give the checkerboard "reflections"

take advantage of the empty depth buffer, render the true depth afterwards to embed the teapot wall into the scene

src/main.rs

@@ -20,12 +20,16 @@ struct Entity {
 //temp?
 struct ModelData {
 	transform: glam::Mat4,
+	transform_depth: glam::Mat4,
+	use_depth: glam::Vec4,
 	vertex_buf: wgpu::Buffer,
 	entities: Vec<Entity>,
 }
 
 struct Model {
 	transform: glam::Mat4,
+	transform_depth: glam::Mat4,
+	use_depth: glam::Vec4,
 	vertex_buf: wgpu::Buffer,
 	entities: Vec<Entity>,
 	bind_group: wgpu::BindGroup,
@@ -126,11 +130,15 @@ pub struct Skybox {
 	sky_pipeline: wgpu::RenderPipeline,
 	entity_pipeline: wgpu::RenderPipeline,
 	ground_pipeline: wgpu::RenderPipeline,
+	special_teapot: Model,
+	checkered_pipeline: wgpu::RenderPipeline,
+	depth_overwrite_pipeline: wgpu::RenderPipeline,
 	main_bind_group: wgpu::BindGroup,
 	camera_buf: wgpu::Buffer,
 	models: Vec<Model>,
 	depth_view: wgpu::TextureView,
 	staging_belt: wgpu::util::StagingBelt,
+	start_time: Instant,
 }
 
 impl Skybox {
@@ -159,9 +167,18 @@ impl Skybox {
 	}
 }
 
-fn get_transform_uniform_data(transform:&glam::Mat4) -> [f32; 4*4] {
+fn get_model_uniform_data(model:&Model) -> [f32; 4*4*2+4] {
-	let mut raw = [0f32; 4*4];
+	let mut raw = [0f32; 4*4*2+4];
-	raw[0..16].copy_from_slice(&AsRef::<[f32; 4*4]>::as_ref(transform)[..]);
+	raw[0..16].copy_from_slice(&AsRef::<[f32; 4*4]>::as_ref(&model.transform)[..]);
+	raw[16..32].copy_from_slice(&AsRef::<[f32; 4*4]>::as_ref(&model.transform_depth)[..]);
+	raw[32..36].copy_from_slice(AsRef::<[f32; 4]>::as_ref(&model.use_depth));
+	raw
+}
+fn get_modeldata_uniform_data(model:&ModelData) -> [f32; 4*4*2+4] {
+	let mut raw = [0f32; 4*4*2+4];
+	raw[0..16].copy_from_slice(&AsRef::<[f32; 4*4]>::as_ref(&model.transform)[..]);
+	raw[16..32].copy_from_slice(&AsRef::<[f32; 4*4]>::as_ref(&model.transform_depth)[..]);
+	raw[32..36].copy_from_slice(AsRef::<[f32; 4]>::as_ref(&model.use_depth));
 	raw
 }
 
@@ -209,6 +226,8 @@ fn add_obj(device:&wgpu::Device,modeldatas:& mut Vec<ModelData>,source:&[u8]){
 		});
 		modeldatas.push(ModelData {
 			transform: glam::Mat4::default(),
+			transform_depth: glam::Mat4::default(),
+			use_depth: glam::Vec4::ZERO,
 			vertex_buf,
 			entities,
 		})
@@ -234,7 +253,13 @@ impl strafe_client::framework::Example for Skybox {
 		add_obj(device,& mut modeldatas,include_bytes!("../models/teapot.obj"));
 		println!("models.len = {:?}", modeldatas.len());
 		modeldatas[1].transform=glam::Mat4::from_translation(glam::vec3(10.,5.,10.));
-		modeldatas[2].transform=glam::Mat4::from_translation(glam::vec3(-10.,5.,10.));
+
+		let proj1 = glam::Mat4::orthographic_rh(-20.0, 20.0, -20.0, 20.0, -20.0, 20.0);
+		let model0 = glam::Mat4::from_translation(glam::vec3(-10.,5.,10.)) * glam::Mat4::from_scale(glam::vec3(10.0,10.0,10.0));
+
+		modeldatas[2].transform=model0;
+		modeldatas[2].transform_depth=proj1;// * view1_inv
+		modeldatas[2].use_depth=glam::Vec4::Z;
 
