vello/piet-wgsl/shader/shared/ptcl.wgsl

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

// Layout of per-tile command list
// Initial allocation, in u32's.
const PTCL_INITIAL_ALLOC = 64u;
const PTCL_INCREMENT = 256u;

// Amount of space taken by jump
const PTCL_HEADROOM = 2u;

// Tags for PTCL commands
const CMD_END = 0u;
const CMD_FILL = 1u;
const CMD_STROKE = 2u;
const CMD_SOLID = 3u;
const CMD_COLOR = 5u;
const CMD_LIN_GRAD = 6u;
const CMD_RAD_GRAD = 7u;
const CMD_BEGIN_CLIP = 9u;
const CMD_END_CLIP = 10u;
const CMD_JUMP = 11u;

// The individual PTCL structs are written here, but read/write is by
// hand in the relevant shaders

struct CmdFill {
    tile: u32,
    backdrop: i32,
}

struct CmdStroke {
    tile: u32,
    half_width: f32,
}

struct CmdJump {
    new_ix: u32,
}

struct CmdColor {
    rgba_color: u32,
}

struct CmdLinGrad {
    index: u32,
    line_x: f32,
    line_y: f32,
    line_c: f32,
}

struct CmdRadGrad {
    index: u32,
    matrx: vec4<f32>,
    xlat: vec2<f32>,
    c1: vec2<f32>,
    ra: f32,
    roff: f32,
}

struct CmdEndClip {
    blend: u32,
    alpha: f32,
}