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Line_of_sight: Improve using VoxelLineIterator

This commit rewrites line_of_sight with VoxelLineIterator.
Stepsize is no longer needed, the results will be always accurate.
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juhdanad authored and paramat committed Dec 1, 2016
1 parent ca64f56 commit 2153965cf92ab61b0d7e095cf3c2755924fdc221
Showing with 28 additions and 36 deletions.
  1. +3 −4 doc/lua_api.txt
  2. +3 −8 src/script/lua_api/l_env.cpp
  3. +1 −1 src/script/lua_api/l_env.h
  4. +12 −21 src/serverenvironment.cpp
  5. +9 −2 src/serverenvironment.h
@@ -2876,13 +2876,12 @@ and `minetest.auth_reload` call the authentication handler.
* parameter was absent)
* `minetest.delete_area(pos1, pos2)`
* delete all mapblocks in the area from pos1 to pos2, inclusive
* `minetest.line_of_sight(pos1, pos2, stepsize)`: returns `boolean, pos`
* Check if there is a direct line of sight between `pos1` and `pos2`
* `minetest.line_of_sight(pos1, pos2)`: returns `boolean, pos`
* Checks if there is anything other than air between pos1 and pos2.
* Returns false if something is blocking the sight.
* Returns the position of the blocking node when `false`
* `pos1`: First position
* `pos2`: Second position
* `stepsize`: smaller gives more accurate results but requires more computing
time. Default is `1`.
* `minetest.raycast(pos1, pos2, objects, liquids)`: returns `Raycast`
* Creates a `Raycast` object.
* `pos1`: start of the ray
@@ -966,24 +966,19 @@ int ModApiEnvMod::l_clear_objects(lua_State *L)
return 0;
}

// line_of_sight(pos1, pos2, stepsize) -> true/false, pos
// line_of_sight(pos1, pos2) -> true/false, pos
int ModApiEnvMod::l_line_of_sight(lua_State *L)
{
float stepsize = 1.0;

GET_ENV_PTR;

// read position 1 from lua
v3f pos1 = checkFloatPos(L, 1);
// read position 2 from lua
v3f pos2 = checkFloatPos(L, 2);
//read step size from lua
if (lua_isnumber(L, 3)) {
stepsize = lua_tonumber(L, 3);
}

v3s16 p;
bool success = env->line_of_sight(pos1, pos2, stepsize, &p);

bool success = env->line_of_sight(pos1, pos2, &p);
lua_pushboolean(L, success);
if (!success) {
push_v3s16(L, p);
@@ -156,7 +156,7 @@ class ModApiEnvMod : public ModApiBase {
// spawn_tree(pos, treedef)
static int l_spawn_tree(lua_State *L);

// line_of_sight(pos1, pos2, stepsize) -> true/false
// line_of_sight(pos1, pos2) -> true/false
static int l_line_of_sight(lua_State *L);

// raycast(pos1, pos2, objects, liquids) -> Raycast
@@ -489,30 +489,21 @@ bool ServerEnvironment::removePlayerFromDatabase(const std::string &name)
return m_player_database->removePlayer(name);
}

bool ServerEnvironment::line_of_sight(v3f pos1, v3f pos2, float stepsize, v3s16 *p)
bool ServerEnvironment::line_of_sight(v3f pos1, v3f pos2, v3s16 *p)
{
float distance = pos1.getDistanceFrom(pos2);

//calculate normalized direction vector
v3f normalized_vector = v3f((pos2.X - pos1.X)/distance,
(pos2.Y - pos1.Y)/distance,
(pos2.Z - pos1.Z)/distance);

//find out if there's a node on path between pos1 and pos2
for (float i = 1; i < distance; i += stepsize) {
v3s16 pos = floatToInt(v3f(normalized_vector.X * i,
normalized_vector.Y * i,
normalized_vector.Z * i) +pos1,BS);

MapNode n = getMap().getNodeNoEx(pos);

if(n.param0 != CONTENT_AIR) {
if (p) {
*p = pos;
}
// Iterate trough nodes on the line
voxalgo::VoxelLineIterator iterator(pos1 / BS, (pos2 - pos1) / BS);
do {
MapNode n = getMap().getNodeNoEx(iterator.m_current_node_pos);

// Return non-air
if (n.param0 != CONTENT_AIR) {
if (p)
*p = iterator.m_current_node_pos;
return false;
}
}
iterator.next();
} while (iterator.m_current_index <= iterator.m_last_index);
return true;
}

@@ -328,8 +328,15 @@ class ServerEnvironment : public Environment
// This makes stuff happen
void step(f32 dtime);

//check if there's a line of sight between two positions
bool line_of_sight(v3f pos1, v3f pos2, float stepsize=1.0, v3s16 *p=NULL);
/*!
* Returns false if the given line intersects with a
* non-air node, true otherwise.
* \param pos1 start of the line
* \param pos2 end of the line
* \param p output, position of the first non-air node
* the line intersects
*/
bool line_of_sight(v3f pos1, v3f pos2, v3s16 *p = NULL);

u32 getGameTime() const { return m_game_time; }

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