GEM-dev August 2007

gem-dev@lists.iem.at

14 participants
22 discussions

added me as a developer
by Hans-Christoph Steiner 13 Sep '07

13 Sep '07

Hey, I just talked with IOhannes about getting added to the pd-gem sourceforge project as a developer. He told me to post here in the same style as pd-dev. For anyone who might not know me, I've been using Pd since 2000, I was a lurker for a couple years, then 2002 starting posting and working on Pd itself. I am currently the main developer of the Pd- extended package, and am working USB HID and arduino interfaces, as well as the mapping library. I would like to be added as a gem dev so that I can update and maintain the Gem help and example patches. I could also fix very minor bugs, like a couple I recently submitted, but I have no plans to start writing Gem objects or extensions since my OpenGL knowledge is theory only, no practice. So now... it's lazy consensus time! .hc ------------------------------------------------------------------------ ---- Mistrust authority - promote decentralization. - the hacker ethic

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rectangle texture coords in GLSL shaders
by chris clepper 30 Aug '07

30 Aug '07

In order to make certain texture manipulations work using rectangle textures (sampler2DRect) the shader needs to know the absolute pixel dimensions of the image. The only way to do this is to pass the shader those values from an outside source. The two methods I have figured out are as follows: 1) Create a reserved uniform variable like 'TextureUnit1Dimensions' and pass the dimensions from the GemState to any shader with that uniform in the shader. 2) Use pix_info to read the dimensions and pass them to the shader using a message to glsl_program. The shader just needs a uniform vec2 that matches the message. The first one is more automagic but it requires knowing the exact magic variable name(s) to make working shaders. The second follows the Pd paradigm better and allows for the shader to use any name for the uniform. I'm leaning to the second option as the most flexible and sensible even though it probably presents a higher margin of user error and makes for additional patch clutter. It also requires no change to the existing code! Thoughts? cgc PS- This came up while working with Anton to get the vade shader set fully functional in GEM. These changes will make that happen.

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[ pd-gem-Bugs-1784219 ] closing gemwin on OSX does not destroy the window
by SourceForge.net 29 Aug '07

29 Aug '07

Bugs item #1784219, was opened at 2007-08-29 11:47 Message generated for change (Tracker Item Submitted) made by Item Submitter You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=507079&aid=1784219&group_… Please note that this message will contain a full copy of the comment thread, including the initial issue submission, for this request, not just the latest update. Category: None Group: None Status: Open Resolution: None Priority: 5 Private: No Submitted By: Hans-Christoph Steiner (eighthave) Assigned to: Nobody/Anonymous (nobody) Summary: closing gemwin on OSX does not destroy the window Initial Comment: On Mac OS X 10.4.10 Intel, when you close a gemwin using the red close button on the menubar of the gemwin, it does not destroy the window. In order to recreate it, you have to first send a destroy message, then a create. I haven't tested on other Macs. ---------------------------------------------------------------------- You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=507079&aid=1784219&group_…

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[ pd-gem-Bugs-1784169 ] pix_video help patch not found on Mac OS X
by SourceForge.net 29 Aug '07

29 Aug '07

Bugs item #1784169, was opened at 2007-08-29 10:39 Message generated for change (Tracker Item Submitted) made by Item Submitter You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=507079&aid=1784169&group_… Please note that this message will contain a full copy of the comment thread, including the initial issue submission, for this request, not just the latest update. Category: None Group: None Status: Open Resolution: None Priority: 5 Private: No Submitted By: Hans-Christoph Steiner (eighthave) Assigned to: Nobody/Anonymous (nobody) Summary: pix_video help patch not found on Mac OS X Initial Comment: pix_movie now works, but pix_video seems to have the same problem. When I try to get the help patch on Mac OS X, I get this: sorry, couldn't find help patch for "Gem/pix_videoDarwin.pd" ---------------------------------------------------------------------- You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=507079&aid=1784169&group_…

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[ pd-gem-Bugs-1781501 ] curve object doesn't instantiate without arguments
by SourceForge.net 25 Aug '07

25 Aug '07

Bugs item #1781501, was opened at 2007-08-24 18:32 Message generated for change (Tracker Item Submitted) made by Item Submitter You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=507079&aid=1781501&group_… Please note that this message will contain a full copy of the comment thread, including the initial issue submission, for this request, not just the latest update. Category: None Group: None Status: Open Resolution: None Priority: 5 Private: No Submitted By: Hans-Christoph Steiner (eighthave) Assigned to: Nobody/Anonymous (nobody) Summary: curve object doesn't instantiate without arguments Initial Comment: WHen you try to create [curve] without arguments, it fails saying bad arguments. It would be helpful if the object instantiated with a warning, then the user can get the help patch to see what the arguments are. ---------------------------------------------------------------------- You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=507079&aid=1781501&group_…

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Drawing textured dice
by Frank Barknecht 19 Aug '07

