Added starfield tinting

src/render/gpustate.rs

@@ -304,6 +304,7 @@ impl GPUState {
 						position: (s.pos + offset).into(),
 						parallax: s.parallax,
 						height: s.height,
+						tint: s.tint.into(),
 					})
 				}
 			}

src/render/shaders/starfield.wgsl

@@ -3,6 +3,7 @@ struct InstanceInput {
 	@location(2) position: vec2<f32>,
 	@location(3) parallax: f32,
 	@location(4) height: f32,
+	@location(5) tint: vec2<f32>,
 };
 
 struct VertexInput {
@@ -13,6 +14,7 @@ struct VertexInput {
 struct VertexOutput {
 	@builtin(position) position: vec4<f32>,
 	@location(0) texture_coords: vec2<f32>,
+	@location(1) tint: vec2<f32>,
 }
 
 @group(1) @binding(0)
@@ -37,6 +39,10 @@ fn vertex_shader_main(
 	instance: InstanceInput,
 ) -> VertexOutput {
 
+	var out: VertexOutput;
+	out.texture_coords = vertex.texture_coords;
+	out.tint = instance.tint;
+
 	// Center of the tile the camera is currently in, in game coordinates.
 	// x div y = x - (x mod y)
 	let tile_center = (
@@ -55,8 +61,15 @@ fn vertex_shader_main(
 
 	// Minimum scale to prevent flicker at large zoom levels
 	var real_size = scale * global.window_size.xy;
+	// TODO: configurable.
+	// Uniform distribution!
+	if (real_size.x < 0.5 || real_size.y < 0.5) {
+		out.position = vec4<f32>(2.0, 2.0, 0.0, 1.0);
+		return out;
+	}
 	if (real_size.x < 2.0 || real_size.y < 2.0) {
-		scale = 2.0 / min(global.window_size.x, global.window_size.y);
+		scale = 2.0 / max(global.window_size.x, global.window_size.y);
+
 	}
 
 
@@ -77,9 +90,7 @@ fn vertex_shader_main(
 		/ vec2<f32>(global.window_aspect.x, 1.0)
 	);
 
-	var out: VertexOutput;
 	out.position = vec4<f32>(pos, 0.0, 1.0) * instance.parallax;
-	out.texture_coords = vertex.texture_coords;
 	return out;
 }
 
@@ -92,10 +103,17 @@ var sampler_array: binding_array<sampler>;
 // Fragment shader
 @fragment
 fn fragment_shader_main(in: VertexOutput) -> @location(0) vec4<f32> {
+	let b = 1.0 - (in.tint.x / 1.2); // brightness
+	let c = in.tint.y; // color
+
+	let c_top = vec3<f32>(0.369, 0.819, 0.796);
+	let c_bot = vec3<f32>(0.979, 0.556, 0.556);
+	let c_del = c_bot - c_top;
+
 	return textureSampleLevel(
 		texture_array[global.starfield_texture.x],
 		sampler_array[global.starfield_texture.x],
 		in.texture_coords,
 		0.0
-	).rgba * vec4<f32>(0.5, 0.5, 0.5, 1.0);
+	).rgba * vec4<f32>((c_top + c_del * c) * b, 1.0);
 }

src/render/vertexbuffer/types.rs

@@ -46,6 +46,8 @@ pub struct StarfieldInstance {
 
 	/// Height of (unrotated) sprite in world units
 	pub height: f32,
+
+	pub tint: [f32; 2],
 }
 
 impl BufferObject for StarfieldInstance {
@@ -72,6 +74,12 @@ impl BufferObject for StarfieldInstance {
 					shader_location: 4,
 					format: wgpu::VertexFormat::Float32,
 				},
+				// Tint
+				wgpu::VertexAttribute {
+					offset: mem::size_of::<[f32; 4]>() as wgpu::BufferAddress,
+					shader_location: 5,
+					format: wgpu::VertexFormat::Float32x2,
+				},
 			],
 		}
 	}

src/system.rs

@@ -3,15 +3,20 @@ use crate::{
 	Doodad, Sprite, Spriteable, STARFIELD_COUNT, STARFIELD_PARALLAX_MAX, STARFIELD_PARALLAX_MIN,
 	STARFIELD_SIZE,
 };
-use cgmath::{Deg, Point2};
+use cgmath::{Deg, Point2, Vector2};
 use rand::{self, Rng};
 
 pub struct StarfieldStar {
-	// Star coordinates, in world space.
+	/// Star coordinates, in world space.
-	// These are relative to the center of a starfield tile.
+	/// These are relative to the center of a starfield tile.
 	pub pos: Point2<Pfloat>,
+
 	pub parallax: Pfloat,
 	pub height: Pfloat,
+
+	/// Color/brightness variation.
+	/// See shader.
+	pub tint: Vector2<Pfloat>,
 }
 
 pub struct System {
@@ -32,7 +37,11 @@ impl System {
 						y: rng.gen_range(-sz..=sz),
 					},
 					parallax: rng.gen_range(STARFIELD_PARALLAX_MIN..STARFIELD_PARALLAX_MAX),
-					height: rng.gen_range(1.0..2.0),
+					height: rng.gen_range(0.2..0.8), // TODO: configurable
+					tint: Vector2 {
+						x: rng.gen_range(0.0..=1.0),
+						y: rng.gen_range(0.0..=1.0),
+					},
 				})
 				.collect(),
 		};