Fix qrcode generation (#708)

- [x] Changelog updated

CHANGELOG.md

@@ -7,6 +7,11 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+### Fixed
+
+- Fixed the crash screen to show debug text even if the qr code fails to generate.
+- Fixed the crash screen to prevent the qr code always failing to generate.
+
 ## [0.20.1] - 2024/05/17
 
 ### Added

agb/src/panics_render.rs

@@ -1,12 +1,13 @@
 use core::{fmt::Write, panic::PanicInfo};
 
-use alloc::{format, vec::Vec};
+use alloc::{collections::TryReserveError, format, vec::Vec};
+use qrcodegen_no_heap::DataTooLong;
 
 use crate::{
     backtrace,
     display::{bitmap3::Bitmap3, busy_wait_for_vblank, HEIGHT, WIDTH},
     dma::dma3_exclusive,
-    mgba, syscall,
+    mgba, syscall, ExternalAllocator,
 };
 
 mod text;
@@ -26,6 +27,7 @@ pub fn render_backtrace(trace: &backtrace::Frames, info: &PanicInfo) -> ! {
 
             gba.dma.dma().dma3.disable();
             let mut gfx = gba.display.video.bitmap3();
+            gfx.clear(0xFFFF);
 
             let qrcode_string_data = if WEBSITE.is_empty() {
                 format!("{trace}")
@@ -38,14 +40,19 @@ pub fn render_backtrace(trace: &backtrace::Frames, info: &PanicInfo) -> ! {
 
             let mut trace_text_render =
                 text::BitmapTextRender::new(&mut gfx, (location, 8).into(), 0x0000);
-            let _ = write!(
+            let _ = writeln!(
                 &mut trace_text_render,
                 "The game crashed :({}{WEBSITE}\n{trace}",
                 if WEBSITE.is_empty() { "" } else { "\n" }
             );
 
-            let mut panic_text_render =
-                text::BitmapTextRender::new(&mut gfx, (8, location).into(), 0x0000);
+            let trace_location = trace_text_render.head_y_position();
+
+            let mut panic_text_render = text::BitmapTextRender::new(
+                &mut gfx,
+                (8, location.max(trace_location + PADDING)).into(),
+                0x0000,
+            );
             let _ = write!(&mut panic_text_render, "{info}");
 
             // need to wait 2 frames to ensure that mgba finishes rendering before the fatal call below
@@ -62,30 +69,55 @@ pub fn render_backtrace(trace: &backtrace::Frames, info: &PanicInfo) -> ! {
         })
     })
 }
+const PADDING: i32 = 8;
+
+struct QrCodeBuffers {
+    temp_buffer: Vec<u8, ExternalAllocator>,
+    out_buffer: Vec<u8, ExternalAllocator>,
+    version: qrcodegen_no_heap::Version,
+}
+
+impl QrCodeBuffers {
+    fn new(version: qrcodegen_no_heap::Version) -> Result<Self, TryReserveError> {
+        let buffer_length = version.buffer_len();
+        let mut temp = Vec::try_with_capacity_in(buffer_length, ExternalAllocator)?;
+        let mut out = Vec::try_with_capacity_in(buffer_length, ExternalAllocator)?;
+        temp.resize(buffer_length, 0);
+        out.resize(buffer_length, 0);
+
+        Ok(Self {
+            temp_buffer: temp,
+            out_buffer: out,
+            version,
+        })
+    }
+
+    fn generate_qr_code(&mut self, data: &str) -> Result<qrcodegen_no_heap::QrCode, DataTooLong> {
+        qrcodegen_no_heap::QrCode::encode_text(
+            data,
+            &mut self.temp_buffer,
+            &mut self.out_buffer,
+            qrcodegen_no_heap::QrCodeEcc::Medium,
+            qrcodegen_no_heap::Version::MIN,
+            self.version,
+            None,
+            true,
+        )
+    }
+}
 
 /// Returns the width / height of the QR code + padding in pixels
 fn draw_qr_code(gfx: &mut Bitmap3<'_>, qrcode_string_data: &str) -> i32 {
     const MAX_VERSION: qrcodegen_no_heap::Version = qrcodegen_no_heap::Version::new(6);
-    const PADDING: i32 = 8;
 
-    let (Ok(mut temp_buffer), Ok(mut out_buffer)) = (
-        Vec::try_with_capacity_in(MAX_VERSION.buffer_len(), crate::ExternalAllocator),
-        Vec::try_with_capacity_in(MAX_VERSION.buffer_len(), crate::ExternalAllocator),
-    ) else {
+    let Ok(mut buffers) = QrCodeBuffers::new(MAX_VERSION) else {
         crate::println!("Failed to allocate memory to generate QR code");
         return PADDING;
     };
 
-    let qr_code = match qrcodegen_no_heap::QrCode::encode_text(
-        qrcode_string_data,
-        &mut temp_buffer,
-        &mut out_buffer,
-        qrcodegen_no_heap::QrCodeEcc::Medium,
-        qrcodegen_no_heap::Version::MIN,
-        MAX_VERSION,
-        None,
-        true,
-    ) {
+    let qr_code = buffers.generate_qr_code(qrcode_string_data);
+
+    let qr_code = match qr_code {
         Ok(qr_code) => qr_code,
         Err(e) => {
             crate::println!("Error generating qr code: {e:?}");
@@ -106,3 +138,19 @@ fn draw_qr_code(gfx: &mut Bitmap3<'_>, qrcode_string_data: &str) -> i32 {
 
     qr_code.size() * 2 + PADDING * 2
 }
+
+#[cfg(test)]
+mod tests {
+    use super::QrCodeBuffers;
+
+    const MAX_VERSION: qrcodegen_no_heap::Version = qrcodegen_no_heap::Version::new(6);
+
+    #[test_case]
+    fn check_qr_code_generation(_: &mut crate::Gba) {
+        let mut buffers =
+            QrCodeBuffers::new(MAX_VERSION).expect("should be able to allocate buffers");
+        buffers
+            .generate_qr_code("https://agbrs.dev/crash#09rESxF0r0Cz06hv1")
+            .expect("should be able to generate qr code");
+    }
+}

agb/src/panics_render/text.rs

@@ -30,6 +30,10 @@ impl<'bitmap, 'gba> BitmapTextRender<'bitmap, 'gba> {
         }
     }
 
+    pub fn head_y_position(&self) -> i32 {
+        self.head_position.y
+    }
+
     fn render_letter(&mut self, c: char) {
         let letter = FONT.letter(c);