19 Aug '07

Hallo, I'd like to draw dice in Gem, complete with textures that show the 1 to 6 dots correctly on each cube side. A tedious approach would be to draw six [square]s, texture them and translate and rotate them to the six sides of the cube. However I wonder, if there also is a way to do this by texturing [cube] directly in a smart way. Is this possible and does anyone have any pointers to a tutorial or maybe a ready-made patch? Ciao -- Frank Barknecht _ ______footils.org_ __goto10.org__

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Re: [GEM-dev] shader library
by Dave Griffiths 19 Aug '07

19 Aug '07

On Tue, 2007-08-14 at 14:35 -0700, Wesley Smith wrote: > If you want a good place to look for ideas, download Jitter from > cycling 74 and look at the shader folder. There are a ton of shaders > in there that can be borrowed from. Some have copyright notices, so > you just need to leave those in the files to distribute them. That sounds interesting, but I can't seem to break into the installer package on linux. I think that in an ideal world we'd build a structured library of shaders - potentially with standard functions for the illumination models etc, and naming conventions to make it easier for people to play with. However, having a grab bag of shaders (under a free licence) with some documentation for people to try out and experiment with, under any platform/app, is a more realistic target at this point. It would be nice if they came from this community too I think. > I've been working on an audiovisual composition system using Lua I've fought with the idea of embedding glsl in scheme, but doing this makes it harder to share - although maybe it's not too bad if we can extract the code easily. I quite like treating shaders like any other assets though, and having them in search paths like textures. cheers, dave

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pix_buffer_read alters pix_buffer contents?
by B. Bogart 18 Aug '07

18 Aug '07

Hey all, I'm using pix_buffers to store images, and using various gemchains with pix_buffer_read to represent those same images in different ways. The problem I'm having is that it seems that putting a pix_mask below pix_buffer_read will actually add that alpha channel to the pix_buffer. The contents of the image actually change. I expect pix_buffer_read to only read, and never alter the contents of the buffer. I tried a bunch of methods, but no matter what I do the only way to clear the alpha added by pix_buffer_read is to reload an image into pix_buffer using pix_buffer_write. Perhaps a new object pix_stripalpha ? Attached is a demo patch. Any ideas for workaround would be appreciated. .b. #N canvas 474 380 716 404 10; #X obj 20 23 gemhead; #X obj 35 360 rectangle 5.333 4; #X obj 23 49 translateXYZ 5.333 0 0; #X obj 32 175 pix_buffer_write buffer; #X obj 273 22 gemhead; #X obj 288 335 pix_texture; #X obj 288 359 rectangle 2.6666 2; #X obj 255 66 translateXYZ 8 -2 0; #X obj 87 132 hradio 15 1 0 4 empty empty empty 0 -6 0 8 -262144 -1 -1 0; #X obj 344 108 hradio 15 1 0 4 empty empty empty 0 -6 0 8 -262144 -1 -1 1; #X floatatom 168 129 5 0 0 0 - - -; #X floatatom 301 107 5 0 0 0 - - -; #X obj 282 234 pix_mask; #X obj 334 209 pix_buffer_read video-mask; #X obj 339 182 gemhead; #X msg 505 180 0; #X obj 287 310 alpha; #X obj 566 24 gemhead; #X obj 637 110 hradio 15 1 0 4 empty empty empty 0 -6 0 8 -262144 -1 -1 1; #X floatatom 594 109 5 0 0 0 - - -; #X obj 536 142 pix_buffer_read buffer; #X obj 544 272 rectangle 2.6666 2; #X obj 540 207 alpha; #X obj 548 68 translateXYZ 8 2 0; #X obj 249 30 tgl 15 0 empty empty empty 0 -6 0 8 -262144 -1 -1 1 1 ; #X obj 538 27 tgl 15 0 empty empty empty 0 -6 0 8 -262144 -1 -1 1 1 ; #X obj 35 263 pix_texture; #X obj 32 91 pix_image test-image.jpg; #X obj 86 24 tgl 15 0 empty empty empty 0 -6 0 8 -262144 -1 -1 1 1 ; #X obj 264 263 pix_texture; #X obj 243 140 pix_buffer_read buffer; #X obj 544 248 pix_texture; #X obj 232 196 spigot 1; #X obj 292 171 tgl 15 0 empty empty empty 0 -6 0 8 -262144 -1 -1 0 1; #X connect 0 0 2 0; #X connect 2 0 27 0; #X connect 3 0 26 0; #X connect 4 0 7 0; #X connect 5 0 6 0; #X connect 7 0 30 0; #X connect 8 0 3 1; #X connect 9 0 30 1; #X connect 10 0 3 1; #X connect 11 0 30 1; #X connect 12 0 29 0; #X connect 13 0 12 1; #X connect 14 0 13 0; #X connect 15 0 13 1; #X connect 16 0 5 0; #X connect 17 0 23 0; #X connect 18 0 20 1; #X connect 19 0 20 1; #X connect 20 0 22 0; #X connect 22 0 31 0; #X connect 23 0 20 0; #X connect 24 0 4 0; #X connect 25 0 17 0; #X connect 26 0 1 0; #X connect 27 0 3 0; #X connect 28 0 0 0; #X connect 29 0 16 0; #X connect 30 0 32 0; #X connect 31 0 21 0; #X connect 32 0 12 0; #X connect 33 0 32 1;

