Spritepublic class Sprite extends Layer | A Sprite is a basic visual element that can be rendered with one of
several frames stored in an Image; different frames can be shown to
animate the Sprite. Several transforms such as flipping and rotation
can also be applied to a Sprite to further vary its appearance. As with
all Layer subclasses, a Sprite's location can be changed and it can also
be made visible or invisible.
Sprite Frames
The raw frames used to render a Sprite are provided in a single Image
object, which may be mutable or immutable. If more than one frame is used,
the Image is broken up into a series of equally-sized frames of a specified
width and height. As shown in the figure below, the same set of frames may
be stored in several different arrangements depending on what is the most
convenient for the game developer.
Each frame is assigned a unique index number. The frame located in the
upper-left corner of the Image is assigned an index of 0. The remaining
frames are then numbered consecutively in row-major order (indices are
assigned across the first row, then the second row, and so on). The method
{@link #getRawFrameCount()} returns the total number of raw frames.
Frame Sequence
A Sprite's frame sequence defines an ordered list of frames to be displayed.
The default frame sequence mirrors the list of available frames, so
there is a direct mapping between the sequence index and the corresponding
frame index. This also means that the length of the default frame sequence
is equal to the number of raw frames. For example, if a Sprite has 4
frames, its default frame sequence is {0, 1, 2, 3}.
The developer must manually switch the current frame in the frame sequence.
This may be accomplished by calling {@link #setFrame},
{@link #prevFrame()}, or {@link #nextFrame()}. Note that these methods
always operate on the sequence index, they do not operate on frame indices;
however, if the default frame sequence is used, then the sequence indices
and the frame indices are interchangeable.
If desired, an arbitrary frame sequence may be defined for a Sprite.
The frame sequence must contain at least one element, and each element must
reference a valid frame index. By defining a new frame sequence, the
developer can conveniently display the Sprite's frames in any order
desired; frames may be repeated, omitted, shown in reverse order, etc.
For example, the diagram below shows how a special frame sequence might be
used to animate a mosquito. The frame sequence is designed so that the
mosquito flaps its wings three times and then pauses for a moment before
the cycle is repeated.
By calling {@link #nextFrame} each time the display is updated, the
resulting animation would like this:
Reference Pixel
Being a subclass of Layer, Sprite inherits various methods for setting and
retrieving its location such as {@link #setPosition setPosition(x,y)},
{@link #getX getX()}, and {@link #getY getY()}. These methods all define
position in terms of the upper-left corner of the Sprite's visual bounds;
however, in some cases, it is more convenient to define the Sprite's position
in terms of an arbitrary pixel within its frame, especially if transforms
are applied to the Sprite.
Therefore, Sprite includes the concept of a reference pixel.
The reference pixel is defined by specifying its location in the
Sprite's untransformed frame using
{@link #defineReferencePixel defineReferencePixel(x,y)}.
By default, the reference pixel is defined to be the pixel at (0,0)
in the frame. If desired, the reference pixel may be defined outside
of the frame's bounds.
In this example, the reference pixel is defined to be the pixel that
the monkey appears to be hanging from:
{@link #getRefPixelX getRefPixelX()} and {@link #getRefPixelY getRefPixelY()}
can be used to query the location of the reference pixel in the painter's
coordinate system. The developer can also use
{@link #setRefPixelPosition setRefPixelPosition(x,y)} to position the Sprite
so that reference pixel appears at a specific location in the painter's
coordinate system. These methods automatically account for any transforms
applied to the Sprite.
In this example, the reference pixel's position is set to a point at the end
of a tree branch; the Sprite's location changes so that the reference pixel
appears at this point and the monkey appears to be hanging from the branch:
Sprite Transforms
Various transforms can be applied to a Sprite. The available transforms
include rotations in multiples of 90 degrees, and mirrored (about
the vertical axis) versions of each of the rotations. A Sprite's transform
is set by calling {@link #setTransform setTransform(transform)}.
When a transform is applied, the Sprite is automatically repositioned
such that the reference pixel appears stationary in the painter's
coordinate system. Thus, the reference pixel effectively becomes the
center of the transform operation. Since the reference pixel does not
move, the values returned by {@link #getRefPixelX()} and
{@link #getRefPixelY()} remain the same; however, the values returned by
{@link #getX getX()} and {@link #getY getY()} may change to reflect the
movement of the Sprite's upper-left corner.
Referring to the monkey example once again, the position of the
reference pixel remains at (48, 22) when a 90 degree rotation
is applied, thereby making it appear as if the monkey is swinging
from the branch:
Sprite Drawing
Sprites can be drawn at any time using the {@link #paint(Graphics)} method.
The Sprite will be drawn on the Graphics object according to the current
state information maintained by the Sprite (i.e. position, frame,
visibility). Erasing the Sprite is always the responsibility of code
outside the Sprite class.
Sprites can be implemented using whatever techniques a manufacturers
wishes to use (e.g hardware acceleration may be used for all Sprites, for
certain sizes of Sprites, or not at all).
For some platforms, certain Sprite sizes may be more efficient than others;
manufacturers may choose to provide developers with information about
device-specific characteristics such as these.
|
| Fields Summary |
|---|
| public static final int | TRANS_NONENo transform is applied to the Sprite.
This constant has a value of 0. | | public static final int | TRANS_ROT90Causes the Sprite to appear rotated clockwise by 90 degrees.
This constant has a value of 5. | | public static final int | TRANS_ROT180Causes the Sprite to appear rotated clockwise by 180 degrees.
This constant has a value of 3. | | public static final int | TRANS_ROT270Causes the Sprite to appear rotated clockwise by 270 degrees.
This constant has a value of 6. | | public static final int | TRANS_MIRRORCauses the Sprite to appear reflected about its vertical
center.
This constant has a value of 2. | | public static final int | TRANS_MIRROR_ROT90Causes the Sprite to appear reflected about its vertical
center and then rotated clockwise by 90 degrees.
This constant has a value of 7. | | public static final int | TRANS_MIRROR_ROT180Causes the Sprite to appear reflected about its vertical
center and then rotated clockwise by 180 degrees.
This constant has a value of 1. | | public static final int | TRANS_MIRROR_ROT270Causes the Sprite to appear reflected about its vertical
center and then rotated clockwise by 270 degrees.
