Unigine.LandscapeFetch Class
This class is used to fetch data of the Landscape Terrain Object at a certain point (e.g. a height request) or check for an intersection with a traced line. The following performance optimizations are available:
- For each request you can engage or disengage certain data types (albedo, heights, masks, etc.). When the data type is engaged, you can obtain information via the corresponding get() method. Disengaging unnecessary data when performing requests saves some performance (e.g., you can engage albedo data only if you need only color information at a certain point).
- Both fetch and intersection requests can be performed asynchronously when an instant result is not required.
The workflow is as follows:
- Create a new LandscapeFetch object instance.
- Set necessary parameters (e.g. which data layers are to be used, whether to enable holes or not, etc.).
- To get terrain data for a certain point call the fetchForce() method providing coordinates for the desired point.NoticeYou can also fetch terrain data asynchronously via the fetchAsync() method.
- To find an intersection of a traced line with the terrain call either the intersectionForce() method or the intersectionAsync() method, if you want to perform an asynchronous request.
Usage Example#
Source code (C++)
// creating a fetch object and setting necessary parameters
LandscapeFetchPtr landscape_fetch = LandscapeFetch::create();
landscape_fetch->setUses(0);
landscape_fetch->setUsesHeight(true);
landscape_fetch->setHolesEnabled(true);
// ...
// getting terrain data for a point at (100, 100) and printing the height value
landscape_fetch->setFetchPosition(Vec2(100, 100));
if (landscape_fetch->fetchForce())
Log::message("Terrain height at the specified point is: %f", Scalar(landscape_fetch->getHeight()));Asynchronous Operations Example#
Source code (C++)
// creating a fetch object and setting necessary parameters
LandscapeFetchPtr landscape_fetch = LandscapeFetch::create();
landscape_fetch->setUses(0);
landscape_fetch->setUsesHeight(true);
landscape_fetch->setHolesEnabled(true);
// ...
// making an asynchronous fetch request for a point at (2.05, 2.05)
landscape_fetch->setFetchPosition(Vec2(2.05f, 2.05f));
landscape_fetch->fetchAsync();
// ...
// checking if our asynchronous fetch request is completed and printing the height value
if (landscape_fetch->isAsyncCompleted()) {
Log::message("Terrain height at the specified point is: %f", Scalar(landscape_fetch->getHeight()));
}LandscapeFetch Class
Properties
vec3 Position#
The coordinates of the fetch/intersection point.
float Height#
The height value at the point.
vec3 Normal#
The normal vector coordinates at the point.
Notice
To get valid normal information via this method, engage normal data for the fetch/intersection request.
vec4 Albedo#
The albedo color information at the point.
Notice
To get valid albedo color information via this method, engage albedo data for the fetch/intersection request.
bool IsIntersection#
The value indicating if an intersection was detected.
int Uses#
The flags engaging/disengaging certain data types for the fetch/intersection request.
bool UsesHeight#
The value indicating if heights data is engaged in the fetch/intersection request. When the data type is engaged, you can obtain it via the corresponding get() method. Disengaging unnecessary data when performing requests saves some performance (e.g., you can engage albedo data only if you need only color information at a certain point). This option is enabled by default.
bool UsesNormal#
The value indicating if normals data is engaged in the fetch/intersection request. When the data type is engaged, you can obtain it via the corresponding get() method. Disengaging unnecessary data when performing requests saves some performance (e.g., you can engage albedo data only if you need only color information at a certain point).
Notice
Enable this option to get normal information for the point.
bool UsesAlbedo#
The value indicating if albedo data is engaged in the fetch/intersection request. When the data type is engaged, you can obtain it via the corresponding get() method. Disengaging unnecessary data when performing requests saves some performance (e.g., you can engage albedo data only if you need only color information at a certain point).
