From 3475759d1adbd4a64c6250fd87981f783e64f69c Mon Sep 17 00:00:00 2001
From: sfan5 <sfan5@live.de>
Date: Tue, 14 Apr 2020 14:11:33 +0200
Subject: Expose collision information to LuaEntity on_step

---
 src/script/common/c_content.cpp | 54 +++++++++++++++++++++++++++++++++++++++++
 src/script/common/c_content.h   |  4 ++-
 src/script/cpp_api/s_entity.cpp | 12 ++++++---
 src/script/cpp_api/s_entity.h   |  4 ++-
 4 files changed, 68 insertions(+), 6 deletions(-)

(limited to 'src/script')

diff --git a/src/script/common/c_content.cpp b/src/script/common/c_content.cpp
index 8335fccb5..6ff642738 100644
--- a/src/script/common/c_content.cpp
+++ b/src/script/common/c_content.cpp
@@ -21,6 +21,7 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 #include "common/c_types.h"
 #include "nodedef.h"
 #include "object_properties.h"
+#include "collision.h"
 #include "cpp_api/s_node.h"
 #include "lua_api/l_object.h"
 #include "lua_api/l_item.h"
@@ -2002,3 +2003,56 @@ HudElementStat read_hud_change(lua_State *L, HudElement *elem, void **value)
 	}
 	return stat;
 }
+
+/******************************************************************************/
+
+// Indices must match values in `enum CollisionType` exactly!!
+static const char *collision_type_str[] = {
+	"node",
+	"object",
+};
+
+// Indices must match values in `enum CollisionAxis` exactly!!
+static const char *collision_axis_str[] = {
+	"x",
+	"y",
+	"z",
+};
+
+void push_collision_move_result(lua_State *L, const collisionMoveResult &res)
+{
+	lua_createtable(L, 0, 4);
+
+	setboolfield(L, -1, "touching_ground", res.touching_ground);
+	setboolfield(L, -1, "collides", res.collides);
+	setboolfield(L, -1, "standing_on_object", res.standing_on_object);
+
+	/* collisions */
+	lua_createtable(L, res.collisions.size(), 0);
+	int i = 1;
+	for (const auto &c : res.collisions) {
+		lua_createtable(L, 0, 5);
+
+		lua_pushstring(L, collision_type_str[c.type]);
+		lua_setfield(L, -2, "type");
+
+		assert(c.axis != COLLISION_AXIS_NONE);
+		lua_pushstring(L, collision_axis_str[c.axis]);
+		lua_setfield(L, -2, "axis");
+
+		if (c.type == COLLISION_NODE) {
+			push_v3s16(L, c.node_p);
+			lua_setfield(L, -2, "node_pos");
+		}
+
+		push_v3f(L, c.old_speed / BS);
+		lua_setfield(L, -2, "old_speed");
+
+		push_v3f(L, c.new_speed / BS);
+		lua_setfield(L, -2, "new_speed");
+
+		lua_rawseti(L, -2, i++);
+	}
+	lua_setfield(L, -2, "collisions");
+	/**/
+}
diff --git a/src/script/common/c_content.h b/src/script/common/c_content.h
index 9e755682f..8f32e58eb 100644
--- a/src/script/common/c_content.h
+++ b/src/script/common/c_content.h
@@ -63,7 +63,9 @@ struct EnumString;
 struct NoiseParams;
 class Schematic;
 class ServerActiveObject;
+struct collisionMoveResult;
 
+extern struct EnumString es_TileAnimationType[];
 
 ContentFeatures    read_content_features     (lua_State *L, int index);
 void               push_content_features     (lua_State *L,
@@ -196,4 +198,4 @@ void               push_hud_element          (lua_State *L, HudElement *elem);
 
 HudElementStat     read_hud_change           (lua_State *L, HudElement *elem, void **value);
 
-extern struct EnumString es_TileAnimationType[];
+void               push_collision_move_result(lua_State *L, const collisionMoveResult &res);
diff --git a/src/script/cpp_api/s_entity.cpp b/src/script/cpp_api/s_entity.cpp
index 26c7e8cd4..ea9320051 100644
--- a/src/script/cpp_api/s_entity.cpp
+++ b/src/script/cpp_api/s_entity.cpp
@@ -178,12 +178,11 @@ void ScriptApiEntity::luaentity_GetProperties(u16 id,
 	lua_pop(L, 1);
 }
 
-void ScriptApiEntity::luaentity_Step(u16 id, float dtime)
+void ScriptApiEntity::luaentity_Step(u16 id, float dtime,
+	const collisionMoveResult *moveresult)
 {
 	SCRIPTAPI_PRECHECKHEADER
 
-	//infostream<<"scriptapi_luaentity_step: id="<<id<<std::endl;
-
 	int error_handler = PUSH_ERROR_HANDLER(L);
 
 	// Get core.luaentities[id]
@@ -199,9 +198,14 @@ void ScriptApiEntity::luaentity_Step(u16 id, float dtime)
 	luaL_checktype(L, -1, LUA_TFUNCTION);
 	lua_pushvalue(L, object); // self
 	lua_pushnumber(L, dtime); // dtime
+	/* moveresult */
+	if (moveresult)
+		push_collision_move_result(L, *moveresult);
+	else
+		lua_pushnil(L);
 
 	setOriginFromTable(object);
-	PCALL_RES(lua_pcall(L, 2, 0, error_handler));
+	PCALL_RES(lua_pcall(L, 3, 0, error_handler));
 
 	lua_pop(L, 2); // Pop object and error handler
 }
diff --git a/src/script/cpp_api/s_entity.h b/src/script/cpp_api/s_entity.h
index cc08c46e8..b5f7a6586 100644
--- a/src/script/cpp_api/s_entity.h
+++ b/src/script/cpp_api/s_entity.h
@@ -24,6 +24,7 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 
 struct ObjectProperties;
 struct ToolCapabilities;
+struct collisionMoveResult;
 
 class ScriptApiEntity
 		: virtual public ScriptApiBase
@@ -36,7 +37,8 @@ public:
 	std::string luaentity_GetStaticdata(u16 id);
 	void luaentity_GetProperties(u16 id,
 			ServerActiveObject *self, ObjectProperties *prop);
-	void luaentity_Step(u16 id, float dtime);
+	void luaentity_Step(u16 id, float dtime,
+		const collisionMoveResult *moveresult);
 	bool luaentity_Punch(u16 id,
 			ServerActiveObject *puncher, float time_from_last_punch,
 			const ToolCapabilities *toolcap, v3f dir, s16 damage);
-- 
cgit v1.2.3