From 34c0065c2d200a0a0dcec7ea7f82421a4fabb4f5 Mon Sep 17 00:00:00 2001
From: Mark <mark@betalupi.com>
Date: Mon, 8 Jan 2024 15:17:05 -0800
Subject: [PATCH] Added radialbar shader

---
 crates/render/shaders/radialbar.wgsl | 109 +++++++++++++++++++++++++++
 1 file changed, 109 insertions(+)
 create mode 100644 crates/render/shaders/radialbar.wgsl

diff --git a/crates/render/shaders/radialbar.wgsl b/crates/render/shaders/radialbar.wgsl
new file mode 100644
index 0000000..0c6176e
--- /dev/null
+++ b/crates/render/shaders/radialbar.wgsl
@@ -0,0 +1,109 @@
+// INCLUDE: global uniform header
+
+struct InstanceInput {
+	@location(2) anchor: u32,
+	@location(3) position: vec2<f32>,
+	@location(4) diameter: f32,
+	@location(5) stroke: f32,
+	@location(6) angle: f32,
+	@location(7) color: vec4<f32>,
+};
+
+struct VertexInput {
+	@location(0) position: vec3<f32>,
+	@location(1) texture_coords: vec2<f32>,
+};
+
+struct VertexOutput {
+	@builtin(position) position: vec4<f32>,
+	@location(2) center: vec2<f32>,
+	@location(3) diameter: f32,
+	@location(4) stroke: f32,
+	@location(5) angle: f32,
+	@location(6) color: vec4<f32>,
+};
+
+
+@group(0) @binding(0)
+var texture_array: binding_array<texture_2d<f32>>;
+@group(0) @binding(1)
+var sampler_array: binding_array<sampler>;
+
+@vertex
+fn vertex_main(
+	vertex: VertexInput,
+	instance: InstanceInput,
+) -> VertexOutput {
+	var out: VertexOutput;
+	out.position = vec4(vertex.position, 1.0);
+	out.diameter = instance.diameter;
+	out.stroke = instance.stroke;
+	out.color = instance.color;
+	out.angle = instance.angle;
+
+	// Center of this radial bar, in logical pixels,
+	// with (0, 0) at the center of the screen.
+	if instance.anchor == u32(0) {
+		out.center = instance.position + (
+			(global_data.window_size / global_data.window_scale.x)
+			- vec2(instance.diameter, instance.diameter)
+		) / 2.0;
+	} else {
+		out.center = vec2(0.0, 0.0);
+	}
+
+	return out;
+}
+
+@fragment
+fn fragment_main(in: VertexOutput) -> @location(0) vec4<f32> {
+	// Fragment position in logical pixels, relative to arc center
+	let p = (
+		vec2(1.0, -1.0) *
+		(in.position.xy - global_data.window_size / 2.0) /
+		global_data.window_scale.x
+	) - in.center;
+
+	let bar_width = in.stroke;                                // Width of filled bar
+	let bar_radius = in.diameter / 2.0 - bar_width / 2.0;     // Middle radius of the bar
+	let angle = in.angle - floor(in.angle / 6.283) * 6.28318; // Sanely handle large angles (fmod(angle, 2pi))
+	let zero_vector = vec2(0.0, 1.0);                         // Draw bar clockwise from this vector
+	let frag_radius = distance(vec2(0.0, 0.0), p);            // Radius of this fragment
+	let feather = 2.0;                                        // Size of feather, in logical pixels
+	
+	// Clockwise angle between zero_vector and fragment location
+	let frag_angle = atan2(
+		p.y*zero_vector.x - p.x*zero_vector.y,
+		-dot(p, zero_vector)
+	) + 3.14159;
+
+
+	// Line fill & feather
+	if abs(frag_radius - bar_radius) <= bar_width / 2.0 && frag_angle <= angle {
+		let x = (abs(frag_radius - bar_radius) - (bar_width/2.0 - feather)) / feather;
+		return in.color * vec4(1.0, 1.0, 1.0, clamp(1.0 - x, 0.0, 1.0));
+	}
+
+	// Round cap centers
+	let cap_start_center = zero_vector * (in.diameter / 2.0 - (bar_width / 2.0));
+	let cap_end_center = mat2x2(
+		vec2(cos(-angle), sin(-angle)),
+		vec2(-sin(-angle), cos(-angle))
+	) * cap_start_center;
+
+	// Cap fill & feather
+	let cap_start_d = distance(p, cap_start_center);
+	let cap_end_d = distance(p, cap_end_center);
+	if (
+		cap_start_d <= bar_width / 2.0 ||
+		cap_end_d <= bar_width / 2.0
+	) {
+		let x = (
+			min(cap_start_d, cap_end_d)
+			- (bar_width/2.0 - feather)
+		) / feather;
+		return in.color * vec4(1.0, 1.0, 1.0, clamp(1.0 - x, 0.0, 1.0));
+	}
+
+	discard;
+}
\ No newline at end of file