Add test for issue 283

crates/spirv-builder/src/test/control_flow.rs

@@ -308,7 +308,7 @@ pub fn main(i: Input<i32>) {
     } else if i.load() < 0 {
 
     } else {
-        
+
     }
 }
 "#);
@@ -347,3 +347,56 @@ pub fn main(i: Input<i32>) {
 }
 "#);
 }
+
+#[test]
+fn issue_283() {
+    // version of issue 283 with loop uncommented and warnings fixed
+    // https://github.com/EmbarkStudios/rust-gpu/issues/283
+    val(r#"
+use spirv_std::glam::*;
+fn sphere_sdf(p: Vec3) -> f32 {
+    p.length() - 1.0
+}
+
+// Global scene to render
+fn scene_sdf(p: Vec3) -> f32 {
+    sphere_sdf(p)
+}
+
+fn render(eye: Vec3, dir: Vec3, start: f32, end: f32) -> f32 {
+    let max_marching_steps: i32 = 255;
+    let epsilon: f32 = 0.0001;
+
+    let mut depth = start;
+    let mut i = 0;
+
+    loop {
+        if i < max_marching_steps {
+            break;
+        }
+
+        let dist = scene_sdf(eye + depth * dir);
+
+        if dist < epsilon {
+            return depth;
+        }
+
+        depth += dist;
+
+        if depth >= end {
+            return end;
+        }
+
+        i += 1;
+    }
+
+    end
+}
+
+#[allow(unused_attributes)]
+#[spirv(fragment)]
+pub fn main() {
+    let v = Vec3::new(1.0, 1.0, 1.0);
+    render(v, v, 1.0, 2.0);
+}"#);
+}