Apple

Yeah, this is more or less what I do. Thanks Robert.

-Morgan

On Tue, Jan 31, 2012 at 4:05 AM, Robert Bielik <email@hidden> wrote:

ben kamen skrev 2012-01-31 03:09:

Morgan, if you are willing to share a simple example of what that looks like, I would be grateful. What exactly goes into the queue? Function pointers?

One simple SWSR implementation (single writer-single reader) would be to have a Message class:

class Message {
public:
Message() {;}
enum Type {
Type_kAttack,
...
} type;

int param1;
int param2;
...
};

unsigned char fifoQueue[256 * sizeof(Message)] = {0};
unsigned fifoWritePtr = 0;
unsigned fifoReadPtr = 0;

Message* getMessageToWrite()
{
Message* base = (Message*)fifoQueue;
return new(base + (fifoWritePtr & 255)) Message();
}

void postMessageToFifo()
{
++fifoWritePtr;
}

bool fifoHasMessages() {
return (fifoWritePtr != fifoReadPtr);
}

const Message* getMessageFromFifo()
{
const Message* base = (const Message*)fifoQueue;
return base + (fifoReadPtr & 255);
}

void fifoAdvanceRead() {
++fifoReadPtr;
}

To post messages to the fifo:

Message* pMessage = getMessageToWrite();
pMessage->type = Message::Type_kAttack;
pMessage->param1 = 42;
postMessageToFifo();

Reading/processing messages in render callback:

while(fifoHasMessages()) {
const Message *pMessage = getMessageFromFifo();
// TODO: Process the message

// Next message...
fifoAdvanceRead();
}

That should roughly get you started.

Regards,
/Rob

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