aviralgarg05 commented on code in PR #3644:
URL: https://github.com/apache/nuttx-apps/pull/3644#discussion_r3597249608
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games/NXDoom/src/doom/r_main.c:
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@@ -685,6 +685,24 @@ fixed_t r_scale_from_global_angle(angle_t visangle)
void r_set_view_size(int blocks, int detail)
{
+ /* screenblocks is only ever meant to hold 3..11 (set that way by the
+ * options menu and by the config default of 9). The renderer's view
+ * geometry math divides by values derived from it - notably
+ * pspriteiscale = FRACUNIT * SCREENWIDTH / viewwidth in
+ * r_execute_set_view_size() - so a 0 or otherwise out-of-range value
+ * turns into a divide-by-zero hardware exception (EXCCAUSE=6), which on
+ * this flat-memory build takes the whole board down rather than just
+ * this task. Clamp defensively so a bad/missing config value degrades
+ * to the default screen size instead of a system crash.
+ */
+
+ if (blocks < 3 || blocks > 11)
+ {
+ printf("r_set_view_size: screenblocks=%d out of range, using 10\n",
+ blocks);
+ blocks = 10;
+ }
Review Comment:
Yes, a truncated config file left screenblocks at 0, and the view-size math
divides by a value derived from it, so it hit a divide-by-zero hardware
exception and took the whole board down.
This clamp is the second, independent layer of defense on top of the
config-parsing fix in m_config.c
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games/NXDoom/src/doom/r_bsp.h:
##########
@@ -52,7 +52,7 @@ extern boolean markceiling;
extern boolean skymap;
-extern drawseg_t drawsegs[CONFIG_GAMES_NXDOOM_MAXDRAWSEGS];
+extern drawseg_t *drawsegs;
Review Comment:
same as above
##########
games/NXDoom/src/doom/r_bsp.c:
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@@ -78,7 +78,7 @@ line_t *linedef;
sector_t *frontsector;
sector_t *backsector;
-drawseg_t drawsegs[CONFIG_GAMES_NXDOOM_MAXDRAWSEGS];
+drawseg_t *drawsegs;
Review Comment:
will put it behind the same Kconfig switch.
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