text: // Copyright (C) 2002-2011 Nikolaus Gebhardt / Thomas Alten
  // This file is part of the "Irrlicht Engine".
  // For conditions of distribution and use, see copyright notice in irrlicht.h
  
  #include "IrrCompileConfig.h"
  #include "IBurningShader.h"
  
  #ifdef _IRR_COMPILE_WITH_BURNINGSVIDEO_
  
  // compile flag for this file
  #undef USE_ZBUFFER
  #undef IPOL_Z
  #undef CMP_Z
  #undef WRITE_Z
  
  #undef IPOL_W
  #undef CMP_W
  #undef WRITE_W
  
  #undef SUBTEXEL
  #undef INVERSE_W
  
  #undef IPOL_C0
  #undef IPOL_T0
  #undef IPOL_T1
  
  // define render case
  #define SUBTEXEL
  #define INVERSE_W
  
  #define USE_ZBUFFER
  #define IPOL_W
  #define CMP_W
  #define WRITE_W
  
  //#define IPOL_C0
  #define IPOL_T0
  #define IPOL_T1
  
  // apply global override
  #ifndef SOFTWARE_DRIVER_2_PERSPECTIVE_CORRECT
  	#undef INVERSE_W
  #endif
  
  #ifndef SOFTWARE_DRIVER_2_SUBTEXEL
  	#undef SUBTEXEL
  #endif
  
  #ifndef SOFTWARE_DRIVER_2_USE_VERTEX_COLOR
  	#undef IPOL_C0
  #endif
  
  #if !defined ( SOFTWARE_DRIVER_2_USE_WBUFFER ) && defined ( USE_ZBUFFER )
  	#ifndef SOFTWARE_DRIVER_2_PERSPECTIVE_CORRECT
  		#undef IPOL_W
  	#endif
  	#define IPOL_Z
  
  	#ifdef CMP_W
  		#undef CMP_W
  		#define CMP_Z
  	#endif
  
  	#ifdef WRITE_W
  		#undef WRITE_W
  		#define WRITE_Z
  	#endif
  
  #endif
  
  namespace irr
  {
  
  namespace video
  {
  
  class CTRTextureLightMap2_Add : public IBurningShader
  {
  public:
  
  	//! constructor
  	CTRTextureLightMap2_Add(CBurningVideoDriver* driver);
  
  	//! draws an indexed triangle list
  	virtual void drawTriangle ( const s4DVertex *a,const s4DVertex *b,const s4DVertex *c );
  
  
  private:
  	void scanline_bilinear ();
  
  	sScanConvertData scan;
  	sScanLineData line;
  
  };
  
  //! constructor
  CTRTextureLightMap2_Add::CTRTextureLightMap2_Add(CBurningVideoDriver* driver)
  : IBurningShader(driver)
  {
  	#ifdef _DEBUG
  	setDebugName("CTRTextureLightMap2_Add");
  	#endif
  }
  
  
  
  /*!
  */
  REALINLINE void CTRTextureLightMap2_Add::scanline_bilinear ()
  {
  	tVideoSample *dst;
  
  #ifdef USE_ZBUFFER
  	fp24 *z;
  #endif
  
  	s32 xStart;
  	s32 xEnd;
  	s32 dx;
  
  
  #ifdef SUBTEXEL
  	f32 subPixel;
  #endif
  
  #ifdef IPOL_Z
  	f32 slopeZ;
  #endif
  #ifdef IPOL_W
  	fp24 slopeW;
  #endif
  #ifdef IPOL_C0
  	sVec4 slopeC;
  #endif
  #ifdef IPOL_T0
  	sVec2 slopeT[BURNING_MATERIAL_MAX_TEXTURES];
  #endif
  
  	// apply top-left fill-convention, left
  	xStart = core::ceil32( line.x[0] );
  	xEnd = core::ceil32( line.x[1] ) - 1;
  
  	dx = xEnd - xStart;
  
  	if ( dx < 0 )
  		return;
  
  	// slopes
  	const f32 invDeltaX = core::reciprocal_approxim ( line.x[1] - line.x[0] );
  
  #ifdef IPOL_Z
  	slopeZ = (line.z[1] - line.z[0]) * invDeltaX;
  #endif
  #ifdef IPOL_W
  	slopeW = (line.w[1] - line.w[0]) * invDeltaX;
  #endif
  #ifdef IPOL_C0
  	slopeC = (line.c[1] - line.c[0]) * invDeltaX;
  #endif
  #ifdef IPOL_T0
  	slopeT[0] = (line.t[0][1] - line.t[0][0]) * invDeltaX;
  #endif
  #ifdef IPOL_T1
  	slopeT[1] = (line.t[1][1] - line.t[1][0]) * invDeltaX;
  #endif
  
  #ifdef SUBTEXEL
  	subPixel = ( (f32) xStart ) - line.x[0];
  #ifdef IPOL_Z
  	line.z[0] += slopeZ * subPixel;
  #endif
  #ifdef IPOL_W
  	line.w[0] += slopeW * subPixel;
  #endif
  #ifdef IPOL_C0
  	line.c[0] += slopeC * subPixel;
  #endif
  #ifdef IPOL_T0
  	line.t[0][0] += slopeT[0] * subPixel;
  #endif
  #ifdef IPOL_T1
  	line.t[1][0] += slopeT[1] * subPixel;
  #endif
  #endif
  
  	dst = (tVideoSample*)RenderTarget->lock() + ( line.y * RenderTarget->getDimension().Width ) + xStart;
  
  #ifdef USE_ZBUFFER
  	z = (fp24*) DepthBuffer->lock() + ( line.y * RenderTarget->getDimension().Width ) + xStart;
  #endif
  
  
  
  
  #ifdef BURNINGVIDEO_RENDERER_FAST
  	u32 dIndex = ( line.y & 3 ) << 2;
  
  
  #else
  	// 
  	tFixPoint r0, g0, b0;
  	tFixPoint r1, g1, b1;
  #endif
  
  
  	for ( s32 i = 0; i <= dx; i++ )
  	{
  #ifdef CMP_Z
  		if ( line.z[0] < z[i] )
  #endif
  #ifdef CMP_W
  		if ( line.w[0] >= z[i] )
  #endif
  		{
  
  #ifdef WRITE_Z
  			z[i] = line.z[0];
  #endif
  #ifdef WRITE_W
  			z[i] = line.w[0];
  #endif
  
  #ifdef BURNINGVIDEO_RENDERER_FAST
  
  #ifdef INVERSE_W
  
  			const f32 inversew = fix_inverse32 ( line.w[0] );
  
  			const tFixPointu d = dithermask [ dIndex | ( i ) & 3 ];
  
  			dst[i] = PixelAdd32 (
  					getTexel_plain ( &IT[0],	d + tofix ( line.t[0][0].x,inversew), 
  												d + tofix ( line.t[0][0].y,inversew) ),
  					getTexel_plain ( &IT[1],	d + tofix ( line.t[1][0].x,inversew), 
  												d + tofix ( line.t[1][0].y,inversew) )
  							);
  #else
  			const tFixPointu d = dithermask [ dIndex | ( i ) & 3 ];
  
  			dst[i] = PixelAdd32 (
  					getTexel_plain ( &IT[0],	d + tofix ( line.t[0][0].x), 
  												d + tofix ( line.t[0][0].y) ),
  					getTexel_plain ( &IT[1],	d + tofix ( line.t[1][0].x), 
  												d + tofix ( line.t[1][0].y) )
  							);
  
  #endif
  
  #else
  			const f32 inversew = fix_inverse32 ( line.w[0] );
  
  			getSample_texture ( r0, g0, b0, &IT[0], tofix ( line.t[0][0].x,inversew), tofix ( line.t[0][0].y,inversew) );
  			getSample_texture ( r1, g1, b1, &IT[1], tofix ( line.t[0][1].x,inversew), tofix ( line.t[0][1].y,inversew) );
  
  			dst[i] = fix_to_color ( clampfix_maxcolor ( r0 + r1 ),
  									clampfix_maxcolor ( g0 + g1 ),
  									clampfix_maxcolor ( b0 + b1 )
  								);
  #endif
  
  		}
  
  #ifdef IPOL_Z
  		line.z[0] += slopeZ;
  #endif
  #ifdef IPOL_W
  		line.w[0] += slopeW;
  #endif
  #ifdef IPOL_C0
  		line.c[0] += slopeC;
  #endif
  #ifdef IPOL_T0
  		line.t[0][0] += slopeT[0];
  #endif
  #ifdef IPOL_T1
  		line.t[1][0] += slopeT[1];
  #endif
  	}
  
  }
  
  void CTRTextureLightMap2_Add::drawTriangle ( const s4DVertex *a,const s4DVertex *b,const s4DVertex *c )
  {
  	// sort on height, y
  	if ( F32_A_GREATER_B ( a->Pos.y , b->Pos.y ) ) swapVertexPointer(&a, &b);
  	if ( F32_A_GREATER_B ( b->Pos.y , c->Pos.y ) ) swapVertexPointer(&b, &c);
  	if ( F32_A_GREATER_B ( a->Pos.y , b->Pos.y ) ) swapVertexPointer(&a, &b);
  
  	const f32 ca = c->Pos.y - a->Pos.y;
  	const f32 ba = b->Pos.y - a->Pos.y;
  	const f32 cb = c->Pos.y - b->Pos.y;
  	// calculate delta y of the edges
  	scan.invDeltaY[0] = core::reciprocal( ca );
  	scan.invDeltaY[1] = core::reciprocal( ba );
  	scan.invDeltaY[2] = core::reciprocal( cb );
  
  	if ( F32_LOWER_EQUAL_0 ( scan.invDeltaY[0] ) )
  		return;
  
  	// find if the major edge is left or right aligned
  	f32 temp[4];
  
  	temp[0] = a->Pos.x - c->Pos.x;
  	temp[1] = -ca;
  	temp[2] = b->Pos.x - a->Pos.x;
  	temp[3] = ba;
  
  	scan.left = ( temp[0] * temp[3] - temp[1] * temp[2] ) > 0.f ? 0 : 1;
  	scan.right = 1 - scan.left;
  
  	// calculate slopes for the major edge
  	scan.slopeX[0] = (c->Pos.x - a->Pos.x) * scan.invDeltaY[0];
  	scan.x[0] = a->Pos.x;
  
  #ifdef IPOL_Z
  	scan.slopeZ[0] = (c->Pos.z - a->Pos.z) * scan.invDeltaY[0];
  	scan.z[0] = a->Pos.z;
  #endif
  
  #ifdef IPOL_W
  	scan.slopeW[0] = (c->Pos.w - a->Pos.w) * scan.invDeltaY[0];
  	scan.w[0] = a->Pos.w;
  #endif
  
  #ifdef IPOL_C0
  	scan.slopeC[0] = (c->Color[0] - a->Color[0]) * scan.invDeltaY[0];
  	scan.c[0] = a->Color[0];
  #endif
  
  #ifdef IPOL_T0
  	scan.slopeT[0][0] = (c->Tex[0] - a->Tex[0]) * scan.invDeltaY[0];
  	scan.t[0][0] = a->Tex[0];
  #endif
  
  #ifdef IPOL_T1
  	scan.slopeT[1][0] = (c->Tex[1] - a->Tex[1]) * scan.invDeltaY[0];
  	scan.t[1][0] = a->Tex[1];
  #endif
  
  	// top left fill convention y run
  	s32 yStart;
  	s32 yEnd;
  