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[ pd-gem-Patches-1774877 ] cleaned up examples in 04.video
by SourceForge.net 15 Aug '07

15 Aug '07

Patches item #1774877, was opened at 2007-08-15 13:10 Message generated for change (Tracker Item Submitted) made by Item Submitter You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=507081&aid=1774877&group_… Please note that this message will contain a full copy of the comment thread, including the initial issue submission, for this request, not just the latest update. Category: None Group: None Status: Open Resolution: None Priority: 5 Private: No Submitted By: Hans-Christoph Steiner (eighthave) Assigned to: Nobody/Anonymous (nobody) Summary: cleaned up examples in 04.video Initial Comment: I am here in Gijón, Asturias teaching at Laboral, and we went thru these patches with the newbies. Many of them were confused by some minor details, so I simplified the patches and added some GUI objects to make them very easy to play with. Plus, I used the gemwin subpatch from the Gem help patches. ---------------------------------------------------------------------- You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=507081&aid=1774877&group_…

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Re: [GEM-dev] shader library
by Wesley Smith 14 Aug '07

14 Aug '07

My first attempt to send this was rejected. Hopefully it will only appear once. If you want a good place to look for ideas, download Jitter from cycling 74 and look at the shader folder. There are a ton of shaders in there that can be borrowed from. Some have copyright notices, so you just need to leave those in the files to distribute them. I've been working on an audiovisual composition system using Lua with some other people here in Santa Barbara and we have a shader file format that is actually Lua code so you can drop functions in it and they will expand to generate shader code for you. The format is basically a translation for Jitter's .jxs XML shader format into Lua tables. It works quite well and allows the shader C++ class to construct an interface to the shader dynamically and set default values for uniform parameters. Here's a phong shader written in this format: Shader { name = "mat.phong.shl", description = [[ Phong Shader (per-pixel lighting) ]], La = Parameter { type = "vec4", default = {0., 0., 0., 1.0}, description = "Ambient Light" }, Li = Parameter { type = "vec4", default = {1., 1., 1., 1.0}, description = "Incident Light" }, eyePosition = Parameter { type = "vec3", default = {0., 0., 4.}, description = "Eye Position in world coordinates" }, Ke = Parameter { type = "vec4", default = {0., 0., 0., 0.}, description = "Emissive Color" }, Ka = Parameter { type = "vec4", default = {0., 0., 0., 1.}, description = "Ambient Color" }, Kd = Parameter { type = "vec4", default = {0.2, 0.2, 0.2, 1.}, description = "Diffuse Color" }, Ks = Parameter { type = "vec4", default = {1., 1., 1., 1.}, description = "Specular Color" }, shininess = Parameter { type = "float", default = 10., description = "Material Shininess" }, vertexParameters = { --none }, fragmentParameters = { "La", "Li", "eyePosition", "Ke", "Kd", "Ks", "shininess", }, -------------------------------------------------------------------------- -------------------------------------------------------------------------- -- Vertex Program -------------------------------------------------------------------------- vertexProgram = [[ varying vec3 N; varying vec3 P; void main (void) { //get the vertices into eye space P = (gl_ModelViewMatrix*gl_Vertex).xyz; //get the normals into eye space N = normalize(gl_Normal); N = mat3( gl_ModelViewMatrixInverseTranspose[0].xyz, gl_ModelViewMatrixInverseTranspose[1].xyz, gl_ModelViewMatrixInverseTranspose[2].xyz)*N; gl_Position = ftransform(); } ]], -------------------------------------------------------------------------- -------------------------------------------------------------------------- -- Fragment Program -------------------------------------------------------------------------- fragmentProgram = [[ uniform vec4 La; uniform vec4 Li; uniform vec3 eyePosition; uniform vec4 Ke; uniform vec4 Ka; uniform vec4 Kd; uniform vec4 Ks; uniform float shininess; varying vec3 N; varying vec3 P; void main (void) { vec3 Nn = normalize(N); //ambient contribution vec4 ambient = La*Ka; vec3 lightPosition = vec3(gl_LightSource[0].position); //diffuse contribution vec3 L = normalize(lightPosition - P); vec4 diffuse = Kd*Li*max(dot(Nn, L), 0.); //calculate specular contribution vec3 V = normalize(eyePosition - P); vec3 H = normalize(L + V); //average of lighting and view vector) not true reflection vector vec4 specular = Ks*Li * pow(max(dot(Nn, H), 0.), shininess); gl_FragColor = Ke + ambient + diffuse + specular; } ]], -------------------------------------------------------------------------- }

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GEM-dev August 2007