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  • Problem with generic list and extension method(C#3.0)

    - by Newbie
    I have an issue. I am making an extension class for a Collection and it is generic.. like public static class ListExtensions { public static ICollection<T> Search<T>(this ICollection<T> collection, string stringToSearch) { ICollection<T> t1=null; foreach (T t in collection) { Type k = t.GetType(); PropertyInfo pi = k.GetProperty("Name"); if (pi.GetValue(t,null).Equals(stringToSearch)) { t1.Add(t); } } return t1; } } But I cannot add items to t1 as it is declared null. Error: object reference not set to an instance of the object. I am calling the method like List<TestClass> listTC = new List<TestClass>(); listTC.Add(new TestClass { Name = "Ishu", Age = 21 }); listTC.Add(new TestClass { Name = "Vivek", Age = 40 }); listTC.Add(new TestClass { Name = "some one else", Age = 12 }); listTC.Search("Ishu"); And the test class is public class TestClass { public string Name { get; set; } public int Age { get; set; } } Using : (C#3.0) & Framework - 3.5 Thanks

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  • Low Level Console Input

    - by Soulseekah
    I'm trying to send commands to to the input of a cmd.exe application using the low level read/write console functions. I have no trouble reading the text (scraping) using the ReadConsole...() and WriteConsole() functions after having attached to the process console, but I've not figured out how to write for example "dir" and have the console interpret it as a sent command. Here's a bit of my code: CreateProcess(NULL, "cmd.exe", NULL, NULL, FALSE, CREATE_NEW_CONSOLE, NULL, NULL, &si, &pi); AttachConsole(pi.dwProcessId); strcpy(buffer, "dir"); WriteConsole(GetStdHandle(STD_INPUT_HANDLE), buffer, strlen(buffer), &charRead, NULL); STARTUPINFO attributes of the process are all set to zero, except, of course, the .cb attribute. Nothing changes on the screen, however I'm getting an Error 6: Invalid Handle returned from WriteConsole to STD_INPUT_HANDLE. If I write to (STD_OUTPUT_HANDLE) I do get my dir written on the screen, but nothing of course happens. I'm guessing SetConsoleMode() might be of help, but I've tried many mode combinations, nothing helped. I've also created a quick console application that waits for input (scanf()) and echoes back whatever goes in, didn't work. I've also tried typing into the scanf() promp and then peek into the input buffer using PeekConsoleInput(), returns 0, but the INPUT_RECORD array is empty. I'm aware that there is another way around this using WriteConsoleInput() to directly inject INPUT_RECORD structured events into the console, but this would be way too long, I'll have to send each keypress into it. I hope the question is clear. Please let me know if you need any further information. Thanks for your help.

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  • Optimally place a pie slice in a rectangle.

    - by Lisa
    Given a rectangle (w, h) and a pie slice with start angle and end angle, how can I place the slice optimally in the rectangle so that it fills the room best (from an optical point of view, not mathematically speaking)? I'm currently placing the pie slice's center in the center of the rectangle and use the half of the smaller of both rectangle sides as the radius. This leaves plenty of room for certain configurations. Examples to make clear what I'm after, based on the precondition that the slice is drawn like a unit circle: A start angle of 0 and an end angle of PI would lead to a filled lower half of the rectangle and an empty upper half. A good solution here would be to move the center up by 1/4*h. A start angle of 0 and an end angle of PI/2 would lead to a filled bottom right quarter of the rectangle. A good solution here would be to move the center point to the top left of the rectangle and to set the radius to the smaller of both rectangle sides. This is fairly easy for the cases I've sketched but it becomes complicated when the start and end angles are arbitrary. I am searching for an algorithm which determines center of the slice and radius in a way that fills the rectangle best. Pseudo code would be great since I'm not a big mathematician.

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  • Suggestions for a django db structure

    - by rh0dium
    Hi Say I have the unknown number of questions. For example: Is the sky blue [y/n] What date were your born on [date] What is pi [3.14] What is a large integ [100] Now each of these questions poses a different but very type specific answer (boolean, date, float, int). Natively django can happily deal with these in a model. class SkyModel(models.Model): question = models.CharField("Is the sky blue") answer = models.BooleanField(default=False) class BirthModel(models.Model): question = models.CharField("What date were your born on") answer = models.DateTimeField(default=today) class PiModel(models.Model) question = models.CharField("What is pi") answer = models.FloatField() But this has the obvious problem in that each question has a specific model - so if we need to add a question later I have to change the database. Yuck. So now I want to get fancy - How do a set up a model where by the answer type conversion happens automagically? ANSWER_TYPES = ( ('boolean', 'boolean'), ('date', 'date'), ('float', 'float'), ('int', 'int'), ('char', 'char'), ) class Questions(models.model): question = models.CharField(() answer = models.CharField() answer_type = models.CharField(choices = ANSWER_TYPES) default = models.CharField() So in theory this would do the following: When I build up my views I look at the type of answer and ensure that I only put in that value. But when I want to pull that answer back out it will return the data in the format specified by the answer_type. Example 3.14 comes back out as a float not as a str. How can I perform this sort of automagic transformation? Or can someone suggest a better way to do this? Thanks much!!

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  • Problem with "moveable-only types" in VC++ 2010

    - by Luc Touraille
    I recently installed Visual Studio 2010 Professional RC to try it out and test the few C++0x features that are implemented in VC++ 2010. I instantiated a std::vector of std::unique_ptr, without any problems. However, when I try to populate it by passing temporaries to push_back, the compiler complains that the copy constructor of unique_ptr is private. I tried inserting an lvalue by moving it, and it works just fine. #include <utility> #include <vector> int main() { typedef std::unique_ptr<int> int_ptr; int_ptr pi(new int(1)); std::vector<int_ptr> vec; vec.push_back(std::move(pi)); // OK vec.push_back(int_ptr(new int(2)); // compiler error } As it turns out, the problem is neither unique_ptr nor vector::push_back but the way VC++ resolves overloads when dealing with rvalues, as demonstrated by the following code: struct MoveOnly { MoveOnly() {} MoveOnly(MoveOnly && other) {} private: MoveOnly(const MoveOnly & other); }; void acceptRValue(MoveOnly && mo) {} int main() { acceptRValue(MoveOnly()); // Compiler error } The compiler complains that the copy constructor is not accessible. If I make it public, the program compiles (even though the copy constructor is not defined). Did I misunderstand something about rvalue references, or is it a (possibly known) bug in VC++ 2010 implementation of this feature?

