fix(rules): a cone/line template excludes the caster's whole footprint, not just the anchor cell (SRD aiming-a-spell.md: 'It starts from any corner of your square' - every occupied square is origin space and never inside its own area) - cone_cells/line_cells take caster_cells; combat passes caster.occupied_cells(); 1x1 casters bit-identical; documented simplification: a grazed caster cell still consumes a length slot

src/pf1e_simulator/areas.py

@@ -5,7 +5,8 @@ PF1e (CRB, Magic — Aiming a Spell):
   direction you designate. It starts from any corner of your square and
   widens out as it goes." — modeled here as every cell whose center lies
   within the cone's length of the origin and within ±45° of the aim
-  direction (a 90°-wide quarter circle), excluding the origin cell.
+  direction (a 90°-wide quarter circle), excluding the caster's whole
+  space (every cell of the footprint, not just the anchor).
 - "A line-shaped spell shoots away from you in a line in the direction you
   designate. It starts from any corner of your square and extends to the
   limit of its range [...]. A line-shaped spell affects all creatures in
@@ -45,7 +46,11 @@ if TYPE_CHECKING:
 
 
 def cone_cells(
-    grid: Grid, origin: Pos, aim: Pos, radius_cells: int
+    grid: Grid,
+    origin: Pos,
+    aim: Pos,
+    radius_cells: int,
+    caster_cells: frozenset[Pos] = frozenset(),
 ) -> frozenset[Pos]:
     """Cells of a 90° cone of ``radius_cells`` squares starting at ``origin``.
 
@@ -53,8 +58,11 @@ def cone_cells(
     resolved target or point-cast center). A cell is affected when its offset
     from the origin is within ``radius_cells`` (5-10-5 grid distance), points
     strictly into the cone's forward half-plane, and stays within ±45° of the
-    aim bearing. The origin cell itself is never affected (CRB: the cone
-    "shoots away from you"). A cell with no line of effect from the origin
+    aim bearing. The caster's own space is never affected: the cone "starts
+    from any corner of your square" (CRB: it "shoots away from you"), so
+    EVERY cell in ``caster_cells`` (the caster's whole footprint; the anchor
+    ``origin`` is always one of them) is outside the template, not just the
+    origin. A cell with no line of effect from the origin
     is dropped (CRB, Line of Effect: a cone "affects only an area, creature,
     or object to which it has line of effect from its origin" - a solid wall
     stops the cone, it does not pass through). A degenerate aim
@@ -68,12 +76,13 @@ def cone_cells(
     d_col = aim[1] - origin[1]
     if d_row == 0 and d_col == 0:
         return frozenset()
+    skip = caster_cells | {origin}
     aim_sq = d_row * d_row + d_col * d_col
     cells: set[Pos] = set()
     for row in range(origin[0] - radius_cells, origin[0] + radius_cells + 1):
         for col in range(origin[1] - radius_cells, origin[1] + radius_cells + 1):
             cell = (row, col)
-            if cell == origin or not grid.in_bounds(cell):
+            if cell in skip or not grid.in_bounds(cell):
                 continue
             v_row = row - origin[0]
             v_col = col - origin[1]
@@ -91,16 +100,25 @@ def cone_cells(
 
 
 def line_cells(
-    grid: Grid, origin: Pos, aim: Pos, length_cells: int
+    grid: Grid,
+    origin: Pos,
+    aim: Pos,
+    length_cells: int,
+    caster_cells: frozenset[Pos] = frozenset(),
 ) -> frozenset[Pos]:
     """Cells of a 5-ft-wide line of ``length_cells`` squares from ``origin``.
 
     The line runs along the Bresenham ray from the origin toward ``aim``,
     extended to ``length_cells`` squares (CRB: it "extends to the limit of
     its range"). The line "starts from any corner of your square" (CRB, Magic
-    - Aiming a Spell), so the CASTER's own square is NOT affected: the
-    ``length_cells`` affected squares are the ones *beyond* the origin along
-    the ray. Out-of-bounds cells simply drop out of the template (creatures
+    - Aiming a Spell), so the CASTER's whole space is NOT affected: every
+    caster cell the ray grazes (the anchor ``origin`` included, i.e. all of
+    ``caster_cells``) is outside the template. For a 1x1 caster that is just
+    the origin, so the ``length_cells`` affected squares are the ones
+    *beyond* the origin along the ray. Documented simplification: a caster
+    cell the ray crosses still consumes one of the ``length_cells`` slots, so
+    a multi-cell caster's line is at most its own footprint shorter.
+    Out-of-bounds cells simply drop out of the template (creatures
     only exist in bounds). The ray stops at the first cell that blocks line
     of effect (CRB, Line: "or until it strikes a barrier that blocks line of
     effect") - the barrier cell itself is the last cell of the template (the
@@ -113,6 +131,7 @@ def line_cells(
     d_col = aim[1] - origin[1]
     if d_row == 0 and d_col == 0:
         return frozenset()
+    skip = caster_cells | {origin}
     # Extend the aim vector so the ray reaches `length_cells` squares BEYOND
     # the origin (the dominant-axis step count of a Bresenham line is
     # max(|d_row|, |d_col|)); the +1 accounts for the origin square we drop.
@@ -124,7 +143,7 @@ def line_cells(
     ray = _bresenham(origin, end)
     cells: list[Pos] = []
     for cell in ray[1 : length_cells + 1]:
-        if not grid.in_bounds(cell):
+        if cell in skip or not grid.in_bounds(cell):
             continue
         cells.append(cell)
         if grid.terrain_at(cell).blocks_los: