// Copyright (C) 2002-2012 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 USE_SBUFFER
#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
#undef IPOL_T2
#undef IPOL_L0

// define render case
#define SUBTEXEL
//#define INVERSE_W

#define USE_ZBUFFER
#define USE_SBUFFER
#define IPOL_W
#define CMP_W
//#define WRITE_W


// apply global override
#ifndef SOFTWARE_DRIVER_2_PERSPECTIVE_CORRECT
	#undef INVERSE_W
#endif

#ifndef SOFTWARE_DRIVER_2_SUBTEXEL
	#undef SUBTEXEL
#endif

#if BURNING_MATERIAL_MAX_COLORS < 1
	#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 CTRStencilShadow : public IBurningShader
{
public:

	//! constructor
	CTRStencilShadow(CBurningVideoDriver* driver);

	//! draws an indexed triangle list
	virtual void drawTriangle(const s4DVertex* burning_restrict a, const s4DVertex* burning_restrict b, const s4DVertex* burning_restrict c) IRR_OVERRIDE;

private:
	void fragmentShader();

};

//! constructor
CTRStencilShadow::CTRStencilShadow(CBurningVideoDriver* driver)
: IBurningShader(driver, EMT_SOLID)
{
	#ifdef _DEBUG
	setDebugName("CTRStencilShadow");
	#endif
}


/*!
*/
void CTRStencilShadow::fragmentShader()
{
#ifdef USE_ZBUFFER
	fp24 *z;
#endif

#ifdef USE_SBUFFER
	tStencilSample *stencil;
#endif

	s32 xStart;
	s32 xEnd;
	s32 dx;

#ifdef SUBTEXEL
	f32 subPixel;
#endif

#ifdef IPOL_Z
	f32 slopeZ;
#endif
#ifdef IPOL_W
	fp24 slopeW;
#endif

	// apply top-left fill-convention, left
	xStart = fill_convention_left( line.x[0] );
	xEnd = fill_convention_right( line.x[1] );

	dx = xEnd - xStart;
	if ( dx < 0 )
		return;

	SOFTWARE_DRIVER_2_CLIPCHECK;

	// slopes
	const f32 invDeltaX = fill_step_x( 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 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
#endif
	SOFTWARE_DRIVER_2_CLIPCHECK;
	//dst = (tVideoSample*)RenderTarget->getData() + ( line.y * RenderTarget->getDimension().Width ) + xStart;

#ifdef USE_ZBUFFER
	z = (fp24*) DepthBuffer->lock() + ( line.y * RenderTarget->getDimension().Width ) + xStart;
#endif

#ifdef USE_SBUFFER
	stencil = (tStencilSample*) Stencil->lock() + ( line.y * RenderTarget->getDimension().Width ) + xStart;
#endif


#ifdef INVERSE_W
	f32 inversew = FIX_POINT_F32_MUL;
#endif

	s32 i;
	for (i = 0; i <= dx; i += SOFTWARE_DRIVER_2_STEP_X)
	{
#ifdef CMP_Z
		if (line.z[0] < z[i])
#endif
#ifdef CMP_W
		if (line.w[0] > z[i])
#endif
		{
			// zpass
			switch (stencilOp[2])
			{
			case StencilOp_INCR: stencil[i] += 1; break;
			case StencilOp_DECR: stencil[i] -= 1; break;// core::s32_max(0, stencil[i] - 1); break;
			default:
			case StencilOp_KEEP: break;
			}
		}
		else
		{
			// zfail
			switch (stencilOp[1])
			{
			case StencilOp_INCR: stencil[i] += 1; break;
			case StencilOp_DECR: stencil[i] -= 1; break;// core::s32_max(0, stencil[i] - 1); break;
			default:
			case StencilOp_KEEP: break;
			}
		}

#ifdef IPOL_Z
		line.z[0] += slopeZ;
#endif
#ifdef IPOL_W
		line.w[0] += slopeW;
#endif
	}

}


void CTRStencilShadow::drawTriangle(const s4DVertex* burning_restrict a, const s4DVertex* burning_restrict b, const s4DVertex* burning_restrict 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] = fill_step_y( ca );
	scan.invDeltaY[1] = fill_step_y( ba );
	scan.invDeltaY[2] = fill_step_y( 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 ? 1 : 0;
	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][0] = (c->Color[0] - a->Color[0]) * scan.invDeltaY[0];
	scan.c[0][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

#ifdef IPOL_T2
	scan.slopeT[2][0] = (c->Tex[2] - a->Tex[2]) * scan.invDeltaY[0];
	scan.t[2][0] = a->Tex[2];
#endif

#ifdef IPOL_L0
	scan.slopeL[0][0] = (c->LightTangent[0] - a->LightTangent[0]) * scan.invDeltaY[0];
	scan.l[0][0] = a->LightTangent[0];
#endif

	// top left fill convention y run
	s32 yStart;
	s32 yEnd;

#ifdef SUBTEXEL
	f32 subPixel;
#endif

	// rasterize upper sub-triangle
	if ( F32_GREATER_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[0][1] = (b->Color[0] - a->Color[0]) * scan.invDeltaY[1];
		scan.c[0][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

#ifdef IPOL_T2
		scan.slopeT[2][1] = (b->Tex[2] - a->Tex[2]) * scan.invDeltaY[1];
		scan.t[2][1] = a->Tex[2];
#endif