Notice
Enable this option to get albedo information for the point.
float IntersectionPrecision#
The precision value used for intersection detection requested by intersectionForce() and intersectionAsync() methods.
vec3 IntersectionPositionBegin#
The coordinates of the starting point for intersection detection.
vec3 IntersectionPositionEnd#
The coordinates of the end point for intersection detection.
vec2 FetchPosition#
The point for which terrain data is to be fetched.
bool IsAsyncCompleted#
The value indicating if async operation is completed. As the operation is completed you can obtain necessary data via get*() methods.
bool HolesEnabled#
The value indicating if checking for terrain holes in the fetch/intersection request is enabled. This option is enabled by default. When disabled terrain holes created using decals are ignored.
Event EventEnd#
The Event triggered on fetch completion. You can subscribe to events via
Connect()
and unsubscribe via
Disconnect(). You can also use
EventConnection
and
EventConnections
classes for convenience (see examples below).
Notice
The event handler signature is as follows: myhandler(For more details see the Event Handling article.
Usage Example
Source code (C#)
// implement the End event handler
void end_event_handler()
{
Log.Message("\Handling End event\n");
}
//////////////////////////////////////////////////////////////////////////////
// 1. Multiple subscriptions can be linked to an EventConnections instance
// class that you can use later to remove all these subscriptions at once
//////////////////////////////////////////////////////////////////////////////
// create an instance of the EventConnections class
EventConnections end_event_connections = new EventConnections();
// link to this instance when subscribing to an event (subscription to various events can be linked)
publisher.EventEnd.Connect(end_event_connections, end_event_handler);
// other subscriptions are also linked to this EventConnections instance
// (e.g. you can subscribe using lambdas)
publisher.EventEnd.Connect(end_event_connections, () => {
Log.Message("Handling End event lambda\n");
}
);
// later all of these linked subscriptions can be removed with a single line
end_event_connections.DisconnectAll();
//////////////////////////////////////////////////////////////////////////////
// 2. You can subscribe and unsubscribe via the handler function directly
//////////////////////////////////////////////////////////////////////////////
// subscribe to the End event with a handler function
publisher.EventEnd.Connect(end_event_handler);
// remove subscription to the End event later by the handler function
publisher.EventEnd.Disconnect(end_event_handler);
//////////////////////////////////////////////////////////////////////////////
// 3. Subscribe to an event and unsubscribe later via an EventConnection instance
//////////////////////////////////////////////////////////////////////////////
// define a connection to be used to unsubscribe later
EventConnection end_event_connection;
// subscribe to the End event with a lambda handler function and keeping the connection
end_event_connection = publisher.EventEnd.Connect(() => {
Log.Message("Handling End event lambda\n");
}
);
// ...
// you can temporarily disable a particular event connection
end_event_connection.Enabled = false;
// ... perform certain actions
// and enable it back when necessary
end_event_connection.Enabled = true;
// ...
// remove the subscription later using the saved connection
end_event_connection.Disconnect();
//////////////////////////////////////////////////////////////////////////////
// 4. Ignoring End events when necessary
//////////////////////////////////////////////////////////////////////////////
// you can temporarily disable the event to perform certain actions without triggering it
publisher.EventEnd.Enabled = false;
// ... actions to be performed
// and enable it back when necessary
publisher.EventEnd.Enabled = true;Event EventStart#
The Event triggered at the beginning of the fetch process. You can subscribe to events via
Connect()
and unsubscribe via
Disconnect(). You can also use
EventConnection
and
EventConnections
classes for convenience (see examples below).
Notice
The event handler signature is as follows: myhandler(For more details see the Event Handling article.
