drawing a grid

Author

556

April 04, 2002 03:33 PM

which way would be the best to draw a simple wireframe/dotframe (is that the right word??) grid? by drawing polys (hopefullt not) or is there a function (glut or no glut - doesn''t matter) that would do the work for me? thanks crispy

"Literally, it means that Bob is everything you can think of, but not dead; i.e., Bob is a purple-spotted, yellow-striped bumblebee/dragon/pterodactyl hybrid with a voracious addiction to Twix candy bars, but not dead."- kSquared

siaspete

208

April 04, 2002 03:39 PM

Are you just looking for GL_LINES?

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Crispy

Author

556

April 04, 2002 04:27 PM

silly me. of course. thanks siaspete. didn''t quite realise to look at glBegin() before i asked. cut myself with the Okkam''s Razor.

crispy

"Literally, it means that Bob is everything you can think of, but not dead; i.e., Bob is a purple-spotted, yellow-striped bumblebee/dragon/pterodactyl hybrid with a voracious addiction to Twix candy bars, but not dead."- kSquared

siaspete

208

April 04, 2002 04:34 PM

Remember to disable texturing before drawing the lines if you don''t want them textured :-)

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How To Ask Questions The Smart Way | Google can help with your question | Search MSDN for help with standard C or Windows functions

Saurus Games, home of the Independent Game Engine

eldee

122

April 04, 2002 04:43 PM

if you''re trying to make a mesh or object you''ve already
created wireframe or "dotframe" or whatever you want,
check out glPolygonMode().
the default is GL_FILLED, but you can pick GL_LINES and make it
wireframe.

for example, to render just one object in wireframe you could
do somethign like this:

if(bWireframe){   glPolygonMode(GL_LINES);   DrawPlayer1();   glPolygonMode(GL_FILLED);}

-eldee;another space monkey;[ Forced Evolution Studios ]

Crispy

Author

556

April 06, 2002 02:58 AM

a question, though...

can i use GL_LINES to draw finer (thinner) lines so that they wouldn''t be so prominent when the grid is dense?

crispy

"Literally, it means that Bob is everything you can think of, but not dead; i.e., Bob is a purple-spotted, yellow-striped bumblebee/dragon/pterodactyl hybrid with a voracious addiction to Twix candy bars, but not dead."- kSquared

siaspete

208

April 06, 2002 03:53 AM

In general, no. You can''t draw anything thinner than a pixel. You can however alter the alpha (using glColor4f) to fade the lines out slightly. This is a bit easier on the eye.

Helpful links:
How To Ask Questions The Smart Way | Google can help with your question | Search MSDN for help with standard C or Windows functions

Saurus Games, home of the Independent Game Engine

Crispy

Author

556

April 06, 2002 12:26 PM

the following code produces no dirrefent a result than the code without the call to glColor4d(). why is that?

glDisable(GL_TEXTURE_2D);glColor4d(0.5, 0.3, 0.7, 0.5);   glBegin(GL_LINES);  	for(int i = -30; i < 30; i++)       	{        	glVertex3d(i * RC.grid_density, 0, -15);        	glVertex3d(i * RC.grid_density, 0, 15);        }  	for(int i = -30; i < 30; i++)       	{        	glVertex3d(15, 0, i * RC.grid_density);        	glVertex3d(-15, 0, i * RC.grid_density);        }   glEnd();glEnable(GL_TEXTURE_2D);

crispy

"Literally, it means that Bob is everything you can think of, but not dead; i.e., Bob is a purple-spotted, yellow-striped bumblebee/dragon/pterodactyl hybrid with a voracious addiction to Twix candy bars, but not dead."- kSquared

_DarkWIng_

602

April 06, 2002 12:55 PM

you have to use something like
glBlendFunc( GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA );
and enable blending

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