static gboolean
intersect_box (GimpVector3 scale,
GimpVector3 viewp,
GimpVector3 dir,
FaceIntersectInfo *face_intersect)
{
GimpVector3 v, d, tmp, axis[3];
FaceIntersectInfo face_tmp;
gboolean result = FALSE;
gfloat m[16];
gint i = 0;
gimp_vector3_set (&axis[0], 1.0, 0.0, 0.0);
gimp_vector3_set (&axis[1], 0.0, 1.0, 0.0);
gimp_vector3_set (&axis[2], 0.0, 0.0, 1.0);
/* Front side */
/* ========== */
if (intersect_rect (scale.x, scale.y, scale.z / 2.0,
viewp, dir, &face_intersect[i]) == TRUE)
{
face_intersect[i].face = 0;
gimp_vector3_set (&face_intersect[i++].n, 0.0, 0.0, 1.0);
result = TRUE;
}
/* Back side */
/* ========= */
if (intersect_rect (scale.x, scale.y, -scale.z / 2.0,
viewp, dir, &face_intersect[i]) == TRUE)
{
face_intersect[i].face = 1;
face_intersect[i].u = 1.0 - face_intersect[i].u;
gimp_vector3_set (&face_intersect[i++].n, 0.0, 0.0, -1.0);
result = TRUE;
}
/* Check if we've found the two possible intersection points */
/* ========================================================= */
if (i < 2)
{
/* Top: Rotate viewpoint and direction into rectangle's local coordinate system */
/* ============================================================================ */
rotatemat (90, &axis[0], m);
vecmulmat (&v, &viewp, m);
vecmulmat (&d, &dir, m);
if (intersect_rect (scale.x, scale.z, scale.y / 2.0,
v, d, &face_intersect[i]) == TRUE)
{
face_intersect[i].face = 2;
transpose_mat (m);
vecmulmat(&tmp, &face_intersect[i].s, m);
face_intersect[i].s = tmp;
gimp_vector3_set (&face_intersect[i++].n, 0.0, -1.0, 0.0);
result = TRUE;
}
}
/* Check if we've found the two possible intersection points */
/* ========================================================= */
if (i < 2)
{
/* Bottom: Rotate viewpoint and direction into rectangle's local coordinate system */
/* =============================================================================== */
rotatemat (90, &axis[0], m);
vecmulmat (&v, &viewp, m);
vecmulmat (&d, &dir, m);
if (intersect_rect (scale.x, scale.z, -scale.y / 2.0,
v, d, &face_intersect[i]) == TRUE)
{
face_intersect[i].face = 3;
transpose_mat (m);
vecmulmat (&tmp, &face_intersect[i].s, m);
face_intersect[i].s = tmp;
face_intersect[i].v = 1.0 - face_intersect[i].v;
gimp_vector3_set (&face_intersect[i++].n, 0.0, 1.0, 0.0);
result = TRUE;
}
}
/* Check if we've found the two possible intersection points */
/* ========================================================= */
if (i < 2)
{
/* Left side: Rotate viewpoint and direction into rectangle's local coordinate system */
/* ================================================================================== */
rotatemat (90, &axis[1], m);
vecmulmat (&v, &viewp, m);
vecmulmat (&d, &dir, m);
if (intersect_rect (scale.z, scale.y, scale.x / 2.0,
v, d, &face_intersect[i]) == TRUE)
{
face_intersect[i].face = 4;
transpose_mat (m);
vecmulmat (&tmp, &face_intersect[i].s, m);
face_intersect[i].s = tmp;
gimp_vector3_set (&face_intersect[i++].n, 1.0, 0.0, 0.0);
result = TRUE;
}
}
/* Check if we've found the two possible intersection points */
/* ========================================================= */
if (i < 2)
{
/* Right side: Rotate viewpoint and direction into rectangle's local coordinate system */
/* =================================================================================== */
rotatemat (90, &axis[1], m);
vecmulmat (&v, &viewp, m);
vecmulmat (&d, &dir, m);
if (intersect_rect (scale.z, scale.y, -scale.x / 2.0,
v, d, &face_intersect[i]) == TRUE)
{
face_intersect[i].face = 5;
transpose_mat (m);
vecmulmat (&tmp, &face_intersect[i].s, m);
face_intersect[i].u = 1.0 - face_intersect[i].u;
gimp_vector3_set (&face_intersect[i++].n, -1.0, 0.0, 0.0);
result = TRUE;
}
}
/* Sort intersection points */
/* ======================== */
if (face_intersect[0].t > face_intersect[1].t)
{
face_tmp = face_intersect[0];
face_intersect[0] = face_intersect[1];
face_intersect[1] = face_tmp;
}
return result;
}
static void
draw_wireframe_cylinder (gint startx,
gint starty,
gint pw,
gint ph)
{
GimpVector3 p[2*8], a, axis, scale;
gint n = 0, i;
gdouble cx1, cy1, cx2, cy2;
gfloat m[16], l, angle;
/* Compute wireframe points */
/* ======================== */
init_compute ();
scale = mapvals.scale;
gimp_vector3_mul (&scale, 0.5);
l = mapvals.cylinder_length / 2.0;
angle = 0;
gimp_vector3_set (&axis, 0.0, 1.0, 0.0);
for (i = 0; i < 8; i++)
{
rotatemat (angle, &axis, m);
gimp_vector3_set (&a, mapvals.cylinder_radius, 0.0, 0.0);
vecmulmat (&p[i], &a, m);
p[i+8] = p[i];
p[i].y += l;
p[i+8].y -= l;
angle += 360.0 / 8.0;
}
/* Rotate and translate points */
/* =========================== */
for (i = 0; i < 16; i++)
{
vecmulmat (&a, &p[i], rotmat);
gimp_vector3_add (&p[i], &a, &mapvals.position);
}
/* Draw the box */
/* ============ */
cx1 = (gdouble) startx;
cy1 = (gdouble) starty;
cx2 = cx1 + (gdouble) pw;
cy2 = cy1 + (gdouble) ph;
for (i = 0; i < 7; i++)
{
n = draw_line (n, startx,starty,pw,ph, cx1,cy1,cx2,cy2, p[i],p[i+1]);
n = draw_line (n, startx,starty,pw,ph, cx1,cy1,cx2,cy2, p[i+8],p[i+9]);
n = draw_line (n, startx,starty,pw,ph, cx1,cy1,cx2,cy2, p[i],p[i+8]);
}
n = draw_line (n, startx,starty,pw,ph, cx1,cy1,cx2,cy2, p[7],p[0]);
n = draw_line (n, startx,starty,pw,ph, cx1,cy1,cx2,cy2, p[15],p[8]);
/* Mark end of lines */
/* ================= */
linetab[n].x1 = -1;
}
