Testing compression.

apps/nexus/patch.cpp

@@ -18,6 +18,54 @@ void pad(unsigned int &size) {
   while(size&0x3) size++;
 }
 
+void shuffle(float *buffer, unsigned int size, unsigned int stride) {
+  float *tmp = new float[size];
+  unsigned int count = 0;
+
+  unsigned int nelem = size/stride;
+  for(unsigned int s = 0; s < stride; s++) {
+    float *ptr = buffer + s;
+    for(unsigned int i = 0; i < nelem; i++) {
+      tmp[count++] = *ptr;
+      ptr += stride;
+    }
+  }
+  memcpy(buffer, tmp, size * sizeof(float));
+  delete []tmp;
+}
+
+void unshuffle(float *buffer, unsigned int size, unsigned int stride) {
+  float *tmp = new float[size];
+
+  unsigned int count = 0;
+  unsigned int nelem = size/stride;
+  for(unsigned int s = 0; s < stride; s++) {
+    float *ptr = tmp + s;
+    for(unsigned int i = 0; i < nelem; i++) {
+      *ptr = buffer[count++];
+      ptr += stride;
+    }
+  }
+  memcpy(buffer, tmp, size * sizeof(float));
+  delete []tmp;
+}
+
+void subtract(float *buffer, unsigned int size) {
+  float p = buffer[0];
+  float q;
+  for(unsigned int i = 1; i < size; i++) {
+    q = buffer[i];
+    buffer[i] -= p;
+    p = q;
+  }
+}
+
+void unsubtract(float *buffer, unsigned int size) {
+  for(unsigned int i = 1; i < size; i++) 
+    buffer[i] += buffer[i-1];
+}
+
+
 Patch::Patch(Signature signature, char *s, 
 	     unsigned short nvert, unsigned short nface):
              start(s) {
@@ -121,6 +169,9 @@ unsigned int Patch::ByteSize(Signature signature,
 
 char *Patch::Compress(unsigned int ram_size, unsigned int &size) {
 
+  //lets use differences
+  //  shuffle((float *)VertBegin(), nv * 3, 3);
+  //  subtract((float *)VertBegin(), nv * 3);
 
   //TODO use OVERLAP and test speed
   //TODO fill chunk padding with zeroes?
@@ -164,5 +215,8 @@ void Patch::Decompress(unsigned int ram_size, void *src, unsigned int src_sz) {
   }
   assert(dst_size == ram_size);
   //TODO add 3 to start... so we can use asm_fast decompressor  
+
+  //  unsubtract((float *)VertBegin(), nv * 3);
+  //  unshuffle((float *)VertBegin(), nv * 3, 3);
 }