# bc.ludic - a texture whose .png has a .dds beside it arrives BC7-compressed with its whole mip
# chain (plan 23.3 of maroon-lake), and one without a .dds as the .png it always was. Prints BC OK.
#
#   bin/ludic build examples/rendering/bc.ludic --headless && ./build/bc_headless
program Bc {
  numbers float
  import "ludic.render3d/r3d.ludic"

  property Marker { on: int = 1 }
  model Anchor { Marker }

  function scene_draw(render3d_st: mut Render3dState) -> void { }
  function scene_draw_casters(render3d_st: mut Render3dState, light_vp: floats) -> void { }
  function stream_fill(s: Stream, cx: int, cz: int, band: int) -> void { }

  function check(what: string, cond: bool) -> bool {
    if not cond { print(`bc: FAILED - {what}`) }
    return cond
  }
  # the internal format render3d recorded for a texture
  function fmt_of(render3d_st: mut Render3dState, tex: int) -> int {
    let o = gpu_tx_at(render3d_st, tex)
    if o < 0 { return 0 }
    return render3d_st.gpu_tx[o + 4]
  }

  handler Boot(render3d_st: mut Render3dState) phase Start {
    spawn Anchor {}
    r3d_on_draw(render3d_st, fn scene_draw)
    r3d_on_casters(render3d_st, fn scene_draw_casters)
    r3d_on_stream_fill(render3d_st, fn stream_fill)
    r3d_plate_mode(render3d_st, true)
    let dir = "packages/ludic.lab/plate"
    render3d_st.r3d_sky_path = `{dir}/sky.hdr`
    if not r3d_init(render3d_st, 320, 180, "Bc") {
      quit()
      return
    }
    var ok = true
    ok = check("this device reads BC textures", render3d_st.gvk_has_bc) and ok
    let t = tex_load(render3d_st, `{dir}/plate_diff.png`, true)
    ok = check("the plate's colour loads", t != 0) and ok
    ok = check("from its .dds, as BC7 in sRGB", fmt_of(render3d_st, t) == R3D_BC7_SRGB) and ok
    ok = check("with every level down to 1x1", render3d_st.gvk_tex_levels[t] == gvk_mip_levels(tex_width(render3d_st, t), tex_height(render3d_st, t))) and ok
    let a = tex_load(render3d_st, `{dir}/plate_arm.png`, false)
    ok = check("a data map's .dds is BC7 read as it is (not sRGB)", fmt_of(render3d_st, a) == R3D_BC7) and ok
    let s = tex_load(render3d_st, `{dir}/probe_arm.png`, false)
    ok = check("the second one loads too", s != 0) and ok
    # a picture with no .dds: the .png, uncompressed, as before
    let p = tex_load_ex(render3d_st, `{dir}/plate_diff.png`, true, 1)
    ok = check("a cut-out atlas (edge-padded from the .png) is not the .dds", p != 0 and fmt_of(render3d_st, p) != R3D_BC7_SRGB) and ok
    if ok { print("BC OK") } else { print("BC FAILED") }
    quit()
  }

  handler Present(render3d_st: mut Render3dState) phase Render {
    r3d_present(render3d_st)
  }
}