I have a separate stack in my program with this timer vector attached. When called, the stack pops an element out and the timer keeps track of how long it is out via user input. When the time reaches 0, the element is put back into the stack. I wanted to work through multiple timers so I tried to put them all into a vector and have them all decrement by one time unit when a function is called. Not totally clear on how vectors work so I do not know how to decrement all of a vector's values.
int wait(vector<int> &x){
std::vector<int>::iterator itr;
for(itr = x.begin(); itr < x.end(); itr++)
{ //psuedocode
//x[itr]--;
}
}
I just want to make sure I'm going in the right direction.
Here is how you can decrement all the values in the vector
int wait(vector<int> &x){
for(std::vector<int>::iterator itr = x.begin(); itr != x.end(); itr++)
{
(*itr)--;
}
}
or using C++11
int wait(vector<int> x){
for (int& i : x )
i--;
}
To decrease the value pointed by the iterator in the code, you can do -
for(itr = x.begin(); itr < x.end(); itr++)
{ //psuedocode
(*itr)--;
}
*itr returns the value being pointed by the iterator.
Related
It is my first attempt to implement recursion with CUDA. The goal is to extract all the combinations from a set of chars "12345" using the power of CUDA to parallelize dynamically the task. Here is my kernel:
__device__ char route[31] = { "_________________________"};
__device__ char init[6] = { "12345" };
__global__ void Recursive(int depth) {
// up to depth 6
if (depth == 5) return;
// newroute = route - idx
int x = depth * 6;
printf("%s\n", route);
int o = 0;
int newlen = 0;
for (int i = 0; i<6; ++i)
{
if (i != threadIdx.x)
{
route[i+x-o] = init[i];
newlen++;
}
else
{
o = 1;
}
}
Recursive<<<1,newlen>>>(depth + 1);
}
__global__ void RecursiveCount() {
Recursive <<<1,5>>>(0);
}
The idea is to exclude 1 item (the item corresponding to the threadIdx) in each different thread. In each recursive call, using the variable depth, it works over a different base (variable x) on the route device variable.
I expect the kernel prompts something like:
2345_____________________
1345_____________________
1245_____________________
1234_____________________
2345_345_________________
2345_245_________________
2345_234_________________
2345_345__45_____________
2345_345__35_____________
2345_345__34_____________
..
2345_245__45_____________
..
But it prompts ...
·_____________
·_____________
·_____________
·_____________
·_____________
·2345
·2345
·2345
·2345
...
What I´m doing wrong?
What I´m doing wrong?
I may not articulate every problem with your code, but these items should get you a lot closer.
I recommend providing a complete example. In my view it is basically required by Stack Overflow, see item 1 here, note use of the word "must". Your example is missing any host code, including the original kernel call. It's only a few extra lines of code, why not include it? Sure, in this case, I can deduce what the call must have been, but why not just include it? Anyway, based on the output you indicated, it seems fairly evident the launch configuration of the host launch would have to be <<<1,1>>>.
This doesn't seem to be logical to me:
I expect the kernel prompts something like:
2345_____________________
The very first thing your kernel does is print out the route variable, before making any changes to it, so I would expect _____________________. However we can "fix" this by moving the printout to the end of the kernel.
You may be confused about what a __device__ variable is. It is a global variable, and there is only one copy of it. Therefore, when you modify it in your kernel code, every thread, in every kernel, is attempting to modify the same global variable, at the same time. That cannot possibly have orderly results, in any thread-parallel environment. I chose to "fix" this by making a local copy for each thread to work on.
You have an off-by-1 error, as well as an extent error in this loop:
for (int i = 0; i<6; ++i)
The off-by-1 error is due to the fact that you are iterating over 6 possible items (that is, i can reach a value of 5) but there are only 5 items in your init variable (the 6th item being a null terminator. The correct indexing starts out over 0-4 (with one of those being skipped). On subsequent iteration depths, its necessary to reduce this indexing extent by 1. Note that I've chosen to fix the first error here by increasing the length of init. There are other ways to fix, of course. My method inserts an extra _ between depths in the result.