This constant has a value of 4. | | private static final int | INVERTED_AXESIf this bit is set, it denotes that the transform causes the
axes to be interchanged | | private static final int | X_FLIPIf this bit is set, it denotes that the transform causes the
x axis to be flipped. | | private static final int | Y_FLIPIf this bit is set, it denotes that the transform causes the
y axis to be flipped. | | private static final int | ALPHA_BITMASKBit mask for channel value in ARGB pixel. | | private static final int | FULLY_OPAQUE_ALPHAAlpha channel value for full opacity. | | javax.microedition.lcdui.Image | sourceImageSource image | | int | numberFramesThe number of frames | | int[] | frameCoordsXlist of X coordinates of individual frames | | int[] | frameCoordsYlist of Y coordinates of individual frames | | int | srcFrameWidthWidth of each frame in the source image | | int | srcFrameHeightHeight of each frame in the source image | | int[] | frameSequenceThe sequence in which to display the Sprite frames | | private int | sequenceIndexThe sequence index | | private boolean | customSequenceDefinedSet to true if custom sequence is used. | | int | dRefXHorizontal offset of the reference point
from the top left of the sprite. | | int | dRefYVertical offset of the reference point
from the top left of the sprite. | | int | collisionRectXHorizontal offset of the top left of the collision
rectangle from the top left of the sprite. | | int | collisionRectYVertical offset of the top left of the collision
rectangle from the top left of the sprite. | | int | collisionRectWidthWidth of the bounding rectangle for collision detection. | | int | collisionRectHeightHeight of the bounding rectangle for collision detection. | | int | t_currentTransformationThe current transformation in effect. | | int | t_collisionRectXHorizontal offset of the top left of the collision
rectangle from the top left of the sprite. | | int | t_collisionRectYVertical offset of the top left of the collision
rectangle from the top left of the sprite. | | int | t_collisionRectWidthWidth of the bounding rectangle for collision detection,
with the current transformation in effect. | | int | t_collisionRectHeightHeight of the bounding rectangle for collision detection,
with the current transformation in effect. |
| Constructors Summary |
|---|
public Sprite(javax.microedition.lcdui.Image image)Creates a new non-animated Sprite using the provided Image.
This constructor is functionally equivalent to calling
new Sprite(image, image.getWidth(), image.getHeight())
By default, the Sprite is visible and its upper-left
corner is positioned at (0,0) in the painter's coordinate system.
// ----- Constructors -----
super(image.getWidth(), image.getHeight());
initializeFrames(image, image.getWidth(), image.getHeight(), false);
// initialize collision rectangle
initCollisionRectBounds();
// current transformation is TRANS_NONE
setTransformImpl(TRANS_NONE);
| public Sprite(javax.microedition.lcdui.Image image, int frameWidth, int frameHeight)Creates a new animated Sprite using frames contained in
the provided Image. The frames must be equally sized, with the
dimensions specified by frameWidth and
frameHeight. They may be laid out in the image
horizontally, vertically, or as a grid. The width of the source
image must be an integer multiple of the frame width, and the height
of the source image must be an integer multiple of the frame height.
The values returned by {@link Layer#getWidth} and
{@link Layer#getHeight} will reflect the frame width and frame height
subject to the Sprite's current transform.
Sprites have a default frame sequence corresponding to the raw frame
numbers, starting with frame 0. The frame sequence may be modified
with {@link #setFrameSequence(int[])}.
By default, the Sprite is visible and its upper-left corner is
positioned at (0,0) in the painter's coordinate system.
super(frameWidth, frameHeight);
// if img is null img.getWidth() will throw NullPointerException
if ((frameWidth < 1 || frameHeight < 1) ||
((image.getWidth() % frameWidth) != 0) ||
((image.getHeight() % frameHeight) != 0)) {
throw new IllegalArgumentException();
}
// construct the array of images that
// we use as "frames" for the sprite.
// use default frame , sequence index = 0
initializeFrames(image, frameWidth, frameHeight, false);
// initialize collision rectangle
initCollisionRectBounds();
// current transformation is TRANS_NONE
setTransformImpl(TRANS_NONE);
| public Sprite(Sprite s)Creates a new Sprite from another Sprite.
All instance attributes (raw frames, position, frame sequence, current
frame, reference point, collision rectangle, transform, and visibility)
of the source Sprite are duplicated in the new Sprite.
super(s != null ? s.getWidth() : 0,
s != null ? s.getHeight() : 0);
if (s == null) {
throw new NullPointerException();
}
this.sourceImage = Image.createImage(s.sourceImage);
this.numberFrames = s.numberFrames;
this.frameCoordsX = new int[this.numberFrames];
this.frameCoordsY = new int[this.numberFrames];
System.arraycopy(s.frameCoordsX, 0,
this.frameCoordsX, 0,
s.getRawFrameCount());
System.arraycopy(s.frameCoordsY, 0,
this.frameCoordsY, 0,
s.getRawFrameCount());
this.x = s.getX();
this.y = s.getY();
// these fields are set by defining a reference point
this.dRefX = s.dRefX;
this.dRefY = s.dRefY;
// these fields are set when defining a collision rectangle
this.collisionRectX = s.collisionRectX;
this.collisionRectY = s.collisionRectY;
this.collisionRectWidth = s.collisionRectWidth;
this.collisionRectHeight = s.collisionRectHeight;
// these fields are set when creating a Sprite from an Image
this.srcFrameWidth = s.srcFrameWidth;
this.srcFrameHeight = s.srcFrameHeight;
// the above fields are used in setTransform()
// which is why we set them first, then call setTransformImpl()
// to set up internally used data structures.
setTransformImpl(s.t_currentTransformation);
this.setVisible(s.isVisible());
this.frameSequence = new int[s.getFrameSequenceLength()];
this.setFrameSequence(s.frameSequence);
this.setFrame(s.getFrame());
this.setRefPixelPosition(s.getRefPixelX(), s.getRefPixelY());
|
| Methods Summary |
|---|
| public final boolean | collidesWith(javax.microedition.lcdui.game.Sprite s, boolean pixelLevel)Checks for a collision between this Sprite and the specified Sprite.
If pixel-level detection is used, a collision is detected only if
opaque pixels collide. That is, an opaque pixel in the first
Sprite would have to collide with an opaque pixel in the second
Sprite for a collision to be detected. Only those pixels within
the Sprites' respective collision rectangles are checked.
If pixel-level detection is not used, this method simply
checks if the Sprites' collision rectangles intersect.
Any transforms applied to the Sprites are automatically accounted for.
Both Sprites must be visible in order for a collision to be
detected.
