Added ui sprite masking

crates/render/shaders/ui.wgsl

@@ -7,6 +7,7 @@ struct InstanceInput {
 	@location(5) size: f32,
 	@location(6) color_transform: vec4<f32>,
 	@location(7) sprite_index: u32,
+	@location(8) mask_index: vec2<u32>,
 };
 
 struct VertexInput {
@@ -18,7 +19,9 @@ struct VertexOutput {
 	@builtin(position) position: vec4<f32>,
 	@location(0) texture_coords: vec2<f32>,
 	@location(1) texture_index: u32,
-	@location(2) color_transform: vec4<f32>,
+	@location(2) mask_coords: vec2<f32>,
+	@location(3) mask_index: vec2<u32>,
+	@location(4) color_transform: vec4<f32>,
 }
 
 @group(0) @binding(0)
@@ -72,7 +75,7 @@ fn vertex_main(
 
 
 
-	// TODO: animate
+	// TODO: function to get texture from sprite
 	// Pick texture frame
 	let t = global_atlas[u32(animate(instance.sprite_index, global_data.current_time.x, 0.0))];
 	out.texture_index = u32(t.atlas_texture);
@@ -84,16 +87,55 @@ fn vertex_main(
 		out.texture_coords = vec2(out.texture_coords.x, out.texture_coords.y + t.height);
 	}
 
+	// Pick mask image if mask is enabled
+	// x coordinate of mask index is either 0 or 1, telling us whether or not to use a mask.
+	// y coordinate is mask sprite index
+	if instance.mask_index.x == 1u {
+		let ms = global_sprites[instance.mask_index.y].first_frame;
+		let m = global_atlas[ms];
+		out.mask_index = vec2(1u, u32(m.atlas_texture));
+		out.mask_coords = vec2(m.xpos, m.ypos);
+		if vertex.texture_coords.x == 1.0 {
+			out.mask_coords = vec2(out.mask_coords.x + m.width, out.mask_coords.y);
+		}
+		if vertex.texture_coords.y == 1.0 {
+			out.mask_coords = vec2(out.mask_coords.x, out.mask_coords.y + m.height);
+		}
+	} else {
+		out.mask_coords = vec2(0.0, 0.0);
+		out.mask_index = vec2(0u, 0u);
+	}
+
+
 	return out;
 }
 
 
 @fragment
 fn fragment_main(in: VertexOutput) -> @location(0) vec4<f32> {
-	return textureSampleLevel(
+
+	var mask: f32 = 1.0;
+	if in.mask_index.x == 1u {
+		mask = textureSampleLevel(
+			texture_array[in.mask_index.y],
+			sampler_array[0],
+			in.mask_coords,
+			0.0
+		).a;
+	}
+
+	var color: vec4<f32> = textureSampleLevel(
 		texture_array[in.texture_index],
 		sampler_array[0],
 		in.texture_coords,
 		0.0
 	).rgba * in.color_transform;
+
+	// Apply mask and discard fully transparent pixels
+	color = vec4(color.rgb, color.a *mask);
+	if color.a == 0.0 {
+		discard;
+	}
+
+	return color;
 }

crates/render/src/ui/radar.rs

@@ -68,6 +68,7 @@ impl Radar {
 			size: radar_size,
 			color: [1.0, 1.0, 1.0, 1.0],
 			sprite_index: input.ct.get_sprite_handle("ui::radar").get_index(),
+			mask_index: [0, 0],
 		});
 
 		// Draw system objects
@@ -96,6 +97,7 @@ impl Radar {
 					size,
 					color: [0.5, 0.5, 0.5, 1.0],
 					sprite_index: planet_sprite.get_index(),
+					mask_index: [0, 0],
 				})
 			};
 		}
@@ -149,6 +151,7 @@ impl Radar {
 					size,
 					color,
 					sprite_index: ship_sprite.get_index(),
+					mask_index: [0, 0],
 				});
 			}
 		}
@@ -176,6 +179,7 @@ impl Radar {
 				size,
 				color,
 				sprite_index: sprite.get_index(),
+				mask_index: [0, 0],
 			});
 
 			state.push_ui_buffer(UiInstance {
@@ -189,6 +193,7 @@ impl Radar {
 				size,
 				color,
 				sprite_index: sprite.get_index(),
+				mask_index: [0, 0],
 			});
 
 			state.push_ui_buffer(UiInstance {
@@ -202,6 +207,7 @@ impl Radar {
 				size,
 				color,
 				sprite_index: sprite.get_index(),
+				mask_index: [0, 0],
 			});
 
 			state.push_ui_buffer(UiInstance {
@@ -215,6 +221,7 @@ impl Radar {
 				size,
 				color,
 				sprite_index: sprite.get_index(),
+				mask_index: [0, 0],
 			});
 		}
 
@@ -233,6 +240,7 @@ impl Radar {
 				size: 10.0,
 				color: [1.0, 1.0, 1.0, 1f32.min((m - 200.0) / 400.0)],
 				sprite_index: arrow_sprite.get_index(),
+				mask_index: [0, 0],
 			});
 		}
 	}

crates/render/src/ui/status.rs

@@ -52,6 +52,7 @@ impl Status {
 			size: 200.0,
 			color: [1.0, 1.0, 1.0, 1.0],
 			sprite_index: input.ct.get_sprite_handle("ui::status").get_index(),
+			mask_index: [0, 0],
 		});
 
 		state.push_radialbar_buffer(RadialBarInstance {

crates/render/src/vertexbuffer/types.rs

@@ -140,6 +140,11 @@ pub struct UiInstance {
 
 	/// What texture to use for this sprite
 	pub sprite_index: u32,
+
+	/// What mask to use for this sprite
+	/// If the first element is not 1, no mask is used.
+	/// Second element is sprite index of mask.
+	pub mask_index: [u32; 2],
 }
 
 impl BufferObject for UiInstance {
@@ -187,6 +192,12 @@ impl BufferObject for UiInstance {
 					shader_location: 7,
 					format: wgpu::VertexFormat::Uint32,
 				},
+				// Mask
+				wgpu::VertexAttribute {
+					offset: mem::size_of::<[f32; 10]>() as wgpu::BufferAddress,
+					shader_location: 8,
+					format: wgpu::VertexFormat::Uint32x2,
+				},
 			],
 		}
 	}