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  • Adding class constraints to typeclass instance

    - by BleuM937
    I'm trying to implement the Cantor Pairing Function, as an instance of a generic Pair typeclass, as so: module Pair (Pair, CantorPair) where -- Pair interface class Pair p where pi :: a -> a -> p a k :: p a -> a l :: p a -> a -- Wrapper for typing newtype CantorPair a = P { unP :: a } -- Assume two functions with signatures: cantorPair :: Integral a => a -> a -> CantorPair a cantorUnpair :: Integral a => CantorPair a -> (a, a) -- I need to somehow add an Integral a constraint to this instance, -- but I can't work out how to do it. instance Pair CantorPair where pi = cantorPair k = fst . cantorUnpair l = snd . cantorUnpair How can I add the appropriate Integral constraint to the instance? I have a vague feeling I might need to modify the Pair interface itself, but not sure how to go about this.

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  • Efficient way to remove empty lists from lists without evaluating held expressions?

    - by Alexey Popkov
    In previous thread an efficient way to remove empty lists ({}) from lists was suggested: Replace[expr, x_List :> DeleteCases[x, {}], {0, Infinity}] Using the Trott-Strzebonski in-place evaluation technique this method can be generalized for working also with held expressions: f1[expr_] := Replace[expr, x_List :> With[{eval = DeleteCases[x, {}]}, eval /; True], {0, Infinity}] This solution is more efficient than the one based on ReplaceRepeated: f2[expr_] := expr //. {left___, {}, right___} :> {left, right} But it has one disadvantage: it evaluates held expressions if they are wrapped by List: In[20]:= f1[Hold[{{}, 1 + 1}]] Out[20]= Hold[{2}] So my question is: what is the most efficient way to remove all empty lists ({}) from lists without evaluating held expressions? The empty List[] object should be removed only if it is an element of another List itself. Here are some timings: In[76]:= expr = Tuples[Tuples[{{}, {}}, 3], 4]; First@Timing[#[expr]] & /@ {f1, f2, f3} pl = Plot3D[Sin[x y], {x, 0, Pi}, {y, 0, Pi}]; First@Timing[#[pl]] & /@ {f1, f2, f3} Out[77]= {0.581, 0.901, 5.027} Out[78]= {0.12, 0.21, 0.18} Definitions: Clear[f1, f2, f3]; f3[expr_] := FixedPoint[ Function[e, Replace[e, {a___, {}, b___} :> {a, b}, {0, Infinity}]], expr]; f1[expr_] := Replace[expr, x_List :> With[{eval = DeleteCases[x, {}]}, eval /; True], {0, Infinity}]; f2[expr_] := expr //. {left___, {}, right___} :> {left, right};

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  • Android: Scheduling application to start with repeating alarms not working

    - by vikramagain
    I get my Broadcast receiver to set a recurring alarm, to fire up a service. Unfortunately this does not result in the service being called repeatedly (based on logcat). I've experimented with different values for the time interval too. Can someone help? (I'm testing through Eclipse on Android 3.2 Motorola xoom) Below is the code for the Broadcast receiver. alarm = (AlarmManager) arg0.getSystemService(Context.ALARM_SERVICE); Intent intentUploadService = new Intent (arg0, com.vikramdhunta.UploaderService.class); Calendar calendar = Calendar.getInstance(); calendar.setTimeInMillis(System.currentTimeMillis()); calendar.add(Calendar.SECOND, 3); PendingIntent pi = PendingIntent.getBroadcast(arg0, 0, intentUploadService , 0); alarm.setRepeating(AlarmManager.RTC_WAKEUP, calendar.getTimeInMillis(), 5, pi); Below is the code for the Service class public UploaderService() { super("UploaderService"); mycounterid = globalcounter++; } @Override protected void onHandleIntent(Intent intent) { synchronized(this) { try { for (int i = 1;i < 5;i++) { // doesn't do much right now.. but this should appear in logcat Log.i(TAG,"OK " + globalcounter++ + " uploading..." + System.currentTimeMillis()); } } catch(Exception e) { } } } @Override public void onCreate() { super.onCreate(); Log.d("TAG", "Service created."); } @Override public IBinder onBind(Intent arg0) { return null; } @Override public int onStartCommand(Intent intent, int flags, int startId) { Log.i(TAG, "Starting upload service..." + mycounterid); return super.onStartCommand(intent,flags,startId); }

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  • The sign of zero with float2

    - by JackOLantern
    Consider the following code performing operations on complex numbers with C/C++'s float: float real_part = log(3.f); float imag_part = 0.f; float real_part2 = (imag_part)*(imag_part)-(real_part*real_part); float imag_part2 = (imag_part)*(real_part)+(real_part*imag_part); The result will be real_part2= -1.20695 imag_part2= 0 angle= 3.14159 where angle is the phase of the complex number and, in this case, is pi. Now consider the following code: float real_part = log(3.f); float imag_part = 0.f; float real_part2 = (-imag_part)*(-imag_part)-(real_part)*(real_part); float imag_part2 = (-imag_part)*(real_part)+(real_part)*(-imag_part); The result will be real_part2= -1.20695 imag_part2= 0 angle= -3.14159 The imaginary part of the result is -0 which makes the phase of the result be -pi. Although still accomplishing with the principal argument of a complex number and with the signed property of floating point's 0, this changes is a problem when one is defining functions of complex numbers. For example, if one is defining sqrt of a complex number by the de Moivre formula, this will change the sign of the imaginary part of the result to a wrong value. How to deal with this effect?

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  • Using MPI_Type_Vector and MPI_Gather, in C.

    - by Goloneg
    Hi, I am trying to multiply square matrices in parallele with MPI. I use a MPI_Type_vector to send square submatrixes (arrays of float) to the processes, so they can calculate subproducts. Then, for the next iterations, these submatrices are send to neighbours processes as MPI_Type_contiguous (the whole submatrix is sent). This part is working as expected, and local results are corrects. Then, I use MPI_Gather with the contiguous types to send all local results back to the root process. The problem is, the final matrix is build (obviously, by this method) line by line instead of submatrix by submatrix. I wrote an ugly procedure rearranging the final matrix, but I would like to know if there is a direct way of performing the "inverse" operation of sending MPI_Type_vectors (i.e., sending an array of values and directly arranging it in a subarray form in the receiving array). An example, to try and clarify my long text : A[16] and B[16] are 4x4 matrices to be multiplied ; C[16] will contain the result ; 4 processes are used (Pi with i from 0 to 3) : Pi gets two 2x2 submatrices : subAi[4] and subBi[4] ; their product is stored locally in subCi[4]. For instance, P0 gets : subA0[4] containing A[0], A[1], A[4] and A[5] ; subB0[4] containing B[0], B[1], B[4] and B[5]. After everything is calculed, root process gathers all subCi[4]. Then C[16] contains : [ subC0[0], subC0[1], subC0[2], subC0[3], subC1[0], subC1[1], subC1[2], subC1[3], subC2[0], subC2[1], subC2[2], subC2[3], subC3[0], subC3[1], subC3[2], subC3[3]] and I would like it to be : [ subC0[0], subC0[1], subC1[0], subC1[1], subC0[2], subC0[3], subC1[2], subC1[3], subC2[0], subC2[1], subC3[0], subC3[1], subC2[2], subC2[3], subC3[2], subC3[3]] without further operation. Does someone know a way ? Thanks for your advices.

