From 5a6bee4fe076e06514c6e4e538590dd3a2a5cdc3 Mon Sep 17 00:00:00 2001 From: "N.N." Date: Fri, 6 Nov 2009 18:37:00 +0000 Subject: upgrade gridflow svn path=/trunk/; revision=12728 --- externals/gridflow/doc/stuff.txt | 144 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 144 insertions(+) create mode 100644 externals/gridflow/doc/stuff.txt (limited to 'externals/gridflow/doc/stuff.txt') diff --git a/externals/gridflow/doc/stuff.txt b/externals/gridflow/doc/stuff.txt new file mode 100644 index 00000000..2a495735 --- /dev/null +++ b/externals/gridflow/doc/stuff.txt @@ -0,0 +1,144 @@ +Grid Literals + In every grid-accepting inlet, a list may be sent instead; if + it consists only of integers, it will be converted to a + one-dimensional grid. Else it may contain a single "#" sign and + integers on both sides of it, where the ones to the left of it are + fed as arguments to an imaginary [#redim] object and the one to the + right of it are fed through that [#redim]. + In every grid-accepting inlet, an integer or float may also be sent; + it will be converted to a zero-dimensional grid (a scalar). + +Grid Protocol + a grid has an associated number type that defines what are the possible values for its elements + (and how much space it takes). the default is int32. + a single-dimensional grid of 3 elements (a triplet) is called dim(3). a + three-dimensional grid of 240 rows of 320 columns of triplets is called + dim(240,320,3). + There is a sequence in which elements of a Grid are stored and + transmitted. Dimension 0 is called "first" and dimension N-1 is + called "last". They are called so because if you select a + position in the first dimension of a grid, the selected part is of the same + shape minus the first dimension; so in dim(240,320,3) if you select + row 51 (or whichever valid row number), you get a dim(320,3). if you select + a subpart two more times you get to a single number. + At each such level, elements are sent/stored in their numeric order, + and are numbered using natural numbers starting at 0. This ordering usually + does not matter, but sometimes it does. Most notably, [#import], [#export] and [#redim] care about it. + On the other hand, order of dimensions usually does matter; this is + what distinguishes rows from columns and channels, for example. + Most objects care about the distinction. + A grid with only 1 element in a given dimension is different from one + lacking that dimension; it won't have the same meaning. You can use this + property to your advantage sometimes. + Zero-dimensional grids exist. They are called dim(). They can only contain + a single number. +Picture Protocol + This section is useful if you want to know what a picture is in terms of a grid. + A picture is a three-dimensional Grid: 0:rows 1:columns 2:channels + +Channels for the RGB color model are: 0:red 1:green 2:blue + Because Grids are made of 32-bit integers, a three-channel picture uses + 96 bpp (bits per pixel), and have to be downscaled to 24 bpp (or 16 bpp) + for display. That huge amount of slack is there because when you create + your own effects you often have intermediate results that need to be of + higher precision than a normal picture. Especially, results of multiplications + are big and should not overflow before you divide them back to normal; + and similarly, you can have negative values all over, as long as you take + care of them before they get to the display. + In the final conversion, high bits are just ignored. This means: black is + 0, maximum is 255, and values wrap like with % 256. If you want to + clip them, you may use [# max 0] and [# min 255] objects. + +The following are called VecOps because each operation happens between more than just two numbers. +A first kind of VecOp are those that arise when a pair of numbers (A0,A1) is considered as a single number A0+A1*sqrt(-1). +If you need complex numbers but don't know yet how they work, learn them using a math tutorial and then those VecOps will begin to seem familiar. +All the complex number operators are only for floats. +TODO: fill the last two columns of this table. + +Synchronisation + +In GridFlow you cannot send two grids in different inlets at the +same time. You have to use [#finished] together with (possibly) [fork] and [#store], +which can be cumbersome. If you don't do this, the result is undefined +behaviour (or crash!). +There are two exceptions: [#store] and # allow right-inlet grids to be buffered if an operation is occuring on left inlet. This +should make many programs simpler. + + +Introduction + + The philosophy that guides PureData is a simple but powerful one: + the software must first provide the user with generic tools + rather than imposing pre-cooked effects. In other words the user + should have total freedom. + + GridFlow follows that philosophy: it first defines elementary + mathematical operations. Those can in turn be used as simple + visual effects or be combined to produce more complex effects. + + The strategy followed by most video plugins for PureData and MAX/MSP, is + to provide the user first with constructs for manipulating video + streams at a fairly high level. The strategy put forward by GridFlow + is different. + + It can be said that in all those video plugins there are three layers: + the first, the low level, is not accessible to non-programmers (and fairly + difficult of access even to programmers); the second, mathematical, where + one needs not to be a C++ programmer, but still requires a good + understanding of how numbers and pixels and colours and geometry work; and + a third level that looks more like the software an artist would like to + use. + + In other video plugins there is a fairly low emphasis on the second + layer. In GridFlow that layer is very strong and opens many possibilities. + Even though the third layer in GridFlow is not as developed as it could, + the second layer may be used to produce third-layer object classes much + more quickly. + + GridFlow provides a unifying view of multimedia information. Several + kinds of data -- raster graphics in any number of channels, coordinate + transforms, matrices, vectors -- may all be represented by Grids + (also known as multi-dimensional arrays). Grids exist in several ways: they + are usually streamed from object to object, but they can also be stored in + memory, stored into a file, sent through the network. + + Here is an example of how things work in GridFlow. (if you want more + information, consult the rest of this manual) + + A picture is a three-dimensional Grid: + 0 : rows + 1 : columns + 2 : channels + + Pictures come in all sorts of heights and widths. The channels, however, + are more limited in number. Usually it's three: Red, Green, Blue. + + A coordinate transform, when specified pixel by pixel, may be a + three-dimensional Grid in which the two "channels" are Y and X, + representing row-and-column positions in a separate picture. + + Other shapes of grids could be designed to represent various things; + for example, configuration for blur effects. Grids could be useful for + things not directly related to raster pictures (e.g. sound recordings). + Those are all kinds of things you could actually develop _within_ the + PureData / GridFlow framework. You don't need to wait for me. + + +GridFlow Release + +dir=gridflow-0.9.6; tag=gridflow_0_9_6 +svn copy svn+ssh://gridflow.ca/home/svn/gridflow/trunk svn+ssh://gridflow.ca/home/svn/gridflow/tags/$tag/ +svn export svn+ssh://gridflow.ca/home/svn/gridflow/tags/$tag/ $dir +chmod -R go=u-w $dir && tar cfzvv $dir.tar.gz $dir && rm -rf $dir +scp $dir.tar.gz gridflow@artengine.ca:public_html/download +mv $dir.tar.gz /home/matju/GridFlow +cd doc/homepage; pico index.html; make install + +download somewhere else and try to compile +pd-announce mlist : post release + +Committed revision 4239. +Warning: 'post-commit' hook failed with error output: +/home/svn/gridflow/hooks/post-commit: line 49: /home/svn/gridflow/hooks/svn-mailer.log: Permission denied + +svn copy svn+ssh://gridflow.ca/home/svn/gridflow/tags/$tag/ https://pure-data.svn.sourceforge.net/svnroot/pure-data/trunk/externals/gridflow/ -- cgit v1.2.1