From 82421ca64c3f8fa0a41698899f549a7d2d58cc4a Mon Sep 17 00:00:00 2001
From: Doyle Thai <dyl.thai@gmail.com>
Date: Fri, 23 Sep 2016 19:36:18 +1000
Subject: [PATCH] Improve performance by swapping render groups

Last used render groups are brought to front of render list when searching for
valid group- as per- recently used items are likely to be used again.
---
 src/Renderer.c       | 14 +++++++++++++-
 src/WorldTraveller.c |  2 +-
 src/dengine.c        |  7 ++++++-
 3 files changed, 20 insertions(+), 3 deletions(-)

diff --git a/src/Renderer.c b/src/Renderer.c
index 49b9b9b..c807fa3 100644
--- a/src/Renderer.c
+++ b/src/Renderer.c
@@ -13,6 +13,11 @@
 INTERNAL void addVertexToRenderGroup(Renderer *renderer, Texture *tex, v4 color,
                                      Vertex *vertexList, i32 numVertexes)
 {
+
+#ifdef DENGINE_DEBUG
+	ASSERT(numVertexes > 0);
+#endif
+
 	/* Find vacant/matching render group */
 	RenderGroup *targetGroup = NULL;
 	for (i32 i = 0; i < ARRAY_COUNT(renderer->groups); i++)
@@ -46,7 +51,13 @@ INTERNAL void addVertexToRenderGroup(Renderer *renderer, Texture *tex, v4 color,
 			i32 freeVertexSlots = renderer->groupCapacity - group->vertexIndex;
 			if (numVertexes < freeVertexSlots)
 			{
-				targetGroup  = &renderer->groups[i];
+				if (i != 0)
+				{
+					RenderGroup tmp     = renderer->groups[0];
+					renderer->groups[0] = renderer->groups[i];
+					renderer->groups[i] = tmp;
+				}
+				targetGroup = &renderer->groups[0];
 				break;
 			}
 		}
@@ -289,6 +300,7 @@ void renderer_string(Renderer *const renderer, MemoryArena *arena, Rect camera,
                      v2 pivotPoint, f32 rotate, v4 color)
 {
 	i32 strLen = common_strlen(string);
+	if (strLen <= 0) return;
 
 	// TODO(doyle): Slightly incorrect string length in pixels calculation,
 	// because we use the advance metric of each character for length not
diff --git a/src/WorldTraveller.c b/src/WorldTraveller.c
index d0a123b..b61d6ff 100644
--- a/src/WorldTraveller.c
+++ b/src/WorldTraveller.c
@@ -101,7 +101,7 @@ INTERNAL void rendererInit(GameState *state, v2 windowSize)
 	GL_CHECK_ERROR();
 
 	// TODO(doyle): Lazy allocate render group capacity
-	renderer->groupCapacity = 1024;
+	renderer->groupCapacity = 4096;
 	for (i32 i = 0; i < ARRAY_COUNT(renderer->groups); i++)
 	{
 		renderer->groups[i].vertexList =
diff --git a/src/dengine.c b/src/dengine.c
index 7dfd06e..10aff3e 100644
--- a/src/dengine.c
+++ b/src/dengine.c
@@ -224,9 +224,14 @@ i32 main(void)
 			f32 msPerFrame      = secondsElapsed * 1000.0f;
 			f32 framesPerSecond = 1.0f / secondsElapsed;
 
+			i32 entityCount =
+			    worldTraveller.world[worldTraveller.currWorldIndex]
+			        .freeEntityIndex;
+
 			char textBuffer[256];
 			snprintf(textBuffer, ARRAY_COUNT(textBuffer),
-			         "Dengine | %f ms/f | %f fps", msPerFrame, framesPerSecond);
+			         "Dengine | %f ms/f | %f fps | Entity Count: %d",
+			         msPerFrame, framesPerSecond, entityCount);
 
 			glfwSetWindowTitle(window, textBuffer);
 			titleUpdateFrequencyInSeconds = 0.5f;