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  • Groovy and XML: Not able to insert processing instruction

    - by rhellem
    Scenario Need to update some attributes in an existing XML-file. The file contains a XSL processing instruction, so when the XML is parsed and updated I need to add the instruction before writing it to a file again. Problem is - whatever I do - I'm not able to insert the processing instruction Based on the Java-example found at rgagnon.com I have created the code below Example code ## import groovy.xml.* def xml = '''|<something> | <Settings> | </Settings> |</something>'''.stripMargin() def document = DOMBuilder.parse( new StringReader( xml ) ) def pi = document.createProcessingInstruction('xml-stylesheet', 'type="text/xsl" href="Bp8DefaultView.xsl"'); document.insertBefore(pi, document.documentElement) println document.documentElement Creates output <?xml version="1.0" encoding="UTF-8"?> <something> <Settings> </Settings> </something> What I want <?xml version="1.0" encoding="UTF-8"?> <?xml-stylesheet type="text/xsl" href="Bp8DefaultView.xsl"?> <something> <Settings> </Settings> </something>

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  • Sending an SMS in Android

    - by D4N14L
    Hey, I have been making an Android app which needs to send a text message. Here is the current code I have: public class getMessage extends Service { @Override public IBinder onBind(Intent intent) { return null; } @Override public void onStart(Intent intent, int startId) { super.onStart(intent, startId); client Phone = new client(); String[] msg = Phone.getMsg(user[0],user[1]); PendingIntent pi = PendingIntent.getActivity(this, 0, new Intent(this, getMessage.class), 0); SmsManager man = SmsManager.getDefault(); Log.e("GOT MESSAGE", msg[0]+ " : " +msg[1]); man.sendTextMessage(msg[0], null, msg[1], pi, null); Log.e("Message", "Sent the message?"); } Now, for some reason, the text message will not send using this code, and I'm not sure why. I was hoping that someone here could help me out in finding why this message won't send. No error is raised, nothing appears in the log (except for the log messages that I make myself in the code). Also, the manifest does have the correct tags. Suggestions?

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  • Advance Query with Join

    - by user1462589
    I'm trying to convert a product table that contains all the detail of the product into separate tables in SQL. I've got everything done except for duplicated descriptor details. The problem I am having all the products have size/color/style/other that many other products contain. I want to only have one size or color descriptor for all the items and reuse the "ID" for all the product which I believe is a Parent key to the Product ID which is a ...Foreign Key. The only problem is that every descriptor would have multiple Foreign Keys assigned to it. So I was thinking on the fly just have it skip figuring out a Foreign Parent key for each descriptor and just check to see if that descriptor exist and if it does use its Key for the descriptor. Data Table PI Colo Sz OTHER 1 | Blue | 5 | Vintage 2 | Blue | 6 | Vintage 3 | Blac | 5 | Simple 4 | Blac | 6 | Simple =================================== Its destination table is this =================================== DI Description 1 | Blue 2 | Blac 3 | 5 4 | 6 6 | Vintage 7 | Simple ============================= Select Data.Table Unique.Data.Table.Colo Unique.Data.Table.Sz Unique.Data.Table.Other ======================================= Then the dual part of the questions after we create all the descriptors how to do a new query and assign the product ID to the descriptors. PI| DI 1 | 1 1 | 3 1 | 4 2 | 1 2 | 3 2 | 4 By figuring out how to do this I should be able to duplicate this pattern for all 300 + columns in the product. Some of these fields are 60+ characters large so its going to save a ton of space. Do I use a Array?

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  • Cannot read status the monit daemon, even with allowed group

    - by jefflunt
    I cannot seem to get monit status or other CLI commands to work. I've built monit v5.8 to run on a Raspberry Pi. I'm able to add services to be monitored, and the web interface can be accessed just fine, as I've set it up for public read-only access (it's a test server, not my final production setup, so not a big deal right now). Problem is, when I run monit status while logged in as root I get: # monit status monit: cannot read status from the monit daemon I also have monit started on boot via this /etc/inittab file entry: mo:2345:respawn:/usr/local/bin/monit -Ic /etc/monitrc I've verified that monit is running, and I'm getting email alerts anytime I either kill the monit process manually, or reboot my raspberry pi. So, next I check my monitrc file permissions to see which group is allowed access. # ls -al /etc/monitrc -rw------- 1 root root 2359 Aug 24 14:48 /etc/monitrc Here's my relevant allow section of the control file. set httpd port 80 allow [omitted] readonly allow @root allow localhost allow 0.0.0.0/0.0.0.0 Also tried setting permissions on this file to 640 to allow group read permissions, but no matter what I try I either get the same error as noted above, or when the permissions are set to 640 I get: # monit status monit: The control file '/etc/monitrc' must have permissions no more than -rwx------ (0700); right now permissions are -rw-r----- (0640). What am I missing here? I know that the httpd must be enabled, as that's the interface that the CLI uses to get information (or so I've read), so I've done that. And in terms of monit doing its monitoring job and sending email alerts, that's all working as well. Here's my entire monitrc file - again, this is version v5.8, and it was build with both PAM and SSL support. The process runs under the root user: # Global settings set daemon 300 with start delay 5 set logfile /var/log/monit.log set pidfile /var/run/monit.pid set idfile /var/run/.monit.id set statefile /var/run/.monit.state # Mail alerts ## Set the list of mail servers for alert delivery. Multiple servers may be ## specified using a comma separator. If the first mail server fails, Monit # will use the second mail server in the list and so on. By default Monit uses # port 25 - it is possible to override this with the PORT option. # set mailserver smtp.gmail.com port 587 username [omitted] password [omitted] using tlsv1 ## Send status and events to M/Monit (for more informations about M/Monit ## see http://mmonit.com/). By default Monit registers credentials with ## M/Monit so M/Monit can smoothly communicate back to Monit and you don't ## have to register Monit credentials manually in M/Monit. It is possible to ## disable credential registration using the commented out option below. ## Though, if safety is a concern we recommend instead using https when ## communicating with M/Monit and send credentials encrypted. # # set mmonit http://monit:[email protected]:8080/collector # # and register without credentials # Don't register credentials # # ## Monit by default uses the following format for alerts if the the mail-format ## statement is missing:: set mail-format { from: [email protected] subject: $SERVICE $DESCRIPTION message: $EVENT Service: $SERVICE Date: $DATE Action: $ACTION Host: $HOST Description: $DESCRIPTION Monit instance provided by chicagomeshnet.com } # Web status page set httpd port 80 allow [omitted] readonly allow @root allow localhost allow 0.0.0.0/0.0.0.0 ## You can set alert recipients whom will receive alerts if/when a ## service defined in this file has errors. Alerts may be restricted on ## events by using a filter as in the second example below.

