GL_POINTS

BlitzMax Forums/OpenGL Module/GL_POINTS

beanage(Posted 2009) [#1]
Will the zCoords of glvertex3f's have effect drawing in an XY GL_ORTHO mode like performed in glmax2d?

Thank you,

BeAnAge


ImaginaryHuman(Posted 2009) [#2]
No.

In orthographic projection there is absolutely no change in the appearance of the points when you define Z coordinates. If you call glRotatef() and roate around the X or Y axis, it will sort of attempt to do 3D rotation but it won't look right without a perspective projection. I think, however, that if you define 3D points `behind the camera` they won't be drawn?


beanage(Posted 2009) [#3]
So, does anyone know where the max2d cam is "looking" to? Positive or negative z?

*********|\_____
-Z<--------| |____|--------->+Z
*********|/

?


_JIM(Posted 2009) [#4]
Well, there's only one way to find out :) I would assume it's positive Z, but to make sure you can test it.


ImaginaryHuman(Posted 2009) [#5]
The default in GL is negative Z I think.


beanage(Posted 2009) [#6]
Hey, thanks. it is! So i know that..
Now, one last q (i know my questions sound a little odd, working on it:) :
Is there a glVertex1i? or is it possible to get that behaviour?


ImaginaryHuman(Posted 2009) [#7]
You can have 1 dimensional `bitmaps`, by which i mean the opengl concept of a bitmap, which is usually a 1-bit-per-pixel image, which can be just 1 row. But I think you always must have at least 2 coordinates ie glVertex2i or f because you have to be at least two-dimensional if not 3 or 4. How could you possibly conceive of plotting points with only 1 number passed to glvertex?


beanage(Posted 2009) [#8]
If it means more than its decimal value. e.g. when the "number" is part of a vertex buffer, that has been directly mapped from a 32b cube height map, and the actual vertices coordinates are "created" on the vertex shader as an interpretation of that value. gettin' my point?