-/* Returns zero if a unisolid tile is non-solid due to the movement direction,
- * non-zero if the tile is solid due to direction. */
-int check_movement_unisolid (const Vector& movement, const Tile* tile)
-{
- int slope_info;
- double mv_x;
- double mv_y;
- double mv_tan;
- double slope_tan;
-
-#define MV_NON_SOLID 0
-#define MV_SOLID 1
-
- /* If the tile is not a slope, this is very easy. */
- if ((tile->getAttributes() & Tile::SLOPE) == 0)
- {
- if (movement.y >= 0) /* moving down */
- return MV_SOLID;
- else /* moving up */
- return MV_NON_SOLID;
- }
-
- /* Initialize mv_x and mv_y. Depending on the slope the axis are inverted so
- * that we can always use the "SOUTHEAST" case of the slope. The southeast
- * case is the following:
- * .
- * /!
- * / !
- * +--+
- */
- mv_x = (double) movement.x;
- mv_y = (double) movement.y;
-
- slope_info = tile->getData();
- switch (slope_info & AATriangle::DIRECTION_MASK)
- {
- case AATriangle::SOUTHEAST: /* . */
- /* do nothing */ /* /! */
- break; /* / ! */
- /* +--+ */
- case AATriangle::SOUTHWEST: /* . */
- mv_x *= (-1.0); /* !\ */
- break; /* ! \ */
- /* +--+ */
- case AATriangle::NORTHEAST: /* +--+ */
- mv_y *= (-1.0); /* \ ! */
- break; /* \! */
- /* ' */
- case AATriangle::NORTHWEST: /* +--+ */
- mv_x *= (-1.0); /* ! / */
- mv_y *= (-1.0); /* !/ */
- break; /* ' */
- } /* switch (slope_info & DIRECTION_MASK) */
-
- /* Handle the easy cases first */
- /* If we're moving to the right and down, then the slope is solid. */
- if ((mv_x >= 0.0) && (mv_y >= 0.0)) /* 4th quadrant */
- return MV_SOLID;
- /* If we're moving to the left and up, then the slope is not solid. */
- else if ((mv_x <= 0.0) && (mv_y <= 0.0)) /* 2nd quadrant */
- return MV_NON_SOLID;
-
- /* The pure up-down and left-right movements have already been handled. */
- assert (mv_x != 0.0);
- assert (mv_y != 0.0);
-
- /* calculate tangent of movement */
- mv_tan = (-1.0) * mv_y / mv_x;
-
- /* determine tangent of the slope */
- slope_tan = 1.0;
- if (((slope_info & AATriangle::DEFORM_MASK) == DEFORM_BOTTOM)
- || ((slope_info & AATriangle::DEFORM_MASK) == DEFORM_TOP))
- slope_tan = 0.5; /* ~= 26.6 deg */
- else if (((slope_info & AATriangle::DEFORM_MASK) == DEFORM_LEFT)
- || ((slope_info & AATriangle::DEFORM_MASK) == DEFORM_RIGHT))
- slope_tan = 2.0; /* ~= 63.4 deg */
-
- /* up and right */
- if (mv_x > 0.0) /* 1st quadrant */
- {
- assert (mv_y < 0.0);
- if (mv_tan <= slope_tan)
- return MV_SOLID;
- else
- return MV_NON_SOLID;
- }
- /* down and left */
- else if (mv_x < 0.0) /* 3rd quadrant */
- {
- assert (mv_y > 0.0);
- if (mv_tan >= slope_tan)
- return MV_SOLID;
- else
- return MV_NON_SOLID;
- }
-
- assert (1 != 1);
- return (-1);
-
-#undef MV_NON_SOLID
-#undef MV_SOLID
-} /* int check_movement_unisolid */
-
-int is_above_line (float l_x, float l_y, float m,
- float p_x, float p_y)
-{
- float interp_y = (l_y + (m * (p_x - l_x)));
- if (interp_y == p_y)
- return (1);
- else if (interp_y > p_y)
- return (1);
- else
- return (0);
-}
-
-int is_below_line (float l_x, float l_y, float m,
- float p_x, float p_y)
-{
- if (is_above_line (l_x, l_y, m, p_x, p_y))
- return (0);
- else
- return (1);
-}
-
-int check_position_unisolid (const Rectf& obj_bbox,
- const Rectf& tile_bbox,
- const Tile* tile)
-{
- int slope_info;
- float tile_x;
- float tile_y;
- float gradient;
- float delta_x;
- float delta_y;
- float obj_x;
- float obj_y;
-
-#define POS_NON_SOLID 0
-#define POS_SOLID 1
-
- /* If this is not a slope, this is - again - easy */
- if ((tile->getAttributes() & Tile::SLOPE) == 0)
- {
- if ((obj_bbox.get_bottom () - SHIFT_DELTA) <= tile_bbox.get_top ())
- return POS_SOLID;
- else
- return POS_NON_SOLID;
- }
-
- /* There are 20 different cases. For each case, calculate a line that
- * describes the slope's surface. The line is defined by x, y, and m, the
