From a91889f5ba2b816e424bc420c42d05fbbeba2679 Mon Sep 17 00:00:00 2001
From: fincs <fincs.alt1@gmail.com>
Date: Thu, 9 Feb 2017 19:57:02 +0100
Subject: [PATCH] Added C3D_FrameRate() for controlling output framerate

---
 include/c3d/renderqueue.h |  1 +
 source/renderqueue.c      | 29 +++++++++++++++++++++++++++--
 2 files changed, 28 insertions(+), 2 deletions(-)

diff --git a/include/c3d/renderqueue.h b/include/c3d/renderqueue.h
index 1865663..36b687f 100644
--- a/include/c3d/renderqueue.h
+++ b/include/c3d/renderqueue.h
@@ -24,6 +24,7 @@ enum
 	C3D_FRAME_NONBLOCK = BIT(1), // Return false instead of waiting for the GPU to finish rendering
 };
 
+float C3D_FrameRate(float fps);
 bool C3D_FrameBegin(u8 flags);
 bool C3D_FrameDrawOn(C3D_RenderTarget* target);
 void C3D_FrameEnd(u8 flags);
diff --git a/source/renderqueue.c b/source/renderqueue.c
index 2a637c4..b011013 100644
--- a/source/renderqueue.c
+++ b/source/renderqueue.c
@@ -16,6 +16,8 @@ static struct
 static u8 queueSwap, queuedCount, queuedState;
 
 static bool inFrame, inSafeTransfer, inSafeClear;
+static float framerate = 60.0f;
+static float framerateCounter[2] = { 60.0f, 60.0f };
 
 static void onRenderFinish(void* unused);
 static void onTransferFinish(void* unused);
@@ -47,6 +49,17 @@ static void performClear(void)
 	C3D_RenderBufClearAsync(renderBuf);
 }
 
+static bool framerateLimit(int id)
+{
+	framerateCounter[id] -= framerate;
+	if (framerateCounter[id] <= 0.0f)
+	{
+		framerateCounter[id] += 60.0f;
+		return true;
+	}
+	return false;
+}
+
 static void updateFrameQueue(void)
 {
 	C3D_RenderTarget* a;
@@ -95,7 +108,7 @@ static void clearTarget(C3D_RenderTarget* target)
 
 static void onVBlank0(C3D_UNUSED void* unused)
 {
-	if (!linkedTarget[0]) return;
+	if (!linkedTarget[0] || !framerateLimit(0)) return;
 
 	if (gfxIs3D())
 	{
@@ -117,7 +130,7 @@ static void onVBlank0(C3D_UNUSED void* unused)
 
 static void onVBlank1(C3D_UNUSED void* unused)
 {
-	if (linkedTarget[2] && linkedTarget[2]->transferOk)
+	if (linkedTarget[2] && framerateLimit(1) && linkedTarget[2]->transferOk)
 		transferTarget(linkedTarget[2]);
 }
 
@@ -244,6 +257,18 @@ static bool checkRenderQueueInit(void)
 	return true;
 }
 
+float C3D_FrameRate(float fps)
+{
+	float old = framerate;
+	if (fps > 0.0f && fps <= 60.0f)
+	{
+		framerate = fps;
+		framerateCounter[0] = fps;
+		framerateCounter[1] = fps;
+	}
+	return old;
+}
+
 bool C3D_FrameBegin(u8 flags)
 {
 	if (inFrame) return false;