#ifdef IPOL_L0
		scan.slopeL[0][1] = (b->LightTangent[0] - a->LightTangent[0]) * scan.invDeltaY[1];
		scan.l[0][1] = a->LightTangent[0];
#endif

		// apply top-left fill convention, top part
		yStart = fill_convention_top( a->Pos.y );
		yEnd = fill_convention_down( b->Pos.y );

#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][0] += scan.slopeC[0][0] * subPixel;
		scan.c[0][1] += scan.slopeC[0][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

#ifdef IPOL_T2
		scan.t[2][0] += scan.slopeT[2][0] * subPixel;
		scan.t[2][1] += scan.slopeT[2][1] * subPixel;
#endif

#ifdef IPOL_L0
		scan.l[0][0] += scan.slopeL[0][0] * subPixel;
		scan.l[0][1] += scan.slopeL[0][1] * subPixel;
#endif

#endif

		// rasterize the edge scanlines
		for( line.y = yStart; line.y <= yEnd; line.y += SOFTWARE_DRIVER_2_STEP_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[0][scan.left] = scan.c[0][0];
			line.c[0][scan.right] = scan.c[0][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

#ifdef IPOL_T2
			line.t[2][scan.left] = scan.t[2][0];
			line.t[2][scan.right] = scan.t[2][1];
#endif

#ifdef IPOL_L0
			line.l[0][scan.left] = scan.l[0][0];
			line.l[0][scan.right] = scan.l[0][1];
#endif

			// render a scanline
			if_interlace_scanline fragmentShader ();

			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][0] += scan.slopeC[0][0];
			scan.c[0][1] += scan.slopeC[0][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

#ifdef IPOL_T2
			scan.t[2][0] += scan.slopeT[2][0];
			scan.t[2][1] += scan.slopeT[2][1];
#endif

#ifdef IPOL_L0
			scan.l[0][0] += scan.slopeL[0][0];
			scan.l[0][1] += scan.slopeL[0][1];
#endif

		}
	}

	// rasterize lower sub-triangle
	//if ( (f32) 0.0 != scan.invDeltaY[2] )
	if ( F32_GREATER_0 ( scan.invDeltaY[2] )  )
	{
		// advance to middle point
		//if( (f32) 0.0 != scan.invDeltaY[1] )
		if ( F32_GREATER_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][0] = a->Color[0] + scan.slopeC[0][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
#ifdef IPOL_T2
			scan.t[2][0] = a->Tex[2] + scan.slopeT[2][0] * temp[0];
#endif
#ifdef IPOL_L0
			scan.l[0][0] = a->LightTangent[0] + scan.slopeL[0][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[0][1] = (c->Color[0] - b->Color[0]) * scan.invDeltaY[2];
		scan.c[0][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

#ifdef IPOL_T2
		scan.slopeT[2][1] = (c->Tex[2] - b->Tex[2]) * scan.invDeltaY[2];
		scan.t[2][1] = b->Tex[2];
#endif

#ifdef IPOL_L0
		scan.slopeL[0][1] = (c->LightTangent[0] - b->LightTangent[0]) * scan.invDeltaY[2];
		scan.l[0][1] = b->LightTangent[0];
#endif

		// apply top-left fill convention, top part
		yStart = fill_convention_top( b->Pos.y );
		yEnd = fill_convention_down( c->Pos.y );

#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][0] += scan.slopeC[0][0] * subPixel;
		scan.c[0][1] += scan.slopeC[0][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

#ifdef IPOL_T2
		scan.t[2][0] += scan.slopeT[2][0] * subPixel;
		scan.t[2][1] += scan.slopeT[2][1] * subPixel;
#endif

#ifdef IPOL_L0
		scan.l[0][0] += scan.slopeL[0][0] * subPixel;
		scan.l[0][1] += scan.slopeL[0][1] * subPixel;
#endif

#endif

		// rasterize the edge scanlines
		for( line.y = yStart; line.y <= yEnd; line.y += SOFTWARE_DRIVER_2_STEP_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[0][scan.left] = scan.c[0][0];
			line.c[0][scan.right] = scan.c[0][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

#ifdef IPOL_T2
			line.t[2][scan.left] = scan.t[2][0];
			line.t[2][scan.right] = scan.t[2][1];
#endif

#ifdef IPOL_L0
			line.l[0][scan.left] = scan.l[0][0];
			line.l[0][scan.right] = scan.l[0][1];
#endif

			// render a scanline
			if_interlace_scanline fragmentShader ();

			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][0] += scan.slopeC[0][0];
			scan.c[0][1] += scan.slopeC[0][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
#ifdef IPOL_T2
			scan.t[2][0] += scan.slopeT[2][0];
			scan.t[2][1] += scan.slopeT[2][1];
#endif

#ifdef IPOL_L0
			scan.l[0][0] += scan.slopeL[0][0];
			scan.l[0][1] += scan.slopeL[0][1];
#endif

		}
	}

}


} // end namespace video
} // end namespace irr

#endif // _IRR_COMPILE_WITH_BURNINGSVIDEO_

namespace irr
{
namespace video
{


//! creates a triangle renderer
IBurningShader* createTRStencilShadow(CBurningVideoDriver* driver)
{
	//ETR_STENCIL_SHADOW
	#ifdef _IRR_COMPILE_WITH_BURNINGSVIDEO_
	return new CTRStencilShadow(driver);
	#else
	return 0;
	#endif // _IRR_COMPILE_WITH_BURNINGSVIDEO_
}


} // end namespace video
} // end namespace irr