submap.vert

ogre_media/materials/glsl120/submap.vert is the GLSL 120 vertex shader used to render submap slices.

#version 120

attribute vec4 uv0;

varying vec2 out_submap_texture_coordinate;

void main()
{
  out_submap_texture_coordinate = vec2(uv0);
  gl_Position = ftransform();
}

It takes the texture coordinate attribute uv0, forwards it to the fragment shader as out_submap_texture_coordinate, and computes the clip-space position with ftransform() (the fixed-function model/view/projection transform). Since the slice quads are axis-aligned in the submap frame, the standard transform is sufficient — no per-vertex lighting or special math is needed.