From 4f6e747753fba081fab7bf533f94495ace8e378e Mon Sep 17 00:00:00 2001
From: Robert Chisholm <robadob@robadob.org>
Date: Sat, 25 Mar 2023 19:45:46 +0000
Subject: [PATCH] wip

---
 include/flamegpu/visualiser/ModelVis.h |  4 ++++
 src/flamegpu/visualiser/ModelVis.cpp   | 13 +++++++++----
 2 files changed, 13 insertions(+), 4 deletions(-)

diff --git a/include/flamegpu/visualiser/ModelVis.h b/include/flamegpu/visualiser/ModelVis.h
index ed92c07cc..4b85fa8db 100644
--- a/include/flamegpu/visualiser/ModelVis.h
+++ b/include/flamegpu/visualiser/ModelVis.h
@@ -62,6 +62,10 @@ struct ModelVisData {
      * Only need to register env properties once
      */
     bool env_registered = false;
+    /**
+     * Marked true when first agent data has been passed to vis
+     */
+    bool has_first_agents = true;
     /**
      * Updates all agent renders from corresponding
      * @param sc Step count, the step count value shown in visualisation HUD
diff --git a/src/flamegpu/visualiser/ModelVis.cpp b/src/flamegpu/visualiser/ModelVis.cpp
index 59cff4c6a..5e9fd3d1c 100644
--- a/src/flamegpu/visualiser/ModelVis.cpp
+++ b/src/flamegpu/visualiser/ModelVis.cpp
@@ -34,12 +34,16 @@ void ModelVisData::registerEnvProperties() {
 }
 void ModelVisData::updateBuffers(const unsigned int& sc) {
     if (visualiser) {
-        bool has_agents = false;
+        bool _has_first_agents = false;
         for (auto& a : agents) {
-            has_agents = a.second->requestBufferResizes(visualiser, sc == 0 || sc == UINT_MAX) || has_agents;
+            _has_first_agents = a.second->requestBufferResizes(visualiser, sc == 0 || sc == UINT_MAX) || _has_first_agents;
+        }
+        if (_has_first_agents) {
+            _has_first_agents = !this->has_first_agents;
+            this->has_first_agents = true;
         }
         // Block the sim when we first get agents, until vis has resized buffers, incase vis is being slow to init
-        if (has_agents && (sc == 0 || sc == UINT_MAX)) {
+        if (_has_first_agents) {
             while (!visualiser->buffersReady()) {
                 // Do nothing, just spin until ready
                 std::this_thread::yield();
@@ -56,7 +60,7 @@ void ModelVisData::updateBuffers(const unsigned int& sc) {
         }
         visualiser->releaseMutex();
         // Block the sim again, until vis is fully ready
-        if (has_agents && (sc == 0 || sc == UINT_MAX)) {
+        if (_has_first_agents) {
             while (!visualiser->isReady()) {
                 // Do nothing, just spin until ready
                 std::this_thread::yield();
@@ -135,6 +139,7 @@ void ModelVis::_activate() {
             agent.second->initBindings(data->visualiser);
         }
         data->env_registered = false;
+        data->has_first_agents = false;
         data->registerEnvProperties();
         data->visualiser->start();
     }