wrapping texture around planet

[cbaakman]

The planet is a sphere, so adding a texture to it can be difficult. We need a way to:

• produce NO weird looking artifacts at the edges of textures
• don't stretch the texture in any weird way
• no mirror edges
• leave the option open to make the texture coordinates be bigger than the texture itself, to allow repeated elements

options:

• cube mapping
• uv mapping
• let each vertex have multiple texture coordinates, with weights

[cbaakman]

The type of mapping to use depends on the texture. For a texture consisting mainly of dots (like grass or flowers), the weighted texture coordinate approach works fine. However, not for patterned or striped textures, like farmland for example.