org.lwjgl.stb

Class STBRectPack

java.lang.Object

org.lwjgl.stb.STBRectPack

public class STBRectPack
extends java.lang.Object

Native bindings to stb_rect_pack.h from the stb library.

Useful for e.g. packing rectangular textures into an atlas. Does not do rotation.

This library currently uses the Skyline Bottom-Left algorithm. Not necessarily the awesomest packing method, but better than the totally naive one in stb_truetype (which is primarily what this is meant to replace).

Field Summary

Fields

Modifier and Type	Field and Description
static int	STBRP_HEURISTIC_Skyline_BF_sortHeight Packing heuristics
static int	STBRP_HEURISTIC_Skyline_BL_sortHeight Packing heuristics
static int	STBRP_HEURISTIC_Skyline_default Packing heuristics

Method Summary

Modifier and Type	Method and Description
static void	nstbrp_init_target(long context, int width, int height, long nodes, int num_nodes) Unsafe version of: init_target
static int	nstbrp_pack_rects(long context, long rects, int num_rects) Unsafe version of: pack_rects
static void	nstbrp_setup_allow_out_of_mem(long context, int allow_out_of_mem) Unsafe version of: setup_allow_out_of_mem
static void	nstbrp_setup_heuristic(long context, int heuristic) Unsafe version of: setup_heuristic
static void	stbrp_init_target(STBRPContext context, int width, int height, STBRPNode.Buffer nodes) Initialize a rectangle packer to: pack a rectangle that is width by height in dimensions using temporary storage provided by the array nodes, which is num_nodes long.
static int	stbrp_pack_rects(STBRPContext context, STBRPRect.Buffer rects) Assigns packed locations to rectangles.
static void	stbrp_setup_allow_out_of_mem(STBRPContext context, boolean allow_out_of_mem) Optionally call this function after init but before doing any packing to change the handling of the out-of-temp-memory scenario, described in init_target.
static void	stbrp_setup_heuristic(STBRPContext context, int heuristic) Optionally select which packing heuristic the library should use.

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

STBRP_HEURISTIC_Skyline_default

public static final int STBRP_HEURISTIC_Skyline_default

Packing heuristics

Enum values:

• HEURISTIC_Skyline_default
• HEURISTIC_Skyline_BL_sortHeight
• HEURISTIC_Skyline_BF_sortHeight

See Also:

Constant Field Values

STBRP_HEURISTIC_Skyline_BL_sortHeight

public static final int STBRP_HEURISTIC_Skyline_BL_sortHeight

Packing heuristics

Enum values:

• HEURISTIC_Skyline_default
• HEURISTIC_Skyline_BL_sortHeight
• HEURISTIC_Skyline_BF_sortHeight

See Also:

Constant Field Values

STBRP_HEURISTIC_Skyline_BF_sortHeight

public static final int STBRP_HEURISTIC_Skyline_BF_sortHeight

Packing heuristics

Enum values:

• HEURISTIC_Skyline_default
• HEURISTIC_Skyline_BL_sortHeight
• HEURISTIC_Skyline_BF_sortHeight

See Also:

Constant Field Values

Method Detail

nstbrp_pack_rects

public static int nstbrp_pack_rects(long context,
                                    long rects,
                                    int num_rects)

Unsafe version of: pack_rects

Parameters:

num_rects - the number of structs in rects

stbrp_pack_rects

public static int stbrp_pack_rects(STBRPContext context,
                                   STBRPRect.Buffer rects)

Assigns packed locations to rectangles. The rectangles are of type STBRPRect, stored in the array rects, and there are num_rects many of them.

Rectangles which are successfully packed have the was_packed flag set to a non-zero value and x and y store the minimum location on each axis (i.e. bottom-left in cartesian coordinates, top-left if you imagine y increasing downwards). Rectangles which do not fit have the was_packed flag set to 0.

You should not try to access the rects array from another thread while this function is running, as the function temporarily reorders the array while it executes.

To pack into another rectangle, you need to call init_target again. To continue packing into the same rectangle, you can call this function again. Calling this multiple times with multiple rect arrays will probably produce worse packing results than calling it a single time with the full rectangle array, but the option is available.

Parameters:

context - an STBRPContext struct

rects - an array of STBRPRect structs

Returns:

1 if all of the rectangles were successfully packed and 0 otherwise

nstbrp_init_target

public static void nstbrp_init_target(long context,
                                      int width,
                                      int height,
                                      long nodes,
                                      int num_nodes)

Unsafe version of: init_target

Parameters:

num_nodes - the number of structs in nodes

stbrp_init_target

public static void stbrp_init_target(STBRPContext context,
                                     int width,
                                     int height,
                                     STBRPNode.Buffer nodes)

Initialize a rectangle packer to: pack a rectangle that is width by height in dimensions using temporary storage provided by the array nodes, which is num_nodes long.

You must call this function every time you start packing into a new target.

There is no "shutdown" function. The nodes memory must stay valid for the following pack_rects call (or calls), but can be freed after the call (or calls) finish.

Note: to guarantee best results, either:

1. make sure num_nodes ≥ width
2. or, call setup_allow_out_of_mem with allow_out_of_mem = 1

If you don't do either of the above things, widths will be quantized to multiples of small integers to guarantee the algorithm doesn't run out of temporary storage.

If you do #2, then the non-quantized algorithm will be used, but the algorithm may run out of temporary storage and be unable to pack some rectangles.

Parameters:

context - an STBRPContext struct

width - the rectangle width

height - the rectangle height

nodes - an array of STBRPNode structs

nstbrp_setup_allow_out_of_mem

public static void nstbrp_setup_allow_out_of_mem(long context,
                                                 int allow_out_of_mem)

Unsafe version of: setup_allow_out_of_mem

stbrp_setup_allow_out_of_mem

public static void stbrp_setup_allow_out_of_mem(STBRPContext context,
                                                boolean allow_out_of_mem)

Optionally call this function after init but before doing any packing to change the handling of the out-of-temp-memory scenario, described in init_target. If you call init again, this will be reset to the default (false).

Parameters:

context - an STBRPContext struct

allow_out_of_mem - 1 to allow running out of temporary storage

nstbrp_setup_heuristic

public static void nstbrp_setup_heuristic(long context,
                                          int heuristic)

Unsafe version of: setup_heuristic

stbrp_setup_heuristic

public static void stbrp_setup_heuristic(STBRPContext context,
                                         int heuristic)

Optionally select which packing heuristic the library should use. Different heuristics will produce better/worse results for different data sets. If you call init again, this will be reset to the default.

Parameters:

context - an STBRPContext struct

heuristic - the packing heuristic