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  • How to see if turbo boost is working on I7 860 CPU?

    - by Jan Derk
    I just build myself a new system with a Intel I7 860 CPU. When loading it using a single threaded application like Super PI, CPU-Z shows 2.933Ghz as speed. Now I understood that the I7 goes into turbo boost mode up to 3.46GHz for a single core. How can I check that? Is there a utility to monitor CPU speed per core?

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  • OpenVPN not sending traffic to internet?

    - by coleifer
    I've set up openvpn on my pi and am running into a small issue. I can connect to the VPN server and ping it just fine, and I can also connect to other machines on my local network. However I am unable, when connected to the VPN, to reach the outside world (either by name lookup or IP). here are the details: On the server the tun0 interface: tun0: flags=4305<UP,POINTOPOINT,RUNNING,NOARP,MULTICAST> mtu 1500 inet 10.8.0.1 netmask 255.255.255.255 destination 10.8.0.2 unspec 00-00-00-00-00-00-00-00-00-00-00-00-00-00-00-00 txqueuelen 100 (UNSPEC) RX packets 0 bytes 0 (0.0 B) RX errors 0 dropped 0 overruns 0 frame 0 TX packets 0 bytes 0 (0.0 B) TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0 I can ping it just fine: # ping -c 3 10.8.0.1 PING 10.8.0.1 (10.8.0.1) 56(84) bytes of data. 64 bytes from 10.8.0.1: icmp_seq=1 ttl=64 time=0.159 ms 64 bytes from 10.8.0.1: icmp_seq=2 ttl=64 time=0.155 ms 64 bytes from 10.8.0.1: icmp_seq=3 ttl=64 time=0.156 ms --- 10.8.0.1 ping statistics --- 3 packets transmitted, 3 received, 0% packet loss, time 2002ms Routing table # ip route show default via 192.168.1.1 dev eth0 metric 204 10.8.0.0/24 via 10.8.0.2 dev tun0 10.8.0.2 dev tun0 proto kernel scope link src 10.8.0.1 192.168.1.0/24 dev eth0 proto kernel scope link src 192.168.1.6 metric 204 I also have ip traffic forwarding: net.ipv4.ip_forward = 1 I do not have any custom iptables rules (that I'm aware of). On the client, I can connect to the VPN. Here is my tun0: tun0: flags=4305<UP,POINTOPOINT,RUNNING,NOARP,MULTICAST> mtu 1500 inet 10.8.0.6 netmask 255.255.255.255 destination 10.8.0.5 unspec 00-00-00-00-00-00-00-00-00-00-00-00-00-00-00-00 txqueuelen 100 (UNSPEC) RX packets 0 bytes 0 (0.0 B) RX errors 0 dropped 0 overruns 0 frame 0 TX packets 21 bytes 1527 (1.4 KiB) TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0 And on the client I can ping it: sudo ping -c 3 10.8.0.6 PING 10.8.0.6 (10.8.0.6) 56(84) bytes of data. 64 bytes from 10.8.0.6: icmp_seq=1 ttl=64 time=0.035 ms 64 bytes from 10.8.0.6: icmp_seq=2 ttl=64 time=0.026 ms 64 bytes from 10.8.0.6: icmp_seq=3 ttl=64 time=0.032 ms --- 10.8.0.6 ping statistics --- 3 packets transmitted, 3 received, 0% packet loss, time 1998ms rtt min/avg/max/mdev = 0.026/0.031/0.035/0.003 ms I can ssh from the client into another server on my LAN (192.168.1.x), however I cannot reach anything outside my LAN. Here's some of the server logs at the bottom of this gist: https://gist.github.com/coleifer/6ef95c3008f130249933/edit I am frankly out of ideas! I don't think it's my client because both my laptop and my phone (which has an openvpn client) exhibit the same behavior. I had OpenVPN installed on this pi before using debian and it worked, so I don't think it's my router but of course anything is possible.

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  • Get a script to run at startup (linux)

    - by Dan Graves
    I am trying to get a simple script to run automatically at startup. A friend told me to do this but it did not work. Could someone take a look to see what it is missing? *(Also I am brand new to linux, so this is pretty foreign to me) Here is what I was told to do: In terminal sudo nano /etc/init.d/obabp.sh Then enter this text: #!/bin/bash sudo python /home/pi/gits/RPi-OBABP/src/obabp.py save file and then $ sudo chmod +x /etc/init.d/obabp.sh $ sudo shutdown -r now

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  • How to find vector for the quaternion from X Y Z rotations

