Hi,
it's my first post because I am a OpenGL/LWJGL newbie ;D .
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 :P
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.