render: use left-handed coordinate system and y-up

assets/models/monkey/Monkey.gltf

@@ -1,6 +1,6 @@
 {
     "asset" : {
-        "generator" : "Khronos glTF Blender I/O v1.1.46",
+        "generator" : "Khronos glTF Blender I/O v1.2.75",
         "version" : "2.0"
     },
     "scene" : 0,
@@ -37,63 +37,63 @@
         {
             "bufferView" : 0,
             "componentType" : 5126,
-            "count" : 1968,
+            "count" : 3321,
             "max" : [
-                1.3671875,
-                0.8515625,
-                0.984375
+                1.325934886932373,
+                0.9392361640930176,
+                0.8223199844360352
             ],
             "min" : [
-                -1.3671875,
-                -0.8515625,
-                -0.984375
+                -1.325934886932373,
+                -0.9704862236976624,
+                -0.7782661318778992
             ],
             "type" : "VEC3"
         },
         {
             "bufferView" : 1,
             "componentType" : 5126,
-            "count" : 1968,
+            "count" : 3321,
             "type" : "VEC3"
         },
         {
             "bufferView" : 2,
             "componentType" : 5126,
-            "count" : 1968,
+            "count" : 3321,
             "type" : "VEC2"
         },
         {
             "bufferView" : 3,
             "componentType" : 5123,
-            "count" : 2904,
+            "count" : 11808,
             "type" : "SCALAR"
         }
     ],
     "bufferViews" : [
         {
             "buffer" : 0,
-            "byteLength" : 23616,
+            "byteLength" : 39852,
             "byteOffset" : 0
         },
         {
             "buffer" : 0,
-            "byteLength" : 23616,
-            "byteOffset" : 23616
+            "byteLength" : 39852,
+            "byteOffset" : 39852
         },
         {
             "buffer" : 0,
-            "byteLength" : 15744,
-            "byteOffset" : 47232
+            "byteLength" : 26568,
+            "byteOffset" : 79704
         },
         {
             "buffer" : 0,
-            "byteLength" : 5808,
-            "byteOffset" : 62976
+            "byteLength" : 23616,
+            "byteOffset" : 106272
         }
     ],
     "buffers" : [
         {
-            "byteLength" : 68784,
+            "byteLength" : 129888,
             "uri" : "Monkey.bin"
         }
     ]

crates/bevy_core/src/transform/face_toward.rs

@@ -6,7 +6,7 @@ pub trait FaceToward {
 
 impl FaceToward for Mat4 {
     fn face_toward(eye: Vec3, center: Vec3, up: Vec3) -> Self {
-        let forward = (eye - center).normalize();
+        let forward = (center - eye).normalize();
         let right = up.cross(forward).normalize();
         let up = forward.cross(right);
         Mat4::from_cols(

crates/bevy_pbr/src/pipelines/forward/mod.rs

@@ -17,7 +17,7 @@ pub const FORWARD_PIPELINE_HANDLE: Handle<PipelineDescriptor> =
 pub fn build_forward_pipeline(shaders: &mut Assets<Shader>) -> PipelineDescriptor {
     PipelineDescriptor {
         rasterization_state: Some(RasterizationStateDescriptor {
-            front_face: FrontFace::Ccw,
+            front_face: FrontFace::Cw,
             cull_mode: CullMode::Back,
             depth_bias: 0,
             depth_bias_slope_scale: 0.0,

crates/bevy_render/src/camera/projection.rs

@@ -17,8 +17,7 @@ pub struct PerspectiveProjection {
 
 impl CameraProjection for PerspectiveProjection {
     fn get_projection_matrix(&self) -> Mat4 {
-        let projection = Mat4::perspective_rh_gl(self.fov, self.aspect_ratio, self.near, self.far);
-        projection
+        Mat4::perspective_lh(self.fov, self.aspect_ratio, self.near, self.far)
     }
     fn update(&mut self, width: usize, height: usize) {
         self.aspect_ratio = width as f32 / height as f32;
@@ -56,15 +55,14 @@ pub struct OrthographicProjection {
 
 impl CameraProjection for OrthographicProjection {
     fn get_projection_matrix(&self) -> Mat4 {
-        let projection = Mat4::orthographic_rh(
+        Mat4::orthographic_lh(
             self.left,
             self.right,
             self.bottom,
             self.top,
             self.near,
             self.far,
-        );
-        projection
+        )
     }
     fn update(&mut self, width: usize, height: usize) {
         match self.window_origin {
@@ -93,8 +91,8 @@ impl Default for OrthographicProjection {
             right: 0.0,
             bottom: 0.0,
             top: 0.0,
-            near: -1.0,
-            far: 0.1,
+            near: 0.0,
+            far: 1000.0,
             window_origin: WindowOrigin::Center,
         }
     }

