The Sketch Object
Every instance of jsui has an instance of Sketch bound to the variable "sketch". This is often the only instance of Sketch you will need to use. However, if you want to do things like render sprites, have multiple layers of images, or use drawing commands to create alpha channels for images, then you can create additional instances to render in. By default, when any function in your jsui object has been called the context is already set for the instance of Sketch bound to the variable "sketch".
Sketch Constructor
var mysketch = new Sketch() // create a new instance of Sketch with default width and height
var mysketch = new Sketch(width, height) // create a new instance of sketch with specified width and height
Sketch Simple Line and Polygon Methods
move
Arguments
delta_y [Number]
delta_z [Number]
Moves the drawing position to the location specified by the sum of the current drawing position and the delta x, y, and z arguments.
moveto
Arguments
y [Number]
z [Number]
Moves the drawing position to the location specified by the x, y, and z arguments.
point
Arguments
y [Number]
z [Number]
Draws a point at the location specified by the x, y, and z arguments. After this method has been called, the drawing position is updated to the location specified by the x, y, and z arguments.
line
Arguments
delta_y [Number]
delta_z [Number]
Draws a line from the current drawing position to the location specified the sum of the current drawing position and the delta x, y, and z arguments. After this method has been called, the drawing position is updated to the location specified by the sum of the current drawing position and the delta x, y, and z arguments.
lineto
Arguments
y [Number]
z [Number]
Draws a line from the current drawing position to the location specified by the x, y, and z arguments. After this method has been called, the drawing position is updated to the location specified by the x, y, and z arguments.
linesegment
Arguments
y1 [Number]
z1 [Number]
x2 [Number]
y2 [Number]
z2 [Number]
Draws a line from the location specified by the x1, y1, and z1 arguments to the location specified by the x2, y2, and z2 arguments. After this method has been called, the drawing position is updated to the location specified by the x2, y2, and z2 arguments.
tri
Arguments
y1 [Number]
z1 [Number]
x2 [Number]
y2 [Number]
z2 [Number]
x3 [Number]
y3 [Number]
z3 [Number]
Draws a filled triangle with three corners specified by the x1, y1, z1, x2, y2, z2, x3, y3, and z3 arguments. After this method has been called, the drawing position is updated to the location specified by the x3, y3, and z3 arguments.
frametri
Arguments
y1 [Number]
z1 [Number]
x2 [Number]
y2 [Number]
z2 [Number]
x3 [Number]
y3 [Number]
z3 [Number]
Draws a framed triangle with three corners specified by the x1, y1, z1, x2, y2, z2, x3, y3, and z3 arguments. After this method has been called, the drawing position is updated to the location specified by the x3, y3, and z3 arguments.
quad
Arguments
y1 [Number]
z1 [Number]
x2 [Number]
y2 [Number]
z2 [Number]
x3 [Number]
y3 [Number]
z3 [Number]
x4 [Number]
y4 [Number]
z4 [Number]
Draws a filled quadrilateral with four corners specified by the x1, y1, z1, x2, y2, z2, x3, y3, z3, x4, y4, and z4 arguments. After this method has been called, the drawing position is updated to the location specified by the x4, y4, and z4 arguments.
framequad
Arguments
y1 [Number]
z1 [Number]
x2 [Number]
y2 [Number]
z2 [Number]
x3 [Number]
y3 [Number]
z3 [Number]
x4 [Number]
y4 [Number]
z4 [Number]
Draws a framed quadrilateral with four corners specified by the x1, y1, z1, x2, y2, z2, x3, y3, z3, x4, y4, and z4 arguments. After this method has been called, the drawing position is updated to the location specified by the x4, y4, and z4 arguments.
