From 896a6ef5959043db5463637d84ed524ae7bade1e Mon Sep 17 00:00:00 2001
From: 3gg <3gg@shellblade.net>
Date: Sat, 11 Apr 2026 16:35:25 -0700
Subject: Render only if there was an update

---
 simloop/test/simloop_test.c | 14 ++++++++------
 1 file changed, 8 insertions(+), 6 deletions(-)

(limited to 'simloop/test')

diff --git a/simloop/test/simloop_test.c b/simloop/test/simloop_test.c
index c79ee32..9f11e86 100644
--- a/simloop/test/simloop_test.c
+++ b/simloop/test/simloop_test.c
@@ -44,7 +44,7 @@ TEST_CASE(simloop_initial_render_not_retriggered) {
 
 /// A simulation loop with no render frame cap:
 ///   1. Updates based on the desired update frame rate.
-///   2. Renders at every loop.
+///   2. Renders at every loop (provided there are updates).
 TEST_CASE(simloop_no_render_frame_cap) {
   constexpr int    UPDATE_FPS    = 10;
   const time_delta EXPECT_UPDATE = sec_to_time_delta(1.0 / (double)UPDATE_FPS);
@@ -59,8 +59,10 @@ TEST_CASE(simloop_no_render_frame_cap) {
   for (time_delta t = 0; t < SIM_TIME_SEC; t += STEP) {
     timer_advance(&timer, t);
     simloop_update(&simloop, &simout);
-    TEST_TRUE(simout.should_render);
-    TEST_EQUAL((t > 0) && ((t % EXPECT_UPDATE) == 0), simout.should_update);
+    const bool expect_update = (t > 0) && ((t % EXPECT_UPDATE) == 0);
+    // A render is still expected at time 0.
+    TEST_EQUAL(simout.should_render, (t == 0) || expect_update);
+    TEST_EQUAL(simout.should_update, expect_update);
   }
 }
 
@@ -83,9 +85,9 @@ TEST_CASE(simloop_with_render_frame_cap) {
   for (time_delta t = 0; t < SIM_TIME_SEC; t += STEP) {
     timer_advance(&timer, t);
     simloop_update(&simloop, &simout);
-    // Also expecting initial render at t=0.
-    TEST_EQUAL((t % EXPECT_RENDER) == 0, simout.should_render);
-    TEST_EQUAL((t > 0) && ((t % EXPECT_UPDATE) == 0), simout.should_update);
+    // A render is still expected at time 0.
+    TEST_EQUAL(simout.should_render, (t % EXPECT_RENDER) == 0);
+    TEST_EQUAL(simout.should_update, (t > 0) && ((t % EXPECT_UPDATE) == 0));
   }
 }
 
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