crates/bevy_render/src/mesh.rs

@@ -249,6 +249,17 @@ pub mod shape {
 
     pub struct Quad {
         pub size: Vec2,
+        pub flip: bool,
+    }
+
+    impl Quad {
+        pub fn new(size: Vec2) -> Self {
+            Self { size, flip: false }
+        }
+
+        pub fn flipped(size: Vec2) -> Self {
+            Self { size, flip: true }
+        }
     }
 
     impl From<Quad> for Mesh {
@@ -260,28 +271,53 @@ pub mod shape {
             let north_east = vec2(extent_x, extent_y);
             let south_west = vec2(-extent_x, -extent_y);
             let south_east = vec2(extent_x, -extent_y);
-            let vertices = &[
-                (
-                    [south_west.x(), south_west.y(), 0.0],
-                    [0.0, 0.0, 1.0],
-                    [0.0, 1.0],
-                ),
-                (
-                    [north_west.x(), north_west.y(), 0.0],
-                    [0.0, 0.0, 1.0],
-                    [0.0, 0.0],
-                ),
-                (
-                    [north_east.x(), north_east.y(), 0.0],
-                    [0.0, 0.0, 1.0],
-                    [1.0, 0.0],
-                ),
-                (
-                    [south_east.x(), south_east.y(), 0.0],
-                    [0.0, 0.0, 1.0],
-                    [1.0, 1.0],
-                ),
-            ];
+            let vertices = if quad.flip {
+                [
+                    (
+                        [south_west.x(), south_west.y(), 0.0],
+                        [0.0, 0.0, 1.0],
+                        [0.0, 1.0],
+                    ),
+                    (
+                        [north_west.x(), north_west.y(), 0.0],
+                        [0.0, 0.0, 1.0],
+                        [0.0, 0.0],
+                    ),
+                    (
+                        [north_east.x(), north_east.y(), 0.0],
+                        [0.0, 0.0, 1.0],
+                        [1.0, 0.0],
+                    ),
+                    (
+                        [south_east.x(), south_east.y(), 0.0],
+                        [0.0, 0.0, 1.0],
+                        [1.0, 1.0],
+                    ),
+                ]
+            } else {
+                [
+                    (
+                        [south_east.x(), south_east.y(), 0.0],
+                        [0.0, 0.0, 1.0],
+                        [1.0, 1.0],
+                    ),
+                    (
+                        [north_east.x(), north_east.y(), 0.0],
+                        [0.0, 0.0, 1.0],
+                        [1.0, 0.0],
+                    ),
+                    (
+                        [north_west.x(), north_west.y(), 0.0],
+                        [0.0, 0.0, 1.0],
+                        [0.0, 0.0],
+                    ),
+                    (
+                        [south_west.x(), south_west.y(), 0.0],
+                        [0.0, 0.0, 1.0],
+                        [0.0, 1.0],
+                    ),
+                ]
+            };
 
             let indices = vec![0, 2, 1, 0, 3, 2];
 
@@ -312,10 +348,51 @@ pub mod shape {
 
     impl From<Plane> for Mesh {
         fn from(plane: Plane) -> Self {
-            Quad {
-                size: Vec2::new(plane.size, plane.size),
+            let extent = plane.size / 2.0;
+
+            let vertices = [
+                    (
+                        [extent, 0.0, -extent],
+                        [0.0, 1.0, 0.0],
+                        [1.0, 1.0],
+                    ),
+                    (
+                        [extent, 0.0, extent],
+                        [0.0, 1.0, 0.0],
+                        [1.0, 0.0],
+                    ),
+                    (
+                        [-extent, 0.0, extent],
+                        [0.0, 1.0, 0.0],
+                        [0.0, 0.0],
+                    ),
+                    (
+                        [-extent, 0.0, -extent],
+                        [0.0, 1.0, 0.0],
+                        [0.0, 1.0],
+                    ),
+                ];
+
+            let indices = vec![0, 2, 1, 0, 3, 2];
+
+            let mut positions = Vec::new();
+            let mut normals = Vec::new();
+            let mut uvs = Vec::new();
+            for (position, normal, uv) in vertices.iter() {
+                positions.push(position.clone());
+                normals.push(normal.clone());
+                uvs.push(uv.clone());
+            }
+
+            Mesh {
+                primitive_topology: PrimitiveTopology::TriangleList,
+                attributes: vec![
+                    VertexAttribute::position(positions),
+                    VertexAttribute::normal(normals),
+                    VertexAttribute::uv(uvs),
+                ],
+                indices: Some(indices),
             }
-            .into()
         }
     }
 }

crates/bevy_render/src/pipeline/pipeline.rs

@@ -72,7 +72,7 @@ impl PipelineDescriptor {
             sample_mask: !0,
             alpha_to_coverage_enabled: false,
             rasterization_state: Some(RasterizationStateDescriptor {
-                front_face: FrontFace::Ccw,
+                front_face: FrontFace::Cw,
                 cull_mode: CullMode::Back,
                 depth_bias: 0,
                 depth_bias_slope_scale: 0.0,

