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James Gregory 2013-12-31 11:38:48 +11:00
commit f658bfbb40
203 changed files with 26546 additions and 25801 deletions
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53-04.md
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@ -12,87 +12,89 @@ pages: 1001-1003
**LISTING 53.2 OLIST.C**
/* Object list-related functions. */
#include <stdio.h>
#include "polygon.h"
```c
/* Object list-related functions. */
#include <stdio.h>
#include "polygon.h"
/* Set up the empty object list, with sentinels at both ends to
terminate searches */
void InitializeObjectList()
{
ObjectListStart.NextObject = &ObjectListEnd;
ObjectListStart.PreviousObject = NULL;
ObjectListStart.CenterInView.Z = INT-TO-FIXED(-32768);
ObjectListEnd.NextObject = NULL;
ObjectListEnd.PreviousObject = &ObjectListStart;
ObjectListEnd.CenterInView.Z = 0x7FFFFFFFL;
NumObjects = 0;
}
/* Set up the empty object list, with sentinels at both ends to
terminate searches */
void InitializeObjectList()
{
ObjectListStart.NextObject = &ObjectListEnd;
ObjectListStart.PreviousObject = NULL;
ObjectListStart.CenterInView.Z = INT-TO-FIXED(-32768);
ObjectListEnd.NextObject = NULL;
ObjectListEnd.PreviousObject = &ObjectListStart;
ObjectListEnd.CenterInView.Z = 0x7FFFFFFFL;
NumObjects = 0;
}
/* Adds an object to the object list, sorted by center Z coord. */
void AddObject(Object *ObjectPtr)
{
Object *ObjectListPtr = ObjectListStart.NextObject;
/* Adds an object to the object list, sorted by center Z coord. */
void AddObject(Object *ObjectPtr)
{
Object *ObjectListPtr = ObjectListStart.NextObject;
/* Find the insertion point. Guaranteed to terminate because of
the end sentinel */
while (ObjectPtr->CenterInView.Z > ObjectListPtr->CenterInView.Z) {
ObjectListPtr = ObjectListPtr->NextObject;
}
/* Find the insertion point. Guaranteed to terminate because of
the end sentinel */
while (ObjectPtr->CenterInView.Z > ObjectListPtr->CenterInView.Z) {
ObjectListPtr = ObjectListPtr->NextObject;
}
/* Link in the new object */
ObjectListPtr->PreviousObject->NextObject = ObjectPtr;
ObjectPtr->NextObject = ObjectListPtr;
ObjectPtr->PreviousObject = ObjectListPtr->PreviousObject;
ObjectListPtr->PreviousObject = ObjectPtr;
NumObjects++;
}
/* Link in the new object */
ObjectListPtr->PreviousObject->NextObject = ObjectPtr;
ObjectPtr->NextObject = ObjectListPtr;
ObjectPtr->PreviousObject = ObjectListPtr->PreviousObject;
ObjectListPtr->PreviousObject = ObjectPtr;
NumObjects++;
}
/* Resorts the objects in order of ascending center Z coordinate in view space,
by moving each object in turn to the correct position in the object list. */
void SortObjects()
{
int i;
Object *ObjectPtr, *ObjectCmpPtr, *NextObjectPtr;
/* Resorts the objects in order of ascending center Z coordinate in view space,
by moving each object in turn to the correct position in the object list. */
void SortObjects()
{
int i;
Object *ObjectPtr, *ObjectCmpPtr, *NextObjectPtr;
/* Start checking with the second object */
ObjectCmpPtr = ObjectListStart.NextObject;
ObjectPtr = ObjectCmpPtr->NextObject;
for (i=1; i<NumObjects; i++) {
/* See if we need to move backward through the list */
if (ObjectPtr->CenterInView.Z < ObjectCmpPtr->CenterInView.Z) {
/* Remember where to resume sorting with the next object */
NextObjectPtr = ObjectPtr->NextObject;
/* Yes, move backward until we find the proper insertion
point. Termination guaranteed because of start sentinel */
do {
ObjectCmpPtr = ObjectCmpPtr->PreviousObject;
} while (ObjectPtr->CenterInView.Z <
ObjectCmpPtr->CenterInView.Z);
/* Start checking with the second object */
ObjectCmpPtr = ObjectListStart.NextObject;
ObjectPtr = ObjectCmpPtr->NextObject;
for (i=1; i<NumObjects; i++) {
/* See if we need to move backward through the list */
if (ObjectPtr->CenterInView.Z < ObjectCmpPtr->CenterInView.Z) {
/* Remember where to resume sorting with the next object */
NextObjectPtr = ObjectPtr->NextObject;
/* Yes, move backward until we find the proper insertion
point. Termination guaranteed because of start sentinel */
do {
ObjectCmpPtr = ObjectCmpPtr->PreviousObject;
} while (ObjectPtr->CenterInView.Z <
ObjectCmpPtr->CenterInView.Z);
/* Now move the object to its new location */
/* Unlink the object at the old location */
ObjectPtr->PreviousObject->NextObject =
ObjectPtr->NextObject;
ObjectPtr->NextObject->PreviousObject =
ObjectPtr->PreviousObject;
/* Now move the object to its new location */
/* Unlink the object at the old location */
ObjectPtr->PreviousObject->NextObject =
ObjectPtr->NextObject;
ObjectPtr->NextObject->PreviousObject =
ObjectPtr->PreviousObject;
/* Link in the object at the new location */
ObjectCmpPtr->NextObject->PreviousObject = ObjectPtr;
ObjectPtr->PreviousObject = ObjectCmpPtr;
ObjectPtr->NextObject = ObjectCmpPtr->NextObject;
ObjectCmpPtr->NextObject = ObjectPtr;
/* Link in the object at the new location */
ObjectCmpPtr->NextObject->PreviousObject = ObjectPtr;
ObjectPtr->PreviousObject = ObjectCmpPtr;
ObjectPtr->NextObject = ObjectCmpPtr->NextObject;
ObjectCmpPtr->NextObject = ObjectPtr;
/* Advance to the next object to sort */
ObjectCmpPtr = NextObjectPtr->PreviousObject;
ObjectPtr = NextObjectPtr;
} else {
/* Advance to the next object to sort */
ObjectCmpPtr = ObjectPtr;
ObjectPtr = ObjectPtr->NextObject;
}
}
}
/* Advance to the next object to sort */
ObjectCmpPtr = NextObjectPtr->PreviousObject;
ObjectPtr = NextObjectPtr;
} else {
/* Advance to the next object to sort */
ObjectCmpPtr = ObjectPtr;
ObjectPtr = ObjectPtr->NextObject;
}
}
}
```
#### Rounding {#Heading6}