mach/examples/gkurve/frag.wgsl
Stephen Gutekanst f299d87aa2 {examples,shaderexp}: update to new mach/gpu API
Signed-off-by: Stephen Gutekanst <stephen@hexops.com>
2022-08-12 00:43:43 -07:00

73 lines
2.8 KiB
WebGPU Shading Language
Executable file

struct FragUniform {
type_: u32,
padding: vec3<f32>,
blend_color: vec4<f32>,
}
@binding(1) @group(0) var<storage> ubos: array<FragUniform>;
@binding(2) @group(0) var mySampler: sampler;
@binding(3) @group(0) var myTexture: texture_2d<f32>;
@fragment fn main(
@location(0) uv: vec2<f32>,
@interpolate(linear) @location(1) bary: vec2<f32>,
@interpolate(flat) @location(2) triangle_index: u32,
) -> @location(0) vec4<f32> {
// Example 1: Visualize barycentric coordinates:
// return vec4<f32>(bary.x, bary.y, 0.0, 1.0);
// return vec4<f32>(0.0, bary.x, 0.0, 1.0); // [1.0 (bottom-left vertex), 0.0 (bottom-right vertex)]
// return vec4<f32>(0.0, bary.y, 0.0, 1.0); // [1.0 (bottom-left vertex), 1.0 (top-right face)]
// Example 2: Render gkurve primitives
// Concave (inverted quadratic bezier curve)
// inversion = -1.0;
// Convex (inverted quadratic bezier curve)
// inversion = 1.0;
let inversion = select( 1.0, -1.0, ubos[triangle_index].type_ == 1u);
// Texture uvs
// (These two could be cut with vec2(0.0,1.0) + uv * vec2(1.0,-1.0))
var correct_uv = uv;
correct_uv.y = 1.0 - correct_uv.y;
var color = textureSample(myTexture, mySampler, correct_uv) * ubos[triangle_index].blend_color;
// Gradients
let px = dpdx(bary.xy);
let py = dpdy(bary.xy);
// Chain rule
let fx = (2.0 * bary.x) * px.x - px.y;
let fy = (2.0 * bary.x) * py.x - py.y;
// Signed distance
var dist = (bary.x * bary.x - bary.y) / sqrt(fx * fx + fy * fy);
dist *= inversion;
dist /= 300.0;
// Border rendering.
let border_color = vec4<f32>(1.0, 0.0, 0.0, 1.0);
let border_width = 3.0;
let border_smoothing = 1.0;
// if (dist > 0.0 && dist <= 0.1) { return vec4<f32>(1.0, 0.0, 0.0, 1.0); }
// if (dist > 0.2 && dist <= 0.3) { return vec4<f32>(0.0, 0.0, 1.0, 1.0); }
// // Wireframe rendering.
// let right_face_dist = bary.y;
// let bottom_face_dist = bary.x-bary.y;
// let left_face_dist = 1.0 - ((bottom_face_dist*2.0) + bary.y);
// let normal_bary = vec3<f32>(right_face_dist, bottom_face_dist, left_face_dist);
// let fwd = fwidth(normal_bary);
// let w = smoothstep(border_width * fwd, (border_width + border_smoothing) * fwd, normal_bary);
// let width = 1.0 - min(min(w.x, w.y), w.z);
// let epsilon = 0.001;
// if (right_face_dist >= -epsilon && right_face_dist <= width
// || left_face_dist >= -epsilon && left_face_dist <= width
// || bottom_face_dist >= -epsilon && bottom_face_dist <= width) {
// color = mix(color, border_color, width);
// if (dist < 0.0 && ubos[triangle_index].type_ != 2u) {
// return vec4<f32>(border_color.rgb, width);
// }
// }
return color * f32(dist >= 0.0 || ubos[triangle_index].type_ == 2u);
}