Shape Methods
circle
Arguments
theta_start [Number]
theta_end [Number]
Draws a filled circle with radius specified by the radius argument. If theta_start and theta_end are specified, then an arc will be drawn instead of a full circle. The theta_start and theta_end arguments are in terms of degrees(0-360). The current shapeorient, shapeslice, and shapeprim values will also affect the drawing.
cube
Arguments
scale_y [Number]
scale_z [Number]
Draws a cube with width 2*scale_x, height 2*scale_y, depth 2*scale_z, and center point at the current drawing position. If the scale_y and scale_z arguments are not specified, they will assume the same value as scale_x. The current shapeorient, shapeslice, and shapeprim values will also affect the drawing.
cylinder
Arguments
radius2 [Number]
mag [Number]
theta_start [Number]
theta_end [Number]
Draws a cylinder with top radius specified by the radius1 argument, bottom radius specified by the radius2 argument, length specified by the mag argument, and center point at the current drawing position. If the theta_start and theta_end arguments are specified, then a patch will be drawn instead of a full cylinder. The theta_start and theta_end arguments are in terms of degrees(0-360). The current shapeorient, shapeslice, and shapeprim values will also affect the drawing.
ellipse
Arguments
radius2 [Number]
theta_start [Number]
theta_end [Number]
Draws a filled ellipse with radii specified by the radius1 and radius2 arguments. If theta_start and theta_end are specified, then an arc will be drawn instead of a full ellipse. The theta_start and theta_end arguments are in terms of degrees(0-360). The current shapeorient, shapeslice, and shapeprim values will also affect the drawing.
framecircle
Arguments
theta_start [Number]
theta_end [Number]
Draws a framed circle with radius specified by the radius argument. If theta_start and theta_end are specified, then an arc will be drawn instead of a full circle. The theta_start and theta_end arguments are in terms of degrees(0-360). The current shapeorient, shapeslice, and shapeprim values will also affect the drawing.
frameellipse
Arguments
radius2 [Number]
theta_start [Number]
theta_end [Number]
Draws a framed ellipse with radii specified by the radius1 and radius2 arguments. If theta_start and theta_end are specified, then an arc will be drawn instead of a full ellipse. The theta_start and theta_end arguments are in terms of degrees(0-360). The current shapeorient, shapeslice, and shapeprim values will also affect the drawing.
plane
Arguments
scale_y1 [Number]
scale_x2 [Number]
scale_y2 [Number]
Draws a plane with top width 2*scale_x1, left height 2*scale_y1, bottom width 2*scale_x2, right height 2*scale_y2, and center point at the current drawing position. If scale_y1 is not specified, it will assume the same value as scale_x1. If scale_x2 and scale_y2 are not specified, they will assume the same values as scale_x1 and scale_y1 respectively. The current shapeorient, shapeslice, and shapeprim values will also affect the drawing.
roundedplane
Arguments
scale_x [Number]
scale_y [Number]
Draws a rounded plane with width 2*scale_x, and height 2*scale_y and center point at the current drawing position. The size of the rounded portion of the plane is determined by the round_amount argument. If scale_y is not specified, it will assume the same value as scale_x. The current shapeorient, shapeslice, and shapeprim values will also affect the drawing.
sphere
Arguments
theta1_start [Number]
theta1_end [Number]
theta2_start [Number]
theta2_end [Number]
Draws a sphere with radius specified by the radius argument and center point at the current drawing position. If the theta1_start, theta1_end, theta2_start, and theta2_end arguments are specified, then a patch will be drawn instead of a full sphere. The theta1_start, theta1_end, theta2_start, and theta2_end arguments are in terms of degrees(0-360). The current shapeorient, shapeslice, and shapeprim values will also affect the drawing.
torus
Arguments
radius2 [Number]
theta1_start [Number]
theta1_end [Number]
theta2_start [Number]
theta2_end [Number]
Draws a torus with major radius specified by the radius1 argument, minor radius specified by the radius2 argument, and center point at the current drawing position. If theta1_start, theta1_end, theta2_start, and theta2_end are specified, then a patch will be drawn instead of a full torus. The theta1_start, theta1_end, theta2_start, and theta2_end arguments are in terms of degrees(0-360). The current shapeorient, shapeslice, and shapeprim values will also affect the drawing.
