# height_file_test.ludic - terrain_height_file against terrain_height over a tiles file written here (no
# device): the same answer to the bit, resident or not, and a sweep of the whole map leaves the page
# cache - its slots, what they hold and the clock - exactly as it was
import "ludic.render3d/r3d.ludic"
program HeightFileTest {
  numbers float
  # never called: naming Input links the engine's runtime, which render3d's textures stand on
  function links_runtime() -> bool { return Input.key_pressed(0) }

  # an LTT2 file with heights only (no photograph; normals and the coarse level read short, unused here)
  function hf_write(path: string) -> bool {
    let n = TERRAIN_RES / TT_TEX
    let n2 = TT_TEX * TT_TEX
    let hat = LT_HEAD + n * n * 8
    let size = hat + n * n * n2 * 2
    let b = buffer(size)
    for k in 0 .. LT_HEAD { b[k] = 0 }
    hf_put(b, 0, LT_MAGIC)
    hf_put(b, 4, LT_VERSION)
    hf_put(b, 8, TT_TEX)
    hf_put(b, 12, n)
    hf_put(b, 20, TERRAIN_RES)
    hf_put(b, 28, TT_COARSE)
    hf_put(b, 32, LT_HEAD)
    for k in 10 .. 15 { hf_put(b, k * 4, size) }
    for t in 0 .. n * n {
      hf_put(b, LT_HEAD + t * 8, float_bits(float(t % 50) * 3.5 - 40.0))
      hf_put(b, LT_HEAD + t * 8 + 4, float_bits(0.01 + float(t % 7) * 0.001))
      for i in 0 .. n2 {
        let q = (i * 37 + (i >> 5) * 11 + t * 5) & 65535
        b[hat + (t * n2 + i) * 2] = q & 255
        b[hat + (t * n2 + i) * 2 + 1] = q >> 8
      }
    }
    return Fs.write_bytes(path, b, size)
  }
  function hf_put(b: []byte, at: int, v: int) -> void {
    for k in 0 .. 4 { b[at + k] = (v >> (k * 8)) & 255 }
  }

  function hf_open(render3d_st: mut Render3dState, tag: string) -> bool {
    let path = Os.temp_dir() + "/r3d_height_file_" + tag + ".ltt2"
    if not hf_write(path) { return false }
    render3d_st.TERRAIN_HALF = 4096
    render3d_st.ter_ox = 0.0
    render3d_st.ter_oz = 0.0
    render3d_st.ter_h_scale = 0.0
    return tt_open_ltt2(render3d_st, path, 0)
  }

  test "the same answer as terrain_height, whether its tile is resident or not" (render3d_st: mut Render3dState) {
    expect(hf_open(render3d_st, "same"))
    terrain_tiles_prefetch(render3d_st, 1000.0, -500.0, 200.0, 100)
    let pts = floats(2 * 160 * 160)
    let got = floats(160 * 160)
    for j in 0 .. 160 {
      for i in 0 .. 160 {
        let k = j * 160 + i
        pts[k * 2] = -3000.0 + float(i) * 37.3
        pts[k * 2 + 1] = -3100.0 + float(j) * 41.7
        got[k] = terrain_height_file(render3d_st, pts[k * 2], pts[k * 2 + 1])
      }
    }
    var off = 0
    for k in 0 .. 160 * 160 { if terrain_height(render3d_st, pts[k * 2], pts[k * 2 + 1]) != got[k] { off += 1 } }
    expect_eq(off, 0)
    # and again now that terrain_height has paged most of them in
    for k in 0 .. 160 * 160 { if terrain_height_file(render3d_st, pts[k * 2], pts[k * 2 + 1]) != got[k] { off += 1 } }
    expect_eq(off, 0)
    # a texel square across a tile corner, and the map's edges
    for c in 0 .. 5 {
      let x = -4096.0 + 64.0 * float(c * 13 + 1) - 1.0
      let z = -4096.0 + 64.0 * float(c * 7 + 2) - 0.5
      expect_eq(terrain_height_file(render3d_st, x, z), terrain_height(render3d_st, x, z))
    }
    expect_eq(terrain_height_file(render3d_st, -5000.0, 5000.0), terrain_height(render3d_st, -5000.0, 5000.0))
  }

  test "a sweep of the whole map leaves every slot, what it holds and the clock as they were" (render3d_st: mut Render3dState) {
    expect(hf_open(render3d_st, "sweep"))
    terrain_tiles_prefetch(render3d_st, -200.0, 300.0, 300.0, 200)
    expect(terrain_height(render3d_st, 2000.0, 2000.0) != 0.12345)     # a tile paged the ordinary way too
    let n2 = len(render3d_st.tt_slot_of)
    let slots = len(render3d_st.tt_tile_in)
    let slot_of = words(n2)
    for t in 0 .. n2 { slot_of[t] = render3d_st.tt_slot_of[t] }
    let tile_in = words(slots)
    let refs = words(slots)
    for s in 0 .. slots {
      tile_in[s] = render3d_st.tt_tile_in[s]
      refs[s] = render3d_st.tt_ref[s]
    }
    let h = floats(len(render3d_st.tt_h))
    for i in 0 .. len(h) { h[i] = render3d_st.tt_h[i] }
    let hand = render3d_st.tt_hand
    let reads = render3d_st.tt_reads
    let frame_reads = render3d_st.tt_frame_reads
    var sum = 0.0
    var z = -4096.0
    while z <= 4096.0 {
      var x = -4096.0
      while x <= 4096.0 {
        sum = sum + terrain_height_file(render3d_st, x, z)
        x = x + 16.0
      }
      z = z + 16.0
    }
    expect(sum != 0.0)
    var moved = 0
    for t in 0 .. n2 { if render3d_st.tt_slot_of[t] != slot_of[t] { moved += 1 } }
    for s in 0 .. slots { if render3d_st.tt_tile_in[s] != tile_in[s] or render3d_st.tt_ref[s] != refs[s] { moved += 1 } }
    for i in 0 .. len(h) { if render3d_st.tt_h[i] != h[i] { moved += 1 } }
    expect_eq(moved, 0)
    expect_eq(render3d_st.tt_hand, hand)
    expect_eq(render3d_st.tt_reads, reads)
    expect_eq(render3d_st.tt_frame_reads, frame_reads)
  }

  test "with the whole copy kept it is terrain_height" (render3d_st: mut Render3dState) {
    render3d_st.TERRAIN_HALF = 4096
    render3d_st.ter_heights = floats(TERRAIN_RES * TERRAIN_RES)
    for i in 0 .. TERRAIN_RES * TERRAIN_RES { render3d_st.ter_heights[i] = float(i % 997) * 0.25 + float(i / 4096) * 0.01 }
    for k in 0 .. 400 {
      let x = -4000.0 + float(k) * 19.91
      let z = 3900.0 - float(k) * 17.13
      expect_eq(terrain_height_file(render3d_st, x, z), terrain_height(render3d_st, x, z))
    }
  }
}