- * gradient. */
- slope_info = tile->getData();
- switch (slope_info
- & (AATriangle::DIRECTION_MASK | AATriangle::DEFORM_MASK))
- {
- case AATriangle::SOUTHWEST:
- case AATriangle::SOUTHWEST | DEFORM_TOP:
- case AATriangle::SOUTHWEST | DEFORM_LEFT:
- case AATriangle::NORTHEAST:
- case AATriangle::NORTHEAST | DEFORM_TOP:
- case AATriangle::NORTHEAST | DEFORM_LEFT:
- tile_x = tile_bbox.get_left ();
- tile_y = tile_bbox.get_top ();
- gradient = 1.0;
- break;
-
- case AATriangle::SOUTHEAST:
- case AATriangle::SOUTHEAST | DEFORM_TOP:
- case AATriangle::SOUTHEAST | DEFORM_RIGHT:
- case AATriangle::NORTHWEST:
- case AATriangle::NORTHWEST | DEFORM_TOP:
- case AATriangle::NORTHWEST | DEFORM_RIGHT:
- tile_x = tile_bbox.get_right ();
- tile_y = tile_bbox.get_top ();
- gradient = -1.0;
- break;
-
- case AATriangle::SOUTHEAST | DEFORM_BOTTOM:
- case AATriangle::SOUTHEAST | DEFORM_LEFT:
- case AATriangle::NORTHWEST | DEFORM_BOTTOM:
- case AATriangle::NORTHWEST | DEFORM_LEFT:
- tile_x = tile_bbox.get_left ();
- tile_y = tile_bbox.get_bottom ();
- gradient = -1.0;
- break;
-
- case AATriangle::SOUTHWEST | DEFORM_BOTTOM:
- case AATriangle::SOUTHWEST | DEFORM_RIGHT:
- case AATriangle::NORTHEAST | DEFORM_BOTTOM:
- case AATriangle::NORTHEAST | DEFORM_RIGHT:
- tile_x = tile_bbox.get_right ();
- tile_y = tile_bbox.get_bottom ();
- gradient = 1.0;
- break;
-
- default:
- assert (23 == 42);
- }
-
- /* delta_x, delta_y: Gradient aware version of SHIFT_DELTA. Here, we set the
- * sign of the values only. Also, we determine here which corner of the
- * object's bounding box is the interesting one for us. */
- delta_x = 1.0 * SHIFT_DELTA;
- delta_y = 1.0 * SHIFT_DELTA;
- switch (slope_info & AATriangle::DIRECTION_MASK)
- {
- case AATriangle::SOUTHWEST:
- delta_x *= 1.0;
- delta_y *= -1.0;
- obj_x = obj_bbox.get_left ();
- obj_y = obj_bbox.get_bottom ();
- break;
-
- case AATriangle::SOUTHEAST:
- delta_x *= -1.0;
- delta_y *= -1.0;
- obj_x = obj_bbox.get_right ();
- obj_y = obj_bbox.get_bottom ();
- break;
-
- case AATriangle::NORTHWEST:
- delta_x *= 1.0;
- delta_y *= 1.0;
- obj_x = obj_bbox.get_left ();
- obj_y = obj_bbox.get_top ();
- break;
-
- case AATriangle::NORTHEAST:
- delta_x *= -1.0;
- delta_y *= 1.0;
- obj_x = obj_bbox.get_right ();
- obj_y = obj_bbox.get_top ();
- break;
- }
-
- /* Adapt the delta_x, delta_y and the gradient for the 26.6 deg and 63.4 deg
- * cases. */
- switch (slope_info & AATriangle::DEFORM_MASK)
- {
- case 0:
- delta_x *= .70710678118654752440; /* 1/sqrt(2) */
- delta_y *= .70710678118654752440; /* 1/sqrt(2) */
- break;
-
- case DEFORM_BOTTOM:
- case DEFORM_TOP:
- delta_x *= .44721359549995793928; /* 1/sqrt(5) */
- delta_y *= .89442719099991587856; /* 2/sqrt(5) */
- gradient *= 0.5;
- break;
-
- case DEFORM_LEFT:
- case DEFORM_RIGHT:
- delta_x *= .89442719099991587856; /* 2/sqrt(5) */
- delta_y *= .44721359549995793928; /* 1/sqrt(5) */
- gradient *= 2.0;
- break;
- }
-
- /* With a south slope, check if all points are above the line. If one point
- * isn't, the slope is not solid. => You can pass through a south-slope from
- * below but not from above. */
- if (((slope_info & AATriangle::DIRECTION_MASK) == AATriangle::SOUTHWEST)
- || ((slope_info & AATriangle::DIRECTION_MASK) == AATriangle::SOUTHEAST))
- {
- if (is_below_line (tile_x, tile_y, gradient, obj_x + delta_x, obj_y + delta_y))
- return (POS_NON_SOLID);
- else
- return (POS_SOLID);
- }
- /* northwest or northeast. Same as above, but inverted. You can pass from top
- * to bottom but not vice versa. */
- else
- {
- if (is_above_line (tile_x, tile_y, gradient, obj_x + delta_x, obj_y + delta_y))
- return (POS_NON_SOLID);
- else
- return (POS_SOLID);
- }
-
-#undef POS_NON_SOLID
-#undef POS_SOLID
-} /* int check_position_unisolid */
-