vello/piet-gpu/shader/setup.h
Raph Levien 3b67a4e7c1 New clip implementation
This PR reworks the clip implementation. The highlight is that clip bounding box accounting is now done on GPU rather than CPU. The clip mask is also rasterized on EndClip rather than BeginClip, which decreases memory traffic needed for the clip stack.

This is a pretty good working state, but not all cleanup has been applied. An important next step is to remove the CPU clip accounting (it is computed and encoded, but that result is not used). Another step is to remove the Annotated structure entirely.

Fixes #88. Also relevant to #119
2022-02-17 17:13:28 -08:00

88 lines
2.5 KiB
GLSL

// SPDX-License-Identifier: Apache-2.0 OR MIT OR Unlicense
// Various constants for the sizes of groups and tiles.
// Much of this will be made dynamic in various ways, but for now it's easiest
// to hardcode and keep all in one place.
// A LG_WG_FACTOR of n scales workgroup sizes by 2^n. Use 0 for a
// maximum workgroup size of 128, or 1 for a maximum size of 256.
#define LG_WG_FACTOR 1
#define WG_FACTOR (1<<LG_WG_FACTOR)
#define TILE_WIDTH_PX 16
#define TILE_HEIGHT_PX 16
#define PTCL_INITIAL_ALLOC 1024
// These should probably be renamed and/or reworked. In the binning
// kernel, they represent the number of bins. Also, the workgroup size
// of that kernel is equal to the number of bins, but should probably
// be more flexible (it's 512 in the K&L paper).
#define N_TILE_X 16
#define N_TILE_Y (8 * WG_FACTOR)
#define N_TILE (N_TILE_X * N_TILE_Y)
#define LG_N_TILE (7 + LG_WG_FACTOR)
#define N_SLICE (N_TILE / 32)
#define GRADIENT_WIDTH 512
#ifdef ERR_MALLOC_FAILED
struct Config {
uint n_elements; // paths
uint n_pathseg;
uint width_in_tiles;
uint height_in_tiles;
Alloc tile_alloc;
Alloc bin_alloc;
Alloc ptcl_alloc;
Alloc pathseg_alloc;
Alloc anno_alloc;
Alloc trans_alloc;
// new element pipeline stuff follows
// Bounding boxes of paths, stored as int (so atomics work)
Alloc bbox_alloc;
// Monoid for draw objects
Alloc drawmonoid_alloc;
// BeginClip(path_ix) / EndClip
Alloc clip_alloc;
// Intermediate bicyclic semigroup
Alloc clip_bic_alloc;
// Intermediate stack
Alloc clip_stack_alloc;
// Clip processing results (path_ix + bbox)
Alloc clip_bbox_alloc;
// Number of transforms in scene
// This is probably not needed.
uint n_trans;
// This *should* count only actual paths, but in the current
// implementation is redundant with n_elements.
uint n_path;
// Total number of BeginClip and EndClip draw objects.
uint n_clip;
// Offset (in bytes) of transform stream in scene buffer
uint trans_offset;
// Offset (in bytes) of linewidth stream in scene
uint linewidth_offset;
// Offset (in bytes) of path tag stream in scene
uint pathtag_offset;
// Offset (in bytes) of path segment stream in scene
uint pathseg_offset;
};
#endif
// Fill modes.
#define MODE_NONZERO 0
#define MODE_STROKE 1
// Size of kernel4 clip state, in words.
#define CLIP_STATE_SIZE 2
// fill_mode_from_flags extracts the fill mode from tag flags.
uint fill_mode_from_flags(uint flags) {
return flags & 0x1;
}