Function draw_envbox

source/src/texture.cpp:630–676

float skyfloor = 1e16f;

void draw_envbox(int w)
{
    extern float skyfloor;

    float zclip = skyclip && skyfloor >= camera1->o.z ? 0.5f + float(skyfloor-camera1->o.z)/w : 0.0f,
          vclip = 1-zclip,
          z = 2*w*(vclip-0.5f);

    if(vclip < 0) return;

    glDepthMask(GL_FALSE);

    draw_envbox_face(0.0f, 0.0f, -w, -w, -w,
                     1.0f, 0.0f, -w,  w, -w,
                     1.0f, vclip, -w,  w,  z,
                     0.0f, vclip, -w, -w,  z, sky[0] ? sky[0] : notexture);

    draw_envbox_face(1.0f, vclip, +w, -w,  z,
                     0.0f, vclip, +w,  w,  z,
                     0.0f, 0.0f, +w,  w, -w,
                     1.0f, 0.0f, +w, -w, -w, sky[1] ? sky[1] : notexture);

    draw_envbox_face(1.0f, vclip, -w, -w,  z,
                     0.0f, vclip,  w, -w,  z,
                     0.0f, 0.0f,  w, -w, -w,
                     1.0f, 0.0f, -w, -w, -w, sky[2] ? sky[2] : notexture);

    draw_envbox_face(1.0f, vclip, +w,  w,  z,
                     0.0f, vclip, -w,  w,  z,
                     0.0f, 0.0f, -w,  w, -w,
                     1.0f, 0.0f, +w,  w, -w, sky[3] ? sky[3] : notexture);

    if(!zclip)
        draw_envbox_face(0.0f, 1.0f, -w,  w,  w,
                         0.0f, 0.0f, +w,  w,  w,
                         1.0f, 0.0f, +w, -w,  w,
                         1.0f, 1.0f, -w, -w,  w, sky[4] ? sky[4] : notexture);

    draw_envbox_face(0.0f, 1.0f, +w,  w, -w,
                     0.0f, 0.0f, -w,  w, -w,
                     1.0f, 0.0f, -w, -w, -w,
                     1.0f, 1.0f, +w, -w, -w, sky[5] ? sky[5] : notexture);

    glDepthMask(GL_TRUE);

    skyfloor = 1e16f;
}

struct tmufunc
{