  #ifdef SUBTEXEL
  	f32 subPixel;
  #endif
  
  	// rasterize upper sub-triangle
  	if ( (f32) 0.0 != scan.invDeltaY[1]  )
  	{
  		// calculate slopes for top edge
  		scan.slopeX[1] = (b->Pos.x - a->Pos.x) * scan.invDeltaY[1];
  		scan.x[1] = a->Pos.x;
  
  #ifdef IPOL_Z
  		scan.slopeZ[1] = (b->Pos.z - a->Pos.z) * scan.invDeltaY[1];
  		scan.z[1] = a->Pos.z;
  #endif
  
  #ifdef IPOL_W
  		scan.slopeW[1] = (b->Pos.w - a->Pos.w) * scan.invDeltaY[1];
  		scan.w[1] = a->Pos.w;
  #endif
  
  #ifdef IPOL_C0
  		scan.slopeC[1] = (b->Color[0] - a->Color[0]) * scan.invDeltaY[1];
  		scan.c[1] = a->Color[0];
  #endif
  
  #ifdef IPOL_T0
  		scan.slopeT[0][1] = (b->Tex[0] - a->Tex[0]) * scan.invDeltaY[1];
  		scan.t[0][1] = a->Tex[0];
  #endif
  
  #ifdef IPOL_T1
  		scan.slopeT[1][1] = (b->Tex[1] - a->Tex[1]) * scan.invDeltaY[1];
  		scan.t[1][1] = a->Tex[1];
  #endif
  
  		// apply top-left fill convention, top part
  		yStart = core::ceil32( a->Pos.y );
  		yEnd = core::ceil32( b->Pos.y ) - 1;
  
  #ifdef SUBTEXEL
  		subPixel = ( (f32) yStart ) - a->Pos.y;
  
  		// correct to pixel center
  		scan.x[0] += scan.slopeX[0] * subPixel;
  		scan.x[1] += scan.slopeX[1] * subPixel;		
  
  #ifdef IPOL_Z
  		scan.z[0] += scan.slopeZ[0] * subPixel;
  		scan.z[1] += scan.slopeZ[1] * subPixel;		
  #endif
  
  #ifdef IPOL_W
  		scan.w[0] += scan.slopeW[0] * subPixel;
  		scan.w[1] += scan.slopeW[1] * subPixel;		
  #endif
  
  #ifdef IPOL_C0
  		scan.c[0] += scan.slopeC[0] * subPixel;
  		scan.c[1] += scan.slopeC[1] * subPixel;		
  #endif
  
  #ifdef IPOL_T0
  		scan.t[0][0] += scan.slopeT[0][0] * subPixel;
  		scan.t[0][1] += scan.slopeT[0][1] * subPixel;		
  #endif
  
  #ifdef IPOL_T1
  		scan.t[1][0] += scan.slopeT[1][0] * subPixel;
  		scan.t[1][1] += scan.slopeT[1][1] * subPixel;		
  #endif
  
  #endif
  
  		// rasterize the edge scanlines
  		for( line.y = yStart; line.y <= yEnd; ++line.y)
  		{
  			line.x[scan.left] = scan.x[0];
  			line.x[scan.right] = scan.x[1];
  
  #ifdef IPOL_Z
  			line.z[scan.left] = scan.z[0];
  			line.z[scan.right] = scan.z[1];
  #endif
  
  #ifdef IPOL_W
  			line.w[scan.left] = scan.w[0];
  			line.w[scan.right] = scan.w[1];
  #endif
  
  #ifdef IPOL_C0
  			line.c[scan.left] = scan.c[0];
  			line.c[scan.right] = scan.c[1];
  #endif
  
  #ifdef IPOL_T0
  			line.t[0][scan.left] = scan.t[0][0];
  			line.t[0][scan.right] = scan.t[0][1];
  #endif
  