// check if either of the Sprite's are not visible
if (!(s.visible && this.visible)) {
return false;
}
// these are package private
// and can be accessed directly
int otherLeft = s.x + s.t_collisionRectX;
int otherTop = s.y + s.t_collisionRectY;
int otherRight = otherLeft + s.t_collisionRectWidth;
int otherBottom = otherTop + s.t_collisionRectHeight;
int left = this.x + this.t_collisionRectX;
int top = this.y + this.t_collisionRectY;
int right = left + this.t_collisionRectWidth;
int bottom = top + this.t_collisionRectHeight;
// check if the collision rectangles of the two sprites intersect
if (intersectRect(otherLeft, otherTop, otherRight, otherBottom,
left, top, right, bottom)) {
// collision rectangles intersect
if (pixelLevel) {
// we need to check pixel level collision detection.
// use only the coordinates within the Sprite frame if
// the collision rectangle is larger than the Sprite
// frame
if (this.t_collisionRectX < 0) {
left = this.x;
}
if (this.t_collisionRectY < 0) {
top = this.y;
}
if ((this.t_collisionRectX + this.t_collisionRectWidth)
> this.width) {
right = this.x + this.width;
}
if ((this.t_collisionRectY + this.t_collisionRectHeight)
> this.height) {
bottom = this.y + this.height;
}
// similarly for the other Sprite
if (s.t_collisionRectX < 0) {
otherLeft = s.x;
}
if (s.t_collisionRectY < 0) {
otherTop = s.y;
}
if ((s.t_collisionRectX + s.t_collisionRectWidth)
> s.width) {
otherRight = s.x + s.width;
}
if ((s.t_collisionRectY + s.t_collisionRectHeight)
> s.height) {
otherBottom = s.y + s.height;
}
// recheck if the updated collision area rectangles intersect
if (!intersectRect(otherLeft, otherTop, otherRight, otherBottom,
left, top, right, bottom)) {
// if they don't intersect, return false;
return false;
}
// the updated collision rectangles intersect,
// go ahead with collision detection
// find intersecting region,
// within the collision rectangles
int intersectLeft = (left < otherLeft) ? otherLeft : left;
int intersectTop = (top < otherTop) ? otherTop : top;
// used once, optimize.
int intersectRight = (right < otherRight)
? right : otherRight;
int intersectBottom = (bottom < otherBottom)
? bottom : otherBottom;
int intersectWidth = Math.abs(intersectRight - intersectLeft);
int intersectHeight = Math.abs(intersectBottom - intersectTop);
// have the coordinates in painter space,
// need coordinates of top left and width, height
// in source image of Sprite.
int thisImageXOffset = getImageTopLeftX(intersectLeft,
intersectTop,
intersectRight,
intersectBottom);
int thisImageYOffset = getImageTopLeftY(intersectLeft,
intersectTop,
intersectRight,
intersectBottom);
int otherImageXOffset = s.getImageTopLeftX(intersectLeft,
intersectTop,
intersectRight,
intersectBottom);
int otherImageYOffset = s.getImageTopLeftY(intersectLeft,
intersectTop,
intersectRight,
intersectBottom);
// check if opaque pixels intersect.
return doPixelCollision(thisImageXOffset, thisImageYOffset,
otherImageXOffset, otherImageYOffset,
this.sourceImage,
this.t_currentTransformation,
s.sourceImage,
s.t_currentTransformation,
intersectWidth, intersectHeight);
} else {
// collides!
return true;
}
}
return false;
| | public final boolean | collidesWith(TiledLayer t, boolean pixelLevel)Checks for a collision between this Sprite and the specified
TiledLayer. If pixel-level detection is used, a collision is
detected only if opaque pixels collide. That is, an opaque pixel in
the Sprite would have to collide with an opaque pixel in TiledLayer
for a collision to be detected. Only those pixels within the Sprite's
collision rectangle are checked.
If pixel-level detection is not used, this method simply checks if the
Sprite's collision rectangle intersects with a non-empty cell in the
TiledLayer.
Any transform applied to the Sprite is automatically accounted for.
The Sprite and the TiledLayer must both be visible in order for
a collision to be detected.
// check if either this Sprite or the TiledLayer is not visible
if (!(t.visible && this.visible)) {
return false;
}
// dimensions of tiledLayer, cell, and
// this Sprite's collision rectangle
// these are package private
// and can be accessed directly
int tLx1 = t.x;
int tLy1 = t.y;
int tLx2 = tLx1 + t.width;
int tLy2 = tLy1 + t.height;
int tW = t.getCellWidth();
int tH = t.getCellHeight();
int sx1 = this.x + this.t_collisionRectX;
int sy1 = this.y + this.t_collisionRectY;
int sx2 = sx1 + this.t_collisionRectWidth;
int sy2 = sy1 + this.t_collisionRectHeight;
// number of cells
int tNumCols = t.getColumns();
int tNumRows = t.getRows();
// temporary loop variables.
int startCol; // = 0;
int endCol; // = 0;
int startRow; // = 0;
int endRow; // = 0;
if (!intersectRect(tLx1, tLy1, tLx2, tLy2, sx1, sy1, sx2, sy2)) {
// if the collision rectangle of the sprite
// does not intersect with the dimensions of the entire
// tiled layer
return false;
}
// so there is an intersection
// note sx1 < sx2, tLx1 < tLx2, sx2 > tLx1 from intersectRect()
// use <= for comparison as this saves us some
// computation - the result will be 0
startCol = (sx1 <= tLx1) ? 0 : (sx1 - tLx1)/tW;
startRow = (sy1 <= tLy1) ? 0 : (sy1 - tLy1)/tH;
// since tLx1 < sx2 < tLx2, the computation will yield
// a result between 0 and tNumCols - 1
// subtract by 1 because sx2,sy2 represent
// the enclosing bounds of the sprite, not the
// locations in the coordinate system.
endCol = (sx2 < tLx2) ? ((sx2 - 1 - tLx1)/tW) : tNumCols - 1;
endRow = (sy2 < tLy2) ? ((sy2 - 1 - tLy1)/tH) : tNumRows - 1;
if (!pixelLevel) {
// check for intersection with a non-empty cell,
for (int row = startRow; row <= endRow; row++) {
for (int col = startCol; col <= endCol; col++) {
if (t.getCell(col, row) != 0) {
return true;
}
}
}
// worst case! we scanned through entire
// overlapping region and
// all the cells are empty!
return false;
} else {
// do pixel level
// we need to check pixel level collision detection.