You assume that at each iteration depth, the correct choice of items is the same, and in the same order, i.e. init. However this is not the case. At each depth, the choices of items must be selected not from the unchanging init variable, but from the choices passed from previous depth. Therefore we need a local, per-thread copy of init also.
A few other comments about CUDA Dynamic Parallelism (CDP). When passing pointers to data from one kernel scope to a child scope, local space pointers cannot be used. Therefore I allocate for the local copy of route from the heap, so it can be passed to child kernels. init can be deduced from route, so we can use an ordinary local variable for myinit.
You're going to quickly hit some dynamic parallelism (and perhaps memory) limits here if you continue this. I believe the total number of kernel launches for this is 5^5, which is 3125 (I'm doing this quickly, I may be mistaken). CDP has a pending launch limit of 2000 kernels by default. We're not hitting this here according to what I see, but you'll run into that sooner or later if you increase the depth or width of this operation. Furthermore, in-kernel allocations from the device heap are by default limited to 8KB. I don't seem to be hitting that limit, but probably I am, so my design should probably be modified to fix that.
Finally, in-kernel printf output is limited to the size of a particular buffer. If this technique is not already hitting that limit, it will soon if you increase the width or depth.
Here is a worked example, attempting to address the various items above. I'm not claiming it is defect free, but I think the output is closer to your expectations. Note that due to character limits on SO answers, I've truncated/excerpted some of the output.
$ cat t1639.cu
#include <stdio.h>
__device__ char route[31] = { "_________________________"};
__device__ char init[7] = { "12345_" };
__global__ void Recursive(int depth, const char *oroute) {
char *nroute = (char *)malloc(31);
char myinit[7];
if (depth == 0) memcpy(myinit, init, 6);
else memcpy(myinit, oroute+(depth-1)*6, 6);
myinit[6] = 0;
if (nroute == NULL) {printf("oops\n"); return;}
memcpy(nroute, oroute, 30);
nroute[30] = 0;
// up to depth 6
if (depth == 5) return;
// newroute = route - idx
int x = depth * 6;
//printf("%s\n", nroute);
int o = 0;
int newlen = 0;
for (int i = 0; i<(6-depth); ++i)
{
if (i != threadIdx.x)
{
nroute[i+x-o] = myinit[i];
newlen++;
}
else
{
o = 1;
}
}
printf("%s\n", nroute);
Recursive<<<1,newlen>>>(depth + 1, nroute);
}
__global__ void RecursiveCount() {
Recursive <<<1,5>>>(0, route);
}
int main(){
RecursiveCount<<<1,1>>>();
cudaDeviceSynchronize();
}
$ nvcc -o t1639 t1639.cu -rdc=true -lcudadevrt -arch=sm_70
$ cuda-memcheck ./t1639
========= CUDA-MEMCHECK
2345_____________________
1345_____________________
1245_____________________
1235_____________________
1234_____________________
2345__345________________
2345__245________________
2345__235________________
2345__234________________
2345__2345_______________
2345__345___45___________
2345__345___35___________
2345__345___34___________
2345__345___345__________
2345__345___45____5______
2345__345___45____4______
2345__345___45____45_____
2345__345___45____5______
2345__345___45____5_____5
2345__345___45____4______
2345__345___45____4_____4
2345__345___45____45____5
2345__345___45____45____4
2345__345___35____5______
2345__345___35____3______
2345__345___35____35_____
2345__345___35____5______
2345__345___35____5_____5
2345__345___35____3______
2345__345___35____3_____3
2345__345___35____35____5
2345__345___35____35____3
2345__345___34____4______
2345__345___34____3______
2345__345___34____34_____
2345__345___34____4______
2345__345___34____4_____4
2345__345___34____3______
2345__345___34____3_____3
2345__345___34____34____4
2345__345___34____34____3
2345__345___345___45_____
2345__345___345___35_____
2345__345___345___34_____
2345__345___345___45____5
2345__345___345___45____4
2345__345___345___35____5
2345__345___345___35____3
2345__345___345___34____4
2345__345___345___34____3
2345__245___45___________
2345__245___25___________
2345__245___24___________
