jit.gl.render

Render Open GL

Description

The jit.gl.render object requires a single argument -- a name that will be attached to its OpenGL context. The OpenGL drawing can be sent to any named jit.window, jit.pwindow or jit.matrix object. Use the drawto destination message to change the destination on which the drawing results will be visible. When drawing to a jit.matrix object, the matrix must be sent to a pwindow or otherwise made visible in order to view the drawing.

There are two ways of drawing things with jit.gl.render : creating Jitter OpenGL objects such as the jit.gl.plato object, and sending drawing commands directly to the jit.gl.render object. When you create new jit.gl objects, they appear automatically in the OpenGL scene and are redrawn each time a bang is sent to the jit.gl.render object. This provides an easy way to begin drawing 3D scenes. When you use drawing commands directly to a jit.gl.render object, you must create a patch which sends the desired sequence of drawing messages for each frame. This method of drawing offers lots of flexibility.

The most commonly used drawing command is jit_matrix . Matrices sent using this command are drawn as 2D or 3D geometry, according to the currently set graphics primitive or one set explicitly in the command. Other drawing commands include draw_pixels , which draws the matrix contents as a 2D picture, and test , which draw standard SMPTE color bars.

OpenGL is a standard for 3D drawing based on a complex virtual machine with commands for viewing, lighting, texturing, 2D imaging, and frame buffer control. A full discussion of OpenGL is beyond the scope of this reference. A valuable starter reference is the OpenGL "Red Book". please see www.opengl.org for more information.

Information for Jitter 3D Object (OB3D) messages and attributes to this object

Messages

erase Overwrites the image buffer with the color and opacity selected by the erase_color attribute.
deletetexture texture-name [symbol]
Followed by a texture name, delete the named texture.
depth_grab Copy the depth buffer to a named texture
draw_pixels Followed by a jit.matrix, draw the matrix data as a 2D image filling the screen.
drawclients layer [int]
Draw all automatic clients, optionally with specific layer number.
drawswap Draw all automatic clients, and copy the rendered image to the destination jit.window, jit.pwindow or jit.matrix.
jit_glchunk For internal use only.
interp 0/1 [int]
Toggles interpolation for the currently selected named texture (default = 0)
line_loop Sets the draw primitive to draw the matrix geometry as a loop of lines connecting each vertex and then returning to the first.
line_strip Sets the draw primitive to draw the matrix geometry as a strip of lines connecting each vertex.
lines Sets the draw primitive to draw the matrix geometry as unconnected lines between each pair of vertices.
points Sets the draw primitive to draw the matrix geometry as points.
quad_grid Sets the draw primitive to draw the matrix geometry as a grid connecting neighboring matrix elements. Each vertex in the matrix is connected to the vertices next to it in the x and y directions. Each square of vertices ((x,y), (x+1,y), (x,y+1),(x+1,y+1)) is then drawn as one quadrilateral.
quad_strip Sets the draw primitive to draw the matrix geometry as a strip of connected quadrilaterals.
quads Sets the draw primitive to draw the matrix geometry as unconnected quadrilaterals.
point_sprite Set point sprites as the render primitive for the object.
polygon Sets the draw primitive to draw the matrix geometry as vertices of one simple polygon.
test Draws a set of SMPTE standard color bars to the output.
sendtexture message [list]
Sends the internal jit.gl.texture object, currently selected with the usetexture method, the corresponding message.
swap Copy the rendered image to the destination jit.window, jit.pwindow or jit.matrix.
updateclients Update the render list (list of attached jit.gl objects).
usetexture texture-name [symbol]
Use the named texture for drawing primitives.
to_texture Copy the previously drawn frame to the named texture. Useful for feedback effects.
tri_fan Sets the draw primitive to draw the matrix geometry as a fan of connected triangles.
tri_grid Sets the draw primitive to draw the matrix geometry as a grid connecting neighboring matrix elements. Each vertex in the matrix is connected to the vertices next to it in the x and y directions. Each square of vertices ((x,y), (x+1,y), (x,y+1),(x+1,y+1)) is then drawn as two triangles.
tri_strip Sets the draw primitive to draw the matrix geometry as a strip of connected triangles.
triangles Sets the draw primitive to draw the matrix geometry as unconnected triangles.
screentoworld x [float]
y [float]
z [float]
Converts screen coordinates to world coordinates, output out the dump outlet. The input x and y input coordinates are in pixels, and the input z coordinate is in normalized distance from camera (0.-1.), where 0. is the near clipping plane and 1. is the far clipping plane.
worldtoscreen x [float]
y [float]
z [float]
Converts screen coordinates to world coordinates, output out the dump outlet. The output x and y input coordinates are in pixels, and the output z coordinate is in normalized distance from camera (0.-1.), where 0. is the near clipping plane and 1. is the far clipping plane.