// use only the coordinates within the Sprite frame if
// the collision rectangle is larger than the Sprite
// frame
if (this.t_collisionRectX < 0) {
sx1 = this.x;
}
if (this.t_collisionRectY < 0) {
sy1 = this.y;
}
if ((this.t_collisionRectX + this.t_collisionRectWidth)
> this.width) {
sx2 = this.x + this.width;
}
if ((this.t_collisionRectY + this.t_collisionRectHeight)
> this.height) {
sy2 = this.y + this.height;
}
if (!intersectRect(tLx1, tLy1, tLx2, tLy2, sx1, sy1, sx2, sy2)) {
return (false);
}
// we have an intersection between the Sprite and
// one or more cells of the tiledlayer
// note sx1 < sx2, tLx1 < tLx2, sx2 > tLx1 from intersectRect()
// use <= for comparison as this saves us some
// computation - the result will be 0
startCol = (sx1 <= tLx1) ? 0 : (sx1 - tLx1)/tW;
startRow = (sy1 <= tLy1) ? 0 : (sy1 - tLy1)/tH;
// since tLx1 < sx2 < tLx2, the computation will yield
// a result between 0 and tNumCols - 1
// subtract by 1 because sx2,sy2 represent
// the enclosing bounds of the sprite, not the
// locations in the coordinate system.
endCol = (sx2 < tLx2) ? ((sx2 - 1 - tLx1)/tW) : tNumCols - 1;
endRow = (sy2 < tLy2) ? ((sy2 - 1 - tLy1)/tH) : tNumRows - 1;
// current cell coordinates
int cellTop = startRow * tH + tLy1;
int cellBottom = cellTop + tH;
// the index of the current tile.
int tileIndex; // = 0;
for (int row = startRow; row <= endRow;
row++, cellTop += tH, cellBottom += tH) {
// current cell coordinates
int cellLeft = startCol * tW + tLx1;
int cellRight = cellLeft + tW;
for (int col = startCol; col <= endCol;
col++, cellLeft += tW, cellRight += tW) {
tileIndex = t.getCell(col, row);
if (tileIndex != 0) {
// current cell/sprite intersection coordinates
// in painter coordinate system.
// find intersecting region,
int intersectLeft = (sx1 < cellLeft) ? cellLeft : sx1;
int intersectTop = (sy1 < cellTop) ? cellTop : sy1;
// used once, optimize.
int intersectRight = (sx2 < cellRight) ?
sx2 : cellRight;
int intersectBottom = (sy2 < cellBottom) ?
sy2 : cellBottom;
if (intersectLeft > intersectRight) {
int temp = intersectRight;
intersectRight = intersectLeft;
intersectLeft = temp;
}
if (intersectTop > intersectBottom) {
int temp = intersectBottom;
intersectBottom = intersectTop;
intersectTop = temp;
}
int intersectWidth = intersectRight - intersectLeft;
int intersectHeight = intersectBottom - intersectTop;
int image1XOffset = getImageTopLeftX(intersectLeft,
intersectTop,
intersectRight,
intersectBottom);
int image1YOffset = getImageTopLeftY(intersectLeft,
intersectTop,
intersectRight,
intersectBottom);
int image2XOffset = t.tileSetX[tileIndex] +
(intersectLeft - cellLeft);
int image2YOffset = t.tileSetY[tileIndex] +
(intersectTop - cellTop);
if (doPixelCollision(image1XOffset,
image1YOffset,
image2XOffset,
image2YOffset,
this.sourceImage,
this.t_currentTransformation,
t.sourceImage,
TRANS_NONE,
intersectWidth, intersectHeight)) {
// intersection found with this tile
return true;
}
}
} // end of for col
}// end of for row
// worst case! we scanned through entire
// overlapping region and
// no pixels collide!
return false;
}
| | public final boolean | collidesWith(javax.microedition.lcdui.Image image, int inp_x, int inp_y, boolean pixelLevel)Checks for a collision between this Sprite and the specified Image
with its upper left corner at the specified location. If pixel-level
detection is used, a collision is detected only if opaque pixels
collide. That is, an opaque pixel in the Sprite would have to collide
with an opaque pixel in Image for a collision to be detected. Only
those pixels within the Sprite's collision rectangle are checked.
If pixel-level detection is not used, this method simply checks if the
Sprite's collision rectangle intersects with the Image's bounds.
Any transform applied to the Sprite is automatically accounted for.
The Sprite must be visible in order for a collision to be
detected.
// check if this Sprite is not visible
if (!(visible)) {
return false;
}
// if image is null
// image.getWidth() will throw NullPointerException
int otherLeft = inp_x;
int otherTop = inp_y;
int otherRight = inp_x + image.getWidth();
int otherBottom = inp_y + image.getHeight();
int left = x + t_collisionRectX;
int top = y + t_collisionRectY;
int right = left + t_collisionRectWidth;
int bottom = top + t_collisionRectHeight;
// first check if the collision rectangles of the two sprites intersect
if (intersectRect(otherLeft, otherTop, otherRight, otherBottom,
left, top, right, bottom)) {
// collision rectangles intersect
if (pixelLevel) {
// find intersecting region,
// we need to check pixel level collision detection.
// use only the coordinates within the Sprite frame if
// the collision rectangle is larger than the Sprite
// frame
if (this.t_collisionRectX < 0) {
left = this.x;
}
if (this.t_collisionRectY < 0) {
top = this.y;
}
if ((this.t_collisionRectX + this.t_collisionRectWidth)
> this.width) {
right = this.x + this.width;
}
if ((this.t_collisionRectY + this.t_collisionRectHeight)
> this.height) {
bottom = this.y + this.height;
}
// recheck if the updated collision area rectangles intersect
if (!intersectRect(otherLeft, otherTop,
otherRight, otherBottom,
left, top, right, bottom)) {
// if they don't intersect, return false;
return false;
}
// within the collision rectangles
int intersectLeft = (left < otherLeft) ? otherLeft : left;
int intersectTop = (top < otherTop) ? otherTop : top;
// used once, optimize.
int intersectRight = (right < otherRight)
? right : otherRight;
int intersectBottom = (bottom < otherBottom)
? bottom : otherBottom;
int intersectWidth = Math.abs(intersectRight - intersectLeft);
int intersectHeight = Math.abs(intersectBottom - intersectTop);
// have the coordinates in painter space,
// need coordinates of top left and width, height
// in source image of Sprite.
int thisImageXOffset = getImageTopLeftX(intersectLeft,
intersectTop,
intersectRight,
intersectBottom);
int thisImageYOffset = getImageTopLeftY(intersectLeft,
intersectTop,
intersectRight,
intersectBottom);
int otherImageXOffset = intersectLeft - inp_x;
int otherImageYOffset = intersectTop - inp_y;
// check if opaque pixels intersect.
return doPixelCollision(thisImageXOffset, thisImageYOffset,
otherImageXOffset, otherImageYOffset,
this.sourceImage,
this.t_currentTransformation,
image,
Sprite.TRANS_NONE,
intersectWidth, intersectHeight);
} else {
// collides!
