Path: chuka.playstation.co.uk!news
From: Developer Support <dev_support@interactive.sony.com>
Newsgroups: scee.yaroze.programming.3d_graphics
Subject: Re: GPU Code xxh not supported
Date: Fri, 04 Jul 1997 10:13:52 +0100
Organization: PlayStation Net Yaroze (SCEE)
Lines: 44
Message-ID: <33BCBED0.429@interactive.sony.com>
References: <5pga0c$8c3@chuka.playstation.co.uk> <33BBB432.FF5@interactive.sony.com> <5ph02c$8c4@chuka.playstation.co.uk> <33BCB28A.6366@interactive.sony.com>
NNTP-Posting-Host: 194.203.13.10
Mime-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Transfer-Encoding: 7bit
X-Mailer: Mozilla 3.01 (Win95; I)

Developer Support wrote:
> 
> We haven't tested all the TMD primatives, so it does look like 3D lines
> is another one thats not supported. As for drawing 3D lines, you could
> try a polygon with points the same (not at all ideal), or you could
> perform your own transformation and then draw to the screen (still not
> ideal, GsLINE is the structure, GsSortLine to add to ordering table).
> I'll look into both methods, even though I'm not convinced about this
> wireframe stuff (controvertial).
> 
> Stuart

I've had a look at both methods, and drawing a polygon isn't very good,
as the polygon has to have a width. The second method is much more
straight forward, and looks something like this.

GsCOORDINATE2 coord;	// coordinate system line is in
GsOT OT[2];		// ordering table
int buffer;		// drawing buffer number
int pri;		// priority in ordering table
SVECTOR v0,v1;		// the vertices of the line
VECTOR p0,p1;		// the points on the screen
MATRIX m;		// the matrix to go from the vertices to points
GsLINE line;		// the line to be drawn;

GsGetLs(&coord,&m);	// calculate local to screen matrix

ApplyMatrix(&m,&v0,&p0);// transform vertices
ApplyMatrix(&m,&v1,&p1);

line.attribute = 0;	// set up line
line.x0 = p0.vx;
line.y0 = p0.vy;
line.x1 = p1.vx;
line.y1 = p1.vy;
line.r = 127;
line.g = 127;
line.b = 127;

GsSortLine(&line,&OT[buffer],pri);

Hope this is enough to get you on your way.

Stuart