Michael Jones (mtj++at++babar)
Tue, 7 Jun 1994 13:37:06 -0700
:This is the third pass at this problem. There have been two suggestions
:made by Michael Jones and Jim Helman which have been incorporated into
:the code stub below. The problem persists. When the only object in view
:is the grid, it is drawn in blue (as expected). However, when another
:object enters the view, the grid loses its color and goes dark. I have
:this code written into smallfly so it is the only non-sgi code in the
:application. The problem has to be in the way I define the geostate for
:the grid.
What's your experience with the code below? It's my attempt to draw
lines, and seems to work. I added it to Perfly and all seems well.
/*
* Make a "grid of lines" graphic object
*/
pfNode *
MakeGrid (void)
{
void *arena = NULL;
pfMaterial *material = NULL;
pfGeoState *geostate = NULL;
pfGeoSet *geoset = NULL;
pfGeode *geode = NULL;
pfVec3 *v = NULL;
pfVec3 *vp = NULL;
pfVec4 *c = NULL;
int nx = 30;
int ny = 30;
float x0 = -10.0f;
float y0 = -10.0f;
float z0 = 5.0f;
float x1 = 10.0f;
float y1 = 10.0f;
float dx = x1 - x0;
float dy = y1 - y0;
int x;
int y;
/* access the global shared-memory arena */
arena = pfGetSharedArena();
/* make a material that specifies LMC_AD mode */
material = pfNewMtl(arena);
pfMtlColor(material, PFMTL_AMBIENT, 0.1, 0.1, 0.1);
pfMtlColor(material, PFMTL_SPECULAR, 0.8, 0.8, 0.8);
pfMtlColorMode(material, PFMTL_FRONT, LMC_AD);
/* specify material but inherit all other geostate attributes */
geostate = pfNewGState(arena);
pfGStateAttr(geostate, PFSTATE_FRONTMTL, material);
/* create geoset at attach geostate to it */
geoset = pfNewGSet(arena);
pfGSetPrimType(geoset, PFGS_LINES);
pfGSetGState(geoset, geostate);
/* build and attach vertex array */
vp = v = (pfVec3 *)pfMalloc((2*nx + 2*ny)*sizeof(pfVec3), arena);
for (x = 0; x < nx; x++)
{
pfSetVec3(vp++, x0 + x*dx/(nx-1), y0, z0);
pfSetVec3(vp++, x0 + x*dx/(nx-1), y1, z0);
}
for (y = 0; y < ny; y++)
{
pfSetVec3(vp++, x0, y0 + y*dy/(ny-1), z0);
pfSetVec3(vp++, x1, y0 + y*dy/(ny-1), z0);
}
pfGSetAttr(geoset, PFGS_COORD3, PFGS_PER_VERTEX, v, NULL);
pfGSetNumPrims(geoset, nx + ny);
/* build and attach color array */
c = (pfVec4 *)pfMalloc(sizeof(pfVec4), arena);
pfSetVec4(c, 1.0f, 0.0f, 0.0f, 1.0f);
pfGSetAttr(geoset, PFGS_COLOR4, PFGS_OVERALL, c, NULL);
/* create geode and attach geoset to it */
geode = pfNewGeode();
pfAddGSet(geode, geoset);
/* return address of geode to caller */
return (pfNode *)geode;
}
--Be seeing you, Phone:415.390.1455 Fax:415.390.2658 M/S:9U-590 Michael T. Jones Silicon Graphics, Advanced Graphics Division mtj++at++sgi.com 2011 N. Shoreline Blvd., Mtn. View, CA 94039-7311
This archive was generated by hypermail 2.0b2 on Mon Aug 10 1998 - 17:50:19 PDT