return true;
}
}
return false;
| | private void | computeTransformedBounds(int transform)Calculate transformed sprites collision rectangle
and transformed width and height
switch (transform) {
case TRANS_NONE:
t_collisionRectX = collisionRectX;
t_collisionRectY = collisionRectY;
t_collisionRectWidth = collisionRectWidth;
t_collisionRectHeight = collisionRectHeight;
this.width = srcFrameWidth;
this.height = srcFrameHeight;
break;
case TRANS_MIRROR:
// flip across vertical
// NOTE: top left x and y coordinate must reflect the transformation
// performed around the reference point
// the X-offset of the reference point from the top left corner
// changes.
t_collisionRectX = srcFrameWidth -
(collisionRectX + collisionRectWidth);
t_collisionRectY = collisionRectY;
t_collisionRectWidth = collisionRectWidth;
t_collisionRectHeight = collisionRectHeight;
// the Y-offset of the reference point from the top left corner
// remains the same,
// top left X-co-ordinate changes
this.width = srcFrameWidth;
this.height = srcFrameHeight;
break;
case TRANS_MIRROR_ROT180:
// flip across horizontal
// NOTE: top left x and y coordinate must reflect the transformation
// performed around the reference point
// the Y-offset of the reference point from the top left corner
// changes
t_collisionRectY = srcFrameHeight -
(collisionRectY + collisionRectHeight);
t_collisionRectX = collisionRectX;
t_collisionRectWidth = collisionRectWidth;
t_collisionRectHeight = collisionRectHeight;
// width and height are as before
this.width = srcFrameWidth;
this.height = srcFrameHeight;
// the X-offset of the reference point from the top left corner
// remains the same.
// top left Y-co-ordinate changes
break;
case TRANS_ROT90:
// NOTE: top left x and y coordinate must reflect the transformation
// performed around the reference point
// the bottom-left corner of the rectangle becomes the
// top-left when rotated 90.
// both X- and Y-offset to the top left corner may change
// update the position information for the collision rectangle
t_collisionRectX = srcFrameHeight -
(collisionRectHeight + collisionRectY);
t_collisionRectY = collisionRectX;
t_collisionRectHeight = collisionRectWidth;
t_collisionRectWidth = collisionRectHeight;
// set width and height
this.width = srcFrameHeight;
this.height = srcFrameWidth;
break;
case TRANS_ROT180:
// NOTE: top left x and y coordinate must reflect the transformation
// performed around the reference point
// width and height are as before
// both X- and Y- offsets from the top left corner may change
t_collisionRectX = srcFrameWidth - (collisionRectWidth +
collisionRectX);
t_collisionRectY = srcFrameHeight - (collisionRectHeight +
collisionRectY);
t_collisionRectWidth = collisionRectWidth;
t_collisionRectHeight = collisionRectHeight;
// set width and height
this.width = srcFrameWidth;
this.height = srcFrameHeight;
break;
case TRANS_ROT270:
// the top-right corner of the rectangle becomes the
// top-left when rotated 270.
// both X- and Y-offset to the top left corner may change
// update the position information for the collision rectangle
t_collisionRectX = collisionRectY;
t_collisionRectY = srcFrameWidth - (collisionRectWidth +
collisionRectX);
t_collisionRectHeight = collisionRectWidth;
t_collisionRectWidth = collisionRectHeight;
// set width and height
this.width = srcFrameHeight;
this.height = srcFrameWidth;
break;
case TRANS_MIRROR_ROT90:
// both X- and Y- offset from the top left corner may change
// update the position information for the collision rectangle
t_collisionRectX = srcFrameHeight - (collisionRectHeight +
collisionRectY);
t_collisionRectY = srcFrameWidth - (collisionRectWidth +
collisionRectX);
t_collisionRectHeight = collisionRectWidth;
t_collisionRectWidth = collisionRectHeight;
// set width and height
this.width = srcFrameHeight;
this.height = srcFrameWidth;
break;
case TRANS_MIRROR_ROT270:
// both X- and Y- offset from the top left corner may change
// update the position information for the collision rectangle
t_collisionRectY = collisionRectX;
t_collisionRectX = collisionRectY;
t_collisionRectHeight = collisionRectWidth;
t_collisionRectWidth = collisionRectHeight;
// set width and height
this.width = srcFrameHeight;
this.height = srcFrameWidth;
break;
default:
// INVALID TRANSFORMATION!
throw new IllegalArgumentException();
}
| | public void | defineCollisionRectangle(int inp_x, int inp_y, int width, int height)Defines the Sprite's bounding rectangle that is used for collision
detection purposes. This rectangle is specified relative to the
un-transformed Sprite's upper-left corner and defines the area that is
checked for collision detection. For pixel-level detection, only those
pixels within the collision rectangle are checked.
By default, a Sprite's collision rectangle is located at 0,0 as has the
same dimensions as the Sprite. The collision rectangle may be
specified to be larger or smaller than the default rectangle; if made
larger, the pixels outside the bounds of the Sprite are considered to be
transparent for pixel-level collision detection.
if (width < 0 || height < 0) {
throw new IllegalArgumentException();
}
collisionRectX = inp_x;
collisionRectY = inp_y;
collisionRectWidth = width;
collisionRectHeight = height;
// call set transform with current transformation to
// update transformed sprites collision rectangle
setTransformImpl(t_currentTransformation);
| | public void | defineReferencePixel(int inp_x, int inp_y)Defines the reference pixel for this Sprite. The pixel is
defined by its location relative to the upper-left corner of
the Sprite's un-transformed frame, and it may lay outside of
the frame's bounds.
When a transformation is applied, the reference pixel is
defined relative to the Sprite's initial upper-left corner
before transformation. This corner may no longer appear as the
upper-left corner in the painter's coordinate system under
current transformation.
By default, a Sprite's reference pixel is located at (0,0); that is,
the pixel in the upper-left corner of the raw frame.