Usage Example
Source code (C#)
// implement the Start event handler
void start_event_handler()
{
Log.Message("\Handling Start event\n");
}
//////////////////////////////////////////////////////////////////////////////
// 1. Multiple subscriptions can be linked to an EventConnections instance
// class that you can use later to remove all these subscriptions at once
//////////////////////////////////////////////////////////////////////////////
// create an instance of the EventConnections class
EventConnections start_event_connections = new EventConnections();
// link to this instance when subscribing to an event (subscription to various events can be linked)
publisher.EventStart.Connect(start_event_connections, start_event_handler);
// other subscriptions are also linked to this EventConnections instance
// (e.g. you can subscribe using lambdas)
publisher.EventStart.Connect(start_event_connections, () => {
Log.Message("Handling Start event lambda\n");
}
);
// later all of these linked subscriptions can be removed with a single line
start_event_connections.DisconnectAll();
//////////////////////////////////////////////////////////////////////////////
// 2. You can subscribe and unsubscribe via the handler function directly
//////////////////////////////////////////////////////////////////////////////
// subscribe to the Start event with a handler function
publisher.EventStart.Connect(start_event_handler);
// remove subscription to the Start event later by the handler function
publisher.EventStart.Disconnect(start_event_handler);
//////////////////////////////////////////////////////////////////////////////
// 3. Subscribe to an event and unsubscribe later via an EventConnection instance
//////////////////////////////////////////////////////////////////////////////
// define a connection to be used to unsubscribe later
EventConnection start_event_connection;
// subscribe to the Start event with a lambda handler function and keeping the connection
start_event_connection = publisher.EventStart.Connect(() => {
Log.Message("Handling Start event lambda\n");
}
);
// ...
// you can temporarily disable a particular event connection
start_event_connection.Enabled = false;
// ... perform certain actions
// and enable it back when necessary
start_event_connection.Enabled = true;
// ...
// remove the subscription later using the saved connection
start_event_connection.Disconnect();
//////////////////////////////////////////////////////////////////////////////
// 4. Ignoring Start events when necessary
//////////////////////////////////////////////////////////////////////////////
// you can temporarily disable the event to perform certain actions without triggering it
publisher.EventStart.Enabled = false;
// ... actions to be performed
// and enable it back when necessary
publisher.EventStart.Enabled = true;Members
LandscapeFetch ( ) #
The LandscapeFetch constructor.float GetMask ( int num ) #
Returns information stored for the point in the detail mask with the specified number.Notice
To get valid detail mask information via this method, engage mask data for the fetch/intersection request.
Arguments
- int num - Number of the detail mask in the [0; 19] range.
Return value
Value for the point stored in the detail mask with the specified number.void SetUsesMask ( int num, bool value ) #
Sets a value indicating if data of the specified detail mask is engaged in the fetch/intersection request. When the data type is engaged, you can obtain it via the corresponding get() method. Disengaging unnecessary data when performing requests saves some performance (e.g., you can engage albedo data only if you need only color information at a certain point).Notice
Enable this option to get detail mask data for the point.
Arguments
- int num - Detail mask number in the [0; 19] range.
- bool value - true to engage data of the specified detail mask in the fetch/intersection request, false - to disengage.
bool IsUsesMask ( int num ) #
Returns a value indicating if data of the specified detail mask is engaged in the fetch/intersection request. When the data type is engaged, you can obtain it via the corresponding get() method. Disengaging unnecessary data when performing requests saves some performance (e.g., you can engage albedo data only if you need only color information at a certain point).Notice
Enable this option to get detail mask data for the point.
Arguments
- int num - Detail mask number in the [0; 19] range.
Return value
true if data of the specified detail mask is engaged in the fetch/intersection request; otherwise, false.bool FetchForce ( ) #
Fetches terrain data in forced mode for the point specified by the setFetchPosition(). You can use the fetchAsync() method to reduce load, when an instant result is not required.Return value
true if terrain data was successfully obtained for the specified point; otherwise, false.bool FetchForce ( vec2 position ) #
Fetches terrain data in forced mode for the specified point. You can use the fetchAsync() method to reduce load, when an instant result is not required.Arguments
- vec2 position - Coordinates of the point.