crates/bevy_render/src/pipeline/state_descriptors.rs

@@ -74,7 +74,7 @@ pub enum FrontFace {
 
 impl Default for FrontFace {
     fn default() -> Self {
-        FrontFace::Ccw
+        FrontFace::Cw
     }
 }
 

crates/bevy_sprite/src/lib.rs

@@ -50,9 +50,8 @@ impl AppPlugin for SpritePlugin {
         let mut meshes = resources.get_mut::<Assets<Mesh>>().unwrap();
         meshes.set(
             QUAD_HANDLE,
-            Mesh::from(shape::Quad {
-                size: Vec2::new(1.0, 1.0),
-            }),
+            // Use a flipped quad because the camera is facing "forward" but quads should face backward 
+            Mesh::from(shape::Quad::flipped(Vec2::new(1.0, 1.0))),
         );
 
         let mut color_materials = resources.get_mut::<Assets<ColorMaterial>>().unwrap();

crates/bevy_sprite/src/render/mod.rs

@@ -21,7 +21,7 @@ pub const SPRITE_SHEET_PIPELINE_HANDLE: Handle<PipelineDescriptor> =
 pub fn build_sprite_sheet_pipeline(shaders: &mut Assets<Shader>) -> PipelineDescriptor {
     PipelineDescriptor {
         rasterization_state: Some(RasterizationStateDescriptor {
-            front_face: FrontFace::Ccw,
+            front_face: FrontFace::Cw,
             cull_mode: CullMode::None,
             depth_bias: 0,
             depth_bias_slope_scale: 0.0,
@@ -66,7 +66,7 @@ pub fn build_sprite_sheet_pipeline(shaders: &mut Assets<Shader>) -> PipelineDesc
 pub fn build_sprite_pipeline(shaders: &mut Assets<Shader>) -> PipelineDescriptor {
     PipelineDescriptor {
         rasterization_state: Some(RasterizationStateDescriptor {
-            front_face: FrontFace::Ccw,
+            front_face: FrontFace::Cw,
             cull_mode: CullMode::None,
             depth_bias: 0,
             depth_bias_slope_scale: 0.0,

crates/bevy_transform/src/components/rotation.rs

@@ -10,11 +10,6 @@ impl Rotation {
     pub fn identity() -> Self {
         Self(Quat::identity())
     }
-
-    #[inline(always)]
-    pub fn from_euler_angles(yaw: f32, pitch: f32, roll: f32) -> Self {
-        Self(Quat::from_rotation_ypr(yaw, pitch, roll))
-    }
 }
 
 impl Default for Rotation {

crates/bevy_ui/src/render/mod.rs

@@ -14,7 +14,7 @@ pub const UI_PIPELINE_HANDLE: Handle<PipelineDescriptor> =
 pub fn build_ui_pipeline(shaders: &mut Assets<Shader>) -> PipelineDescriptor {
     PipelineDescriptor {
         rasterization_state: Some(RasterizationStateDescriptor {
-            front_face: FrontFace::Ccw,
+            front_face: FrontFace::Cw,
             cull_mode: CullMode::None,
             depth_bias: 0,
             depth_bias_slope_scale: 0.0,

crates/bevy_ui/src/ui_update_system.rs

@@ -6,7 +6,7 @@ use bevy_window::Windows;
 use glam::Vec2;
 use legion::{prelude::*, systems::SubWorld};
 
-pub const UI_Z_STEP: f32 = 0.0001;
+pub const UI_Z_STEP: f32 = 0.001;
 
 pub fn ui_update_system() -> Box<dyn Schedulable> {
     SystemBuilder::new("ui_update")
@@ -20,7 +20,7 @@ pub fn ui_update_system() -> Box<dyn Schedulable> {
                 let mut window_quad = Quad {
                     size: Vec2::new(window.width as f32, window.height as f32),
                     position: Vec2::new(0.0, 0.0),
-                    z_index: 0.0,
+                    z_index: 999.0,
                 };
                 for entity in node_query
                     .iter_entities(world)
@@ -57,7 +57,7 @@ fn update_node_entity(world: &mut SubWorld, entity: Entity, parent_quad: Quad) -
                 return Some(Quad {
                     size: quad.size,
                     position: quad.position - quad.size / 2.0,
-                    z_index: quad.z_index + UI_Z_STEP,
+                    z_index: quad.z_index - UI_Z_STEP,
                 });
             }
         }
@@ -69,6 +69,6 @@ fn update_node_entity(world: &mut SubWorld, entity: Entity, parent_quad: Quad) -
 fn process_child_result(_parent_result: Quad, child_result: Quad) -> Quad {
     // "earlier" children are sorted behind "later" children
     let mut result = child_result.clone();
-    result.z_index += UI_Z_STEP;
+    result.z_index -= UI_Z_STEP;
     result
 }