fix(ar2): compute the random template index in double precision (#40)

[kalwalt]

Closes #40.

Summary

lib/SRC/AR2/selectTemplate.c:279 picks a random candidate index:

-k = (int)((float )j * rand() / (RAND_MAX + 1.0F));
+k = (int)((double)j * rand() / ((double)RAND_MAX + 1.0));

RAND_MAX + 1.0F converted 2147483647 to a float, which cannot hold it exactly (-Wimplicit-const-int-float-conversion). A double represents RAND_MAX + 1 exactly, and j * rand() no longer loses precision in single-precision float. rand() / (RAND_MAX + 1.0) stays below 1, so k is still in [0, j-1].

⚠️ This touches the vendored ARToolKit5 sources (lib/SRC/**): one line, as proposed in #40.

Test plan

• emcc -Wall on selectTemplate.c (emsdk 4.0.17): the warning is gone
• WebARKitNFT builds with Emscripten 4.0.17
• Native (Ubuntu 24.04, GCC 13): webarkit_nft_test 12/12, webarkit_test 28/28

🤖 Generated with Claude Code

[qodo-free-for-open-source-projects]

Code Review by Qodo

🐞 Bugs (0) 📘 Rule violations (0) 📎 Requirement gaps (0)

Great, no issues found!

Qodo reviewed your code and found no material issues that require review

Tip of the day

💡 Did you know, you can add REVIEW.md to your repo root and Qodo follows it on every PR

More tips ↗ | Customize Qodo ↗ | Qodo docs ↗

[qodo-free-for-open-source-projects]

PR Summary by Qodo

Compute AR2 random template indices in double precision

🐞 Bug fix 🕐 Less than 5 minutes

AI Description

• Use double precision when choosing a random AR2 template candidate.
• Eliminate the float-conversion warning while preserving the intended index range.

Diagram

graph TD
  C["Count candidates"] --> R["Draw random value"] --> I["Compute double index"] --> S["Select template"]

Loading

High-Level Assessment

The targeted double-precision conversion is appropriate for the reported warning and avoids a broader change to vendored selection logic. Replacing the sampling algorithm would add scope without addressing a demonstrated need.

Files changed (1) +1 / -1

Bug fix (1) +1 / -1

selectTemplate.cCalculate random candidate index in double precision +1/-1

Calculate random candidate index in double precision

• Replaces float arithmetic in the fallback template-selection index calculation with double arithmetic. This avoids converting RAND_MAX to an imprecise float and removes the reported compiler warning.

lib/SRC/AR2/selectTemplate.c