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; }