 		let main_bind_group_layout = device.create_bind_group_layout(&wgpu::BindGroupLayoutDescriptor {
 			label: None,
@@ -404,6 +429,60 @@ impl strafe_client::framework::Example for Skybox {
 			multisample: wgpu::MultisampleState::default(),
 			multiview: None,
 		});
+		let checkered_pipeline = device.create_render_pipeline(&wgpu::RenderPipelineDescriptor {
+			label: Some("Checkered"),
+			layout: Some(&pipeline_layout),
+			vertex: wgpu::VertexState {
+				module: &shader,
+				entry_point: "vs_square",
+				buffers: &[],
+			},
+			fragment: Some(wgpu::FragmentState {
+				module: &shader,
+				entry_point: "fs_checkered",
+				targets: &[Some(config.view_formats[0].into())],
+			}),
+			primitive: wgpu::PrimitiveState {
+				front_face: wgpu::FrontFace::Cw,
+				..Default::default()
+			},
+			depth_stencil: Some(wgpu::DepthStencilState {
+				format: Self::DEPTH_FORMAT,
+				depth_write_enabled: false,
+				depth_compare: wgpu::CompareFunction::Always,
+				stencil: wgpu::StencilState::default(),
+				bias: wgpu::DepthBiasState::default(),
+			}),
+			multisample: wgpu::MultisampleState::default(),
+			multiview: None,
+		});
+		let depth_overwrite_pipeline = device.create_render_pipeline(&wgpu::RenderPipelineDescriptor {
+			label: Some("Overwrite"),
+			layout: Some(&pipeline_layout),
+			vertex: wgpu::VertexState {
+				module: &shader,
+				entry_point: "vs_square",
+				buffers: &[],
+			},
+			fragment: Some(wgpu::FragmentState {
+				module: &shader,
+				entry_point: "fs_overwrite",
+				targets: &[Some(config.view_formats[0].into())],
+			}),
+			primitive: wgpu::PrimitiveState {
+				front_face: wgpu::FrontFace::Cw,
+				..Default::default()
+			},
+			depth_stencil: Some(wgpu::DepthStencilState {
+				format: Self::DEPTH_FORMAT,
+				depth_write_enabled: true,
+				depth_compare: wgpu::CompareFunction::Always,
+				stencil: wgpu::StencilState::default(),
+				bias: wgpu::DepthBiasState::default(),
+			}),
+			multisample: wgpu::MultisampleState::default(),
+			multiview: None,
+		});
 
 		let sampler = device.create_sampler(&wgpu::SamplerDescriptor {
 			label: None,
@@ -510,7 +589,7 @@ impl strafe_client::framework::Example for Skybox {
 		//drain the modeldata vec so entities can be /moved/ to models.entities
 		let mut models = Vec::<Model>::with_capacity(modeldatas.len());
 		for (i,modeldata) in modeldatas.drain(..).enumerate() {
-			let model_uniforms = get_transform_uniform_data(&modeldata.transform);
+			let model_uniforms = get_modeldata_uniform_data(&modeldata);
 			let model_buf = device.create_buffer_init(&wgpu::util::BufferInitDescriptor {
 				label: Some(format!("Model{}",i).as_str()),
 				contents: bytemuck::cast_slice(&model_uniforms),
@@ -529,6 +608,8 @@ impl strafe_client::framework::Example for Skybox {
 			//all of these are being moved here
 			models.push(Model{
 				transform: modeldata.transform,
+				transform_depth: modeldata.transform_depth,
+				use_depth: modeldata.use_depth,
 				vertex_buf:modeldata.vertex_buf,
 				entities: modeldata.entities,
 				bind_group: model_bind_group,
@@ -536,6 +617,8 @@ impl strafe_client::framework::Example for Skybox {
 			})
 		}
 
