Fixed a PsychoBlend bug that resulted in render not being fully displayed.

Getting the interplay between the reading the process output and
polling to see if it's finished is a tad tricky.  I think I got
it right this time.

psychoblend/render.py

@@ -132,10 +132,12 @@ class PsychopathRender(bpy.types.RenderEngine):
         # Process output from rendering process
         reached_first_bucket = False
         output = b""
-        while self._process.poll() == None:
+        render_process_finished = False
-            # Wait for render process output while checking for render
+        all_output_consumed = False
-            # cancellation
+        while not (render_process_finished and all_output_consumed):
-            while True:
+            if self._process.poll() != None:
+                render_process_finished = True
+
             # Check for render cancel
             if self.test_break():
                 self._process.terminate()
@@ -144,10 +146,10 @@ class PsychopathRender(bpy.types.RenderEngine):
             # Get render output from stdin
             tmp = self._process.stdout.read1(2**16)
             if len(tmp) == 0:
-                    time.sleep(0.01)
+                time.sleep(0.0001) # Don't spin on the CPU
+                if render_process_finished:
+                    all_output_consumed = True
                 continue
-                else:
-                    break
             output += tmp
             outputs = output.split(b'DIV\n')
 

src/renderer.rs

@@ -264,6 +264,14 @@ impl<'a> Renderer<'a> {
                 }
                 stats.sample_writing_time += timer.tick() as f64;
 
+                // Pre-calculate base64 encoding if needed
+                let base64_enc = if do_blender_output {
+                    use color::xyz_to_rec709e;
+                    Some(img_bucket.rgba_base64(xyz_to_rec709e))
+                } else {
+                    None
+                };
+
                 // Print render progress, and image data if doing blender output
                 let guard = pixels_rendered.lock().unwrap();
                 let mut pr = (*guard).get();
@@ -276,15 +284,16 @@ impl<'a> Renderer<'a> {
                 let old_string = format!("{:.2}%", percentage_old);
                 let new_string = format!("{:.2}%", percentage_new);
 
-                if do_blender_output {
+                if let Some(bucket_data) = base64_enc {
-                    use color::xyz_to_rec709e;
+                    // If doing Blender output
                     println!("DIV");
                     println!("{}", new_string);
                     println!("{} {} {} {}", min.0, min.1, max.0, max.1);
-                    println!("{}", img_bucket.rgba_base64(xyz_to_rec709e));
+                    println!("{}", bucket_data);
                     println!("BUCKET_END");
                     println!("DIV");
                 } else {
+                    // If doing console output
                     if new_string != old_string {
                         print!("\r{}", new_string);
                     }