render: implement sprite pivot, fix sprite centering in ortho projection

crates/lyra-game/src/render/graph/passes/sprite.rs

@@ -17,20 +17,18 @@ use crate::{
     render::{
         graph::{Node, NodeDesc, NodeType, SlotAttribute},
         resource::{FragmentState, RenderPipeline, RenderPipelineDescriptor, VertexState},
-        transform_buffer_storage::{TransformBuffers, TransformIndex},
         vertex::Vertex2D,
     },
     sprite::{AtlasSprite, Sprite},
 };
 
-use super::{BasePassSlots, RenderAssets};
+use super::{BasePassSlots, InterpTransform, RenderAssets};
 
 #[derive(Clone)]
 pub struct RenderJob {
     pub entity: Entity,
     pub shader_id: u64,
     pub asset_uuid: uuid::Uuid,
-    pub transform_id: TransformIndex,
     pub atlas_frame_id: u64,
 }
 
@@ -64,11 +62,8 @@ pub struct SpritePass {
     pipeline: Option<RenderPipeline>,
     texture_bgl: Option<Arc<wgpu::BindGroupLayout>>,
     jobs: VecDeque<RenderJob>,
-    /// Buffer that stores a `Rect` with `min` and `max` set to zero.
+    sprite_instances_buf: Option<Arc<wgpu::Buffer>>,
-    /// This can be used for sprites that are not from an atlas.
-    atlas_frames_buf: Option<Arc<wgpu::Buffer>>,
 
-    transform_buffers: Option<ResourceData>,
     texture_store: Option<ResourceData>,
     buffer_store: Option<ResourceData>,
 }
@@ -175,7 +170,7 @@ impl SpritePass {
             },
         );
 
-        let frames = self.atlas_frames_buf.as_ref().unwrap();
+        let sprite_instances = self.sprite_instances_buf.as_ref().unwrap();
         let bgl = self.texture_bgl.as_ref().unwrap();
         let tex_bg = device.create_bind_group(&wgpu::BindGroupDescriptor {
             label: Some(&format!("sprite_texture_bg_{}", uuid_str)),
@@ -192,7 +187,7 @@ impl SpritePass {
                 wgpu::BindGroupEntry {
                     binding: 2,
                     resource: wgpu::BindingResource::Buffer(wgpu::BufferBinding {
-                        buffer: &frames,
+                        buffer: &sprite_instances,
                         offset: 0,
                         size: None,
                     }),
@@ -211,16 +206,13 @@ impl Node for SpritePass {
     ) -> crate::render::graph::NodeDesc {
         let device = &graph.device;
 
-        let atlas_frames = device.create_buffer(&wgpu::BufferDescriptor {
+        let sprite_instances = device.create_buffer(&wgpu::BufferDescriptor {
-            label: Some("default_sprite_atlas_frame"),
+            label: Some("sprite_instances"),
-            size: std::mem::size_of::<URect>() as u64 * 1000,
+            size: std::mem::size_of::<SpriteInstance>() as u64 * 1000,
             usage: wgpu::BufferUsages::STORAGE | wgpu::BufferUsages::COPY_DST,
             mapped_at_creation: false,
         });
-        // write the rect for sprites that aren't part of the texture atlas.
+        self.sprite_instances_buf = Some(Arc::new(sprite_instances));
-        graph
-            .queue
-            .write_buffer(&atlas_frames, 0, bytemuck::bytes_of(&URect::ZERO));
 
         let bgl = device.create_bind_group_layout(&wgpu::BindGroupLayoutDescriptor {
             label: Some("bgl_sprite_main"),
@@ -243,7 +235,7 @@ impl Node for SpritePass {
                 },
                 wgpu::BindGroupLayoutEntry {
                     binding: 2,
-                    visibility: wgpu::ShaderStages::FRAGMENT,
+                    visibility: wgpu::ShaderStages::VERTEX_FRAGMENT,
                     ty: wgpu::BindingType::Buffer {
                         ty: wgpu::BufferBindingType::Storage { read_only: true },
                         has_dynamic_offset: false,
@@ -254,7 +246,6 @@ impl Node for SpritePass {
             ],
         });
         self.texture_bgl = Some(Arc::new(bgl));
-        self.atlas_frames_buf = Some(Arc::new(atlas_frames));
 
         let mut desc = NodeDesc::new(NodeType::Render, None, vec![]);
 