Changing the reference pixel does not change the
Sprite's physical position in the painter's coordinate system;
that is, the values returned by {@link #getX getX()} and
{@link #getY getY()} will not change as a result of defining the
reference pixel. However, subsequent calls to methods that
involve the reference pixel will be impacted by its new definition.
dRefX = inp_x;
dRefY = inp_y;
| | private static boolean | doPixelCollision(int image1XOffset, int image1YOffset, int image2XOffset, int image2YOffset, javax.microedition.lcdui.Image image1, int transform1, javax.microedition.lcdui.Image image2, int transform2, int width, int height)Detect opaque pixel intersection between regions of two images
// starting point of comparison
int startY1;
// x and y increments
int xIncr1, yIncr1;
// .. for image 2
int startY2;
int xIncr2, yIncr2;
int numPixels = height * width;
int[] argbData1 = new int[numPixels];
int[] argbData2 = new int[numPixels];
if (0x0 != (transform1 & INVERTED_AXES)) {
// inverted axes
// scanlength = height
if (0x0 != (transform1 & Y_FLIP)) {
xIncr1 = -(height); // - scanlength
startY1 = numPixels - height; // numPixels - scanlength
} else {
xIncr1 = height; // + scanlength
startY1 = 0;
}
if (0x0 != (transform1 & X_FLIP)) {
yIncr1 = -1;
startY1 += (height - 1);
} else {
yIncr1 = +1;
}
image1.getRGB(argbData1, 0, height, // scanlength = height
image1XOffset, image1YOffset, height, width);
} else {
// scanlength = width
if (0x0 != (transform1 & Y_FLIP)) {
startY1 = numPixels - width; // numPixels - scanlength
yIncr1 = -(width); // - scanlength
} else {
startY1 = 0;
yIncr1 = width; // + scanlength
}
if (0x0 != (transform1 & X_FLIP)) {
xIncr1 = -1;
startY1 += (width - 1);
} else {
xIncr1 = +1;
}
image1.getRGB(argbData1, 0, width, // scanlength = width
image1XOffset, image1YOffset, width, height);
}
if (0x0 != (transform2 & INVERTED_AXES)) {
// inverted axes
if (0x0 != (transform2 & Y_FLIP)) {
xIncr2 = -(height);
startY2 = numPixels - height;
} else {
xIncr2 = height;
startY2 = 0;
}
if (0x0 != (transform2 & X_FLIP)) {
yIncr2 = -1;
startY2 += height - 1;
} else {
yIncr2 = +1;
}
image2.getRGB(argbData2, 0, height,
image2XOffset, image2YOffset, height, width);
} else {
if (0x0 != (transform2 & Y_FLIP)) {
startY2 = numPixels - width;
yIncr2 = -(width);
} else {
startY2 = 0;
yIncr2 = +width;
}
if (0x0 != (transform2 & X_FLIP)) {
xIncr2 = -1;
startY2 += (width - 1);
} else {
xIncr2 = +1;
}
image2.getRGB(argbData2, 0, width,
image2XOffset, image2YOffset, width, height);
}
int x1, x2;
int xLocalBegin1, xLocalBegin2;
// the loop counters
int numIterRows;
int numIterColumns;
for (numIterRows = 0, xLocalBegin1 = startY1, xLocalBegin2 = startY2;
numIterRows < height;
xLocalBegin1 += yIncr1, xLocalBegin2 += yIncr2, numIterRows++) {
for (numIterColumns = 0, x1 = xLocalBegin1, x2 = xLocalBegin2;
numIterColumns < width;
x1 += xIncr1, x2 += xIncr2, numIterColumns++) {
if (((argbData1[x1] & ALPHA_BITMASK) == FULLY_OPAQUE_ALPHA) &&
((argbData2[x2] & ALPHA_BITMASK) == FULLY_OPAQUE_ALPHA)) {
return true;
}
} // end for x
} // end for y
// worst case! couldn't find a single colliding pixel!
return false;
| | public final int | getFrame()Gets the current index in the frame sequence.
The index returned refers to the current entry in the frame sequence,
not the index of the actual frame that is displayed.
return sequenceIndex;
| | public int | getFrameSequenceLength()Gets the number of elements in the frame sequence. The value returned
reflects the length of the Sprite's frame sequence; it does not reflect
the number of raw frames. However, these two values will be the same
if the default frame sequence is used.
return frameSequence.length;
| | private int | getImageTopLeftX(int x1, int y1, int x2, int y2)Given a rectangle that lies within the sprite
in the painter's coordinates,
find the X coordinate of the top left corner
in the source image of the sprite
int retX = 0;
// left = this.x
// right = this.x + this.width
// top = this.y
// bottom = this.y + this.height
switch (this.t_currentTransformation) {
case TRANS_NONE:
case TRANS_MIRROR_ROT180:
retX = x1 - this.x;
break;
case TRANS_MIRROR:
case TRANS_ROT180:
retX = (this.x + this.width) - x2;
break;
case TRANS_ROT90:
case TRANS_MIRROR_ROT270:
retX = y1 - this.y;
break;
case TRANS_ROT270:
case TRANS_MIRROR_ROT90:
retX = (this.y + this.height) - y2;
break;
default:
// for safety/completeness.
Logging.report(Logging.ERROR, LogChannels.LC_HIGHUI,
"Sprite: t_currentTransformation=" +
t_currentTransformation);
return retX;
}
retX += frameCoordsX[frameSequence[sequenceIndex]];
return retX;
| | private int | getImageTopLeftY(int x1, int y1, int x2, int y2)Given a rectangle that lies within the sprite
in the painter's coordinates,
find the Y coordinate of the top left corner
in the source image of the sprite
int retY = 0;
// left = this.x
// right = this.x + this.width
// top = this.y
// bottom = this.y + this.height
switch (this.t_currentTransformation) {
case TRANS_NONE:
case TRANS_MIRROR:
retY = y1 - this.y;
break;
case TRANS_ROT180:
case TRANS_MIRROR_ROT180:
retY = (this.y + this.height) - y2;
break;
case TRANS_ROT270:
case TRANS_MIRROR_ROT270:
retY = x1 - this.x;
break;
case TRANS_ROT90:
case TRANS_MIRROR_ROT90:
retY = (this.x + this.width) - x2;
break;
default:
// for safety/completeness.
