r_draw.c

quake1 dos源代码最新版本

						(((edge_t *)((unsigned long)r_edges +
						 r_pedge->cachededgeoffset))->owner == r_pedge))
					{
						R_EmitCachedEdge ();
						r_lastvertvalid = false;
						continue;
					}
				}
			}

		// assume it's cacheable
			cacheoffset = (byte *)edge_p - (byte *)r_edges;
			r_leftclipped = r_rightclipped = false;
			R_ClipEdge (&r_pcurrentvertbase[r_pedge->v[0]],
						&r_pcurrentvertbase[r_pedge->v[1]],
						pclip);
			r_pedge->cachededgeoffset = cacheoffset;

			if (r_leftclipped)
				makeleftedge = true;
			if (r_rightclipped)
				makerightedge = true;
			r_lastvertvalid = true;
		}
		else
		{
			lindex = -lindex;
			r_pedge = &pedges[lindex];
		// if the edge is cached, we can just reuse the edge
			if (!insubmodel)
			{
				if (r_pedge->cachededgeoffset & FULLY_CLIPPED_CACHED)
				{
					if ((r_pedge->cachededgeoffset & FRAMECOUNT_MASK) ==
						r_framecount)
					{
						r_lastvertvalid = false;
						continue;
					}
				}
				else
				{
				// it's cached if the cached edge is valid and is owned
				// by this medge_t
					if ((((unsigned long)edge_p - (unsigned long)r_edges) >
						 r_pedge->cachededgeoffset) &&
						(((edge_t *)((unsigned long)r_edges +
						 r_pedge->cachededgeoffset))->owner == r_pedge))
					{
						R_EmitCachedEdge ();
						r_lastvertvalid = false;
						continue;
					}
				}
			}

		// assume it's cacheable
			cacheoffset = (byte *)edge_p - (byte *)r_edges;
			r_leftclipped = r_rightclipped = false;
			R_ClipEdge (&r_pcurrentvertbase[r_pedge->v[1]],
						&r_pcurrentvertbase[r_pedge->v[0]],
						pclip);
			r_pedge->cachededgeoffset = cacheoffset;

			if (r_leftclipped)
				makeleftedge = true;
			if (r_rightclipped)
				makerightedge = true;
			r_lastvertvalid = true;
		}
	}

// if there was a clip off the left edge, add that edge too
// FIXME: faster to do in screen space?
// FIXME: share clipped edges?
	if (makeleftedge)
	{
		r_pedge = &tedge;
		r_lastvertvalid = false;
		R_ClipEdge (&r_leftexit, &r_leftenter, pclip->next);
	}

// if there was a clip off the right edge, get the right r_nearzi
	if (makerightedge)
	{
		r_pedge = &tedge;
		r_lastvertvalid = false;
		r_nearzionly = true;
		R_ClipEdge (&r_rightexit, &r_rightenter, view_clipplanes[1].next);
	}

// if no edges made it out, return without posting the surface
	if (!r_emitted)
		return;

	r_polycount++;

	surface_p->data = (void *)fa;
	surface_p->nearzi = r_nearzi;
	surface_p->flags = fa->flags;
	surface_p->insubmodel = insubmodel;
	surface_p->spanstate = 0;
	surface_p->entity = currententity;
	surface_p->key = r_currentkey++;
	surface_p->spans = NULL;

	pplane = fa->plane;
// FIXME: cache this?
	TransformVector (pplane->normal, p_normal);
// FIXME: cache this?
	distinv = 1.0 / (pplane->dist - DotProduct (modelorg, pplane->normal));

	surface_p->d_zistepu = p_normal[0] * xscaleinv * distinv;
	surface_p->d_zistepv = -p_normal[1] * yscaleinv * distinv;
	surface_p->d_ziorigin = p_normal[2] * distinv -
			xcenter * surface_p->d_zistepu -
			ycenter * surface_p->d_zistepv;

//JDC	VectorCopy (r_worldmodelorg, surface_p->modelorg);
	surface_p++;
}


/*
================
R_RenderBmodelFace
================
*/
void R_RenderBmodelFace (bedge_t *pedges, msurface_t *psurf)
{
	int			i;
	unsigned	mask;
	mplane_t	*pplane;
	float		distinv;
	vec3_t		p_normal;
	medge_t		tedge;
	clipplane_t	*pclip;

// skip out if no more surfs
	if (surface_p >= surf_max)
	{
		r_outofsurfaces++;
		return;
	}

// ditto if not enough edges left, or switch to auxedges if possible
	if ((edge_p + psurf->numedges + 4) >= edge_max)
	{
		r_outofedges += psurf->numedges;
		return;
	}

	c_faceclip++;

