Apply HiDPI scaling to quads

The anti-aliasing strategy is pretty naive, but we will manage for now.

wgpu/src/quad.rs

@@ -6,7 +6,7 @@ use std::mem;
 pub struct Pipeline {
     pipeline: wgpu::RenderPipeline,
     constants: wgpu::BindGroup,
-    transform: wgpu::Buffer,
+    constants_buffer: wgpu::Buffer,
     vertices: wgpu::Buffer,
     indices: wgpu::Buffer,
     instances: wgpu::Buffer,
@@ -23,20 +23,20 @@ impl Pipeline {
                 }],
             });
 
-        let transform = device
+        let constants_buffer = device
             .create_buffer_mapped(
-                16,
+                1,
                 wgpu::BufferUsage::UNIFORM | wgpu::BufferUsage::COPY_DST,
             )
-            .fill_from_slice(Transformation::identity().as_ref());
+            .fill_from_slice(&[Uniforms::default()]);
 
         let constants = device.create_bind_group(&wgpu::BindGroupDescriptor {
             layout: &constant_layout,
             bindings: &[wgpu::Binding {
                 binding: 0,
                 resource: wgpu::BindingResource::Buffer {
-                    buffer: &transform,
-                    range: 0..64,
+                    buffer: &constants_buffer,
+                    range: 0..std::mem::size_of::<Uniforms>() as u64,
                 },
             }],
         });
@@ -124,7 +124,7 @@ impl Pipeline {
                             },
                             wgpu::VertexAttributeDescriptor {
                                 shader_location: 4,
-                                format: wgpu::VertexFormat::Uint,
+                                format: wgpu::VertexFormat::Float,
                                 offset: 4 * (2 + 2 + 4),
                             },
                         ],
@@ -151,7 +151,7 @@ impl Pipeline {
         Pipeline {
             pipeline,
             constants,
-            transform,
+            constants_buffer,
             vertices,
             indices,
             instances,
@@ -164,19 +164,22 @@ impl Pipeline {
         encoder: &mut wgpu::CommandEncoder,
         instances: &[Quad],
         transformation: Transformation,
+        scale: f32,
         bounds: Rectangle<u32>,
         target: &wgpu::TextureView,
     ) {
-        let transform_buffer = device
-            .create_buffer_mapped(16, wgpu::BufferUsage::COPY_SRC)
-            .fill_from_slice(transformation.as_ref());
+        let uniforms = Uniforms::new(transformation, scale);
+
+        let constants_buffer = device
+            .create_buffer_mapped(1, wgpu::BufferUsage::COPY_SRC)
+            .fill_from_slice(&[uniforms]);
 
         encoder.copy_buffer_to_buffer(
-            &transform_buffer,
+            &constants_buffer,
             0,
-            &self.transform,
+            &self.constants_buffer,
             0,
-            16 * 4,
+            std::mem::size_of::<Uniforms>() as u64,
         );
 
         let mut i = 0;
@@ -271,9 +274,34 @@ pub struct Quad {
     pub position: [f32; 2],
     pub scale: [f32; 2],
     pub color: [f32; 4],
-    pub border_radius: u32,
+    pub border_radius: f32,
 }
 
 impl Quad {
     const MAX: usize = 100_000;
 }
+
+#[repr(C)]
+#[derive(Debug, Clone, Copy)]
+struct Uniforms {
+    transform: [f32; 16],
+    scale: f32,
+}
+
+impl Uniforms {
+    fn new(transformation: Transformation, scale: f32) -> Uniforms {
+        Self {
+            transform: *transformation.as_ref(),
+            scale,
+        }
+    }
+}
+
+impl Default for Uniforms {
+    fn default() -> Self {
+        Self {
+            transform: *Transformation::identity().as_ref(),
+            scale: 1.0,
+        }
+    }
+}

