// Copyright (C) 1996 Keith Whitwell.
// This file may only be copied under the terms of the GNU Library General
// Public License - see the file COPYING in the lib3d distribution.

#include <Lib3d/Model.H>
#include <Lib3d/Light.H>
#include <Lib3d/WirePipeline.H>
#include <Lib3d/internals/Material.H>
#include <minmax.h>

WirePipeline::WirePipeline()
    : FlatPipeline()
{
}

WirePipeline::~WirePipeline()
{
}

void
WirePipeline::render(Model &model,
		     Viewport &viewport, 
		     const Light *lights, 
		     uint nrLights,
		     uint clipPlanes,
		     uint flags)
{
    stitchModel(model);
    expand(nrLights);

    thisFrame++;
    renderFlags = flags;
    have_backface_info = false;
    clip = false;

    if ( !clipPlanes ) {
	transform( viewport );
    } else if ( !transformForClipping( viewport ) ) {
	return;
    }
    
    if (!clip) {
	using_lit_normals =  (nrLights && 
			      (nrPolygonNormals*nrMaterials < nrPolygons/2));
	calculateLightData( viewport, lights, nrLights );
	renderPolygons( viewport, nrLights ); 
    } else {
	using_lit_normals = (nrLights &&
			     (nrPolygonNormals*nrMaterials < nrPolygons));

	calculateLightData( viewport, lights, nrLights );
	clipAndRenderPolygons( viewport, nrLights );
    }

    viewport.setDirty( xmin, ymin, xmax, ymax );
}




void
WirePipeline::renderPolygons( Viewport &viewport, uint nrLights )
{
    if (have_backface_info) {
	for (int j = nrPolygons ; j-- ;  ) {
	    const Polygon &poly = polygons[j];
	    if (!ppool[j].backface) {
		pv[0] = &vpool[poly.vertex0];
		pv[1] = &vpool[poly.vertex1];
		pv[2] = &vpool[poly.vertex2];
		
		uint colour = lightPolygon(poly, viewport, nrLights);
		viewport.wireTriangle(pv, colour);
	    }
	}
    } else {
	for (int j = nrPolygons ; j-- ;  ) {
	    const Polygon &poly = polygons[j];
	    pv[0] = &vpool[poly.vertex0];
	    pv[1] = &vpool[poly.vertex1];
	    pv[2] = &vpool[poly.vertex2];

	    uint colour = lightPolygon(poly, viewport, nrLights);
	    viewport.wireTriangle(pv, colour);
	}
    }
}

void
WirePipeline::cullAndRenderPolygons( Viewport &viewport, uint nrLights )
{
    for (int j = nrPolygons ; j-- ;  ) {
        const Polygon &poly = polygons[j];

	pv[0] = &vpool[poly.vertex0];
	pv[1] = &vpool[poly.vertex1];
	pv[2] = &vpool[poly.vertex2];
	
	bool cw =(   ((pv[1]->device.v[1] - pv[0]->device.v[1]) *
		      (pv[2]->device.v[0] - pv[0]->device.v[0]))
		  >= ((pv[1]->device.v[0] - pv[0]->device.v[0]) *
		      (pv[2]->device.v[1] - pv[0]->device.v[1])));

	if (cw) {
	    uint colour = lightPolygon(poly, viewport, nrLights);
	    viewport.wireTriangle(pv, colour);
	}
    }
}

void
WirePipeline::clipAndRenderPolygons( Viewport &viewport, uint nrLights )
{
    const Polygon *poly = polygons;
    Flat_PolygonData *pp = ppool;
    int j = nrPolygons;

    if (have_backface_info) {
	do {
	    if (!pp->backface) {
		pv[0] = &vpool[poly->vertex0];
		uint oc0 = vpool[poly->vertex0].outcodes;
		pv[1] = &vpool[poly->vertex1];
		uint oc1 = vpool[poly->vertex1].outcodes;
		pv[2] = &vpool[poly->vertex2];
		uint oc2 = vpool[poly->vertex2].outcodes;

		if ((oc0&oc1&oc2) == 0) {
		    uint intersections = oc0|oc1|oc2;
		    uint colour = lightPolygon(*poly, viewport, nrLights);

		    if (intersections == 0) {
			viewport.wireTriangle(pv, colour);
		    } else {
			uint nr = nrVpool;
			if (clipPolygon(*poly, intersections))
			    viewport.wirePolygon(nrClippedVertices, pv, colour);
			nrVpool = nr;	
		    }
		}
	    }
	    poly++;
	    pp++;
	} while (--j);
    } else {
	do {
	    pv[0] = &vpool[poly->vertex0];
	    uint oc0 = vpool[poly->vertex0].outcodes;
	    pv[1] = &vpool[poly->vertex1];
	    uint oc1 = vpool[poly->vertex1].outcodes;
	    pv[2] = &vpool[poly->vertex2];
	    uint oc2 = vpool[poly->vertex2].outcodes;
	    
	    if ((oc0&oc1&oc2) == 0) {
		uint intersections = oc0|oc1|oc2;
		uint colour = lightPolygon(*poly, viewport, nrLights);
		
		if (intersections == 0) {
		    viewport.wireTriangle(pv, colour);
		} else {
		    uint nr = nrVpool;
		    if (clipPolygon(*poly, intersections))
			viewport.wirePolygon(nrClippedVertices, pv, colour);
		    nrVpool = nr;	
		}
	    }
	    poly++;
	    pp++;
	} while (--j);
    }
}