2345__245___245__________
2345__245___45____5______
2345__245___45____4______
2345__245___45____45_____
2345__245___45____5______
2345__245___45____5_____5
2345__245___45____4______
2345__245___45____4_____4
2345__245___45____45____5
2345__245___45____45____4
2345__245___25____5______
2345__245___25____2______
2345__245___25____25_____
2345__245___25____5______
2345__245___25____5_____5
2345__245___25____2______
2345__245___25____2_____2
2345__245___25____25____5
2345__245___25____25____2
2345__245___24____4______
2345__245___24____2______
2345__245___24____24_____
2345__245___24____4______
2345__245___24____4_____4
2345__245___24____2______
2345__245___24____2_____2
2345__245___24____24____4
2345__245___24____24____2
2345__245___245___45_____
2345__245___245___25_____
2345__245___245___24_____
2345__245___245___45____5
2345__245___245___45____4
2345__245___245___25____5
2345__245___245___25____2
2345__245___245___24____4
2345__245___245___24____2
2345__235___35___________
2345__235___25___________
2345__235___23___________
2345__235___235__________
2345__235___35____5______
2345__235___35____3______
2345__235___35____35_____
2345__235___35____5______
2345__235___35____5_____5
2345__235___35____3______
2345__235___35____3_____3
2345__235___35____35____5
2345__235___35____35____3
2345__235___25____5______
2345__235___25____2______
2345__235___25____25_____
2345__235___25____5______
2345__235___25____5_____5
2345__235___25____2______
2345__235___25____2_____2
2345__235___25____25____5
2345__235___25____25____2
2345__235___23____3______
2345__235___23____2______
2345__235___23____23_____
2345__235___23____3______
2345__235___23____3_____3
2345__235___23____2______
2345__235___23____2_____2
2345__235___23____23____3
2345__235___23____23____2
2345__235___235___35_____
2345__235___235___25_____
2345__235___235___23_____
2345__235___235___35____5
2345__235___235___35____3
2345__235___235___25____5
2345__235___235___25____2
2345__235___235___23____3
2345__235___235___23____2
2345__234___34___________
2345__234___24___________
2345__234___23___________
2345__234___234__________
2345__234___34____4______
2345__234___34____3______
2345__234___34____34_____
2345__234___34____4______
2345__234___34____4_____4
2345__234___34____3______
2345__234___34____3_____3
2345__234___34____34____4
2345__234___34____34____3
2345__234___24____4______
2345__234___24____2______
2345__234___24____24_____
2345__234___24____4______
2345__234___24____4_____4
2345__234___24____2______
2345__234___24____2_____2
2345__234___24____24____4
2345__234___24____24____2
2345__234___23____3______
2345__234___23____2______
2345__234___23____23_____
2345__234___23____3______
2345__234___23____3_____3
2345__234___23____2______
2345__234___23____2_____2
2345__234___23____23____3
2345__234___23____23____2
2345__234___234___34_____
2345__234___234___24_____
2345__234___234___23_____
2345__234___234___34____4
2345__234___234___34____3
2345__234___234___24____4
2345__234___234___24____2
2345__234___234___23____3
2345__234___234___23____2
2345__2345__345__________
2345__2345__245__________
2345__2345__235__________
2345__2345__234__________
2345__2345__345___45_____
2345__2345__345___35_____
2345__2345__345___34_____
2345__2345__345___45____5
2345__2345__345___45____4
2345__2345__345___35____5
2345__2345__345___35____3
2345__2345__345___34____4
2345__2345__345___34____3
2345__2345__245___45_____
2345__2345__245___25_____
2345__2345__245___24_____
2345__2345__245___45____5
2345__2345__245___45____4
2345__2345__245___25____5
2345__2345__245___25____2
2345__2345__245___24____4
2345__2345__245___24____2
2345__2345__235___35_____
2345__2345__235___25_____
2345__2345__235___23_____
2345__2345__235___35____5
2345__2345__235___35____3
2345__2345__235___25____5
2345__2345__235___25____2
2345__2345__235___23____3
2345__2345__235___23____2
2345__2345__234___34_____
2345__2345__234___24_____
2345__2345__234___23_____
2345__2345__234___34____4
2345__2345__234___34____3
2345__2345__234___24____4
2345__2345__234___24____2
2345__2345__234___23____3
2345__2345__234___23____2
1345__345________________
1345__145________________
1345__135________________
1345__134________________