    - by can poyrazoglu
    I am creating a very simple project on OpenGL and I'm stuck with rotations. I am trying to rotate an object indepentdently in all 3 axes: X, Y, and Z. I've had sleepless nights due to the "gimbal lock" problem after rotating about one axis. I've then learned that quaternions would solve my problem. I've researched about quaternions and implementd it, but I havent't been able to convert my rotations to quaternions. For example, if I want to rotate around Z axis 90 degrees, I just create the {0,0,1} vector for my quaternion and rotate it around that axis 90 degrees using the code here: http://iphonedevelopment.blogspot.com/2009/06/opengl-es-from-ground-up-part-7_04.html (the most complicated matrix towards the bottom) That's ok for one vector, but, say, I first want to rotate 90 degrees around Z, then 90 degrees around X (just as an example). What vector do I need to pass in? How do I calculate that vector. I am not good with matrices and trigonometry (I know the basics and the general rules, but I'm just not a whiz) but I need to get this done. There are LOTS of tutorials about quaternions, but I seem to understand none (or they don't answer my question). I just need to learn to construct the vector for rotations around more than one axis combined. UPDATE: I've found this nice page about quaternions and decided to implement them this way: http://www.cprogramming.com/tutorial/3d/quaternions.html Here is my code for quaternion multiplication: void cube::quatmul(float* q1, float* q2, float* resultRef){ float w = q1[0]*q2[0] - q1[1]*q2[1] - q1[2]*q2[2] - q1[3]*q2[3]; float x = q1[0]*q2[1] + q1[1]*q2[0] + q1[2]*q2[3] - q1[3]*q2[2]; float y = q1[0]*q2[2] - q1[1]*q2[3] + q1[2]*q2[0] + q1[3]*q2[1]; float z = q1[0]*q2[3] + q1[1]*q2[2] - q1[2]*q2[1] + q1[3]*q2[0]; resultRef[0] = w; resultRef[1] = x; resultRef[2] = y; resultRef[3] = z; } Here is my code for applying a quaternion to my modelview matrix (I have a tmodelview variable that is my target modelview matrix): void cube::applyquat(){ float& x = quaternion[1]; float& y = quaternion[2]; float& z = quaternion[3]; float& w = quaternion[0]; float magnitude = sqrtf(w * w + x * x + y * y + z * z); if(magnitude == 0){ x = 1; w = y = z = 0; }else if(magnitude != 1){ x /= magnitude; y /= magnitude; z /= magnitude; w /= magnitude; } tmodelview[0] = 1 - (2 * y * y) - (2 * z * z); tmodelview[1] = 2 * x * y + 2 * w * z; tmodelview[2] = 2 * x * z - 2 * w * y; tmodelview[3] = 0; tmodelview[4] = 2 * x * y - 2 * w * z; tmodelview[5] = 1 - (2 * x * x) - (2 * z * z); tmodelview[6] = 2 * y * z - 2 * w * x; tmodelview[7] = 0; tmodelview[8] = 2 * x * z + 2 * w * y; tmodelview[9] = 2 * y * z + 2 * w * x; tmodelview[10] = 1 - (2 * x * x) - (2 * y * y); tmodelview[11] = 0; glMatrixMode(GL_MODELVIEW); glPushMatrix(); glLoadMatrixf(tmodelview); glMultMatrixf(modelview); glGetFloatv(GL_MODELVIEW_MATRIX, tmodelview); glPopMatrix(); } And my code for rotation (that I call externally), where quaternion is a class variable of the cube: void cube::rotatex(int angle){ float quat[4]; float ang = angle * PI / 180.0; quat[0] = cosf(ang / 2); quat[1] = sinf(ang/2); quat[2] = 0; quat[3] = 0; quatmul(quat, quaternion, quaternion); applyquat(); } void cube::rotatey(int angle){ float quat[4]; float ang = angle * PI / 180.0; quat[0] = cosf(ang / 2); quat[1] = 0; quat[2] = sinf(ang/2); quat[3] = 0; quatmul(quat, quaternion, quaternion); applyquat(); } void cube::rotatez(int angle){ float quat[4]; float ang = angle * PI / 180.0; quat[0] = cosf(ang / 2); quat[1] = 0; quat[2] = 0; quat[3] = sinf(ang/2); quatmul(quat, quaternion, quaternion); applyquat(); } I call, say rotatex, for 10-11 times for rotating only 1 degree, but my cube gets rotated almost 90 degrees after 10-11 times of 1 degree, which doesn't make sense. Also, after calling rotation functions in different axes, My cube gets skewed, gets 2 dimensional, and disappears (a column in modelview matrix becomes all zeros) irreversibly, which obviously shouldn't be happening with a correct implementation of the quaternions.

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  • How to convert objects in reflection (Linq to XML)

    - by user829174
    I have the following code which is working fine, the code creates plugins in reflection via run time: using System; using System.Collections.Generic; using System.Linq; using System.IO; using System.Xml.Linq; using System.Reflection; using System.Text; namespace WindowsFormsApplication1 { public abstract class Plugin { public string Type { get; set; } public string Message { get; set; } } public class FilePlugin : Plugin { public string Path { get; set; } } public class RegsitryPlugin : Plugin { public string Key { get; set; } public string Name { get; set; } public string Value { get; set; } } static class MyProgram { [STAThread] static void Main(string[] args) { string xmlstr =@" <Client> <Plugin Type=""FilePlugin""> <Message>i am a file plugin</Message> <Path>c:\</Path> </Plugin> <Plugin Type=""RegsitryPlugin""> <Message>i am a registry plugin</Message> <Key>HKLM\Software\Microsoft</Key> <Name>Version</Name> <Value>3.5</Value> </Plugin> </Client> "; Assembly asm = Assembly.GetExecutingAssembly(); XDocument xDoc = XDocument.Load(new StringReader(xmlstr)); Plugin[] plugins = xDoc.Descendants("Plugin") .Select(plugin => { string typeName = plugin.Attribute("Type").Value; var type = asm.GetTypes().Where(t => t.Name == typeName).First(); Plugin p = Activator.CreateInstance(type) as Plugin; p.Type = typeName; foreach (var prop in plugin.Descendants()) { var pi = type.GetProperty(prop.Name.LocalName); object newVal = Convert.ChangeType(prop.Value, pi.PropertyType); pi.SetValue(p, newVal, null); } return p; }).ToArray(); // //"plugins" ready to use // } } } I am trying to modify the code and adding new class named DetailedPlugin so it will be able to read the following xml: string newXml = @" <Client> <Plugin Type=""FilePlugin""> <Message>i am a file plugin</Message> <Path>c:\</Path> <DetailedPlugin Type=""DetailedFilePlugin""> <Message>I am a detailed file plugin</Message> </DetailedPlugin> </Plugin> <Plugin Type=""RegsitryPlugin""> <Message>i am a registry plugin</Message> <Key>HKLM\Software\Microsoft</Key> <Name>Version</Name> <Value>3.5</Value> <DetailedPlugin Type=""DetailedRegsitryPlugin""> <Message>I am a detailed registry plugin</Message> </DetailedPlugin> </Plugin> </Client> "; for this i modified my classes to the following: public abstract class Plugin { public string Type { get; set; } public string Message { get; set; } public DetailedPlugin DetailedPlugin { get; set; } // new } public class FilePlugin : Plugin { public string Path { get; set; } } public class RegsitryPlugin : Plugin { public string Key { get; set; } public string Name { get; set; } public string Value { get; set; } } // new classes: public abstract class DetailedPlugin { public string Type { get; set; } public string Message { get; set; } } public class DetailedFilePlugin : Plugin { public string ExtraField1 { get; set; } } public class DetailedRegsitryPlugin : Plugin { public string ExtraField2{ get; set; } } from here i need some help to accomplish reading the xml and create the plugins with the nested DetailedPlugin

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  • C++ Little Wonders: The C++11 auto keyword redux