Sketch Shape Attribute Methods
shapeorient
Arguments
rotation_y [Number]
rotation_z [Number]
Sets the rotation for drawing internal to any of the "shape" drawing methods to the rotation specified by the x_rot, y_rot, and rotation_x, rotation_y, and rotation_z arguments. Its use internal to a given shape method such as torus(0.1) would essentially be equivalent to the following set of OpenGL calls.
with (sketch) {
glmatrixmode("modelview")
glpushmatrix()
glrotate(rotation_x, 1, 0, 0)
glrotate(rotation_y, 1, 1, 0)
glrotate(rotation_z, 0, 0, 1)
torus(0.5, 0.2)
glpopmatrix()
}
shapeslice
Arguments
slice_b [Number]
Sets the number of slices to use when rendering any of the "shape" drawing methods. Increasing the slice_a and slice_b arguments will increase the quality at which the shape is rendered, while decreasing these values will improve performance.
shapeprim
Arguments
Sets the OpenGL drawing primitive to use within any of the "shape" drawing methods. Acceptable values for the draw_prim argument are the following strings: lines, line_loop, line_strip, points, polygon, quads, quad_grid, quad_strip, triangles, tri_grid, tri_fan, tri_strip.
Sketch Text Methods
font
Arguments
Sets the current font to the fontname specified by the fontname argument.
fontsize
Arguments
Sets the fontsize to the size specified by the points argument. Note that this size is an absolute, rather than relative value.
gettextinfo
Arguments
Returns an array containing the width and height of the given string in absolute screen coordinates, taking into account the current font and fontsize.
text
Arguments
Draws the text specified by the string argument at the current drawing position, taking into account the current font, fontsize, and text alignment. Text is strictly 2D, and does not take into account any world transformations. After calling the text method, if the x axis text alignment is set to "left", the current drawing position will be updated to reflect the world position associated with the end of the string. If the x axis text alignment is set to "right", the current drawing position will be updated to reflect the world position associated with the end of the string. If the x axis text alignment is set to "center", the current drawing position will remain unchanged.
textalign
Arguments
align_y [String]
Sets the alignment of text to be drawn with respect to the current drawing position. Acceptable values for the x axis alignment are: "left", "right", or "center". Acceptable values for the y axis alignment are: "bottom", "top", or "center". The default alignment is "left", "bottom".
Sketch Pixel Methods Methods
copypixels
Arguments
destination_x [Number]
destination_y [Number]
source_x [Number]
source_y [Number]
width [Number]
height [Number]
Copies pixels from the source object to the location specified by the destination_x and destination_y arguments. The initial x and y offset into the source and size of the rectangle copied can be speified by the source_x, source_y, width and height arguments. If these are not present an x and y offset of zero and width and height equal to the source image is assumed. No scaling of pixels is supported. The source object can either be an instance of Image, or Sketch. If blending is enabled in the destination sketch object, alpha blending will be performed and the current alpha color will also be applied globally. The copypixels method is much faster than obtaining the equivalent result using glbindtexture() to texture a plane, and is the recommended means of drawing images when scaling and rotation is not required.
depthatpixel
Arguments
y [Number]
Returns the depth value associated with the currently rendered pixel at a given absolute screen coordinate.
freepeer
Frees the image data from the native c peer, which is not considered by the JavaScript garbage collector, and may consume lots of memory until the garbage collector decides to run based on JS allocated memory. Once called, the Sketch object is not available for any other use.
getpixel
Arguments
y [Number]
Returns an array containing the pixel value at the specified location. This array is ordered RGBA, i.e. array element 0 is red, 1, green, 2, blue, 3 alpha. Color values are floating point numbers in the range 0.-1.
setpixel
Arguments
y [Number]
red [Number]
green [Number]
blue [Number]
alpha [Number]
Sets the pixel value at the specified location. Color values are floating point numbers in the range 0.-1.
screentoworld
Arguments
y [Number]
Returns an array containing the x, y, and z world coordinates associated with a given screen pixel using the same the depth from the camera as 0,0,0. Optionally a third depth arg may be specified, which may be useful for hit detection and other applications. The depth value is typically specified in the range 0.-1. where 0 is the near clipping plane, and 1. is the far clipping plane. The worldtoscreen method can be used to determine the depth value of a given world coordinate, and the depthatpixel method can be used to determine the depth value associated with the currently rendered pixel at a given absolute screen coordinate.
worldtoscreen
Arguments
y [Number]
z [Number]
Returns an array containing the x, y, and depth screen coordinates associated with a given world coordinate. The depth value is typically specified in the range 0.-1. where 0 is the near clipping plane, and 1. is the far clipping plane.
