#4604 Tweak range decrease

isSystemMemoryLow() and factor check were too agressive for draw range.

4 files changed, 24 insertions, 16 deletions

diff --git a/indra/newview/llviewermessage.cpp b/indra/newview/llviewermessage.cpp
index d0e6af799c..16b7ac33b8 100644
--- a/indra/newview/llviewermessage.cpp
+++ b/indra/newview/llviewermessage.cpp
@@ -3366,13 +3366,10 @@ void send_agent_update(bool force_send, bool send_reliable)
     static F32 last_draw_disatance_step = 1024;
     F32 memory_limited_draw_distance = gAgentCamera.mDrawDistance;
 
-    if (LLViewerTexture::sDesiredDiscardBias > 2.f && LLViewerTexture::isSystemMemoryLow())
+    if (LLViewerTexture::isSystemMemoryCritical())
     {
         // If we are low on memory, reduce requested draw distance
-        // Discard's bias is clamped to 4 so we need to check 2 to 4 range
-        // Factor is intended to go from 1.0 to 2.0
-        F32 factor = 1.f + (LLViewerTexture::sDesiredDiscardBias - 2.f) / 2.f;
-        memory_limited_draw_distance = llmax(gAgentCamera.mDrawDistance / factor, gAgentCamera.mDrawDistance / 2.f);
+        memory_limited_draw_distance = llmax(gAgentCamera.mDrawDistance / LLViewerTexture::getSystemMemoryBudgetFactor(), gAgentCamera.mDrawDistance / 2.f);
     }
 
     if (tp_state == LLAgent::TELEPORT_ARRIVING || LLStartUp::getStartupState() < STATE_MISC)
diff --git a/indra/newview/llviewertexture.cpp b/indra/newview/llviewertexture.cpp
index 7a25fb03a5..3142c9950b 100644
--- a/indra/newview/llviewertexture.cpp
+++ b/indra/newview/llviewertexture.cpp
@@ -657,23 +657,35 @@ U32Megabytes LLViewerTexture::getFreeSystemMemory()
     return physical_res;
 }
 
-//static
-bool LLViewerTexture::isSystemMemoryLow()
+S32Megabytes get_render_free_main_memory_treshold()
 {
     static LLCachedControl<U32> min_free_main_memory(gSavedSettings, "RenderMinFreeMainMemoryThreshold", 512);
     const U32Megabytes MIN_FREE_MAIN_MEMORY(min_free_main_memory);
-    return getFreeSystemMemory() < MIN_FREE_MAIN_MEMORY;
+    return MIN_FREE_MAIN_MEMORY;
+}
+
+//static
+bool LLViewerTexture::isSystemMemoryLow()
+{
+    return getFreeSystemMemory() < get_render_free_main_memory_treshold();
+}
+
+//static
+bool LLViewerTexture::isSystemMemoryCritical()
+{
+    return getFreeSystemMemory() < get_render_free_main_memory_treshold() / 2;
 }
 
 F32 LLViewerTexture::getSystemMemoryBudgetFactor()
 {
-    static LLCachedControl<U32> min_free_main_memory(gSavedSettings, "RenderMinFreeMainMemoryThreshold", 512);
-    const S32Megabytes MIN_FREE_MAIN_MEMORY(min_free_main_memory);
+    const S32Megabytes MIN_FREE_MAIN_MEMORY(get_render_free_main_memory_treshold() / 2);
     S32 free_budget = (S32Megabytes)getFreeSystemMemory() - MIN_FREE_MAIN_MEMORY;
     if (free_budget < 0)
     {
-        // Result should range from 1 (0 free budget) to 2 (-512 free budget)
-        return 1.f - free_budget / MIN_FREE_MAIN_MEMORY;
+        // Leave some padding, otherwise we will crash out of memory before hitting factor 2.
+        const S32Megabytes PAD_BUFFER(32);
+        // Result should range from 1 at 0 free budget to 2 at -224 free budget, 2.14 at -256MB
+        return 1.f - free_budget / (MIN_FREE_MAIN_MEMORY - PAD_BUFFER);
     }
     return 1.f;
 }
diff --git a/indra/newview/llviewertexture.h b/indra/newview/llviewertexture.h
index d32c302d8e..2937651995 100644
--- a/indra/newview/llviewertexture.h
+++ b/indra/newview/llviewertexture.h
@@ -115,6 +115,7 @@ public:
     static void initClass();
     static void updateClass();
     static bool isSystemMemoryLow();
+    static bool isSystemMemoryCritical();
     static F32 getSystemMemoryBudgetFactor();
 
     LLViewerTexture(bool usemipmaps = true);
diff --git a/indra/newview/llvocache.cpp b/indra/newview/llvocache.cpp
index ac73c2def6..52a6afc2d0 100644
--- a/indra/newview/llvocache.cpp
+++ b/indra/newview/llvocache.cpp
@@ -488,13 +488,11 @@ void LLVOCacheEntry::updateDebugSettings()
     static const F32 MIN_RADIUS = 1.0f;
 
     F32 draw_radius = gAgentCamera.mDrawDistance;
-    if (LLViewerTexture::sDesiredDiscardBias > 2.f && LLViewerTexture::isSystemMemoryLow())
+    if (LLViewerTexture::isSystemMemoryCritical())
     {
-        // Discard's bias maximum is 4 so we need to check 2 to 4 range
         // Factor is intended to go from 1.0 to 2.0
-        F32 factor = 1.f + (LLViewerTexture::sDesiredDiscardBias - 2.f) / 2.f;
         // For safety cap reduction at 50%, we don't want to go below half of draw distance
-        draw_radius = llmax(draw_radius / factor, draw_radius / 2.f);
+        draw_radius = llmax(draw_radius / LLViewerTexture::getSystemMemoryBudgetFactor(), draw_radius / 2.f);
     }
     const F32 clamped_min_radius = llclamp((F32) min_radius, MIN_RADIUS, draw_radius); // [1, mDrawDistance]
     sNearRadius = MIN_RADIUS + ((clamped_min_radius - MIN_RADIUS) * adjust_factor);