    - by James Michael Hare
    I’ve decided to create a sub-series of my Little Wonders posts to focus on C++.  Just like their C# counterparts, these posts will focus on those features of the C++ language that can help improve code by making it easier to write and maintain.  The index of the C# Little Wonders can be found here. This has been a busy week with a rollout of some new website features here at my work, so I don’t have a big post for this week.  But I wanted to write something up, and since lately I’ve been renewing my C++ skills in a separate project, it seemed like a good opportunity to start a C++ Little Wonders series.  Most of my development work still tends to focus on C#, but it was great to get back into the saddle and renew my C++ knowledge.  Today I’m going to focus on a new feature in C++11 (formerly known as C++0x, which is a major move forward in the C++ language standard).  While this small keyword can seem so trivial, I feel it is a big step forward in improving readability in C++ programs. The auto keyword If you’ve worked on C++ for a long time, you probably have some passing familiarity with the old auto keyword as one of those rarely used C++ keywords that was almost never used because it was the default. That is, in the code below (before C++11): 1: int foo() 2: { 3: // automatic variables (allocated and deallocated on stack) 4: int x; 5: auto int y; 6:  7: // static variables (retain their value across calls) 8: static int z; 9:  10: return 0; 11: } The variable x is assumed to be auto because that is the default, thus it is unnecessary to specify it explicitly as in the declaration of y below that.  Basically, an auto variable is one that is allocated and de-allocated on the stack automatically.  Contrast this to static variables, that are allocated statically and exist across the lifetime of the program. Because auto was so rarely (if ever) used since it is the norm, they decided to remove it for this purpose and give it new meaning in C++11.  The new meaning of auto: implicit typing Now, if your compiler supports C++ 11 (or at least a good subset of C++11 or 0x) you can take advantage of type inference in C++.  For those of you from the C# world, this means that the auto keyword in C++ now behaves a lot like the var keyword in C#! For example, many of us have had to declare those massive type declarations for an iterator before.  Let’s say we have a std::map of std::string to int which will map names to ages: 1: std::map<std::string, int> myMap; And then let’s say we want to find the age of a given person: 1: // Egad that's a long type... 2: std::map<std::string, int>::const_iterator pos = myMap.find(targetName); Notice that big ugly type definition to declare variable pos?  Sure, we could shorten this by creating a typedef of our specific map type if we wanted, but now with the auto keyword there’s no need: 1: // much shorter! 2: auto pos = myMap.find(targetName); The auto now tells the compiler to determine what type pos should be based on what it’s being assigned to.  This is not dynamic typing, it still determines the type as if it were explicitly declared and once declared that type cannot be changed.  That is, this is invalid: 1: // x is type int 2: auto x = 42; 3:  4: // can't assign string to int 5: x = "Hello"; Once the compiler determines x is type int it is exactly as if we typed int x = 42; instead, so don’t' confuse it with dynamic typing, it’s still very type-safe. An interesting feature of the auto keyword is that you can modify the inferred type: 1: // declare method that returns int* 2: int* GetPointer(); 3:  4: // p1 is int*, auto inferred type is int 5: auto *p1 = GetPointer(); 6:  7: // ps is int*, auto inferred type is int* 8: auto p2 = GetPointer(); Notice in both of these cases, p1 and p2 are determined to be int* but in each case the inferred type was different.  because we declared p1 as auto *p1 and GetPointer() returns int*, it inferred the type int was needed to complete the declaration.  In the second case, however, we declared p2 as auto p2 which means the inferred type was int*.  Ultimately, this make p1 and p2 the same type, but which type is inferred makes a difference, if you are chaining multiple inferred declarations together.  In these cases, the inferred type of each must match the first: 1: // Type inferred is int 2: // p1 is int* 3: // p2 is int 4: // p3 is int& 5: auto *p1 = GetPointer(), p2 = 42, &p3 = p2; Note that this works because the inferred type was int, if the inferred type was int* instead: 1: // syntax error, p1 was inferred to be int* so p2 and p3 don't make sense 2: auto p1 = GetPointer(), p2 = 42, &p3 = p2; You could also use const or static to modify the inferred type: 1: // inferred type is an int, theAnswer is a const int 2: const auto theAnswer = 42; 3:  4: // inferred type is double, Pi is a static double 5: static auto Pi = 3.1415927; Thus in the examples above it inferred the types int and double respectively, which were then modified to const and static. Summary The auto keyword has gotten new life in C++11 to allow you to infer the type of a variable from it’s initialization.  This simple little keyword can be used to cut down large declarations for complex types into a much more readable form, where appropriate.   Technorati Tags: C++, C++11, Little Wonders, auto

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  • Event Logging in LINQ C# .NET

