Add test for find_ray.

Tests for the existence of unobstructed rays to points within LOS.

1 files changed, 83 insertions, 0 deletions

diff --git a/crawl-ref/source/test/findray.lua b/crawl-ref/source/test/findray.lua
new file mode 100644
index 0000000000..b98f23e5d4
--- /dev/null
+++ b/crawl-ref/source/test/findray.lua
@@ -0,0 +1,83 @@
+-- Check basic find_ray functionality.
+
+local FAILMAP = 'losfail.map'
+local checks = 0
+
+local function test_losight_symmetry()
+  -- Clear messages to prevent them accumulating and forcing a --more--
+  crawl.mesclr()
+  -- Send the player to a random spot on the level.
+  you.random_teleport()
+
+  -- Forcibly redo LOS.
+  you.losight()
+
+  checks = checks + 1
+  local you_x, you_y = you.pos()
+  local you_p = dgn.point(you_x, you_y)
+
+  local visible_spots = { }
+  for y = -8, 8 do
+    for x = -8, 8 do
+      if x ~= 0 or y ~= 0 then
+        local px, py = x + you_x, y + you_y
+        if you.see_grid(px, py) then
+          table.insert(visible_spots, { px, py })
+        end
+      end
+    end
+  end
+
+  -- For each position in LOS, shoot a ray there
+  -- and make sure it doesn't go through an opaque cell.
+  for _, spot in ipairs(visible_spots) do
+    local x, y = unpack(spot)
+    local p = dgn.point(x, y)
+    local ray = los.findray(you_x, you_y, x, y)
+    if not ray then
+      dgn.grid(x, y, "floor_special")
+      dgn.dbg_dump_map(FAILMAP)
+      assert(false, "Can't find ray to " .. p ..
+                    " although it's in view.")
+    end
+    local rx, ry = ray:pos()
+    local ray_p = dgn.point(rx, ry)
+    assert(ray_p == you_p,
+           "Ray doesn't start at player position " .. you_p ..
+           " but " .. ray_p .. ".")
+    ray:advance()
+    rx, ry = ray:pos()
+    ray_p = dgn.point(rx, ry)
+    while(ray_p ~= p) do
+      if dgn.is_opaque(rx, ry) then
+        dgn.grid(x, y, "floor_special")
+        dgn.dbg_dump_map(FAILMAP)
+        assert(false,
+               "Ray from " .. you_p .. " to " .. p ..
+               " passes through opaque cell " .. ray_p
+               .. ".")
+      end
+      ray:advance()
+      rx, ry = ray:pos()
+      ray_p = dgn.point(rx, ry)
+    end
+  end
+end
+
+local function run_los_tests(depth, nlevels, tests_per_level)
+  local place = "D:" .. depth
+  crawl.mpr("Running LOS tests on " .. place)
+  dgn.dbg_goto_place(place)
+
+  for lev_i = 1, nlevels do
+    dgn.dbg_flush_map_memory()
+    dgn.dbg_generate_level()
+    for t_i = 1, tests_per_level do
+      test_losight_symmetry()
+    end
+  end
+end
+
+for depth = 1, 27 do
+  run_los_tests(depth, 1, 10)
+end