// this is a dummy to give the caching mechanism someplace to write to
	r_pedge = &tedge;

// set up clip planes
	pclip = NULL;

	for (i=3, mask = 0x08 ; i>=0 ; i--, mask >>= 1)
	{
		if (r_clipflags & mask)
		{
			view_clipplanes[i].next = pclip;
			pclip = &view_clipplanes[i];
		}
	}

// push the edges through
	r_emitted = 0;
	r_nearzi = 0;
	r_nearzionly = false;
	makeleftedge = makerightedge = false;
// FIXME: keep clipped bmodel edges in clockwise order so last vertex caching
// can be used?
	r_lastvertvalid = false;

	for ( ; pedges ; pedges = pedges->pnext)
	{
		r_leftclipped = r_rightclipped = false;
		R_ClipEdge (pedges->v[0], pedges->v[1], pclip);

		if (r_leftclipped)
			makeleftedge = true;
		if (r_rightclipped)
			makerightedge = true;
	}

// if there was a clip off the left edge, add that edge too
// FIXME: faster to do in screen space?
// FIXME: share clipped edges?
	if (makeleftedge)
	{
		r_pedge = &tedge;
		R_ClipEdge (&r_leftexit, &r_leftenter, pclip->next);
	}

// if there was a clip off the right edge, get the right r_nearzi
	if (makerightedge)
	{
		r_pedge = &tedge;
		r_nearzionly = true;
		R_ClipEdge (&r_rightexit, &r_rightenter, view_clipplanes[1].next);
	}

// if no edges made it out, return without posting the surface
	if (!r_emitted)
		return;

	r_polycount++;

	surface_p->data = (void *)psurf;
	surface_p->nearzi = r_nearzi;
	surface_p->flags = psurf->flags;
	surface_p->insubmodel = true;
	surface_p->spanstate = 0;
	surface_p->entity = currententity;
	surface_p->key = r_currentbkey;
	surface_p->spans = NULL;

	pplane = psurf->plane;
// FIXME: cache this?
	TransformVector (pplane->normal, p_normal);
// FIXME: cache this?
	distinv = 1.0 / (pplane->dist - DotProduct (modelorg, pplane->normal));

	surface_p->d_zistepu = p_normal[0] * xscaleinv * distinv;
	surface_p->d_zistepv = -p_normal[1] * yscaleinv * distinv;
	surface_p->d_ziorigin = p_normal[2] * distinv -
			xcenter * surface_p->d_zistepu -
			ycenter * surface_p->d_zistepv;

//JDC	VectorCopy (r_worldmodelorg, surface_p->modelorg);
	surface_p++;
}


/*
================
R_RenderPoly
================
*/
void R_RenderPoly (msurface_t *fa, int clipflags)
{
	int			i, lindex, lnumverts, s_axis, t_axis;
	float		dist, lastdist, lzi, scale, u, v, frac;
	unsigned	mask;
	vec3_t		local, transformed;
	clipplane_t	*pclip;
	medge_t		*pedges;
	mplane_t	*pplane;
	mvertex_t	verts[2][100];	//FIXME: do real number
	polyvert_t	pverts[100];	//FIXME: do real number, safely
	int			vertpage, newverts, newpage, lastvert;
	qboolean	visible;

// FIXME: clean this up and make it faster
// FIXME: guard against running out of vertices

	s_axis = t_axis = 0;	// keep compiler happy

// set up clip planes
	pclip = NULL;

	for (i=3, mask = 0x08 ; i>=0 ; i--, mask >>= 1)
	{
		if (clipflags & mask)
		{
			view_clipplanes[i].next = pclip;
			pclip = &view_clipplanes[i];
		}
	}

// reconstruct the polygon
// FIXME: these should be precalculated and loaded off disk
	pedges = currententity->model->edges;
	lnumverts = fa->numedges;
	vertpage = 0;

	for (i=0 ; i<lnumverts ; i++)
	{
		lindex = currententity->model->surfedges[fa->firstedge + i];

		if (lindex > 0)
		{
			r_pedge = &pedges[lindex];
			verts[0][i] = r_pcurrentvertbase[r_pedge->v[0]];
		}
		else
		{
			r_pedge = &pedges[-lindex];
			verts[0][i] = r_pcurrentvertbase[r_pedge->v[1]];
		}
	}