1345__1345_______________
1345__345___45___________
1345__345___35___________
1345__345___34___________
1345__345___345__________
1345__345___45____5______
1345__345___45____4______
1345__345___45____45_____
1345__345___45____5______
1345__345___45____5_____5
1345__345___45____4______
1345__345___45____4_____4
1345__345___45____45____5
1345__345___45____45____4
1345__345___35____5______
1345__345___35____3______
1345__345___35____35_____
1345__345___35____5______
1345__345___35____5_____5
1345__345___35____3______
1345__345___35____3_____3
1345__345___35____35____5
1345__345___35____35____3
1345__345___34____4______
1345__345___34____3______
1345__345___34____34_____
1345__345___34____4______
1345__345___34____4_____4
1345__345___34____3______
1345__345___34____3_____3
1345__345___34____34____4
1345__345___34____34____3
1345__345___345___45_____
1345__345___345___35_____
1345__345___345___34_____
1345__345___345___45____5
1345__345___345___45____4
1345__345___345___35____5
1345__345___345___35____3
1345__345___345___34____4
1345__345___345___34____3
1345__145___45___________
1345__145___15___________
1345__145___14___________
1345__145___145__________
1345__145___45____5______
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1345__145___45____45_____
1345__145___45____5______
1345__145___45____5_____5
1345__145___45____4______
1345__145___45____4_____4
1345__145___45____45____5
1345__145___45____45____4
1345__145___15____5______
1345__145___15____1______
1345__145___15____15_____
1345__145___15____5______
1345__145___15____5_____5
1345__145___15____1______
1345__145___15____1_____1
1345__145___15____15____5
1345__145___15____15____1
1345__145___14____4______
1345__145___14____1______
1345__145___14____14_____
1345__145___14____4______
1345__145___14____4_____4
1345__145___14____1______
1345__145___14____1_____1
1345__145___14____14____4
1345__145___14____14____1
1345__145___145___45_____
1345__145___145___15_____
1345__145___145___14_____
1345__145___145___45____5
1345__145___145___45____4
1345__145___145___15____5
1345__145___145___15____1
1345__145___145___14____4
1345__145___145___14____1
1345__135___35___________
1345__135___15___________
1345__135___13___________
1345__135___135__________
1345__135___35____5______
1345__135___35____3______
1345__135___35____35_____
1345__135___35____5______
1345__135___35____5_____5
1345__135___35____3______
1345__135___35____3_____3
1345__135___35____35____5
1345__135___35____35____3
1345__135___15____5______
1345__135___15____1______
1345__135___15____15_____
1345__135___15____5______
1345__135___15____5_____5
1345__135___15____1______
1345__135___15____1_____1
1345__135___15____15____5
1345__135___15____15____1
1345__135___13____3______
1345__135___13____1______
1345__135___13____13_____
1345__135___13____3______
1345__135___13____3_____3
1345__135___13____1______
1345__135___13____1_____1
1345__135___13____13____3
1345__135___13____13____1
1345__135___135___35_____
1345__135___135___15_____
1345__135___135___13_____
1345__135___135___35____5
1345__135___135___35____3
1345__135___135___15____5
1345__135___135___15____1
1345__135___135___13____3
1345__135___135___13____1
1345__134___34___________
1345__134___14___________
1345__134___13___________
1345__134___134__________
1345__134___34____4______
1345__134___34____3______
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1345__134___34____4______
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1345__134___34____3______
1345__134___34____3_____3
1345__134___34____34____4
1345__134___34____34____3
1345__134___14____4______
1345__134___14____1______
1345__134___14____14_____
1345__134___14____4______
1345__134___14____4_____4
1345__134___14____1______
1345__134___14____1_____1
1345__134___14____14____4
1345__134___14____14____1
1345__134___13____3______
1345__134___13____1______
1345__134___13____13_____
1345__134___13____3______
1345__134___13____3_____3
1345__134___13____1______
1345__134___13____1_____1
1345__134___13____13____3
1345__134___13____13____1
1345__134___134___34_____
1345__134___134___14_____
1345__134___134___13_____
1345__134___134___34____4
1345__134___134___34____3