@@ -282,16 +273,12 @@ impl Node for SpritePass {
 
             let diffuse_bgl = self.texture_bgl.clone().unwrap();
             let camera_bgl = graph.bind_group_layout(BasePassSlots::Camera).clone();
-            let transforms = world
-                .get_resource::<TransformBuffers>()
-                .expect("Missing transform buffers");
-            let transform_bgl = transforms.bindgroup_layout.clone();
 
             self.pipeline = Some(RenderPipeline::create(
                 device,
                 &RenderPipelineDescriptor {
                     label: Some("sprite_pass".into()),
-                    layouts: vec![diffuse_bgl, transform_bgl, camera_bgl],
+                    layouts: vec![diffuse_bgl, camera_bgl],
                     push_constant_ranges: vec![],
                     vertex: VertexState {
                         module: shader.clone(),
@@ -317,7 +304,6 @@ impl Node for SpritePass {
                 },
             ));
 
-            drop(transforms);
             world.add_resource_default_if_absent::<RenderAssets<SpriteTexture>>();
             let texture_store = world
                 .get_resource_data::<RenderAssets<SpriteTexture>>().unwrap();
@@ -327,22 +313,17 @@ impl Node for SpritePass {
             let buffer_store = world
                 .get_resource_data::<FxHashMap<Entity, SpriteBuffers>>().unwrap();
             self.buffer_store = Some(buffer_store.clone());
-
-            let transforms = world
-                .get_resource_data::<TransformBuffers>()
-                .expect("Missing transform buffers");
-            self.transform_buffers = Some(transforms.clone());
         }
 
-        let mut v = Vec::with_capacity(500);
+        let mut sprite_instances = Vec::with_capacity(500);
 
         let world_tick = world.current_tick();
         let queue = &graph.queue;
-        for (entity, (sprite, atlas_sprite), transform_idx, mut texture_store, mut buffer_store) in world
+        for (entity, (sprite, atlas_sprite), interp_transform, mut texture_store, mut buffer_store) in world
             .view::<(
                 Entities,
                 Or<&Sprite, (&AtlasSprite, TickOf<AtlasSprite>)>,
-                &TransformIndex,
+                &InterpTransform,
                 ResMut<RenderAssets<SpriteTexture>>,
                 ResMut<FxHashMap<Entity, SpriteBuffers>>,
             )>()
@@ -374,13 +355,14 @@ impl Node for SpritePass {
                     }
                 }
 
-                if !buffer_store.contains_key(&entity) {
+                let dim = rect
-                    let dim = rect.unwrap_or_else(|| {
+                    .map(|r| r.dimensions())
+                    .unwrap_or_else(|| {
                         let i = image.dimensions();
-                        URect::new(0, 0, i.0, i.1)
+                        UVec2::new(i.0, i.1)
                     });
-                    debug!("storing rect: {dim:?}");
+
-                    let dim = dim.dimensions();
+                if !buffer_store.contains_key(&entity) {
                     let (vertex, index) = self.create_vertex_index_buffers(device, dim);
                     buffer_store.insert(entity, SpriteBuffers { vertex_buffers: vertex, index_buffers: index });
                 } else if let Some((ats, tick)) = &atlas_sprite {
@@ -393,29 +375,36 @@ impl Node for SpritePass {
                     }
                 }
 
-                let frame_id = match rect {
+                let pivot = atlas_sprite.map(|ats| ats.0.pivot)
-                    Some(r) => {
+                    // unwrap is safe since its either AtlasSprite or Sprite.
-                        v.push(r);
+                    .unwrap_or_else(|| sprite.unwrap().pivot)
-                        // No -1 here since the gpu buffer is already offset by 1
+                    .as_vec();
-                        // to store the default rect at the front
+
-                        v.len() as u64
+                let pivot_pos = dim.as_vec2() * (pivot - Vec2::splat(0.5));
-                    }
+                let transform = interp_transform.last_transform
-                    None => 0
+                    + lyra_math::Transform::from_translation(Vec3::new(pivot_pos.x, pivot_pos.y, 0.0));
+
+                let inst = SpriteInstance {
+                    atlas_frame: rect.unwrap_or(URect::ZERO),
+                    transform: transform.calculate_mat4(),
+                    pivot,
+                    _padding: [0; 2],
                 };
+                sprite_instances.push(inst);
+                let inst_id = sprite_instances.len() as u64 - 1;
 
                 self.jobs.push_back(RenderJob {
                     entity,
                     shader_id: 0,
                     asset_uuid: texture_uuid,
-                    transform_id: *transform_idx,
+                    atlas_frame_id: inst_id,
-                    atlas_frame_id: frame_id,
                 });
             };
         }
 