Logging.report(Logging.ERROR, LogChannels.LC_HIGHUI,
"Sprite: t_currentTransformation=" +
this.t_currentTransformation);
return retY;
}
retY += frameCoordsY[frameSequence[sequenceIndex]];
return retY;
| | public int | getRawFrameCount()Gets the number of raw frames for this Sprite. The value returned
reflects the number of frames; it does not reflect the length of the
Sprite's frame sequence. However, these two values will be the same
if the default frame sequence is used.
return numberFrames;
| | public int | getRefPixelX()Gets the horizontal position of this Sprite's reference pixel
in the painter's coordinate system.
return (this.x +
getTransformedPtX(dRefX, dRefY, this.t_currentTransformation));
| | public int | getRefPixelY()Gets the vertical position of this Sprite's reference pixel
in the painter's coordinate system.
return (this.y +
getTransformedPtY(dRefX, dRefY, this.t_currentTransformation));
| | int | getTransformedPtX(int inp_x, int inp_y, int transform)Given the x and y offsets off a pixel from the top left
corner, in an untransformed sprite,
calculates the x coordinate of the pixel when the same sprite
is transformed, with the coordinates of the top-left pixel
of the transformed sprite as (0,0).
int t_x = 0;
switch (transform) {
case TRANS_NONE:
t_x = inp_x;
break;
case TRANS_MIRROR:
t_x = srcFrameWidth - inp_x - 1;
break;
case TRANS_MIRROR_ROT180:
t_x = inp_x;
break;
case TRANS_ROT90:
t_x = srcFrameHeight - inp_y - 1;
break;
case TRANS_ROT180:
t_x = srcFrameWidth - inp_x - 1;
break;
case TRANS_ROT270:
t_x = inp_y;
break;
case TRANS_MIRROR_ROT90:
t_x = srcFrameHeight - inp_y - 1;
break;
case TRANS_MIRROR_ROT270:
t_x = inp_y;
break;
default:
// for safety/completeness.
Logging.report(Logging.ERROR, LogChannels.LC_HIGHUI,
"Sprite: transform=" + transform);
break;
}
return t_x;
| | int | getTransformedPtY(int inp_x, int inp_y, int transform)Given the x and y offsets off a pixel from the top left
corner, in an untransformed sprite,
calculates the y coordinate of the pixel when the same sprite
is transformed, with the coordinates of the top-left pixel
of the transformed sprite as (0,0).
int t_y = 0;
switch (transform) {
case TRANS_NONE:
t_y = inp_y;
break;
case TRANS_MIRROR:
t_y = inp_y;
break;
case TRANS_MIRROR_ROT180:
t_y = srcFrameHeight - inp_y - 1;
break;
case TRANS_ROT90:
t_y = inp_x;
break;
case TRANS_ROT180:
t_y = srcFrameHeight - inp_y - 1;
break;
case TRANS_ROT270:
t_y = srcFrameWidth - inp_x - 1;
break;
case TRANS_MIRROR_ROT90:
t_y = srcFrameWidth - inp_x - 1;
break;
case TRANS_MIRROR_ROT270:
t_y = inp_x;
break;
default:
// for safety/completeness.
Logging.report(Logging.ERROR, LogChannels.LC_HIGHUI,
"Sprite: transform=" + transform);
break;
}
return t_y;
| | private void | initCollisionRectBounds()initialize the collision rectangle
// reset x and y of collision rectangle
collisionRectX = 0;
collisionRectY = 0;
// intialize the collision rectangle bounds to that of the sprite
collisionRectWidth = this.width;
collisionRectHeight = this.height;
| | private void | initializeFrames(javax.microedition.lcdui.Image image, int fWidth, int fHeight, boolean maintainCurFrame)create the Image Array.
int imageW = image.getWidth();
int imageH = image.getHeight();
int numHorizontalFrames = imageW / fWidth;
int numVerticalFrames = imageH / fHeight;
sourceImage = image;
srcFrameWidth = fWidth;
srcFrameHeight = fHeight;
numberFrames = numHorizontalFrames*numVerticalFrames;
frameCoordsX = new int[numberFrames];
frameCoordsY = new int[numberFrames];
if (!maintainCurFrame) {
sequenceIndex = 0;
}
if (!customSequenceDefined) {
frameSequence = new int[numberFrames];
}
int currentFrame = 0;
for (int yy = 0; yy < imageH; yy += fHeight) {
for (int xx = 0; xx < imageW; xx += fWidth) {
frameCoordsX[currentFrame] = xx;
frameCoordsY[currentFrame] = yy;
if (!customSequenceDefined) {
frameSequence[currentFrame] = currentFrame;
}
currentFrame++;
}
}
| | private boolean | intersectRect(int r1x1, int r1y1, int r1x2, int r1y2, int r2x1, int r2y1, int r2x2, int r2y2)Detect rectangle intersection
if (r2x1 >= r1x2 || r2y1 >= r1y2 || r2x2 <= r1x1 || r2y2 <= r1y1) {
return false;
} else {
return true;
}
| | public void | nextFrame()Selects the next frame in the frame sequence.
The frame sequence is considered to be circular, i.e. if
{@link #nextFrame} is called when at the end of the sequence,
this method will advance to the first entry in the sequence.
sequenceIndex = (sequenceIndex + 1) % frameSequence.length;
| | public final void | paint(javax.microedition.lcdui.Graphics g)Draws the Sprite.
Draws current frame of Sprite using the provided Graphics object.
The Sprite's upper left corner is rendered at the Sprite's current
position relative to the origin of the Graphics object. The current
position of the Sprite's upper-left corner can be retrieved by
calling {@link #getX()} and {@link #getY()}.
Rendering is subject to the clip region of the Graphics object.
The Sprite will be drawn only if it is visible.
If the Sprite's Image is mutable, the Sprite is rendered using the
current contents of the Image.
// managing the painting order is the responsibility of
// the layermanager, so depth is ignored
if (g == null) {
throw new NullPointerException();
}
if (visible) {
// width and height of the source
// image is the width and height
// of the original frame
g.drawRegion(sourceImage,
frameCoordsX[frameSequence[sequenceIndex]],
frameCoordsY[frameSequence[sequenceIndex]],
srcFrameWidth,
srcFrameHeight,
t_currentTransformation,
this.x,
this.y,
Graphics.TOP | Graphics.LEFT);
}
| | public void | prevFrame()Selects the previous frame in the frame sequence.
The frame sequence is considered to be circular, i.e. if
{@link #prevFrame} is called when at the start of the sequence,
this method will advance to the last entry in the sequence.
if (sequenceIndex == 0) {
sequenceIndex = frameSequence.length - 1;
} else {
sequenceIndex--;
}
| | public void | setFrame(int inp_sequenceIndex)Selects the current frame in the frame sequence.
The current frame is rendered when {@link #paint(Graphics)} is called.
The index provided refers to the desired entry in the frame sequence,
not the index of the actual frame itself.
if (inp_sequenceIndex < 0 ||
inp_sequenceIndex >= frameSequence.length) {
throw new IndexOutOfBoundsException();
}
sequenceIndex = inp_sequenceIndex;
| | public void | setFrameSequence(int[] sequence)Set the frame sequence for this Sprite.
All Sprites have a default sequence that displays the Sprites
frames in order. This method allows for the creation of an
arbitrary sequence using the available frames. The current
index in the frame sequence is reset to zero as a result of
calling this method.