1345__134___134___14____4
1345__134___134___14____1
1345__134___134___13____3
1345__134___134___13____1
1345__1345__345__________
1345__1345__145__________
1345__1345__135__________
1345__1345__134__________
1345__1345__345___45_____
1345__1345__345___35_____
1345__1345__345___34_____
1345__1345__345___45____5
1345__1345__345___45____4
1345__1345__345___35____5
1345__1345__345___35____3
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1345__1345__345___34____3
1345__1345__145___45_____
1345__1345__145___15_____
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1345__1345__145___45____5
1345__1345__145___45____4
1345__1345__145___15____5
1345__1345__145___15____1
1345__1345__145___14____4
1345__1345__145___14____1
1345__1345__135___35_____
1345__1345__135___15_____
1345__1345__135___13_____
1345__1345__135___35____5
1345__1345__135___35____3
1345__1345__135___15____5
1345__1345__135___15____1
1345__1345__135___13____3
1345__1345__135___13____1
1345__1345__134___34_____
1345__1345__134___14_____
1345__1345__134___13_____
1345__1345__134___34____4
1345__1345__134___34____3
1345__1345__134___14____4
1345__1345__134___14____1
1345__1345__134___13____3
1345__1345__134___13____1
1245__245________________
1245__145________________
1245__125________________
1245__124________________
1245__1245_______________
1245__245___45___________
1245__245___25___________
1245__245___24___________
1245__245___245__________
1245__245___45____5______
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1245__245___45____5______
1245__245___45____5_____5
1245__245___45____4______
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1245__245___45____45____5
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1245__245___25____5______
1245__245___25____2______
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1245__245___25____2______
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1245__245___25____25____5
1245__245___25____25____2
1245__245___24____4______
1245__245___24____2______
1245__245___24____24_____
1245__245___24____4______
1245__245___24____4_____4
1245__245___24____2______
1245__245___24____2_____2
1245__245___24____24____4
1245__245___24____24____2
1245__245___245___45_____
1245__245___245___25_____
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1245__245___245___45____5
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1245__245___245___25____5
1245__245___245___25____2
1245__245___245___24____4
1245__245___245___24____2
1245__145___45___________
1245__145___15___________
1245__145___14___________
1245__145___145__________
1245__145___45____5______
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1245__145___45____45_____
1245__145___45____5______
1245__145___45____5_____5
1245__145___45____4______
...
1235__1235__235___25_____
1235__1235__235___23_____
1235__1235__235___35____5
1235__1235__235___35____3
1235__1235__235___25____5
1235__1235__235___25____2
1235__1235__235___23____3
1235__1235__235___23____2
1235__1235__135___35_____
1235__1235__135___15_____
1235__1235__135___13_____
1235__1235__135___35____5
1235__1235__135___35____3
1235__1235__135___15____5
1235__1235__135___15____1
1235__1235__135___13____3
1235__1235__135___13____1
1235__1235__125___25_____
1235__1235__125___15_____
1235__1235__125___12_____
1235__1235__125___25____5
1235__1235__125___25____2
1235__1235__125___15____5
1235__1235__125___15____1
1235__1235__125___12____2
1235__1235__125___12____1
1235__1235__123___23_____
1235__1235__123___13_____
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========= ERROR SUMMARY: 0 errors
$
The answer given by Robert Crovella is correct at the 5th point, the mistake was in the using of init in every recursive call, but I want to clarify something that can be useful for other beginners with CUDA.
I used this variable because when I tried to launch a child kernel passing a local variable I always got the exception: Error: a pointer to local memory cannot be passed to a launch as an argument.
As I´m C# expert developer I´m not used to using pointers (Ref does the low-level-work for that) so I thought there was no way to do it in CUDA/c programming.
