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2018-06-28T17:51:32Z

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2007年7月31日 (火) 00:35にwiki>Joeedhによる

2007-07-31T00:35:00Z

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=Introduction=
Deep shadow maps are a technique to create filtered, transparent, colored shadow maps.

Papers used:

http://graphics.stanford.edu/papers/deepshadows/deepshad.pdf

http://www.tabellion.org/et/paper07/egsr07_mtsm.pdf

=Design=

==DSM Structure==

<code><pre>

/*Each tile has its own memarena to work better with caching.*/
typedef struct DSMTile {
struct TCS_Tile tile;

/*each of the arrays pointed in these 2 array rects has the length
as the first element, stored in the int format. this way
we can use a binary search to make things easier.*/
float **color_rect; //includes alpha
unsigned int **depth_rect;
int x, y;
int sizex, sizey;
struct MemArena *arena;
} DSMTile;

typedef struct DSMBuffer {
TCS_Buffer buffer;
float winmat[4][4];
float clipstart, clipend;
float lens; /*this is in degrees, for field of view*/

DSMTile *poly_rect;
int sizex, sizey;
int tilex, tiley;
int max_depth; /*the maximum number of samples in a single pixel*/
struct TCS_TileBuffer *cachebuffer;
} DSMBuffer;
</pre></code>

These are the deep shadow buffer structures. Each deep shadow buffer is divided into tiles, each of which is allocated with its own memarena. Each tile has 2 2d pointer arrays, one where each cell points to an array of RGBA values, and another where the cell points to an array of depth values (note that these 2 arrays correspond to each other). The initial implementation simply stores depth/rgba pairs instead of visibility functions.

For zbuffering, a special version of zbuffer_abuf has been created, that works with all faces (for now, to avoid the complexity of using 2 zbuffer schemes), rather then just ztransp ones, and allows setting an arbitrary number of oversamples.

==Generic Tile System Structure==
These are the structures I wrote for the tile system:

<code><pre>typedef struct TCS_Tile {
struct TCS_Tile *next, *prev;
void (*loadFromCache)(struct TCS_Tile *self, struct FILE *file, unsigned long start);

/*returns length*/
unsigned int (*saveToCache(struct TCS_Tile *self, struct FILE *file, unsigned
long current_position);
int is_cached;
struct TCS_TilePool *pool;
struct TCS_TileBuffer *buffer; /*parent buffer*/
} TCS_Tile;

/*pools manage tiles, but the the tiles themselves belong to TCS_TileBuffers
this is a generic container structure.*/
typedef struct TCS_TilePool {
struct TCS_TilePool *next, *prev;
ListBase tiles;

unsigned int tottiles;
unsigned long maxmem;
} TCS_TilePool;

typedef struct TCS_TileBuffer {
struct TCS_TileBuffer *next, *prev;
void (*makeTiles)(TCS_TileBuffer *self, TCS_TilePool *cachepool);
void (*freeBuffer)(TCS_TileBuffer *self);

/*as may dimensions can be used as needed, others can just be passed in as 0.*/
void (*getTile)(TCS_TileBuffer *self, int x, int y, int z);
void (*getTileMemUsage)(TCS_TileBuffer *self, int x, int y, int z);
TCS_TilePool *pool;
} TCS_TileBuffer;</pre></code>

Note that I havn't done any implementation for this yet. Just needed to figure out how it'd work so I knew how to design the DSM structures.

==Low-level Memory Cache System==
I've written the start of a system for disk-caching memory chunks with compressed file
I/O. The system is designed to support pointer restoration.

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Yamyam: 1版 をインポートしました

2007年7月31日 (火) 00:35にwiki>Joeedhによる

Yamyam: 1版をインポートしました