// clip the polygon, done if not visible
	while (pclip)
	{
		lastvert = lnumverts - 1;
		lastdist = DotProduct (verts[vertpage][lastvert].position,
							   pclip->normal) - pclip->dist;

		visible = false;
		newverts = 0;
		newpage = vertpage ^ 1;

		for (i=0 ; i<lnumverts ; i++)
		{
			dist = DotProduct (verts[vertpage][i].position, pclip->normal) -
					pclip->dist;

			if ((lastdist > 0) != (dist > 0))
			{
				frac = dist / (dist - lastdist);
				verts[newpage][newverts].position[0] =
						verts[vertpage][i].position[0] +
						((verts[vertpage][lastvert].position[0] -
						  verts[vertpage][i].position[0]) * frac);
				verts[newpage][newverts].position[1] =
						verts[vertpage][i].position[1] +
						((verts[vertpage][lastvert].position[1] -
						  verts[vertpage][i].position[1]) * frac);
				verts[newpage][newverts].position[2] =
						verts[vertpage][i].position[2] +
						((verts[vertpage][lastvert].position[2] -
						  verts[vertpage][i].position[2]) * frac);
				newverts++;
			}

			if (dist >= 0)
			{
				verts[newpage][newverts] = verts[vertpage][i];
				newverts++;
				visible = true;
			}

			lastvert = i;
			lastdist = dist;
		}

		if (!visible || (newverts < 3))
			return;

		lnumverts = newverts;
		vertpage ^= 1;
		pclip = pclip->next;
	}

// transform and project, remembering the z values at the vertices and
// r_nearzi, and extract the s and t coordinates at the vertices
	pplane = fa->plane;
	switch (pplane->type)
	{
	case PLANE_X:
	case PLANE_ANYX:
		s_axis = 1;
		t_axis = 2;
		break;
	case PLANE_Y:
	case PLANE_ANYY:
		s_axis = 0;
		t_axis = 2;
		break;
	case PLANE_Z:
	case PLANE_ANYZ:
		s_axis = 0;
		t_axis = 1;
		break;
	}

	r_nearzi = 0;

	for (i=0 ; i<lnumverts ; i++)
	{
	// transform and project
		VectorSubtract (verts[vertpage][i].position, modelorg, local);
		TransformVector (local, transformed);

		if (transformed[2] < NEAR_CLIP)
			transformed[2] = NEAR_CLIP;

		lzi = 1.0 / transformed[2];

		if (lzi > r_nearzi)	// for mipmap finding
			r_nearzi = lzi;

	// FIXME: build x/yscale into transform?
		scale = xscale * lzi;
		u = (xcenter + scale*transformed[0]);
		if (u < r_refdef.fvrectx_adj)
			u = r_refdef.fvrectx_adj;
		if (u > r_refdef.fvrectright_adj)
			u = r_refdef.fvrectright_adj;

		scale = yscale * lzi;
		v = (ycenter - scale*transformed[1]);
		if (v < r_refdef.fvrecty_adj)
			v = r_refdef.fvrecty_adj;
		if (v > r_refdef.fvrectbottom_adj)
			v = r_refdef.fvrectbottom_adj;

		pverts[i].u = u;
		pverts[i].v = v;
		pverts[i].zi = lzi;
		pverts[i].s = verts[vertpage][i].position[s_axis];
		pverts[i].t = verts[vertpage][i].position[t_axis];
	}

// build the polygon descriptor, including fa, r_nearzi, and u, v, s, t, and z
// for each vertex
	r_polydesc.numverts = lnumverts;
	r_polydesc.nearzi = r_nearzi;
	r_polydesc.pcurrentface = fa;
	r_polydesc.pverts = pverts;

// draw the polygon
	D_DrawPoly ();
}


/*
================
R_ZDrawSubmodelPolys
================
*/
void R_ZDrawSubmodelPolys (model_t *pmodel)
{
	int			i, numsurfaces;
	msurface_t	*psurf;
	float		dot;
	mplane_t	*pplane;

	psurf = &pmodel->surfaces[pmodel->firstmodelsurface];
	numsurfaces = pmodel->nummodelsurfaces;

	for (i=0 ; i<numsurfaces ; i++, psurf++)
	{
	// find which side of the node we are on
		pplane = psurf->plane;

		dot = DotProduct (modelorg, pplane->normal) - pplane->dist;

	// draw the polygon
		if (((psurf->flags & SURF_PLANEBACK) && (dot < -BACKFACE_EPSILON)) ||
			(!(psurf->flags & SURF_PLANEBACK) && (dot > BACKFACE_EPSILON)))
		{
		// FIXME: use bounding-box-based frustum clipping info?
			R_RenderPoly (psurf, 15);
		}
	}
}