As Robert shows in its code it is possible copying the pointer with memalloc for using it as a referable argument.
Here is a kernel simplified as an example of deep recursion.
__device__ char init[6] = { "12345" };
__global__ void Recursive(int depth, const char* route) {
// up to depth 6
if (depth == 5) return;
//declaration for a referable argument (point 6)
char* newroute = (char*)malloc(6);
memcpy(newroute, route, 5);
int o = 0;
int newlen = 0;
for (int i = 0; i < (6 - depth); ++i)
{
if (i != threadIdx.x)
{
newroute[i - o] = route[i];
newlen++;
}
else
{
o = 1;
}
}
printf("%s\n", newroute);
Recursive <<<1, newlen>>>(depth + 1, newroute);
}
__global__ void RecursiveCount() {
Recursive <<<1, 5>>>(0, init);
}
I don't add the main call because I´m using ManagedCUDA for C# but as Robert says it can be figured-out how the call RecursiveCount is.
About ending arrays of char with /0 ... sorry but I don't know exactly what is the benefit; this code works fine without them.
i'm trying to make this interaction with keyboard for movement using some sprites and i got stuck with two situations.
1) The character movement is not going acording to the animation itself (it only begin moving after one second or so while it's already being animated). What i really want it to do is, to move without a "initial acceleration feeling" that i get because of this problem
2) I can't think of a way to make the character face the position it should be facing when the key is released. I'll post the code here, but since it need images to work correctly and is not so small i made a skecth available at this link if you want to check it out: https://www.openprocessing.org/sketch/439572
PImage[] reverseRun = new PImage [16];
PImage[] zeroArray = new PImage [16];
void setup(){
size(800,600);
//Right Facing
for(int i = 0; i < zeroArray.length; i++){
zeroArray[i] = loadImage (i + ".png");
zeroArray[i].resize(155,155);
}
//Left Facing
for( int z = 0; z < reverseRun.length; z++){
reverseRun[z] = loadImage ( "mirror" + z + ".png");
reverseRun[z].resize(155,155);
}
}
void draw(){
frameRate(15);
background(255);
imageMode(CENTER);
if(x > width+10){
x = 0;
} else if (x < - 10){
x = width;}
if (i >= zeroArray.length){
i = 3;} //looping to generate constant motiion
if ( z >= reverseRun.length){
z = 3;} //looping to generate constant motiion
if (isRight) {
image(zeroArray[i], x, 300);
i++;
} //going through the images at the array
else if (isLeft) {
image(reverseRun[z],x,300);
z++;
} going through the images at the array
else if(!isRight){
image(zeroArray[i], x, 300);
i = 0; } //"stoped" sprite
}
}
//movement
float x = 300;
float y = 300;
float i = 0;
float z = 0;
float speed = 25;
boolean isLeft, isRight, isUp, isDown;
void keyPressed() {
setMove(keyCode, true);
if (isLeft ){
x -= speed;
}
if(isRight){
x += speed;
}
}
void keyReleased() {
setMove(keyCode, false);
}
boolean setMove(int k, boolean b) {
switch (k) {
case UP:
return isUp = b;
case DOWN:
return isDown = b;
case LEFT:
return isLeft = b;
case RIGHT:
return isRight = b;
default:
return b; }
}
The movement problem is caused by your operating system setting a delay between key presses. Try this out by going to a text editor and holding down a key. You'll notice that a character shows up immediately, followed by a delay, followed by the character repeating until you release the key.
That delay is also happening between calls to the keyPressed() function. And since you're moving the character (by modifying the x variable) inside the keyPressed() function, you're seeing a delay in the movement.
The solution to this problem is to check which key is pressed instead of relying solely on the keyPressed() function. You could use the keyCode variable inside the draw() function, or you could keep track of which key is pressed using a set of boolean variables.
Note that you're actually already doing that with the isLeft and isRight variables. But you're only checking them in the keyPressed() function, which defeats the purpose of them because of the problem I outlined above.
In other words, move this block from the keyPressed() function so it's inside the draw() function instead:
if (isLeft ){
x -= speed;
}
if(isRight){
x += speed;
}
As for knowing which way to face when the character is not moving, you could do that using another boolean value that keeps track of which direction you're facing.
