From 65e9ae163ff757ca15af78da4a753a7ee1d25a16 Mon Sep 17 00:00:00 2001
From: Walter van Niftrik
Date: Tue, 11 Aug 2009 20:18:15 +0000
Subject: SCI: Added a crude speed throttler.

svn-id: r43289
---
 engines/sci/engine/state.h | 42 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 42 insertions(+)

(limited to 'engines/sci/engine/state.h')

diff --git a/engines/sci/engine/state.h b/engines/sci/engine/state.h
index 3db926ab3d..a814a20df8 100644
--- a/engines/sci/engine/state.h
+++ b/engines/sci/engine/state.h
@@ -119,6 +119,46 @@ public:
 	bool isOpen() const;
 };
 
+
+class SpeedThrottler {
+public:
+	enum {
+		kSegmentLength = 20 /**< Time segment length in ms */
+	};
+
+	SpeedThrottler(sci_version_t version) {
+		if (version >= SCI_VERSION_1_1)
+			_maxInstructions = 3300;
+		else if (version >= SCI_VERSION_1)
+			_maxInstructions = 2200;
+		else
+			_maxInstructions = 1100;
+		reset();
+	}
+
+	void postInstruction() {
+		if (++_curInstructions >= _maxInstructions) {
+			uint32 time = g_system->getMillis();
+			uint32 elapsed = time - _timestamp;
+
+			if (elapsed < kSegmentLength)
+				g_system->delayMillis(kSegmentLength - elapsed);
+
+			reset();
+		}
+	}
+
+	void reset() {
+		_timestamp = g_system->getMillis();
+		_curInstructions = 0;
+	}
+
+private:
+	uint32 _timestamp; /**< Timestamp of current time segment */
+	uint32 _maxInstructions; /**< Maximum amount of instructions per time segment */
+	uint32 _curInstructions; /**< Amount of instructions executed in current time segment */
+};
+
 struct EngineState : public Common::Serializable {
 public:
 	EngineState(ResourceManager *res, sci_version_t version, uint32 flags);
@@ -258,6 +298,8 @@ public:
 
 	MessageState _msgState;
 
+	SpeedThrottler *speedThrottler;
+
 	EngineState *successor; /**< Successor of this state: Used for restoring */
 
 private:
-- 
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