Sketch Stroke Methods
beginstroke
Arguments
Begin definition of a stroked path of the style specified by the stroke_style argument. Currently supported stroke styles are "basic2d" and "line".
endstroke
End definition of a stroked path, and render the path.
strokeparam
Arguments
parameter_values [Anything]
arguments [Anything]
Set the current value of the parameter specified by the parameter_name argument to be the value specified by parameter_values argument(s). Some parameters are global for the extent of a stroked path definition, while others may vary on a point by point basis.
strokepoint
Arguments
y [Number]
z [Number]
Defines an anchor point at the location specified by the x, y, and z arguments. Some stroke styles such as "basic2d" will ignore the z coordinate.
Basic 2D Stroke Style Parameters
alpha
May vary point to point. Value is specified as an alpha value. Useful if alpha is the only color channel which will vary throughout the path.
color
May vary point to point. Values are specified as red, green, blue, and alpha values.
order
global. Value is specified as interpolation order. The default order is 3, or bi-cubic interpolation.
outline
global. Value is specified as on/off (0/1). The default is 1.
outcolor
May vary point to point. Values are specified as red, green, blue, and alpha values. If no outcolor has been specified, then the current color is assumed.
scale
May vary point to point. Value is specified as an width value. This value controls how wide the stroked path is.
slices
global. Value is specified as number of slices per curve section. The default is 20.
Line Stroke Style Parameters
alpha
May vary point to point. Value is specified as an alpha value. Useful if alpha is the only color channel which will vary throughout the path.
color
May vary point to point. Values are specified as red, green, blue, and alpha values.
order
global. Value is specified as interpolation order. The default order is 3, or bi-cubic interpolation.
slices
global. Value is specified as number of slices per curve section. The default is 20.
Sketch Setup Methods
default2d
The default2d method is a simple way to set the graphics state to default properties useful for 2D graphics. It is called everytime your object is resized if default2d() has been called more recently than default3d(). It is essentially equivalent to the following set of calls:
with (sketch) {
glpolygonmode("front_and_back", "fill")
glpointsize(1)
gllinewidth(1)
gldisable("depth_test")
gldisable("fog")
glcolor(0, 0, 0, 1)
glshademodel("smooth")
gldisable("lighting")
gldisable("normalize")
gldisable("texture")
glmatrixmode("projection")
glloadidentity()
glortho(-aspect, aspect, -1, 1, -1, 100)
glmatrixmode("modelview")
glloadidentity()
glulookat(0, 0, 2, 0, 0, 0, 0, 0, 1)
glclearcolor(1, 1, 1, 1)
glclear()
glenable("blend")
glblendfunc("src_alpha", "one_minus_src_alpha")
}
default3d
The default3d method is a simple way to set the graphics state to default properties useful for 3D graphics. It is called everytime the jsui object is resized if default3d() has been called more recently than default2d().
It is essentially equivalent to the following set of calls:
with (sketch) {
glpolygonmode("front_and_back", "fill")
glpointsize(1)
gllinewidth(1)
glenable("depth_test")
glenable("fog")
glcolor(0, 0, 0, 1)
glshademodel("smooth")
gllightmodel("two_side", "true")
glenable("lighting")
glenable("light0")
glenable("normalize")
gldisable("texture")
glmatrixmode("projection")
glloadidentity()
gluperspective(default_lens_angle, aspect, 0.1, 100)
glmatrixmode("modelview")
glloadidentity()
glulookat(0, 0, 2, 0, 0, 0, 0, 0, 1)
glclearcolor(1, 1, 1, 1)
glclear()
glenable("blend")
glblendfunc("src_alpha", "one_minus_src_alpha")
}
ortho3d
Arguments
The orth3d method is a simple way to set the graphics state to default properties useful for 3D graphics, using an orthographic projection (i.e. object scale is not affected by distance from the camera). It is called every time the jsui object is resized if ortho3d() has been called more recently than default2d(), or default3d().