Return value
true if terrain data was successfully obtained for the specified point; otherwise, false.bool IntersectionForce ( ) #
Performs tracing along the line from the p0 point specified by the setIntersectionPositionBegin() to the p1 point specified by the setIntersectionPositionEnd() to find an intersection with the terrain in forced mode. You can use the intersectionAsync() method to reduce load, when an instant result is not required.Return value
true if an intersection with the terrain was found; otherwise, false.bool IntersectionForce ( vec3 p0, vec3 p1 ) #
Performs tracing along the line from the p0 point to the p1 point to find an intersection with the terrain in forced mode. You can use the intersectionAsync() method to reduce load, when an instant result is not required.Arguments
Return value
true if an intersection with the terrain was found; otherwise, false.void FetchAsync ( bool critical = false ) #
Fetches terrain data for the point specified by the setFetchPosition() in asynchronous mode (the corresponding task shall be put to the queue, to wait until the result is obtained use the wait() method). For an instant result use the fetchForce() method.Arguments
- bool critical - true to set high priority for the fetch task, false - to set normal priority.
void FetchAsync ( vec2 position, bool critical = false ) #
Fetches terrain data for the specified point in asynchronous mode (the corresponding task shall be put to the queue, to wait until the result is obtained use the wait() method). For an instant result use the fetchForce() method.Arguments
- vec2 position - Coordinates of the point.
- bool critical - true to set high priority for the fetch task, false - to set normal priority.
void IntersectionAsync ( bool critical = false ) #
Performs tracing along the line from the p0 point specified by the setIntersectionPositionBegin() to the p1 point specified by the setIntersectionPositionEnd() to find an intersection with the terrain in asynchronous mode (the corresponding task shall be put to the queue, to wait until the result is obtained use the wait() method). For an instant result use the intersectionForce() method.Arguments
- bool critical - true to set high priority for the intersection task, false - to set normal priority.
void IntersectionAsync ( vec3 p0, vec3 p1, bool critical = false ) #
Performs tracing along the line from the p0 point to the p1 point to find an intersection with the terrain in asynchronous mode (the corresponding task shall be put to the queue, to wait until the result is obtained use the wait() method). For an instant result use the intersectionForce() method.Arguments
- vec3 p0 - Coordinates of the p0 point.
- vec3 p1 - Coordinates of the p1 point.
- bool critical - true to set high priority for the intersection task, false - to set normal priority.
void FetchForce ( LandscapeFetch[] fetches ) #
Fetches (batch) terrain data in forced mode for the point specified by the setFetchPosition(). You can use the fetchAsync() method to reduce load, when an instant result is not required.Arguments
- LandscapeFetch[] fetches - List of fetch requests to be completed.
void IntersectionForce ( LandscapeFetch[] fetches ) #
Performs tracing (batch) along the line from the p0 point specified by the setIntersectionPositionBegin() to the p1 point specified by the setIntersectionPositionEnd() to find an intersection with the terrain in forced mode. You can use the intersectionAsync() method to reduce load, when an instant result is not required.Arguments
- LandscapeFetch[] fetches - List of fetch requests to be completed.
void FetchAsync ( LandscapeFetch[] fetches, bool critical = false ) #
Fetches (batch) terrain data for the point specified by the setFetchPosition() in asynchronous mode (the corresponding task shall be put to the queue, to wait until the result is obtained use the wait() method). For an instant result use the fetchForce() method.Arguments
- LandscapeFetch[] fetches - List of fetch requests to be completed.
- bool critical - true to set high priority for the fetch task, false - to set normal priority.
void IntersectionAsync ( LandscapeFetch[] fetches, bool critical = false ) #
Performs tracing (batch) along the line from the p0 point specified by the setIntersectionPositionBegin() to the p1 point specified by the setIntersectionPositionEnd() to find an intersection with the terrain in asynchronous mode (the corresponding task shall be put to the queue, to wait until the result is obtained use the wait() method). For an instant result use the intersectionForce() method.Arguments
- LandscapeFetch[] fetches - List of fetch requests to be completed.
- bool critical - true to set high priority for the intersection task, false - to set normal priority.
void Wait ( ) #
Waits for completion of the fetch operation. As the operation is completed you can obtain necessary data via get*() methods.void Wait ( LandscapeFetch[] fetches ) #
Waits for completion of the specified fetch operations. As the operations are completed you can obtain necessary data via get*() methods.Arguments
- LandscapeFetch[] fetches - List of fetch requests to be completed.
Last update:
2024-03-27
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