+		let teapot = models.pop().unwrap();
+
 		let depth_view = Self::create_depth_texture(config, device);
 
 		Skybox {
@@ -543,11 +626,15 @@ impl strafe_client::framework::Example for Skybox {
 			sky_pipeline,
 			entity_pipeline,
 			ground_pipeline,
+			special_teapot: teapot,
+			checkered_pipeline,
+			depth_overwrite_pipeline,
 			main_bind_group,
 			camera_buf,
 			models,
 			depth_view,
 			staging_belt: wgpu::util::StagingBelt::new(0x100),
+			start_time: Instant::now(),
 		}
 	}
 
@@ -658,6 +745,11 @@ impl strafe_client::framework::Example for Skybox {
 			}
 		}
 
+		let proj1 = glam::Mat4::orthographic_rh(-20.0, 20.0, -20.0, 20.0, -20.0, 20.0);
+		let model1 = glam::Mat4::from_euler(glam::EulerRot::YXZ, self.start_time.elapsed().as_secs_f32(),0f32,0f32);
+
+		self.special_teapot.transform_depth=proj1 * model1;
+
 		let mut encoder =
 			device.create_command_encoder(&wgpu::CommandEncoderDescriptor { label: None });
 
@@ -672,9 +764,22 @@ impl strafe_client::framework::Example for Skybox {
 				device,
 			)
 			.copy_from_slice(bytemuck::cast_slice(&camera_uniforms));
+		//special teapot
+		{
+			let model_uniforms = get_model_uniform_data(&self.special_teapot);
+			self.staging_belt
+				.write_buffer(
+					&mut encoder,
+					&self.special_teapot.model_buf,//description of where data will be written when command is executed
+					0,//offset in staging belt?
+					wgpu::BufferSize::new((model_uniforms.len() * 4) as wgpu::BufferAddress).unwrap(),
+					device,
+				)
+				.copy_from_slice(bytemuck::cast_slice(&model_uniforms));
+		}
 		//This code only needs to run when the uniforms change
 		for model in self.models.iter() {
-			let model_uniforms = get_transform_uniform_data(&model.transform);
+			let model_uniforms = get_model_uniform_data(&model);
 			self.staging_belt
 				.write_buffer(
 					&mut encoder,
@@ -715,6 +820,23 @@ impl strafe_client::framework::Example for Skybox {
 
 			rpass.set_bind_group(0, &self.main_bind_group, &[]);
 
+			//draw special teapot
+			rpass.set_bind_group(1, &self.special_teapot.bind_group, &[]);
+			rpass.set_pipeline(&self.checkered_pipeline);
+			rpass.draw(0..6, 0..1);
+
+			rpass.set_pipeline(&self.entity_pipeline);
+			rpass.set_vertex_buffer(0, self.special_teapot.vertex_buf.slice(..));
+
+			for entity in self.special_teapot.entities.iter() {
+				rpass.set_index_buffer(entity.index_buf.slice(..), wgpu::IndexFormat::Uint16);
+				rpass.draw_indexed(0..entity.index_count, 0, 0..1);
+			}
+
+			rpass.set_pipeline(&self.depth_overwrite_pipeline);
+			rpass.draw(0..6, 0..1);
+
+			//draw models
 			rpass.set_pipeline(&self.entity_pipeline);
 			for model in self.models.iter() {
 				rpass.set_bind_group(1, &model.bind_group, &[]);

src/shader.wgsl

@@ -68,9 +68,15 @@ struct EntityOutput {
 	@location(3) view: vec3<f32>,
 };
 
+struct TransformData {
+	transform: mat4x4<f32>,
+	depth: mat4x4<f32>,
+	use_depth: vec4<f32>,
+};
+
 @group(1)
 @binding(0)
-var<uniform> r_EntityTransform: mat4x4<f32>;
+var<uniform> transform: TransformData;
 
