scanconverter.h

手机 ＧＡＭＥ ｃ＋＋ 版

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//
// ScanConverter.h
//
// Copyright (c) 2003 Nokia Phones Ltd  All rights reserved.
//
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#ifndef _SCANCONVERTER_H
#define _SCANCONVERTER_H

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#include "Camera.h"

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class TScreenVertex;

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class TIntersectionBuffer
	{
	public:
		TIntersectionBuffer();
		void Reset();
		void ScanEdge
			(
			const TScreenVertex &aVertexA, 
			const TScreenVertex &aVertexB, 
			TMathLookup &aMath
			);

	public:
		enum
		{
			// Hardwired to current Series 60 screen height: will need
			// changing for other Symbian OS variants. (A more sophisticated
			// solution would be to allocate the entry array at construction
			// time, but note that this would require re-implementing as a C class.)
			//
			// NB: the value must be at least as large as the screen height, but 
			// a larger value does no harm.
			//
			numEntries	= 208,

			interpolationUnityLog	= 14,
			interpolationUnity		= ( 1 << interpolationUnityLog ),
			//
			// resultUnityLog == number of fractional bits to be left in result (screen) coords:
			//
			resultUnityLog	= Geometry3D::screenCoordUnityLog,
			resultDownshift	= ( interpolationUnityLog - resultUnityLog ),

		};

		TInt iMinY;
		TInt iMaxY;

		TInt iEntry[numEntries];
	};


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class TScanConverter
	{
	//
	// NB: This class assumes 16 bpp and a pixel format of 444 RGB.
	//
	public:
		TScanConverter(const TSize& aSize);

		void SetScreenPtr(TUint16 * aScreenPtr){ iScreenPtr = aScreenPtr; }
		void TransformVerts
			( 
			TInt aNumVerts, 
			const TVector3 * aSrcVertPtr, 
			TAffineTransform &aAffine, 
			TScreenVertex * aDestVertPtr, 
			TVector3 &aCameraInModelSpace 
			);

		void ClipAndRender( TClipFace &aFaceA, TClipFace &aFaceB, TMathLookup &aMath );

		void ClearScreen(TUint16 aFillColor);
		void PlotPixel(TInt aX, TInt aY, TUint16 aFillColor);

		void ResetScan();

		void ScanEdge
			(
			const TScreenVertex &aVertexA, 
			const TScreenVertex &aVertexB, 
			TMathLookup &aMath
			);

		void Fill(TUint16 aFlatColor);

	private:
		TCamera		iCamera;

		TSize		iSize;
		TUint16 *	iScreenPtr;

		TInt		iLeftX;
		TInt		iRightX;
		TInt		iTopY;
		TInt		iBottomY;

		TIntersectionBuffer	iLeftBuffer;
		TIntersectionBuffer	iRightBuffer;
	};

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#endif

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