-        let buf = self.atlas_frames_buf.as_ref().unwrap();
+        let buf = self.sprite_instances_buf.as_ref().unwrap();
         // skip default rect
-        queue.write_buffer(buf, std::mem::size_of::<URect>() as _, bytemuck::cast_slice(&v));
+        queue.write_buffer(buf, 0, bytemuck::cast_slice(&sprite_instances));
     }
 
     fn execute(
@@ -430,8 +419,6 @@ impl Node for SpritePass {
         let texture_store: AtomicRef<RenderAssets<SpriteTexture>> = texture_store.get();
         let buffer_store = self.buffer_store.clone().unwrap();
         let buffer_store: AtomicRef<FxHashMap<Entity, SpriteBuffers>> = buffer_store.get();
-        let transforms = self.transform_buffers.clone().unwrap();
-        let transforms: AtomicRef<TransformBuffers> = transforms.get();
 
         let vt = graph.view_target();
         let view = vt.render_view();
@@ -468,12 +455,7 @@ impl Node for SpritePass {
                     .expect("failed to find SpriteTexture for job asset_uuid");
                 pass.set_bind_group(0, &tex.texture_bg, &[]);
 
-                // Get the bindgroup for job's transform and bind to it using an offset.
+                pass.set_bind_group(1, camera_bg, &[]);
-                let bindgroup = transforms.bind_group(job.transform_id);
-                let offset = transforms.buffer_offset(job.transform_id);
-                pass.set_bind_group(1, bindgroup, &[offset]);
-
-                pass.set_bind_group(2, camera_bg, &[]);
 
                 // set vertex and index buffers
                 let bufs = buffer_store
@@ -489,3 +471,12 @@ impl Node for SpritePass {
         }
     }
 }
+
+#[repr(C)]
+#[derive(Copy, Clone, bytemuck::Pod, bytemuck::Zeroable)]
+struct SpriteInstance {
+    atlas_frame: URect,
+    transform: glam::Mat4,
+    pivot: glam::Vec2,
+    _padding: [u32; 2],
+}

crates/lyra-game/src/render/graph/passes/transform.rs

@@ -25,8 +25,8 @@ use crate::{
 /// transform is updated less often than rendering.
 #[derive(Clone, Debug, Component)]
 pub struct InterpTransform {
-    last_transform: Transform,
+    pub last_transform: Transform,
-    alpha: f32,
+    pub alpha: f32,
 }
 
 #[derive(Default, Debug, Clone, Copy, Hash, RenderGraphLabel)]

crates/lyra-game/src/render/shaders/2d/sprite_main.wgsl

@@ -23,6 +23,12 @@ struct URect {
     max: vec2<u32>,
 }
 
+struct SpriteInstance {
+    atlas_frame: URect,
+    transform: mat4x4<f32>,
+    pivot: vec2<f32>,
+}
+
 struct CameraUniform {
     view: mat4x4<f32>,
     inverse_projection: mat4x4<f32>,
@@ -33,21 +39,21 @@ struct CameraUniform {
 }
 
 @group(1) @binding(0)
-var<uniform> u_model_transform_data: TransformData;
-
-@group(2) @binding(0)
 var<uniform> u_camera: CameraUniform;
 
 @vertex
 fn vs_main(
     in: VertexInput,
 ) -> VertexOutput {
+    let transform = u_sprite_instances[in.instance_index].transform;
+    var world_position: vec4<f32> = transform * vec4<f32>(in.position, 1.0);
+    
     var out: VertexOutput;
-    var world_position: vec4<f32> = u_model_transform_data.transform * vec4<f32>(in.position, 1.0);
     out.world_position = world_position.xyz;
     out.tex_coords = in.tex_coords;
     out.clip_position = u_camera.view_projection * world_position;
     out.instance_index = in.instance_index;
+    
     return out;
 }
 