 @vertex
 fn vs_entity(
@@ -78,12 +84,42 @@ fn vs_entity(
 	@location(1) texture: vec2<f32>,
 	@location(2) normal: vec3<f32>,
 ) -> EntityOutput {
-	var position: vec4<f32> = r_EntityTransform * vec4<f32>(pos, 1.0);
+	var position_depth: vec4<f32> = transform.depth * vec4<f32>(pos, 1.0);
+	var position_depth_0: vec4<f32> = position_depth;
+	position_depth_0.z=0.0;
+	var position: vec4<f32> = transform.transform * mix(position_depth,position_depth_0,transform.use_depth);
+
 	var result: EntityOutput;
-	result.normal = (r_EntityTransform * vec4<f32>(normal, 0.0)).xyz;
+	result.normal = (transform.transform * mix(vec4<f32>(normal,0.0),vec4<f32>(0.0,0.0,1.0,0.0),transform.use_depth.z)).xyz;
 	result.texture=texture;
 	result.view = position.xyz - r_data.cam_pos.xyz;
-	result.position = r_data.proj * r_data.view * position;
+	var screen_position: vec4<f32> = r_data.proj * r_data.view * position;
+	result.position = mix(screen_position,position_depth,transform.use_depth);
+	return result;
+}
+
+struct SquareOutput {
+	@builtin(position) position: vec4<f32>,
+	@location(2) normal: vec3<f32>,
+	@location(3) view: vec3<f32>,
+	@location(4) pos: vec3<f32>,
+};
+@vertex
+fn vs_square(@builtin(vertex_index) vertex_index: u32) -> SquareOutput {
+	// hacky way to draw two triangles that make a square
+	let tmp1 = i32(vertex_index)/2-i32(vertex_index)/3;
+	let tmp2 = i32(vertex_index)&1;
+	let pos = vec3<f32>(
+		(f32(tmp1) - 0.5)*1.8,
+		f32(tmp2) - 0.5,
+		0.0
+	);
+
+	var result: SquareOutput;
+	result.normal = vec3<f32>(0.0,0.0,1.0);
+	result.pos = (transform.transform * vec4<f32>(pos, 1.0)).xyz;
+	result.view = result.pos - r_data.cam_pos.xyz;
+	result.position = r_data.proj * r_data.view * transform.transform * vec4<f32>(pos, 1.0);
 	return result;
 }
 
@@ -129,3 +165,24 @@ fn fs_ground(vertex: GroundOutput) -> @location(0) vec4<f32> {
 	let dir = vec3<f32>(-1.0)+vec3<f32>(modulo_euclidean(vertex.pos.x/16.,1.0),0.0,modulo_euclidean(vertex.pos.z/16.,1.0))*2.0;
 	return vec4<f32>(textureSample(r_texture, r_sampler, dir).rgb, 1.0);
 }
+
+@fragment
+fn fs_checkered(vertex: SquareOutput) -> @location(0) vec4<f32> {
+	let voxel_parity: f32 = f32(
+		u32(modulo_euclidean(vertex.pos.x,2.0)<1.0)
+		^ u32(modulo_euclidean(vertex.pos.y,2.0)<1.0)
+		//^ u32(modulo_euclidean(vertex.pos.z,2.0)<1.0)
+	);
+
+	let incident = normalize(vertex.view);
+	let normal = normalize(vertex.normal);
+	let d = dot(normal, incident);
+	let reflected = incident - 2.0 * d * normal;
+
+	let texture_color = vec3<f32>(1.0)*voxel_parity;
+	let reflected_color = textureSample(r_texture, r_sampler, reflected).rgb;
+	return vec4<f32>(mix(vec3<f32>(0.1) + 0.5 * reflected_color,texture_color,1.0-pow(1.0-abs(d),2.0)), 1.0);
+}
+
+@fragment
+fn fs_overwrite(vertex: SquareOutput) {}