opengl - Cylinder Normals -

-

i'm developing opengl application right draws big tube consisting of several small cylinders (kind of slinky). i'm getting annoying effect when turn lighting , normals on, angles these annoying black dots on cylinders' borders:

black dots on individual cylinders borders

i belive byproduct of fact cylinders thin. set normal (0,0,+/- 1) when setting top/base, , side normals (cos(toradian(beta)), sin(toradian(beta)), 0).

is possible remove effect whitout getting 'fatter' cylinders? or there wrong in way define normals?

thanks

this appears rendering of sides of cylinders. yellow in image corresponds tops of cylinders. sides of cylinders @ 90 degrees tops, not lit (i'm guessing light in same direction camera) , appear black. cylinders being thin these not fill make pixels don't show much.

how fix it? i've got couple of ideas:

1) draw tops , bottoms, not sides - fix problem when viewed angle, lead further problems if camera moves.

2) disable lighting, faces drawn same colour (assuming sides same colour top).

3) use multi-sampling - means of edges won't appear (as each pixel more top side due angle).

4) add more lights around scene, perpendicular current light.

1 & 2 best bet depending on you're trying achieve.


Comments

Post a Comment

Popular posts from this blog

javascript - Enclosure Memory Copies -

-
function myclass() { //lots , lots of vars , code here. this.bar = function() { //do numerous enclosed myclass vars } this.foo = function() { alert('hello'); //don't enclosed variables. } } each instance of myclass gets own copy of bar , foo, why prototyped methods use less memory. however, know more memory use of inner methods. it seems obvious me (1) below must true. agree? not distinct myclass instances have own distinct copies of bar, must have own distinct copies of myclass enclosure. (or else how bar method keep myclass variables straight on per instance basis?) now (2) question i'm after. since inner foo method doesn't use in myclass enclosure natural qustion is: javascript smart enough not keep myclass enclosure in memory use of foo? this depend entirely on implementation not language. naive implementations keep far more around others. answer true e.g. v8 (chrome's js engine) may not true spider...
Read more

php - Replacing tags in braces, even nested tags, with regex -

-
example preg_replace('/\{[a-za-z.,\(\)0-9]+\}/', 'replaced', 'lorem ipsum dolor sit {tag1({tag2()})}, consectetur adipiscing elit.'); the result: lorem ipsum dolor sit {tag1(replaced)}, consectetur adipiscing elit. question as can see "tag2" has been replaced, want replace "tag1" know how can this? (in cases might this: {tag1({tag2({tag3()})})}) , on.) btw using preg_replace_callback, easier show preg_replace here site can test code: http://www.spaweditor.com/scripts/regex/index.php you need add curly braces character set. here's pattern used: /\{[a-za-z.,\(\)\{\}0-9]+\}/ and here result: "lorem ipsum dolor sit replaced, consectetur adipiscing elit."
Read more