@@ -58,11 +64,12 @@ var t_diffuse: texture_2d<f32>;
 var s_diffuse: sampler;
 
 @group(0) @binding(2)
-var<storage, read> u_sprite_atlas_frames: array<URect>;
+var<storage, read> u_sprite_instances: array<SpriteInstance>;
 
 @fragment
 fn fs_main(in: VertexOutput) -> @location(0) vec4<f32> {
-    let frame = u_sprite_atlas_frames[in.instance_index];
+    let sprite = u_sprite_instances[in.instance_index];
+    let frame = sprite.atlas_frame;
     var region_coords = in.tex_coords;
 
     if (frame.min.x != 0 || frame.min.y != 0 || frame.max.x != 0 || frame.max.y != 0) {

crates/lyra-game/src/scene/camera.rs

@@ -34,6 +34,7 @@ impl Default for ScaleMode {
 
 #[derive(Debug, Clone, Copy, PartialEq, Reflect)]
 pub struct OrthographicProjection {
+    pub viewport_origin: Vec2,
     pub scale_mode: ScaleMode,
     pub scale: f32,
     pub znear: f32,
@@ -43,6 +44,7 @@ pub struct OrthographicProjection {
 impl Default for OrthographicProjection {
     fn default() -> Self {
         Self {
+            viewport_origin: Vec2::new(0.5, 0.5),
             scale_mode: Default::default(),
             scale: 1.0,
             znear: 0.0,
@@ -53,52 +55,44 @@ impl Default for OrthographicProjection {
 
 impl OrthographicProjection {
     fn get_rect(&self, viewport_size: Vec2) -> Rect {
-        let origin;
+        //let origin;
         let size;
 
         match self.scale_mode {
             ScaleMode::Viewport => {
-                origin = viewport_size * 0.5;
                 size = viewport_size;
             },
             ScaleMode::Width(width) => {
                 let aspect = viewport_size.x / viewport_size.y;
-                let origin_x = width * 0.5;
                 let scaled_height = width / aspect;
-                let origin_y  = scaled_height * 0.5;
 
-                origin = Vec2::new(origin_x, origin_y);
                 size = Vec2::new(width, scaled_height);
             },
             ScaleMode::Height(height) => {
                 let aspect = viewport_size.x / viewport_size.y;
-                let origin_y = height * 0.5;
                 let scaled_width = height * aspect;
-                let origin_x = scaled_width * 0.5;
 
-                origin = Vec2::new(origin_x, origin_y);
                 size = Vec2::new(scaled_width, height);
             },
             ScaleMode::Size(s) => {
-                origin = s * 0.5;
                 size = s;
             },
             ScaleMode::MaxSize(s) => {
                 let clamped = s.min(viewport_size);
-                origin = clamped * 0.5;
                 size = clamped;
             },
             ScaleMode::MinSize(s) => {
                 let clamped = s.max(viewport_size);
-                origin = clamped * 0.5;
                 size = clamped;
             }
         }
 
+        let origin = size * self.viewport_origin;
+
         Rect::new(self.scale * -origin.x,
             self.scale * -origin.y,
-            self.scale * size.x - origin.x,
+            self.scale * (size.x - origin.x),
-            self.scale * size.y - origin.y)
+            self.scale * (size.y - origin.y))
     }
 
     pub fn to_mat(&self, viewport_size: Vec2) -> Mat4 {

crates/lyra-game/src/sprite/animation_sheet.rs

@@ -12,7 +12,7 @@ use tracing::error;
 
 use crate::DeltaTime;
 
-use super::{AtlasSprite, TextureAtlas};
+use super::{AtlasSprite, Pivot, TextureAtlas};
 