  #ifdef IPOL_T1
  			line.t[1][scan.left] = scan.t[1][0];
  			line.t[1][scan.right] = scan.t[1][1];
  #endif
  
  			// render a scanline
  			scanline_bilinear ();
  
  			scan.x[0] += scan.slopeX[0];
  			scan.x[1] += scan.slopeX[1];
  
  #ifdef IPOL_Z
  			scan.z[0] += scan.slopeZ[0];
  			scan.z[1] += scan.slopeZ[1];
  #endif
  
  #ifdef IPOL_W
  			scan.w[0] += scan.slopeW[0];
  			scan.w[1] += scan.slopeW[1];
  #endif
  
  #ifdef IPOL_C0
  			scan.c[0] += scan.slopeC[0];
  			scan.c[1] += scan.slopeC[1];
  #endif
  
  #ifdef IPOL_T0
  			scan.t[0][0] += scan.slopeT[0][0];
  			scan.t[0][1] += scan.slopeT[0][1];
  #endif
  
  #ifdef IPOL_T1
  			scan.t[1][0] += scan.slopeT[1][0];
  			scan.t[1][1] += scan.slopeT[1][1];
  #endif
  
  		}
  	}
  
  	// rasterize lower sub-triangle
  	if ( (f32) 0.0 != scan.invDeltaY[2] )
  	{
  		// advance to middle point
  		if( (f32) 0.0 != scan.invDeltaY[1] )
  		{
  			temp[0] = b->Pos.y - a->Pos.y;	// dy
  
  			scan.x[0] = a->Pos.x + scan.slopeX[0] * temp[0];
  #ifdef IPOL_Z
  			scan.z[0] = a->Pos.z + scan.slopeZ[0] * temp[0];
  #endif
  #ifdef IPOL_W
  			scan.w[0] = a->Pos.w + scan.slopeW[0] * temp[0];
  #endif
  #ifdef IPOL_C0
  			scan.c[0] = a->Color[0] + scan.slopeC[0] * temp[0];
  #endif
  #ifdef IPOL_T0
  			scan.t[0][0] = a->Tex[0] + scan.slopeT[0][0] * temp[0];
  #endif
  #ifdef IPOL_T1
  			scan.t[1][0] = a->Tex[1] + scan.slopeT[1][0] * temp[0];
  #endif
  
  		}
  
  		// calculate slopes for bottom edge
  		scan.slopeX[1] = (c->Pos.x - b->Pos.x) * scan.invDeltaY[2];
  		scan.x[1] = b->Pos.x;
  
  #ifdef IPOL_Z
  		scan.slopeZ[1] = (c->Pos.z - b->Pos.z) * scan.invDeltaY[2];
  		scan.z[1] = b->Pos.z;
  #endif
  
  #ifdef IPOL_W
  		scan.slopeW[1] = (c->Pos.w - b->Pos.w) * scan.invDeltaY[2];
  		scan.w[1] = b->Pos.w;
  #endif
  
  #ifdef IPOL_C0
  		scan.slopeC[1] = (c->Color[0] - b->Color[0]) * scan.invDeltaY[2];
  		scan.c[1] = b->Color[0];
  #endif
  
  #ifdef IPOL_T0
  		scan.slopeT[0][1] = (c->Tex[0] - b->Tex[0]) * scan.invDeltaY[2];
  		scan.t[0][1] = b->Tex[0];
  #endif
  
  #ifdef IPOL_T1
  		scan.slopeT[1][1] = (c->Tex[1] - b->Tex[1]) * scan.invDeltaY[2];
  		scan.t[1][1] = b->Tex[1];
  #endif
  
  		// apply top-left fill convention, top part
  		yStart = core::ceil32( b->Pos.y );
  		yEnd = core::ceil32( c->Pos.y ) - 1;
  
  #ifdef SUBTEXEL
  
  		subPixel = ( (f32) yStart ) - b->Pos.y;
  