It is essentially equivalent to the following set of calls:
with (sketch) {
glpolygonmode("front_and_back", "fill")
glpointsize(1)
gllinewidth(1)
glenable("depth_test")
glenable("fog")
glcolor(0, 0, 0, 1)
glshademodel("smooth")
gllightmodel("two_side", "true")
glenable("lighting")
glenable("light0")
glenable("normalize")
gldisable("texture")
glmatrixmode("projection")
glloadidentity()
glortho(-aspect, aspect, -1, 1, -1, 100)
glmatrixmode("modelview")
glloadidentity()
glulookat(0, 0, 2, 0, 0, 0, 0, 0, 1)
glclearcolor(1, 1, 1, 1)
glclear()
glenable("blend")
glblendfunc("src_alpha", "one_minus_src_alpha")
}
Sketch OpenGL Methods
glbegin
Arguments
glbindtexture
Arguments
Note: this method also calls glenable(texture)
glblendfunc
Arguments
dst_function [String]
glclear
glclearcolor
Arguments
green [Number]
blue [Number]
alpha [Number]
glcleardepth
Arguments
glclipplane
Arguments
coeff1 [Number]
coeff2 [Number]
coeff3 [Number]
coeff4 [Number]
glcolor
Arguments
green [Number]
blue [Number]
alpha [Number]
glcolormask
Arguments
green [Number]
blue [Number]
alpha [Number]
glcolormaterial
Arguments
mode []
glcullface
Arguments
gldepthmask
Arguments
gldepthrange
Arguments
far [Number]
gldisable
Arguments
gldrawpixels
Arguments
gledgeflag
Arguments
glenable
Arguments
glend
glfinish
glflush
glfog
Arguments
value [Number]
glfrustum
Arguments
right [Number]
bottom [Number]
top [Number]
near [Number]
far [Number]
glhint
Arguments
mode [Number]
gllight
Arguments
parameter_name [String]
value [Number]
gllightmodel
Arguments
value [Number]
gllinestipple
Arguments
bit-pattern []
gllinewidth
Arguments
glloadidentity
glloadmatrix
Arguments
gllogicop
Arguments
glmaterial
glmatrixmode
Arguments
glmultmatrix
Arguments
glnormal
Arguments
y [Number]
z [Number]
glortho
Arguments
right [Number]
bottom [Number]
top [Number]
near [Number]
far [Number]
glpointsize
Arguments
glpolygonmode
Arguments
mode [Number]
glpolygonoffset
Arguments
units [Number]
glpopattrib
glpopmatrix
glpushattrib
glpushmatrix
glrect
Arguments
y1 [Number]
x2 [Number]
y2 [Number]
glrotate
Arguments
x [Number]
y [Number]
z [Number]
glscale
Arguments
y_scale [Number]
z_scale [Number]
glscissor
Arguments
y [Number]
width [Number]
height [Number]
glshademodel
Arguments
gltexcoord
Arguments
t []
gltexenv
Arguments
val1 [String]
val2 [String]
val3 [String]
val4 [String]
gltexgen
Arguments
parameter_name [String]
val1 [String]
val2 [String]
val3 [String]
val4 [String]
gltexparameter
Arguments
val1 [String]
val2 [String]
val3 [String]
val4 [String]
gltranslate
Arguments
delta_y [Number]
delta_z [Number]
glulookat
Arguments
eye_y [Number]
eye_z [Number]
center_x [Number]
center_y [Number]
center_z [Number]
up_x [Number]
up_y [Number]
up_z [Number]
gluortho2d
Arguments
right [Number]
bottom [Number]
top [Number]
gluperspective
Arguments
aspect [Number]
near [Number]
far [Number]
glvertex
Arguments
y [Number]
z [Number]
glviewport
Arguments
y [Number]
width [Number]
height [Number]
See Also
| Name | Description |
|---|---|
| JavaScript Usage | JavaScript Usage |