    The first thing you'll want to do before using this code is to create a table in your database called TableHistory: CREATE TABLE [dbo].[TableHistory] (     [TableHistoryID] [int] IDENTITY NOT NULL ,     [TableName] [varchar] (50) NOT NULL ,     [Key1] [varchar] (50) NOT NULL ,     [Key2] [varchar] (50) NULL ,     [Key3] [varchar] (50) NULL ,     [Key4] [varchar] (50) NULL ,     [Key5] [varchar] (50) NULL ,     [Key6] [varchar] (50)NULL ,     [ActionType] [varchar] (50) NULL ,     [Property] [varchar] (50) NULL ,     [OldValue] [varchar] (8000) NULL ,     [NewValue] [varchar] (8000) NULL ,     [ActionUserName] [varchar] (50) NOT NULL ,     [ActionDateTime] [datetime] NOT NULL ) Once you have created the table, you'll need to add it to your custom LINQ class (which I will refer to as DboDataContext), thus creating the TableHistory class. Then, you'll need to add the History.cs file to your project. You'll also want to add the following code to your project to get the system date: public partial class DboDataContext{ [Function(Name = "GetDate", IsComposable = true)] public DateTime GetSystemDate() { MethodInfo mi = MethodBase.GetCurrentMethod() as MethodInfo; return (DateTime)this.ExecuteMethodCall(this, mi, new object[] { }).ReturnValue; }}private static Dictionary<type,> _cachedIL = new Dictionary<type,>();public static T CloneObjectWithIL<t>(T myObject){ Delegate myExec = null; if (!_cachedIL.TryGetValue(typeof(T), out myExec)) { // Create ILGenerator DynamicMethod dymMethod = new DynamicMethod("DoClone", typeof(T), new Type[] { typeof(T) }, true); ConstructorInfo cInfo = myObject.GetType().GetConstructor(new Type[] { }); ILGenerator generator = dymMethod.GetILGenerator(); LocalBuilder lbf = generator.DeclareLocal(typeof(T)); //lbf.SetLocalSymInfo("_temp"); generator.Emit(OpCodes.Newobj, cInfo); generator.Emit(OpCodes.Stloc_0); foreach (FieldInfo field in myObject.GetType().GetFields( System.Reflection.BindingFlags.Instance | System.Reflection.BindingFlags.Public | System.Reflection.BindingFlags.NonPublic)) { // Load the new object on the eval stack... (currently 1 item on eval stack) generator.Emit(OpCodes.Ldloc_0); // Load initial object (parameter) (currently 2 items on eval stack) generator.Emit(OpCodes.Ldarg_0); // Replace value by field value (still currently 2 items on eval stack) generator.Emit(OpCodes.Ldfld, field); // Store the value of the top on the eval stack into // the object underneath that value on the value stack. // (0 items on eval stack) generator.Emit(OpCodes.Stfld, field); } // Load new constructed obj on eval stack -> 1 item on stack generator.Emit(OpCodes.Ldloc_0); // Return constructed object. --> 0 items on stack generator.Emit(OpCodes.Ret); myExec = dymMethod.CreateDelegate(typeof(Func<t,>)); _cachedIL.Add(typeof(T), myExec); } return ((Func<t,>)myExec)(myObject);}I got both of the above methods off of the net somewhere (maybe even from CodeProject), but it's been long enough that I can't recall where I got them.Explanation of the History ClassThe History class records changes by creating a TableHistory record, inserting the values for the primary key for the table being modified into the Key1, Key2, ..., Key6 columns (if you have more than 6 values that make up a primary key on any table, you'll want to modify this), setting the type of change being made in the ActionType column (INSERT, UPDATE, or DELETE), old value and new value if it happens to be an update action, and the date and Windows identity of the user who made the change.Let's examine what happens when a call is made to the RecordLinqInsert method:public static void RecordLinqInsert(DboDataContext dbo, IIdentity user, object obj){ TableHistory hist = NewHistoryRecord(obj); hist.ActionType = "INSERT"; hist.ActionUserName = user.Name; hist.ActionDateTime = dbo.GetSystemDate(); dbo.TableHistories.InsertOnSubmit(hist);}private static TableHistory NewHistoryRecord(object obj){ TableHistory hist = new TableHistory(); Type type = obj.GetType(); PropertyInfo[] keys; if (historyRecordExceptions.ContainsKey(type)) { keys = historyRecordExceptions[type].ToArray(); } else { keys = type.GetProperties().Where(o => AttrIsPrimaryKey(o)).ToArray(); } if (keys.Length > KeyMax) throw new HistoryException("object has more than " + KeyMax.ToString() + " keys."); for (int i = 1; i <= keys.Length; i++) { typeof(TableHistory) .GetProperty("Key" + i.ToString()) .SetValue(hist, keys[i - 1].GetValue(obj, null).ToString(), null); } hist.TableName = type.Name; return hist;}protected static bool AttrIsPrimaryKey(PropertyInfo pi){ var attrs = from attr in pi.GetCustomAttributes(typeof(ColumnAttribute), true) where ((ColumnAttribute)attr).IsPrimaryKey select attr; if (attrs != null && attrs.Count() > 0) return true; else return false;}RecordLinqInsert takes as input a data context which it will use to write to the database, the user, and the LINQ object to be recorded (a single object, for instance, a Customer or Order object if you're using AdventureWorks). It then calls the NewHistoryRecord method, which uses LINQ to Objects in conjunction with the AttrIsPrimaryKey method to pull all the primary key properties, set the Key1-KeyN properties of the TableHistory object, and return the new TableHistory object. The code would be called in an application, like so: Continue span.fullpost {display:none;}

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  • GLSL Atmospheric Scattering Issue

    - by mtf1200
    I am attempting to use Sean O'Neil's shaders to accomplish atmospheric scattering. For now I am just using SkyFromSpace and GroundFromSpace. The atmosphere works fine but the planet itself is just a giant dark sphere with a white blotch that follows the camera. I think the problem might rest in the "v3Attenuation" variable as when this is removed the sphere is show (albeit without scattering). Here is the vertex shader. Thanks for the time! uniform mat4 g_WorldViewProjectionMatrix; uniform mat4 g_WorldMatrix; uniform vec3 m_v3CameraPos; // The camera's current position uniform vec3 m_v3LightPos; // The direction vector to the light source uniform vec3 m_v3InvWavelength; // 1 / pow(wavelength, 4) for the red, green, and blue channels uniform float m_fCameraHeight; // The camera's current height uniform float m_fCameraHeight2; // fCameraHeight^2 uniform float m_fOuterRadius; // The outer (atmosphere) radius uniform float m_fOuterRadius2; // fOuterRadius^2 uniform float m_fInnerRadius; // The inner (planetary) radius uniform float m_fInnerRadius2; // fInnerRadius^2 uniform float m_fKrESun; // Kr * ESun uniform float m_fKmESun; // Km * ESun uniform float m_fKr4PI; // Kr * 4 * PI uniform float m_fKm4PI; // Km * 4 * PI uniform float m_fScale; // 1 / (fOuterRadius - fInnerRadius) uniform float m_fScaleDepth; // The scale depth (i.e. the altitude at which the atmosphere's average density is found) uniform float m_fScaleOverScaleDepth; // fScale / fScaleDepth attribute vec4 inPosition; vec3 v3ELightPos = vec3(g_WorldMatrix * vec4(m_v3LightPos, 1.0)); vec3 v3ECameraPos= vec3(g_WorldMatrix * vec4(m_v3CameraPos, 1.0)); const int nSamples = 2; const float fSamples = 2.0; varying vec4 color; float scale(float fCos) { float x = 1.0 - fCos; return m_fScaleDepth * exp(-0.00287 + x*(0.459 + x*(3.83 + x*(-6.80 + x*5.25)))); } void main(void) { gl_Position = g_WorldViewProjectionMatrix * inPosition; // Get the ray from the camera to the vertex and its length (which is the far point of the ray passing through the atmosphere) vec3 v3Pos = vec3(g_WorldMatrix * inPosition); vec3 v3Ray = v3Pos - v3ECameraPos; float fFar = length(v3Ray); v3Ray /= fFar; // Calculate the closest intersection of the ray with the outer atmosphere (which is the near point of the ray passing through the atmosphere) float B = 2.0 * dot(m_v3CameraPos, v3Ray); float C = m_fCameraHeight2 - m_fOuterRadius2; float fDet = max(0.0, B*B - 4.0 * C); float fNear = 0.5 * (-B - sqrt(fDet)); // Calculate the ray's starting position, then calculate its scattering offset vec3 v3Start = m_v3CameraPos + v3Ray * fNear; fFar -= fNear; float fDepth = exp((m_fInnerRadius - m_fOuterRadius) / m_fScaleDepth); float fCameraAngle = dot(-v3Ray, v3Pos) / fFar; float fLightAngle = dot(v3ELightPos, v3Pos) / fFar; float fCameraScale = scale(fCameraAngle); float fLightScale = scale(fLightAngle); float fCameraOffset = fDepth*fCameraScale; float fTemp = (fLightScale + fCameraScale); // Initialize the scattering loop variables float fSampleLength = fFar / fSamples; float fScaledLength = fSampleLength * m_fScale; vec3 v3SampleRay = v3Ray * fSampleLength; vec3 v3SamplePoint = v3Start + v3SampleRay * 0.5; // Now loop through the sample rays vec3 v3FrontColor = vec3(0.0, 0.0, 0.0); vec3 v3Attenuate; for(int i=0; i<nSamples; i++) { float fHeight = length(v3SamplePoint); float fDepth = exp(m_fScaleOverScaleDepth * (m_fInnerRadius - fHeight)); float fScatter = fDepth*fTemp - fCameraOffset; v3Attenuate = exp(-fScatter * (m_v3InvWavelength * m_fKr4PI + m_fKm4PI)); v3FrontColor += v3Attenuate * (fDepth * fScaledLength); v3SamplePoint += v3SampleRay; } vec3 first = v3FrontColor * (m_v3InvWavelength * m_fKrESun + m_fKmESun); vec3 secondary = v3Attenuate; color = vec4((first + vec3(0.25,0.25,0.25) * secondary), 1.0); // ^^ that color is passed to the frag shader and is used as the gl_FragColor } Here is also an image of the problem image

