Have you ever done graphics programming? Do you know the mathematical implications of the clipping planes? Any idea?
Have you ever done graphics programming? Do you know the mathematical implications of the clipping planes? Any idea?
Originally Posted by LuisAK
This has got to be a joke, right? The near and far clipping plane are only _concepts_ and not even a part of the OpenGL core profile specifications. I strongly urge you to read the specification and learn what are normalized device coordinates. Once you kind of understand what those are, then read what a projection matrix is, and then about various standard projection matrices.
Going further, the "native font support", did you even read what people wrote? OpenGL is a specification meant to exist on many platforms: MS-Windows, Mac OS-X, Unix .. and even to a lesser extent mobile platforms in some cases [at the very least OpenGL ES, but some mobile do OpenGL as well]. A specification needs to specify what to do with the files, what is rendered, etc in a way possible on all these platforms. On the subject of font rendering, hardware font rendering is a highly non-trivial action. Indeed, once hinting gets into play, then without truly extraordinary and heroic efforts one must use the CPU to render a glyph... in truth, I think even with such efforts, once hinting is required, then one must still use a CPU.
As for "better polygonal functions", do you mean triangulation or arbitrary polygons? If you want that, then use GLU to freaking do it for you.. or rip it out of Regal and call it a day.
or you could just ignore him and ask moderator to lock the topic leaving only explanation why initial idea is stupid. that guy obviously have little or nothing to do with graphics programming and keep's posting that crap out of boredom, cause he gets a lot of attention for his extreme ignorance. he obviously didn't read your messages.
i suggest to make a sticky thread for this forum, containing Frequent Suggestions in FAQ format, containing some popular suggestions with short explanations why they are not or shouldn't be implemented.
http://www.opengl.org/sdk/docs/man2/...erspective.xml
gluPerspective — set up a perspective projection matrix C Specification
void gluPerspective( GLdouble fovy,
GLdouble aspect,
GLdouble zNear,
GLdouble zFar);
Parameters
fovy Specifies the field of view angle, in degrees, in the y direction.
aspect Specifies the aspect ratio that determines the field of view in the x direction. The aspect ratio is the ratio of x (width) to y (height).
zNear Specifies the distance from the viewer to the near clipping plane (always positive).
zFar Specifies the distance from the viewer to the far clipping plane (always positive).
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if you have a look at the Parameters zNear and zFar, these are unnecessary restrictions !
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I know, what I´m talking about I´ve been building such a system
and a global player is holding two patents on my name.
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the topic is: suggestions for the next release of OpenGL
an this is my opinion
best regards
Luis
http://www.opengl.org/archives/resou...pping.htm#0050
> When I move the viewpoint close to an object, it starts to disappear. How can I disable OpenGL's zNear clipping plane?
> You can't. If you think about it, it makes sense: What if the viewpoint is in the middle of a scene? Certainly some geometry is behind the viewer and needs to
> be clipped. Rendering it will produce undesirable results.
> For correct perspective and depth buffer calculations to occur, setting the zNear clipping plane to 0.0 is also not an option.
> The zNear clipping plane must be set at a positive (nonzero) distance in front of the eye.
> To avoid the clipping artifacts that can otherwise occur, an application must track the viewpoint location within the scene,
> and ensure it doesn't get too close to any geometry. You can usually do this with a simple form of collision detection.
> This FAQ contains more information on collision detection with OpenGL. .........
what a nonsensical restriction
best regards
Luis
http://www.opengl.org/archives/resou...pping.htm#0050
"setting the zNear clipping plane to 0.0 is also not an option. The zNear clipping plane must be set at a positive (nonzero) distance in front of the eye."
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what a nonsensical restriction.
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It's not at all nonsensical. In a perspective projection, the X and Y coordinates are divided by the distance from the camera, Z. If Z is zero, you'll get divisions by zero. Or, in practical terms, an object zero units from the camera will appear infinitely large. To avoid this, the near clipping plane is nudged slightly out from zero.
It would be nice, in some cases, to have more precision available so that the far:near ratio can be made more than 1,000,000:1 without significant z-fighting. This is a hardware restriction, however, and not something imposed by OpenGL (or DirectX, for that matter). When a 64b z-buffer makes its debut, I suppose you could set the far plane to some huge value and have a nearly-infinite frustum. Until then, you pretty much have to work with the hardware available, and the best it can currently do is a 32b FP z-buffer in the range [0..1].
Actually OpenGL can deal with a literally infinite distant far plane already, it's just not possible to set up this projection via GLU (but then GLU isn't part of OpenGL), it doesn't even have a big impact on Z-buffer precision. Most of the Z-buffer range is used for the distances close to the near plane.
Moving the near clipping plane onto the camera (which happens when zNear = 0.0) will cause the near plane to be shifted to infinity in clip space along with the camera, which will cause a lot of precision issues (24, 32 or even 64 bit integers are a bit too small to store infinity), but for all practical purposes you can get the same effects as zNear = 0.0 by just disabling depth clamp.
You mean enabling depth clamp. Enabling depth clamp disables near clipping.by just disabling depth clamp.
Alfonse is of course right, I meant enabling depth clamp.
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