Path: chuka.playstation.co.uk!news
From: sosman@terratron.com (Steven Osman)
Newsgroups: scee.yaroze.programming.3d_graphics
Subject: Re: Elevation data
Date: Thu, 09 Dec 1999 22:32:36 GMT
Organization: PlayStation Net Yaroze (SCEE)
Lines: 116
Message-ID: <38502d9a.96885804@news.playstation.co.uk>
References: <82luhc$6qr1@chuka.playstation.co.uk> <384eda83.10073394@news.playstation.co.uk> <82p7ct$7rp2@chuka.playstation.co.uk>
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I'm completely speculating here, but there have been threads fairly
recently about different data types needing to be aligned on different
byte-boundaries.

Is it possible that your linked list "sometimes" gets allocated to the
right boundaries, and sometimes doesn't?  (Perhaps depending on
changes you make in your code?)

Again, this is sheer speculation.  I remember somebody mentioning that
taking care of the alignment is "something you need to do", but no
more specifics than that.

Steven

On Thu, 9 Dec 1999 21:31:37 -0000, "Matthew Hardingham"
<MatthewHardingham@RebelWareInteractive.Freeserve.co.uk> wrote:

>Cheers for that but for some reason it's now working !
>odd that I still don't know what caused it.
>
>Matt
>
>Steven Osman <sosman@terratron.com> wrote in message
>news:384eda83.10073394@news.playstation.co.uk...
>> You're performing 16384 memory allocations, I wonder if that has
>> anything to do with it.  Maybe the compiler's memory manager isn't the
>> most efficient.
>>
>> I also wouldn't be surprised if your printf is the problem (did you
>> put that in afterwards?)  You are printing out 16384 lines also!
>>
>> An extremely trivial point (incidentally)... This line:
>>
>> NewVert->Next = NULL;
>>
>> is redundant
>>
>>
>> Steven
>>
>>
>> On Wed, 8 Dec 1999 15:40:58 -0000, "Matthew Hardingham"
>> <MatthewHardingham@RebelWareInteractive.Freeserve.co.uk> wrote:
>>
>> >Right here we go then,
>> >
>> >At the moment I have a set of elevation points stored in an array
>(128x128)
>> >from this I'm creating a link list of vertices.
>> >For some reason it is running very slow or the program is crashing out.
>> >Why ?
>> >It's bugging me me now.
>> >
>> >Here's the vertex structure --
>> >
>> >    /* Vertex list */
>> >    typedef struct Vertex {
>> >        unsigned short IdxX, IdxZ;
>> >        VECTOR Vert;                  /* Vector */
>> >        struct Vertex *Next;
>> >    } VERTEX;
>> >
>> >
>> >Heres a snippet of code where the elevation data is extracted from the
>> >array --
>> >
>> >    /* Loop through the mesh */
>> >    for(MeshZ=0; MeshZ<MESH_SIZE; MeshZ++)
>> >    {
>> >        for(MeshX=0; MeshX<MESH_SIZE; MeshX++)
>> >        {
>> >            NewVert = AllocateVertex();
>> >
>> >            NewVert->IdxX = BlockX;
>> >            NewVert->IdxZ = BlockZ;
>> >
>> >            printf("\n Z - %ld X - %ld", MeshZ, MeshX);
>> >
>> >            /* Set vertices values */
>> >            NewVert->Vert.vx = (MeshX*MESH_INTERVAL);
>> >            NewVert->Vert.vy = HeightArray[MeshZ][MeshX];
>> >            NewVert->Vert.vz = (MeshZ*MESH_INTERVAL);
>> >
>> >            /* Change the pointers and link list positions */
>> >            CurrentVert->Next = NewVert;
>> >            NewVert->Next = NULL;
>> >            CurrentVert = NewVert;
>> >         }
>> >    }
>> >
>> >Here's the allocation part ---
>> >
>> >    /* Vertex memory allocation */
>> >    VERTEX *AllocateVertex(void)
>> >    {
>> >        VERTEX *V = NULL;
>> >
>> >        V = (VERTEX *)malloc(sizeof(VERTEX));
>> >
>> >        V->IdxX = 0; V->IdxZ = 0;
>> >
>> >        /* Vertice values */
>> >        V->Vert.vx = 0; V->Vert.vy = 0; V->Vert.vz = 0;
>> >
>> >        V->Next = NULL;
>> >
>> >        return(V);
>> >    }
>> >
>> >
>> >
>> >
>> >
>>
>