Side note: you should really try to properly indent your code, as right now it's pretty hard to read.
Shameless self-promotion: I wrote a tutorial on user input in Processing available here.
I've got a particle "engine" whom I've implementing a Pool system to and I've tested two different ways of rendering every Particle in a list. Please note that the Pooling really doesn't have anything with the problem to do. I just followed a tutorial and tried to use the second method when I noticed that they behaved differently.
The first way:
for (int i = 0; i < particleList.size(); i++) {
Iterator<Particle> it = particleList.iterator();
while (it.hasNext()) {
Particle p = it.next();
if (p.isDead()){
it.remove();
}
p.render(batch, delta);
}
}
Which works just fine. My particles are sharp and they move with the correct speed.
The second way:
Particle p;
for (int i = 0; i < particleList.size(); i++) {
p = particleList.get(i);
p.render(batch, delta);
if (p.isDead()) {
particleList.remove(i);
bulletPool.free(p);
}
}
Which makes all my particles blurry and moving really slow!
The render method for my particles look like this:
public void render(SpriteBatch batch, float delta) {
sprite.setX(sprite.getX() + (dx * speed) * delta * Assets.FPS);
sprite.setY(sprite.getY() + (dy * speed) * delta * Assets.FPS);
ttl--;
sprite.setScale(sprite.getScaleX() - 0.002f);
if (ttl <= 0 || sprite.getScaleX() <= 0)
isDead = true;
sprite.draw(batch);
}
Why do the different rendering methods provide different results?
Thanks in advance
You are mutating (removing elements from) a list while iterating over it. This is a classic way to make a mess.
The Iterator must have code to handle the delete case correctly. But your index-based for loop does not. Specifically when you call particleList.remove(i) the i is now "out of sync" with the content of the list. Consider what happens when you remove the element at index 3: 'i' will increment to 4, but the old element 4 got shuffled down into index 3, so it will get skipped.
I assume you're avoiding the Iterator to avoid memory allocations. So, one way to side-step this issue is to reverse the loop (go from particleList.size() down to 0). Alternatively, you can only increment i for non-dead particles.
I have an integer : (using xcode for iPhone ) .
int wordCounter=1;
Later on, when i fill arrays with it-as a pointer,in a for loop, it somehow becomes 0 after it becomes a certain number . i have checked my program many times for bugs, and i realize that i dont even have a decrement on it anywhere . i do have wordCounter++.
Now i have seen that i have many lines like this,that after them it becomes 0 :
if(tempBinary[countWords-1][j] != tempBinary[countWords][j])
so i was thinking that countWords-1 decrement it down again and again, is that possible?
i dont have any other decrement or initialization on this variable in my whole program.
i COULD see that when the tempBinary defined as size 7, it initialize at 5, and if tempBinary is 5, it zeroing on 3 ..
is it possible that the array is overflow and is zeroing it? i dont think so..
whats wrong here ?
thanks .