  		// correct to pixel center
  		scan.x[0] += scan.slopeX[0] * subPixel;
  		scan.x[1] += scan.slopeX[1] * subPixel;		
  
  #ifdef IPOL_Z
  		scan.z[0] += scan.slopeZ[0] * subPixel;
  		scan.z[1] += scan.slopeZ[1] * subPixel;		
  #endif
  
  #ifdef IPOL_W
  		scan.w[0] += scan.slopeW[0] * subPixel;
  		scan.w[1] += scan.slopeW[1] * subPixel;		
  #endif
  
  #ifdef IPOL_C0
  		scan.c[0] += scan.slopeC[0] * subPixel;
  		scan.c[1] += scan.slopeC[1] * subPixel;		
  #endif
  
  #ifdef IPOL_T0
  		scan.t[0][0] += scan.slopeT[0][0] * subPixel;
  		scan.t[0][1] += scan.slopeT[0][1] * subPixel;		
  #endif
  
  #ifdef IPOL_T1
  		scan.t[1][0] += scan.slopeT[1][0] * subPixel;
  		scan.t[1][1] += scan.slopeT[1][1] * subPixel;		
  #endif
  
  #endif
  
  		// rasterize the edge scanlines
  		for( line.y = yStart; line.y <= yEnd; ++line.y)
  		{
  			line.x[scan.left] = scan.x[0];
  			line.x[scan.right] = scan.x[1];
  
  #ifdef IPOL_Z
  			line.z[scan.left] = scan.z[0];
  			line.z[scan.right] = scan.z[1];
  #endif
  
  #ifdef IPOL_W
  			line.w[scan.left] = scan.w[0];
  			line.w[scan.right] = scan.w[1];
  #endif
  
  #ifdef IPOL_C0
  			line.c[scan.left] = scan.c[0];
  			line.c[scan.right] = scan.c[1];
  #endif
  
  #ifdef IPOL_T0
  			line.t[0][scan.left] = scan.t[0][0];
  			line.t[0][scan.right] = scan.t[0][1];
  #endif
  
  #ifdef IPOL_T1
  			line.t[1][scan.left] = scan.t[1][0];
  			line.t[1][scan.right] = scan.t[1][1];
  #endif
  
  			// render a scanline
  			scanline_bilinear ();
  
  			scan.x[0] += scan.slopeX[0];
  			scan.x[1] += scan.slopeX[1];
  
  #ifdef IPOL_Z
  			scan.z[0] += scan.slopeZ[0];
  			scan.z[1] += scan.slopeZ[1];
  #endif
  
  #ifdef IPOL_W
  			scan.w[0] += scan.slopeW[0];
  			scan.w[1] += scan.slopeW[1];
  #endif
  
  #ifdef IPOL_C0
  			scan.c[0] += scan.slopeC[0];
  			scan.c[1] += scan.slopeC[1];
  #endif
  
  #ifdef IPOL_T0
  			scan.t[0][0] += scan.slopeT[0][0];
  			scan.t[0][1] += scan.slopeT[0][1];
  #endif
  
  #ifdef IPOL_T1
  			scan.t[1][0] += scan.slopeT[1][0];
  			scan.t[1][1] += scan.slopeT[1][1];
  #endif
  
  		}
  	}
  
  
  }
  
  
  } // end namespace video
  } // end namespace irr
  
  #endif // _IRR_COMPILE_WITH_BURNINGSVIDEO_
  
  namespace irr
  {
  namespace video
  {
  
  //! creates a flat triangle renderer
  IBurningShader* createTriangleRendererTextureLightMap2_Add(CBurningVideoDriver* driver)
  {
  	#ifdef _IRR_COMPILE_WITH_BURNINGSVIDEO_
  	return new CTRTextureLightMap2_Add(driver);
  	#else
  	return 0;
  	#endif // _IRR_COMPILE_WITH_BURNINGSVIDEO_
  }
  
  
  } // end namespace video
  } // end namespace irr
  
  
  
  