The contents of the sequence array are copied when this method
is called; thus, any changes made to the array after this method
returns have no effect on the Sprite's frame sequence.
Passing in null causes the Sprite to revert to the
default frame sequence.
if (sequence == null) {
// revert to the default sequence
sequenceIndex = 0;
customSequenceDefined = false;
frameSequence = new int[numberFrames];
// copy frames indices into frameSequence
for (int i = 0; i < numberFrames; i++)
{
frameSequence[i] = i;
}
return;
}
if (sequence.length < 1) {
throw new IllegalArgumentException();
}
for (int i = 0; i < sequence.length; i++)
{
if (sequence[i] < 0 || sequence[i] >= numberFrames) {
throw new ArrayIndexOutOfBoundsException();
}
}
customSequenceDefined = true;
frameSequence = new int[sequence.length];
System.arraycopy(sequence, 0, frameSequence, 0, sequence.length);
sequenceIndex = 0;
| | public void | setImage(javax.microedition.lcdui.Image img, int frameWidth, int frameHeight)Changes the Image containing the Sprite's frames.
Replaces the current raw frames of the Sprite with a new set of raw
frames. See the constructor {@link #Sprite(Image, int, int)} for
information on how the frames are created from the image. The
values returned by {@link Layer#getWidth} and {@link Layer#getHeight}
will reflect the new frame width and frame height subject to the
Sprite's current transform.
Changing the image for the Sprite could change the number of raw
frames. If the new frame set has as many or more raw frames than the
previous frame set, then:
- The current frame will be unchanged
- If a custom frame sequence has been defined (using
{@link #setFrameSequence(int[])}), it will remain unchanged. If no
custom frame sequence is defined (i.e. the default frame
sequence
is in use), the default frame sequence will be updated to
be the default frame sequence for the new frame set. In other
words, the new default frame sequence will include all of the
frames from the new raw frame set, as if this new image had been
used in the constructor.
If the new frame set has fewer frames than the previous frame set,
then:
- The current frame will be reset to entry 0
- Any custom frame sequence will be discarded and the frame sequence
will revert to the default frame sequence for the new frame
set.
The reference point location is unchanged as a result of calling this
method, both in terms of its defined location within the Sprite and its
position in the painter's coordinate system. However, if the frame
size is changed and the Sprite has been transformed, the position of
the Sprite's upper-left corner may change such that the reference
point remains stationary.
If the Sprite's frame size is changed by this method, the collision
rectangle is reset to its default value (i.e. it is set to the new
bounds of the untransformed Sprite).
// if image is null image.getWidth() will throw NullPointerException
if ((frameWidth < 1 || frameHeight < 1) ||
((img.getWidth() % frameWidth) != 0) ||
((img.getHeight() % frameHeight) != 0)) {
throw new IllegalArgumentException();
}
int noOfFrames =
(img.getWidth() / frameWidth)*(img.getHeight() / frameHeight);
boolean maintainCurFrame = true;
if (noOfFrames < numberFrames) {
// use default frame , sequence index = 0
maintainCurFrame = false;
customSequenceDefined = false;
}
if (! ((srcFrameWidth == frameWidth) &&
(srcFrameHeight == frameHeight))) {
// computing is the location
// of the reference pixel in the painter's coordinate system.
// and then use this to find x and y position of the Sprite
int oldX = this.x +
getTransformedPtX(dRefX, dRefY, this.t_currentTransformation);
int oldY = this.y +
getTransformedPtY(dRefX, dRefY, this.t_currentTransformation);
setWidthImpl(frameWidth);
setHeightImpl(frameHeight);
initializeFrames(img, frameWidth, frameHeight, maintainCurFrame);
// initialize collision rectangle
initCollisionRectBounds();
// set the new x and y position of the Sprite
this.x = oldX -
getTransformedPtX(dRefX, dRefY, this.t_currentTransformation);
this.y = oldY -
getTransformedPtY(dRefX, dRefY, this.t_currentTransformation);
// Calculate transformed sprites collision rectangle
// and transformed width and height
computeTransformedBounds(this.t_currentTransformation);
} else {
// just reinitialize the animation frames.
initializeFrames(img, frameWidth, frameHeight, maintainCurFrame);
}
| | public void | setRefPixelPosition(int inp_x, int inp_y)Sets this Sprite's position such that its reference pixel is located
at (x,y) in the painter's coordinate system.
// update x and y
x = inp_x - getTransformedPtX(dRefX, dRefY,
t_currentTransformation);
y = inp_y - getTransformedPtY(dRefX, dRefY,
t_currentTransformation);
| | public void | setTransform(int transform)Sets the transform for this Sprite. Transforms can be
applied to a Sprite to change its rendered appearance. Transforms
are applied to the original Sprite image; they are not cumulative,
nor can they be combined. By default, a Sprite's transform is
{@link #TRANS_NONE}.
Since some transforms involve rotations of 90 or 270 degrees, their
use may result in the overall width and height of the Sprite
being swapped. As a result, the values returned by
{@link Layer#getWidth} and {@link Layer#getHeight} may change.
The collision rectangle is also modified by the transform so that
it remains static relative to the pixel data of the Sprite.
Similarly, the defined reference pixel is unchanged by this method,
but its visual location within the Sprite may change as a result.
This method repositions the Sprite so that the location of
the reference pixel in the painter's coordinate system does not change
as a result of changing the transform. Thus, the reference pixel
effectively becomes the centerpoint for the transform. Consequently,
the values returned by {@link #getRefPixelX} and {@link #getRefPixelY}
will be the same both before and after the transform is applied, but
the values returned by {@link #getX getX()} and {@link #getY getY()}
may change.
setTransformImpl(transform);
| | private void | setTransformImpl(int transform)Sets the transform for this Sprite
// ---
// setTransform sets up all transformation related data structures
// except transforming the current frame's bitmap.
// x, y, width, height, dRefX, dRefY,
// collisionRectX, collisionRectY, collisionRectWidth,
// collisionRectHeight, t_currentTransformation,
// t_bufferImage
// The actual transformed frame is drawn at paint time.
// ---
// update top-left corner position
this.x = this.x +
getTransformedPtX(dRefX, dRefY, this.t_currentTransformation) -
getTransformedPtX(dRefX, dRefY, transform);
this.y = this.y +
getTransformedPtY(dRefX, dRefY, this.t_currentTransformation) -
getTransformedPtY(dRefX, dRefY, transform);
// Calculate transformed sprites collision rectangle
// and transformed width and height
computeTransformedBounds(transform);
// set the current transform to be the one requested
t_currentTransformation = transform;
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