From f2aa4de527144fbf77fd838561a1d33efb46bd40 Mon Sep 17 00:00:00 2001
From: jazzfool <shamoslover69@gmail.com>
Date: Sun, 15 Dec 2024 15:51:45 +1100
Subject: [PATCH] scale bounds by viewport, set scissor: fixes #21

---
 src/pipeline.rs | 10 ++++------
 src/shader.wgsl | 20 +++++++++-----------
 2 files changed, 13 insertions(+), 17 deletions(-)

diff --git a/src/pipeline.rs b/src/pipeline.rs
index 5ddd8a4..76a0be0 100644
--- a/src/pipeline.rs
+++ b/src/pipeline.rs
@@ -346,15 +346,13 @@ impl VideoPipeline {
 
             pass.set_pipeline(&self.pipeline);
             pass.set_bind_group(0, &video.bg0, &[]);
-            pass.set_viewport(
+            pass.set_scissor_rect(
                 viewport.x as _,
                 viewport.y as _,
                 viewport.width as _,
                 viewport.height as _,
-                0.0,
-                1.0,
             );
-            pass.draw(0..4, 0..1);
+            pass.draw(0..6, 0..1);
         }
     }
 }
@@ -394,7 +392,7 @@ impl Primitive for VideoPrimitive {
         format: wgpu::TextureFormat,
         storage: &mut iced_wgpu::primitive::Storage,
         bounds: &iced::Rectangle,
-        _viewport: &iced_wgpu::graphics::Viewport,
+        viewport: &iced_wgpu::graphics::Viewport,
     ) {
         if !storage.has::<VideoPipeline>() {
             storage.store(VideoPipeline::new(device, format));
@@ -413,7 +411,7 @@ impl Primitive for VideoPrimitive {
             );
         }
 
-        pipeline.prepare(queue, self.video_id, bounds);
+        pipeline.prepare(queue, self.video_id, &(*bounds * viewport.projection()));
     }
 
     fn render(
diff --git a/src/shader.wgsl b/src/shader.wgsl
index 091f8f9..46ceca9 100644
--- a/src/shader.wgsl
+++ b/src/shader.wgsl
@@ -21,20 +21,18 @@ var<uniform> uniforms: Uniforms;
 
 @vertex
 fn vs_main(@builtin(vertex_index) in_vertex_index: u32) -> VertexOutput {
-    let quad = array<vec2<f32>, 6>(
-        uniforms.rect.xy,
-        uniforms.rect.zy,
-        uniforms.rect.xw,
-        uniforms.rect.zy,
-        uniforms.rect.zw,
-        uniforms.rect.xw,
+    var quad = array<vec4<f32>, 6>(
+        vec4<f32>(uniforms.rect.xy, 0.0, 0.0),
+        vec4<f32>(uniforms.rect.zy, 1.0, 0.0),
+        vec4<f32>(uniforms.rect.xw, 0.0, 1.0),
+        vec4<f32>(uniforms.rect.zy, 1.0, 0.0),
+        vec4<f32>(uniforms.rect.zw, 1.0, 1.0),
+        vec4<f32>(uniforms.rect.xw, 0.0, 1.0),
     );
 
     var out: VertexOutput;
-    out.uv = vec2<f32>(0.0);
-    out.uv.x = select(0.0, 2.0, in_vertex_index == 1u);
-    out.uv.y = select(0.0, 2.0, in_vertex_index == 2u);
-    out.position = vec4<f32>(out.uv * vec2<f32>(2.0, -2.0) + vec2<f32>(-1.0, 1.0), 1.0, 1.0);
+    out.uv = quad[in_vertex_index].zw;
+    out.position = vec4<f32>(quad[in_vertex_index].xy, 1.0, 1.0);
     return out;
 }