EDIT (one of the problematic states)
int countWords=1;
int stabilityK=0;
tempBinary[0][0]= tempBinary[0][1]=tempBinary[0][2]=tempBinary[0][3]=tempBinary[0][4]=tempBinary[0][5]=tempBinary[0][6]=tempBinary[0][7]=1 ;
for(int k=0;k<numOfBuffers;k++)
{
NSLog(#"countwords:%d",countWords-1);
float *temp=getFFT(buffersRing[k],buffersRing[k][0]);
for(int j=0;j<wordSize;j++)
{
switch(state_on_signal)
{
case WAIT_FOR_SECOND_CHANGE:
//get new word
if(temp[goodBins[j]] > decisionLine[j])
tempBinary[countWords][j]=1;
else
tempBinary[countWords][j]=0;
if(tempBinary[countWords-1][j] != tempBinary[countWords][j])
newData=1;
NSLog(#"s1: countwords:%d",countWords-1);
if(j==wordSize-1)
{
NSLog(#"s2: countwords:%d",countWords-1);
NSLog(#"PRE TEMP:%d%d%d%d%d%d%d%d",tempBinary[countWords-1][0],tempBinary[countWords-1][1],tempBinary[countWords-1][2],tempBinary[countWords-1][3],tempBinary[countWords-1][4],tempBinary[countWords-1][5],tempBinary[countWords-1][6],tempBinary[countWords-1][7] );
NSLog(#"NEW TEMP-WAIT FOR SECOND CHANGE :%d%d%d%d%d%d%d%d",tempBinary[countWords][0],tempBinary[countWords][1],tempBinary[countWords][2],tempBinary[countWords][3],tempBinary[countWords][4],tempBinary[countWords][5],tempBinary[countWords][6],tempBinary[countWords][7] );
NSLog(#"s3: countwords:%d",countWords-1);
//TAKE NEW DATA
if(newData==1)
{
NSLog(#" TOOK new BINARY at current k:%d, so took data at: %d",k,(k+markedK)/2);
for(int s=0;s<wordSize;s++)
{
if( getFFT(buffersRing[(k+markedK)/2],buffersRing[(k+markedK)/2][0])[goodBins[s] ] >decisionLine[s] )
binary[countWords-1][s]= 1;
else
binary[countWords-1][s]= 0;
}
NSLog(#"s4: countwords:%d",countWords-1);
NSLog(#"BINARY%d: %d%d%d%d%d%d%d%d :%d",(countWords-1), binary[(countWords-1)][0], binary[(countWords-1)][1], binary[(countWords-1)][2], binary[(countWords-1)][3], binary[(countWords-1)][4], binary[(countWords-1)][5], binary[(countWords-1)][6], binary[(countWords-1)][7],[self getDecimal:binary[countWords-1]]);
countWords++;
markedK=k;
state_on_signal=WAIT_FOR_STABILITY;
}
newData=0;
}
break;
so i was thinking that countWords-1 decrement it down again and again,
is that possible?
No
Usually this happens when you misuse a pointer and write a value to the wrong address in memory.
For example: where and how is declared tempBinary ?
As it's not possible (at least for me) to see the problem just looking at your code I'd suggest to step through your code with the debugger and see when countWords gets changed. Here lies the problem (at least one of them).
I have been developing a very simple text game using Objective C and Xcode. It is almost done but I am having a problem, the scanf method stops the loop and asks for user input while I need the computer to be running the rest of the loop, the solution I came up with was running two while loops at the same time, one being the logic loop and another being a loop for user input.
I have been doing my research and it looks like using threads are the way to go, I just have not found a tutorial that will break it down for a n00b in Objective C (I am decent in java, I just have never worked with threads). If anybody could explain them or link me to a very broken down tutorial that would be great. Or if anybody has another idea I am open to anything else.
Necessary Code (The scanf I am having a problem with has asterisks on the line):
while(running != 0)
{
if(gameState == 1)
{
if(timeToGenerateNum == true)
{
while(randNumber < 10000000)
{
randNumber = arc4random() % 100000000;
}
NSLog(#"%i", randNumber);
timeToGenerateNum = false;
}
else
{
while(time <= 2500)
{
NSLog(#"Testing");
time++;
******************scanf("%i", &userNum);************************
if(userNum == randNumber)
{
score += time;
time = 0;
timeToGenerateNum = true;
}
}
NSLog(#"Game Over! Your score was %i!", score);
running = 0;
}
}
else if(gameState == 2)
{
NSLog(#"To play, simply type in the number that appears on the screen.");
NSLog(#"But be careful, you only have a short amount of time before GAME OVER!");
NSLog(#"The quicker you type in the number the more score you get!");
NSLog(#"Are you ready to start, if so type '1' and press enter!");
scanf("%i", &gameState);
}
}
You're going to have to learn a bit about BSD (Unix, Linux) input/output to pull this off: replace your call to scanf with a non-blocking function you write to acquire input from the user's keyboard.
This function should immediately return whatever the user typed, or immediately return with a zero character count if she didn't type anything.
Read up on the select(2) system call, and keep in mind that keyboard input (standard input) is the first file descriptor, file descriptor zero.