// SuperTux
// Copyright (C) 2004 Tobias Glaesser <tobi.web@gmx.de>
// Copyright (C) 2006 Matthias Braun <matze@braunis.de>
+// Copyright (C) 2010 Florian Forster <supertux at octo.it>
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
#include "supertux/tile.hpp"
+#include "supertux/constants.hpp"
#include "supertux/tile_set.hpp"
+#include "math/aatriangle.hpp"
#include "video/drawing_context.hpp"
bool Tile::draw_editor_images = false;
log_debug << " Imagespec: file " << im->file << "; rect " << im->rect << std::endl;
}
+/* 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 Tile::check_movement_unisolid (const Vector movement) const
+{
+ 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 (!this->is_slope ())
+ {
+ int dir = this->getData () & ((int) Tile::UNI_DIR_MASK);
+
+ if (((dir == Tile::UNI_DIR_NORTH) && (movement.y >= 0)) /* moving down */
+ || ((dir == Tile::UNI_DIR_SOUTH) && (movement.y < 0)) /* moving up */
+ || ((dir == Tile::UNI_DIR_WEST) && (movement.x >= 0)) /* moving right */
+ || ((dir == Tile::UNI_DIR_EAST) && (movement.x < 0))) /* moving left */
+ return MV_SOLID;
+ else
+ 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 = this->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) == AATriangle::DEFORM_BOTTOM)
+ || ((slope_info & AATriangle::DEFORM_MASK) == AATriangle::DEFORM_TOP))
+ slope_tan = 0.5; /* ~= 26.6 deg */
+ else if (((slope_info & AATriangle::DEFORM_MASK) == AATriangle::DEFORM_LEFT)
+ || ((slope_info & AATriangle::DEFORM_MASK) == AATriangle::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 Tile::check_position_unisolid (const Rectf& obj_bbox,
+ const Rectf& tile_bbox) const
+{
+ 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 (!this->is_slope ())
+ {
+ int dir = this->getData () & Tile::UNI_DIR_MASK;
+
+ if ((dir == Tile::UNI_DIR_NORTH)
+ && ((obj_bbox.get_bottom () - SHIFT_DELTA) <= tile_bbox.get_top ()))
+ return POS_SOLID;
+ else if ((dir == Tile::UNI_DIR_SOUTH)
+ && ((obj_bbox.get_top () + SHIFT_DELTA) >= tile_bbox.get_bottom ()))
+ return POS_SOLID;
+ else if ((dir == Tile::UNI_DIR_WEST)
+ && ((obj_bbox.get_right () - SHIFT_DELTA) <= tile_bbox.get_left ()))
+ return POS_SOLID;
+ else if ((dir == Tile::UNI_DIR_EAST)
+ && ((obj_bbox.get_left () + SHIFT_DELTA) >= tile_bbox.get_right ()))
+ return POS_SOLID;
+
+ 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 = this->getData();
+ switch (slope_info
+ & (AATriangle::DIRECTION_MASK | AATriangle::DEFORM_MASK))
+ {
+ case AATriangle::SOUTHWEST:
+ case AATriangle::SOUTHWEST | AATriangle::DEFORM_TOP:
+ case AATriangle::SOUTHWEST | AATriangle::DEFORM_LEFT:
+ case AATriangle::NORTHEAST:
+ case AATriangle::NORTHEAST | AATriangle::DEFORM_TOP:
+ case AATriangle::NORTHEAST | AATriangle::DEFORM_LEFT:
+ tile_x = tile_bbox.get_left ();
+ tile_y = tile_bbox.get_top ();
+ gradient = 1.0;
+ break;
+
+ case AATriangle::SOUTHEAST:
+ case AATriangle::SOUTHEAST | AATriangle::DEFORM_TOP:
+ case AATriangle::SOUTHEAST | AATriangle::DEFORM_RIGHT:
+ case AATriangle::NORTHWEST:
+ case AATriangle::NORTHWEST | AATriangle::DEFORM_TOP:
+ case AATriangle::NORTHWEST | AATriangle::DEFORM_RIGHT:
+ tile_x = tile_bbox.get_right ();
+ tile_y = tile_bbox.get_top ();
+ gradient = -1.0;
+ break;
+
+ case AATriangle::SOUTHEAST | AATriangle::DEFORM_BOTTOM:
+ case AATriangle::SOUTHEAST | AATriangle::DEFORM_LEFT:
+ case AATriangle::NORTHWEST | AATriangle::DEFORM_BOTTOM:
+ case AATriangle::NORTHWEST | AATriangle::DEFORM_LEFT:
+ tile_x = tile_bbox.get_left ();
+ tile_y = tile_bbox.get_bottom ();
+ gradient = -1.0;
+ break;
+
+ case AATriangle::SOUTHWEST | AATriangle::DEFORM_BOTTOM:
+ case AATriangle::SOUTHWEST | AATriangle::DEFORM_RIGHT:
+ case AATriangle::NORTHEAST | AATriangle::DEFORM_BOTTOM:
+ case AATriangle::NORTHEAST | AATriangle::DEFORM_RIGHT:
+ tile_x = tile_bbox.get_right ();
+ tile_y = tile_bbox.get_bottom ();
+ gradient = 1.0;
+ break;
+
+ default:
+ assert (23 == 42);
+ return POS_NON_SOLID;
+ }
+
+ /* 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 AATriangle::DEFORM_BOTTOM:
+ case AATriangle::DEFORM_TOP:
+ delta_x *= .44721359549995793928; /* 1/sqrt(5) */
+ delta_y *= .89442719099991587856; /* 2/sqrt(5) */
+ gradient *= 0.5;
+ break;
+
+ case AATriangle::DEFORM_LEFT:
+ case AATriangle::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 */
+
+bool Tile::is_solid (const Rectf& tile_bbox, const Rectf& position, const Vector& movement) const
+{
+ int status;
+
+ if ((attributes & SOLID) == 0)
+ return (false);
+
+ if ((attributes & UNISOLID) == 0)
+ return (true);
+
+ /* Check if the tile is solid given the current movement. This works
+ * for south-slopes (which are solid when moving "down") and
+ * north-slopes (which are solid when moving "up". "up" and "down" is
+ * in quotation marks because because the slope's gradient is taken.
+ * Also, this uses the movement relative to the tilemaps own movement
+ * (if any). --octo */
+ status = check_movement_unisolid (movement);
+ /* If zero is returned, the unisolid tile is non-solid. */
+ if (status == 0)
+ return (false);
+
+ /* Check whether the object is already *in* the tile. If so, the tile
+ * is non-solid. Otherwise, if the object is "above" (south slopes)
+ * or "below" (north slopes), the tile will be solid. */
+ status = check_position_unisolid (position, tile_bbox);
+ if (status == 0)
+ return (false);
+
+ return (true);
+} /* bool Tile::is_solid */
+
+/* vim: set sw=2 sts=2 et : */
/* EOF */
projects / supertux.git / blobdiff