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  • as3 3D camera lookat

    - by Johannes Jensen
    I'm making a 3D camera scene in Flash, draw using drawTriangles() and rotated and translated using a Matrix3D. I've got the camera to look after a specific point, but only on the Y-axis, using the x and z coordinates, here is my code so far: var dx:Number = camera.x - lookAt.x; var dy:Number = camera.y - lookAt.y; var dz:Number = camera.z - lookAt.z; camera.rotationY = Math.atan2(dz, dx) * (180 / Math.PI) + 270; so no matter the x or z position, the point is always on the mid of the screen, IF and only if y matches with the camera. So what I need is to calculate the rotationX (which are measured in degrees not radians), and I was wondering how I would do this?

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  • Render 2 images that uses different shaders

    - by Code Vader
    Based on the giawa/nehe tutorials, how can I render 2 images with different shaders. I'm pretty new to OpenGl and shaders so I'm not completely sure whats happening in my code, but I think the shaders that is called last overwrites the first one. private static void OnRenderFrame() { // calculate how much time has elapsed since the last frame watch.Stop(); float deltaTime = (float)watch.ElapsedTicks / System.Diagnostics.Stopwatch.Frequency; watch.Restart(); // use the deltaTime to adjust the angle of the cube angle += deltaTime; // set up the OpenGL viewport and clear both the color and depth bits Gl.Viewport(0, 0, width, height); Gl.Clear(ClearBufferMask.ColorBufferBit | ClearBufferMask.DepthBufferBit); // use our shader program and bind the crate texture Gl.UseProgram(program); //<<<<<<<<<<<< TOP PYRAMID // set the transformation of the top_pyramid program["model_matrix"].SetValue(Matrix4.CreateRotationY(angle * rotate_cube)); program["enable_lighting"].SetValue(lighting); // bind the vertex positions, UV coordinates and element array Gl.BindBufferToShaderAttribute(top_pyramid, program, "vertexPosition"); Gl.BindBufferToShaderAttribute(top_pyramidNormals, program, "vertexNormal"); Gl.BindBufferToShaderAttribute(top_pyramidUV, program, "vertexUV"); Gl.BindBuffer(top_pyramidTrianlges); // draw the textured top_pyramid Gl.DrawElements(BeginMode.Triangles, top_pyramidTrianlges.Count, DrawElementsType.UnsignedInt, IntPtr.Zero); //<<<<<<<<<< CUBE // set the transformation of the cube program["model_matrix"].SetValue(Matrix4.CreateRotationY(angle * rotate_cube)); program["enable_lighting"].SetValue(lighting); // bind the vertex positions, UV coordinates and element array Gl.BindBufferToShaderAttribute(cube, program, "vertexPosition"); Gl.BindBufferToShaderAttribute(cubeNormals, program, "vertexNormal"); Gl.BindBufferToShaderAttribute(cubeUV, program, "vertexUV"); Gl.BindBuffer(cubeQuads); // draw the textured cube Gl.DrawElements(BeginMode.Quads, cubeQuads.Count, DrawElementsType.UnsignedInt, IntPtr.Zero); //<<<<<<<<<<<< BOTTOM PYRAMID // set the transformation of the bottom_pyramid program["model_matrix"].SetValue(Matrix4.CreateRotationY(angle * rotate_cube)); program["enable_lighting"].SetValue(lighting); // bind the vertex positions, UV coordinates and element array Gl.BindBufferToShaderAttribute(bottom_pyramid, program, "vertexPosition"); Gl.BindBufferToShaderAttribute(bottom_pyramidNormals, program, "vertexNormal"); Gl.BindBufferToShaderAttribute(bottom_pyramidUV, program, "vertexUV"); Gl.BindBuffer(bottom_pyramidTrianlges); // draw the textured bottom_pyramid Gl.DrawElements(BeginMode.Triangles, bottom_pyramidTrianlges.Count, DrawElementsType.UnsignedInt, IntPtr.Zero); //<<<<<<<<<<<<< STAR Gl.Disable(EnableCap.DepthTest); Gl.Enable(EnableCap.Blend); Gl.BlendFunc(BlendingFactorSrc.SrcAlpha, BlendingFactorDest.One); Gl.BindTexture(starTexture); //calculate the camera position using some fancy polar co-ordinates Vector3 position = 20 * new Vector3(Math.Cos(phi) * Math.Sin(theta), Math.Cos(theta), Math.Sin(phi) * Math.Sin(theta)); Vector3 upVector = ((theta % (Math.PI * 2)) > Math.PI) ? Vector3.Up : Vector3.Down; program_2["view_matrix"].SetValue(Matrix4.LookAt(position, Vector3.Zero, upVector)); // make sure the shader program and texture are being used Gl.UseProgram(program_2); // loop through the stars, drawing each one for (int i = 0; i < stars.Count; i++) { // set the position and color of this star program_2["model_matrix"].SetValue(Matrix4.CreateTranslation(new Vector3(stars[i].dist, 0, 0)) * Matrix4.CreateRotationZ(stars[i].angle)); program_2["color"].SetValue(stars[i].color); Gl.BindBufferToShaderAttribute(star, program_2, "vertexPosition"); Gl.BindBufferToShaderAttribute(starUV, program_2, "vertexUV"); Gl.BindBuffer(starQuads); Gl.DrawElements(BeginMode.Quads, starQuads.Count, DrawElementsType.UnsignedInt, IntPtr.Zero); // update the position of the star stars[i].angle += (float)i / stars.Count * deltaTime * 2 * rotate_stars; stars[i].dist -= 0.2f * deltaTime * rotate_stars; // if we've reached the center then move this star outwards and give it a new color if (stars[i].dist < 0f) { stars[i].dist += 5f; stars[i].color = new Vector3(generator.NextDouble(), generator.NextDouble(), generator.NextDouble()); } } Glut.glutSwapBuffers(); } The same goes for the textures, whichever one I mention last gets applied to both object?

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