piet-gpu/shader/bbox_clear.comp

// SPDX-License-Identifier: Apache-2.0 OR MIT OR Unlicense

// Clear path bbox to prepare for atomic min/max.

#version 450
#extension GL_GOOGLE_include_directive : enable

#include "mem.h"
#include "setup.h"

#define LG_WG_SIZE 9
#define WG_SIZE (1 << LG_WG_SIZE)

layout(local_size_x = WG_SIZE, local_size_y = 1) in;

layout(binding = 1) readonly buffer ConfigBuf {
    Config conf;
};

void main() {
    uint ix = gl_GlobalInvocationID.x;
    if (ix < conf.n_path) {
        uint out_ix = (conf.path_bbox_alloc.offset >> 2) + 6 * ix;
        memory[out_ix] = 0xffff;
        memory[out_ix + 1] = 0xffff;
        memory[out_ix + 2] = 0;
        memory[out_ix + 3] = 0;
    }
}