Attributes

Name Type g/s Description
accelerated int Toggles enabling hardware-accelerated rendering.
aux_buffers int Set the number of auxiliary buffers available
camera float The camera position in 3D space (default = 0. 0. 2.) Camera position is specified as a set of floating point numbers that correspond to a camera position with respect to the x, y, and z axes.
copy_texture symbol Named texture to copy the framebuffer to.
debug int If enabled and jit.gl.render detects lack of support for versions of OpenGL later than 1.2, it will print a summary of the capabilities of the rendering context to the Max window for diagnosis.
doublebuffer int Toggles double buffering the drawing context (front and back buffers). You may prefer so set double buffering in the jit.window object instead.
draw_buffer symbol Sets the drawing buffer. This feature is useful for active stereo drawing. Possible values are:

back
front
left
right
back_left
back_right,
front_left
front_right
front_and_back
drawto symbol Select the drawing destination for output. Must be a named jit.window, jit.pwindow or jit.matrix.
erase_color float Color and opacity with which image is overdrawn on receipt of erase message in the form red green blue opacity (default = 0. 0. 0. 1. (opaque black)) All values should be in the range 0.-1.
far_clip float The far clipping plane distance in 3D world (default = 100.)
fsaa int Enables full-scene anti-aliased drawing. You may prefer so set fsaa in the jit.window object using the @fsaa attribute.
geom_rows int Vertex connection mode (default = 0 (connect along columns))
0 = connect vertices in 2D geometry matrix along columns
1 = connect vertices in 2D geometry matrix along rows
lens_angle float The lens angle of the OpenGL camera (default = 45.)
light_ambient float The color and opacity of the ambient light component in the form red green blue opacity (default = 0. 0. 0. 1. (opaque black)) All values should be in the range 0.-1.
light_diffuse float The color and opacity of the diffuse light component in the form red green blue opacity (default = 1. 1. 1. 1. (opaque white)) All values should be in the range 0.-1.
light_global_ambient float The color and opacity of the global ambient light component in the form red green blue opacity (default = 0.2 0.2 0.2 1.) All values should be in the range 0.-1.
light_position float The position of the light source in XYZ coordinates and the light type (default = 1. 1. 1. 0.)
When the last number is 0., t The light is treated as a directional source if 0. is the final number. Otherwise, diffuse and specular lighting calculations are based on the actual location of the light in eye coordinates, and attenuation is enabled.
light_specular float Color and opacity of specular light component (default = 1. 1. 1. 1. (opaque white)) The first three floats in the range 0.-1. specify the RGB components of the specular light color. The fourth float (also in the range 0.-1.) specifies opacity.
lookat float 3D position at which the camera is pointed (default = 0. 0. 0.)
near_clip float The near clipping plane distance in 3D world (default = 0.1)
point_atten float Sets the point attenuation factor for point sprites
point_fade float Sets the point fade threshold for point sprites.
primitive symbol The current drawing primitive (default = tri_grid)
quality int Quality flag when using software renderer (default = 0). (Mac only) Slower than normal SW renderer, but supports larger rendering, shaders, and other advanced features.
shared_context symbol The name of a context to share resources (i.e. textures) with.
stereo int Sets the rendering context as stereo. You may prefer so set this in the jit.window object
sync int Sets the vertical sync of the render context. You may prefer so set this in the jit.window object.
up float The 3D vector towards which the top of the camera points (default = 0. 1. 0.)
verbose int Toggles printing messages to the Max Window.

Information for box attributes common to all objects

Examples

See Also

Name Description
jit.gl.graph Open GL floating-point data visualization
jit.gl.gridshape Generate simple geometric shapes as a connected grid
jit.gl.handle Use mouse movement to control position/rotation
jit.gl.isosurf Generates a GL based surface extraction
jit.gl.mesh Generates GL geometry from existing data
jit.gl.model Read and draw Wavefront .obj models
jit.gl.nurbs Generate NURBS surface
jit.gl.plato Generate platonic solids
jit.gl.shader Manages a GL shader
jit.gl.sketch GL parallel to lcd
jit.gl.slab Performs a GL accelerated grid-based evaluation
jit.gl.text2d Write bitmap text
jit.gl.text3d Write vector text
jit.gl.texture Manages a GL texture
jit.gl.videoplane GL accelerated video plane
jit.gl.volume Creates a GL accelerated volume vizualization
Tutorial 30: Drawing 3D text Tutorial 30: Drawing 3D text
Tutorial 31: Rendering Destinations Tutorial 31: Rendering Destinations
Tutorial 32: Camera View Tutorial 32: Camera View
Tutorial 33: Polygon Modes, Colors and Blending Tutorial 33: Polygon Modes, Colors and Blending
Tutorial 34: Using Textures Tutorial 34: Using Textures
Tutorial 35: Lighting and Fog Tutorial 35: Lighting and Fog
Tutorial 37: Geometry Under the Hood Tutorial 37: Geometry Under the Hood
Tutorial 47: Using Jitter Object Callbacks in JavaScript Tutorial 47: Using Jitter Object Callbacks in JavaScript