From 089475041fe26964d72cb2ebc3559a36ba89a2f2 Mon Sep 17 00:00:00 2001 From: "N.N." Date: Tue, 8 Jul 2008 05:56:10 +0000 Subject: trying to import gridflow 0.9.4 svn path=/trunk/; revision=10148 --- externals/gridflow/doc/architecture.html | 65 ++++++++++++++++++++++++++++++++ 1 file changed, 65 insertions(+) create mode 100644 externals/gridflow/doc/architecture.html (limited to 'externals/gridflow/doc/architecture.html') diff --git a/externals/gridflow/doc/architecture.html b/externals/gridflow/doc/architecture.html new file mode 100644 index 00000000..daa8b3ea --- /dev/null +++ b/externals/gridflow/doc/architecture.html @@ -0,0 +1,65 @@ +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. -- cgit v1.2.1