wgpu/src/renderer.rs

@@ -239,7 +239,7 @@ impl Renderer {
                     color: match background {
                         Background::Color(color) => color.into_linear(),
                     },
-                    border_radius: *border_radius as u32,
+                    border_radius: *border_radius as f32,
                 });
             }
             Primitive::Image { path, bounds } => {
@@ -327,13 +327,14 @@ impl Renderer {
                 encoder,
                 &layer.quads,
                 transformation,
+                dpi,
                 bounds,
                 target,
             );
         }
 
         if layer.images.len() > 0 {
-            let translated = transformation
+            let translated_and_scaled = transformation
                 * Transformation::scale(dpi, dpi)
                 * Transformation::translate(
                     -(layer.offset.x as f32),
@@ -344,7 +345,7 @@ impl Renderer {
                 &mut self.device,
                 encoder,
                 &layer.images,
-                translated,
+                translated_and_scaled,
                 bounds,
                 target,
             );

wgpu/src/shader/quad.frag

@@ -3,7 +3,7 @@
 layout(location = 0) in vec4 v_Color;
 layout(location = 1) in vec2 v_Pos;
 layout(location = 2) in vec2 v_Scale;
-layout(location = 3) in flat uint v_BorderRadius;
+layout(location = 3) in float v_BorderRadius;
 
 layout(location = 0) out vec4 o_Color;
 
@@ -27,11 +27,7 @@ float rounded(in vec2 frag_coord, in vec2 position, in vec2 size, float radius,
 }
 
 void main() {
-    float radius_alpha = 1.0;
-
-    if(v_BorderRadius > 0.0) {
-        radius_alpha = rounded(gl_FragCoord.xy, v_Pos, v_Scale, v_BorderRadius, 0.5);
-    }
+    float radius_alpha = rounded(gl_FragCoord.xy, v_Pos, v_Scale, v_BorderRadius, 0.5);
 
     o_Color = vec4(v_Color.xyz, v_Color.w * radius_alpha);
 }

wgpu/src/shader/quad.vert

@@ -4,29 +4,33 @@ layout(location = 0) in vec2 v_Pos;
 layout(location = 1) in vec2 i_Pos;
 layout(location = 2) in vec2 i_Scale;
 layout(location = 3) in vec4 i_Color;
-layout(location = 4) in uint i_BorderRadius;
+layout(location = 4) in float i_BorderRadius;
 
 layout (set = 0, binding = 0) uniform Globals {
     mat4 u_Transform;
+    float u_Scale;
 };
 
 layout(location = 0) out vec4 o_Color;
 layout(location = 1) out vec2 o_Pos;
 layout(location = 2) out vec2 o_Scale;
-layout(location = 3) out uint o_BorderRadius;
+layout(location = 3) out float o_BorderRadius;
 
 void main() {
+    vec2 p_Pos = i_Pos * u_Scale;
+    vec2 p_Scale = i_Scale  * u_Scale;
+
     mat4 i_Transform = mat4(
-        vec4(i_Scale.x, 0.0, 0.0, 0.0),
-        vec4(0.0, i_Scale.y, 0.0, 0.0),
+        vec4(p_Scale.x + 1.0, 0.0, 0.0, 0.0),
+        vec4(0.0, p_Scale.y + 1.0, 0.0, 0.0),
         vec4(0.0, 0.0, 1.0, 0.0),
-        vec4(i_Pos, 0.0, 1.0)
+        vec4(p_Pos - vec2(0.5, 0.5), 0.0, 1.0)
     );
 
     o_Color = i_Color;
-    o_Pos = i_Pos;
-    o_Scale = i_Scale;
-    o_BorderRadius = i_BorderRadius;
+    o_Pos = p_Pos;
+    o_Scale = p_Scale;
+    o_BorderRadius = i_BorderRadius * u_Scale;
 
     gl_Position = u_Transform * i_Transform * vec4(v_Pos, 0.0, 1.0);
 }