From 9ab41d06b4ff0b52360a8cda756a3b1343a1e2fc Mon Sep 17 00:00:00 2001
From: HampusM <hampus@hampusmat.com>
Date: Thu, 26 Mar 2026 16:42:22 +0100
Subject: fix(engine): prevent uploading textures with invalid row alignments

---
 engine/src/image.rs           | 25 ++++++++++++++++++++
 engine/src/renderer/opengl.rs | 55 ++++++++++++++++++++++++++++++++-----------
 engine/src/texture.rs         |  6 ++++-
 3 files changed, 71 insertions(+), 15 deletions(-)

(limited to 'engine')

diff --git a/engine/src/image.rs b/engine/src/image.rs
index cf31a92..ac95f22 100644
--- a/engine/src/image.rs
+++ b/engine/src/image.rs
@@ -50,6 +50,26 @@ impl Image
         }
     }
 
+    pub fn from_color_and_alpha(
+        dimens: impl Into<Dimens<u32>>,
+        color: impl Into<Color<u8>>,
+        alpha: u8,
+    ) -> Self
+    {
+        let dimens: Dimens<u32> = dimens.into();
+
+        let color: Color<u8> = color.into();
+
+        Self {
+            inner: image_rs::RgbaImage::from_pixel(
+                dimens.width,
+                dimens.height,
+                image_rs::Rgba([color.red, color.green, color.blue, alpha]),
+            )
+            .into(),
+        }
+    }
+
     pub fn dimensions(&self) -> Dimens<u32>
     {
         self.inner.dimensions().into()
@@ -68,6 +88,11 @@ impl Image
         }
     }
 
+    pub fn to_rgba8(&self) -> Self
+    {
+        Self { inner: self.inner.to_rgba8().into() }
+    }
+
     pub fn as_bytes(&self) -> &[u8]
     {
         self.inner.as_bytes()
diff --git a/engine/src/renderer/opengl.rs b/engine/src/renderer/opengl.rs
index 11a4ca9..dc8e561 100644
--- a/engine/src/renderer/opengl.rs
+++ b/engine/src/renderer/opengl.rs
@@ -61,7 +61,7 @@ use opengl_bindings::{ContextWithFns, CurrentContextWithFns};
 use safer_ffi::layout::ReprC;
 use zerocopy::{Immutable, IntoBytes};
 
-use crate::asset::{Assets, Id as AssetId};
+use crate::asset::{Assets, Handle as AssetHandle};
 use crate::data_types::dimens::Dimens;
 use crate::image::{ColorType as ImageColorType, Image};
 use crate::matrix::Matrix;
@@ -100,6 +100,7 @@ use crate::shader::{
 use crate::texture::{
     Filtering as TextureFiltering,
     Properties as TextureProperties,
+    Texture,
     Wrapping as TextureWrapping,
 };
 use crate::vector::{Vec2, Vec3};
@@ -898,17 +899,11 @@ fn handle_commands(
                         continue;
                     };
 
-                    let Some(texture) = assets.get(&texture_asset) else {
-                        tracing::error!("Texture asset is not loaded",);
-                        continue;
-                    };
-
                     if let Err(err) = create_texture_object(
                         curr_gl_ctx,
                         &mut renderer_object_store,
-                        texture_asset.id(),
-                        &texture.image,
-                        &texture.properties,
+                        &assets,
+                        &texture_asset,
                     ) {
                         tracing::error!("Failed to create texture object: {err}");
                     }
@@ -1058,12 +1053,11 @@ fn handle_commands(
 fn create_texture_object(
     curr_gl_ctx: &CurrentContextWithFns<'_>,
     renderer_object_store: &mut RendererObjectStore,
-    texture_image_asset_id: AssetId,
-    image: &Image,
-    texture_properties: &TextureProperties,
+    assets: &Assets,
+    texture_asset: &AssetHandle<Texture>,
 ) -> Result<(), GlTextureGenerateError>
 {
-    let object_id = RendererObjectId::Asset(texture_image_asset_id);
+    let object_id = RendererObjectId::Asset(texture_asset.id());
 
     if renderer_object_store.contains_with_id(&object_id) {
         tracing::error!(
@@ -1073,10 +1067,43 @@ fn create_texture_object(
         return Ok(());
     }
 
+    let Some(texture) = assets.get(&texture_asset) else {
+        tracing::error!("Texture asset is not loaded",);
+        return Ok(());
+    };
+
+    let texture_image = match texture.image.color_type() {
+        ImageColorType::Rgb8 if (texture.image.dimensions().width * 3) % 4 != 0 => {
+            // The texture will be corrupted if the alignment of each horizontal line of
+            // the texture pixel array is not multiple of 4.
+            //
+            // Read more about this at
+            // wikis.khronos.org/opengl/Common_Mistakes#Texture_upload_and_pixel_reads
+            //
+            // To prevent this, the image is converted to RGBA8. RGBA8 images have a pixel
+            // size of 4 bytes so they cannot have any alignment problems
+
+            tracing::warn!(
+                texture_asset = %assets
+                    .get_label(&texture_asset)
+                    .expect("Not possible"),
+                concat!(
+                    "Converting texture image from RGB8 to RGBA8 to prevent alignment ",
+                    "problems. This conversion may be slow. Consider changing the ",
+                    "texture image's pixel format to RGBA8"
+                )
+            );
+
+            &texture.image.to_rgba8()
+        }
+        _ => &texture.image,
+    };
+
     renderer_object_store.insert(
         object_id,
         RendererObject::from_raw(
-            create_gl_texture(curr_gl_ctx, image, texture_properties)?.into_raw(),
+            create_gl_texture(curr_gl_ctx, texture_image, &texture.properties)?
+                .into_raw(),
             RendererObjectKind::Texture,
         ),
     );
diff --git a/engine/src/texture.rs b/engine/src/texture.rs
index b92bc2e..b069228 100644
--- a/engine/src/texture.rs
+++ b/engine/src/texture.rs
@@ -111,7 +111,11 @@ pub(crate) fn initialize(assets: &mut Assets)
     assets.store_with_label(
         WHITE_1X1_ASSET_LABEL.clone(),
         Texture {
-            image: Image::from_color(Dimens { width: 1, height: 1 }, Color::WHITE_U8),
+            image: Image::from_color_and_alpha(
+                Dimens { width: 1, height: 1 },
+                Color::WHITE_U8,
+                1,
+            ),
             properties: Properties::default(),
         },
     );
-- 
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