UV mapping for a dome?

[steelplume]

Hi,

it's my first post because I am a OpenGL/LWJGL newbie   .

I am trying to understand how can I change UV mapping of a dome, I need a different texture map projection than this one coded below:

protected final void createDome(final float radius) {
		int lats=16; 
		int longs=16;
		
		GL11.glEnable(GL11.GL_TEXTURE_2D);
		GL11.glBindTexture(GL11.GL_TEXTURE_2D, textures2x4[0].getTextureID());
		
		int i, j;
		int halfLats = lats / 2; 
		for(i = 0; i <= halfLats; i++)
		{
	        double lat0 	= MathUtils.PI * (-0.5 + (double) (i - 1) / lats);
	        double z0 		= Math.sin(lat0)* radius;
	        double zr0 		= Math.cos(lat0)* radius;
	
	        double lat1 	= MathUtils.PI * (-0.5 + (double) i / lats);
	        double z1 		= Math.sin(lat1)* radius;
	        double zr1 		= Math.cos(lat1)* radius;
	
	        GL11.glBegin(GL11.GL_QUAD_STRIP);
	        for(j = 0; j <= longs; j++)
		   {
			    double lng = 2 * MathUtils.PI * (double) (j - 1) / longs;
			    double x 	= Math.cos(lng);
			    double y 	= Math.sin(lng);

			    double s1, s2, t;
			    s1 		= ((double) i) / halfLats;
			    s2 		= ((double) i + 1) / halfLats;
			    t 		= ((double) j) / longs;

			    GL11.glTexCoord2d(s1, t);
			    GL11.glNormal3d(x * zr0, y * zr0, z0);
			    GL11.glVertex3d(x * zr0, y * zr0, z0);

			    GL11.glTexCoord2d(s2, t);
			    GL11.glNormal3d(x * zr1, y * zr1, z1);
			    GL11.glVertex3d(x * zr1, y * zr1, z1);
		   }
	        GL11.glEnd();
		}

	}

I attached the output image, pratically I need a UV mapping which places the Artic at the zenith/top
of the dome, and the Antartic streched on the bottom side of the dome... the Artic/Antartic map is only
used to figure out what I mean

[Luy]

Hi,

wikipedia explains how to do it on a sphere: http://en.wikipedia.org/wiki/UV_mapping#Finding_UV_on_a_sphere
By replacing phi (or theta) with twice that angle you should be able to get the desired result.