OH Woe is Me!! Picking not working!

Scott W · 2002-01-08T11:10:55

Hi, I''ve been trying to get picking working for my tile based level editor without any luck. my format for a map is simply setup as: void Create_Map() { int x, z; for (z=0;z<size;z++) for (x=0;x<size;x++) { Map.tile[x][z].x = (float)x-(size/2); Map.tile[x][z].y = -1.0f; Map.tile[x][z].z = (float)z-(size/2); } } and I draw my map like so: void Draw_Map() { int x, z; for (z=0;z<size;z++) for (x=0;x<size;x++) { glBegin(GL_QUADS); glVertex3f(Map.tile[x][z].x, Map.tile[x][z].y, Map.tile[x][z].z); glVertex3f(Map.tile[x+1][z].x, Map.tile[x+1][z].y, Map.tile[x+1][z].z); glVertex3f(Map.tile[x+1][z+1].x, Map.tile[x+1][z+1].y, Map.tile[x+1][z+1].z); glVertex3f(Map.tile[x][z+1].x, Map.tile[x][z+1].y, Map.tile[x][z+1].z); glEnd(); } } it goes pretty much something like that. Now how would I go about picking one of the polygons in the map so that i could change it texture/properties and so on? I''ve tried following Lesson 33 on NeHe''s website, and also the OpenGL SuperBible 2nd Edition with no luck. Please help. Thanks, Scott Email Website "If you try and don''t succeed, destroy all evidence that you tried."

NeHe Productions Affiliates

Started by Nibbles September 19, 2001 09:43 PM

14 comments, last by Nibbles 22 years, 3 months ago

Wavarian

850

October 30, 2001 02:47 AM

I once again must agree with Lord Karnus on this issue. Ray casting has got to be the easiest way of detecting if an object has been selected by the mouse in my opinion. I use it in my games all the time, and its great.

Look into it.

Anonymous

January 08, 2002 10:30 AM

Hi wojtos,

I wish I could help you out, sorry. I was wondering though, I noticed your map structure and was wondering how you got x, y and z to be a member of ''tile'' when ''tile'' is a member of ''map''?

-Echo

Anonymous

January 08, 2002 10:43 AM

There is a pretty simple way that I know of... just use colors. Draw each polygon to an off-screen buffer as a different color.. then when you click, get the color of the off-screen buffer, and then you know which polygon it was.. that''s a simple way.. uses a bit more GPU power.. but, is reliable (provided you''re working in true color, or seperate your colors a little bit) and pretty quick since you aren''t texturing or lighting or anything.

Billy

Anonymous

January 08, 2002 10:46 AM

Oh, and i''m assuming his structures are setup like so:

struct Vertex_S
{
float x,y,z;
};

struct Map_S
{
Vertex_S Tiles[32][32]; //Or whatever number
};

Map_S Map;

Billy