 /// A struct describing an animation of a Sprite.
 ///
@@ -266,6 +266,7 @@ fn system_animation_entity_impl(
                 let sprite = AtlasSprite {
                     atlas: animations.atlas.clone(),
                     sprite: rect,
+                    pivot: Pivot::default(),
                 };
 
                 commands.insert(en, sprite);
@@ -286,6 +287,7 @@ fn system_animation_entity_impl(
                 let new_sprite = AtlasSprite {
                     atlas: animations.atlas.clone(),
                     sprite: rect,
+                    pivot: Pivot::default(),
                 };
 
                 let sprite = sprite.as_mut().unwrap();

crates/lyra-game/src/sprite/mod.rs

@@ -24,8 +24,9 @@ pub enum Pivot {
     BottomLeft,
     BottomRight,
     BottomCenter,
-    /// A custom anchor point relative to top left.
+    /// A custom anchor point.
-    /// Top left is `(0.0, 0.0)`.
+    /// 
+    /// Top left is (-0.5, 0.5), center is (0.0, 0.0).
     Custom(Vec2)
 }
 
@@ -35,15 +36,15 @@ impl Pivot {
     /// The point is offset from the top left `(0.0, 0.0)`.
     pub fn as_vec(&self) -> Vec2 {
         match self {
-            Pivot::Center => Vec2::new(0.5, 0.5),
+            Pivot::Center => Vec2::ZERO,
-            Pivot::CenterLeft => Vec2::new(0.0, 0.5),
+            Pivot::CenterLeft => Vec2::new(-0.5, 0.0),
-            Pivot::CenterRight => Vec2::new(1.0, 0.5),
+            Pivot::CenterRight => Vec2::new(0.5, 0.0),
-            Pivot::TopLeft => Vec2::ZERO,
+            Pivot::TopLeft => Vec2::new(-0.5, 0.5),
-            Pivot::TopRight => Vec2::new(1.0, 0.0),
+            Pivot::TopRight => Vec2::new(0.5, 0.5),
             Pivot::TopCenter => Vec2::new(0.0, 0.5),
-            Pivot::BottomLeft => Vec2::new(0.0, 1.0),
+            Pivot::BottomLeft => Vec2::new(-0.5, -0.5),
-            Pivot::BottomRight => Vec2::new(1.0, 1.0),
+            Pivot::BottomRight => Vec2::new(0.5, -0.5),
-            Pivot::BottomCenter => Vec2::new(0.5, 1.0),
+            Pivot::BottomCenter => Vec2::new(0.0, -0.5),
             Pivot::Custom(v) => *v,
         }
     }

crates/lyra-game/src/sprite/texture_atlas.rs

@@ -4,6 +4,8 @@ use lyra_math::URect;
 use lyra_reflect::Reflect;
 use lyra_resource::ResHandle;
 
+use super::Pivot;
+
 /// A texture atlas of multiple sprites.
 #[derive(Clone, Component, Reflect)]
 pub struct TextureAtlas {
@@ -60,17 +62,19 @@ impl lyra_resource::ResourceData for TextureAtlas {
 pub struct AtlasSprite {
     pub atlas: ResHandle<TextureAtlas>,
     pub sprite: URect,
+    pub pivot: Pivot,
 }
 
 impl AtlasSprite {
     #[inline(always)]
     pub fn from_atlas_index(atlas: ResHandle<TextureAtlas>, i: u32) -> Self {
         let a = atlas.data_ref().unwrap();
-        let rect = a.frames.get(i as usize).cloned().unwrap(); //index_rect(i);
+        let rect = a.frames.get(i as usize).cloned().unwrap();
 
         Self {
             atlas: atlas.clone(),
             sprite: rect,
+            pivot: Pivot::default(),
         }
     }
 }

crates/lyra-math/src/transform.rs

@@ -136,4 +136,26 @@ impl std::ops::Add for Transform {
         self.scale *= rhs.scale;
         self
     }
+}
+
+impl std::ops::Sub for Transform {
+    type Output = Transform;
+
+    fn sub(mut self, rhs: Self) -> Self::Output {
+        self.translation -= rhs.translation;
+        self.rotation *= rhs.rotation;
+        self.scale *= rhs.scale;
+        self
+    }
+}
+
+impl std::ops::Mul for Transform {
+    type Output = Transform;
+
+    fn mul(mut self, rhs: Self) -> Self::Output {
+        self.translation *= rhs.translation;
+        self.rotation *= rhs.rotation;
+        self.scale *= rhs.scale;
+        self
+    }
 }