Circle 2D Map

Discuss programming topics that involve the OpenGL API.
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arsenavin
Posts: 3
Joined: Sat Nov 12, 2011 7:11 am

Circle 2D Map

Post by arsenavin »

Hello, i am newbie here..
Currently i am developing 3D environment + 2D map for my final project (Opengl,C++)
My problem is how to draw the "Circle Shape" Map to the 3D environment screen?
It like a GTA interactive map..
Image
Any idea?
leileilol
Posts: 2783
Joined: Fri Oct 15, 2004 3:23 am

Re: Circle 2D Map

Post by leileilol »

GTA3 does it by a circle texture with an alpha with a GE128 blend and a depthwrite, and many small textures of the map in little pieces (since PS2 cache sucks)
then it reads the depth of that circle texture to trim it to that circle
A second alpha-blended circle is applied on top to soften the transition with a black circle border.
i should not be here
arsenavin
Posts: 3
Joined: Sat Nov 12, 2011 7:11 am

Re: Circle 2D Map

Post by arsenavin »

leileilol wrote:GTA3 does it by a circle texture with an alpha with a GE128 blend and a depthwrite, and many small textures of the map in little pieces (since PS2 cache sucks)
then it reads the depth of that circle texture to trim it to that circle
A second alpha-blended circle is applied on top to soften the transition with a black circle border.

I am need a deeper explanation here..thanx by the way.
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