as the surfaces of spheres, cylinders, and cones.

A polygon is simple if the edges intersect only at vertices, there are no duplicate vertices, and exactly two edges meet at any vertex. If your application requires the display of concave polygons, polygons containing holes, or polygons with intersecting edges, those polygons must first be subdivided into simple convex polygons before they can be displayed. Such subdivision is called tessellation, and the GLU provides a collection of routines that perform tessellation. These routines take as input arbitrary contours, which describe hard-to-render polygons, and they return some combination of triangles, triangle meshes, triangle fans, or lines.

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Figure shows some contours of polygons that require tessellation: from left to right, a concave polygon, a polygon with a hole, and a self-intersecting polygon. Use gluTessCallback several times to register callback functions to perform operations during the tessellation. Specify tessellation properties by calling gluTessProperty. The most important property is the winding rule, which determines the regions that should be filled and those that should remain unshaded.

Create and render tessellated polygons by specifying the contours of one or more closed polygons. If the data for the object is static, encapsulate the tessellated polygons in a display list. If you don't have to recalculate the tessellation over and over again, using display lists is more efficient.

If you need to tessellate something else, you may reuse your tessellation object. If you are forever finished with your tessellation object, you may delete it with gluDeleteTess. Note: The tessellator described here was introduced in version 1. As a complex polygon is being described and tessellated, it has associated data, such as the vertices, edges, and callback functions.

All this data is tied to a single tessellation object. To perform tessellation, your program first has to create a tessellation object using the routine gluNewTess. A single tessellation object can be reused for all your tessellations. This object is required only because library routines might need to do their own tessellations, and they should be able to do so without interfering with any tessellation that your program is doing.

It might also be useful to have multiple tessellation objects if you want to use different sets of callbacks for different tessellations. A typical program, however, allocates a single tessellation object and uses it for all its tessellations. There's no real need to free it because it uses a small amount of memory.

On the other hand, it never hurts to be tidy. After you create a tessellation object, you must provide a series of callback routines to be called at appropriate times during the tessellation. After specifying the callbacks, you describe the contours of one or more polygons using GLU routines.

When the description of the contours is complete, the tessellation facility invokes your callback routines as necessary. Any functions that are omitted are simply not called during the tessellation, and any information they might have returned to your program is lost.I am looking for an algorithm to generate spheres, cylinders, and arcs with triangles only.

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I want to provide the dimensions of the shape ie. Basically what Im trying to do is do some collision detection using coldet. From my understanding, you have to have a shape consisting of triangles and… I want to test collisions on these shapes. If there is an easier way, please let me know. I just figured that there was a script or something already out there to do the shape conversions to triangles and that it would be pretty painless. Maybe useless but the red book and in the sample gl code in the sdk has recursive funcs for sphere generation.

And it is quite easy to split each quad in two triangles using the same vertices. Instead, use specialised code to check for intersections between spheres, cylinders and other simple geometric primitives.

Get the sin and cos for each of the 32 sections and you have your x,y pair for your triangles. Store these in an array. If your circle is looking jagged, add more points. Do the same thing for the bottom of the circle, but translate into the screen a bit on the Z axis behind the 1st circle.

Now, go through each pair again, only this time your triangles go between the two circles. You draw triangles between:. It will look like a circle until you rotate the object. Spheres and Cylinder using triangles? OpenGL: Basic Coding. Thanks for any help. Gavin March 17,am 2. HTH Jean-Marc. Thanks for the suggestions guys! Well, just in case anyone is interested… Cylinders were pretty easy to triangulate!Today's Posts. Quick Links. Search Forums. Show Threads. Show Posts.

Draw a 3D cylinder using openGL. Registered User. Join Date: Aug Hi, please give me, how to code to draw 3D cylinder in openGL, that should be rotated in x-direction.

Forum Advisor. Join Date: Mar Is this a homework question? Please post it in the appropriate forums Please show us what have you tried so far. Hi Sir, Sorry for asking code. I made a code to draw cylinder is given below : code : Code :. Last edited by pludi; at AM.

Reason: code tags, please Sector,cylinder,track information.

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Hi all, I am trying to get below information from linux machine, could you please assist me to get this information using a command s or small script: SectorsPerTrack TotalCylinders TotalHeads TotalTracks TracksPerCylinder i am aware of fdisk -l command but the information provided by Red Hat. Warning: extended partition does not start at a cylinder boundary.

Can you please help me to remove this error. Draw multicolor line. But non-horizontal - no good. I rotate pixmap for all lines and then XSetTile for each line with own pixmap, but it's Solaris 8 and openGL. Hi everybody, Sorry to bother you one more time, but I have a problem with my Solaris 8 installation. Cadds works, but the 3D visualization is very slow compare to Partition 0 not aligned on cylinder boundary: ".

Increase root partition by moving starting cylinder. I am trying to expand the root partition on Solaris In this case I would have to expand from the front end following the table below, meaning I would have to move the What is on Your Mind?

opengl sphere to cylinder

Do you draw flowcharts. Do you draw flowcharts while you do the programmingdesign new network or simmilar? How to draw cylinder using openGL. And i have to insert bitmap images on cylinder. How to do this. Thanking You in advance. Hi, i am new to opengl, how to work openGL in ubuntui am not getting which packages as to be install and how to install those packages.