Add `TextureOptions::wrap_mode` (#3954)

Exposes support in both glow and wgpu for texture wrap modes

This would be breaking for manual creations of TextureOptions but would
work with the current TextureOptions::NEAREST and LINEAR without change,
keeping those clamp to edge

I wasn't sure how best to expose the options to the user and added
consts for LINEAR_REPEAT LINEAR_MIRRORED_REPEAT NEAREST_REPEAT
NEAREST_MIRRORED_REPEAT

This does not include wrap mode clamp to border as it worked fine with
glow but with wgpu it panics due to Features
Features(ADDRESS_MODE_CLAMP_TO_BORDER) are required but not enabled on
the device, and I thought it was probably best not to try to enable that
feature, but happy to include that functionality also if that is okay to
be toggled


![image](https://github.com/emilk/egui/assets/5075747/bba71f61-a105-4e5b-b8ce-1083621eb3de)

---------

Co-authored-by: Emil Ernerfeldt <emil.ernerfeldt@gmail.com>

crates/egui-wgpu/src/renderer.rs

@@ -923,12 +923,19 @@ fn create_sampler(
         epaint::textures::TextureFilter::Nearest => wgpu::FilterMode::Nearest,
         epaint::textures::TextureFilter::Linear => wgpu::FilterMode::Linear,
     };
+    let address_mode = match options.wrap_mode {
+        epaint::textures::TextureWrapMode::ClampToEdge => wgpu::AddressMode::ClampToEdge,
+        epaint::textures::TextureWrapMode::Repeat => wgpu::AddressMode::Repeat,
+        epaint::textures::TextureWrapMode::MirroredRepeat => wgpu::AddressMode::MirrorRepeat,
+    };
     device.create_sampler(&wgpu::SamplerDescriptor {
         label: Some(&format!(
             "egui sampler (mag: {mag_filter:?}, min {min_filter:?})"
         )),
         mag_filter,
         min_filter,
+        address_mode_u: address_mode,
+        address_mode_v: address_mode,
         ..Default::default()
     })
 }

crates/egui/src/lib.rs

@@ -395,7 +395,7 @@ pub use emath::{
 pub use epaint::{
     mutex,
     text::{FontData, FontDefinitions, FontFamily, FontId, FontTweak},
-    textures::{TextureFilter, TextureOptions, TexturesDelta},
+    textures::{TextureFilter, TextureOptions, TextureWrapMode, TexturesDelta},
     ClippedPrimitive, ColorImage, FontImage, ImageData, Mesh, PaintCallback, PaintCallbackInfo,
     Rounding, Shape, Stroke, TextureHandle, TextureId,
 };

crates/egui_glow/src/painter.rs

@@ -34,6 +34,20 @@ impl TextureFilterExt for egui::TextureFilter {
     }
 }
 
+trait TextureWrapModeExt {
+    fn glow_code(&self) -> u32;
+}
+
+impl TextureWrapModeExt for egui::TextureWrapMode {
+    fn glow_code(&self) -> u32 {
+        match self {
+            Self::ClampToEdge => glow::CLAMP_TO_EDGE,
+            Self::Repeat => glow::REPEAT,
+            Self::MirroredRepeat => glow::MIRRORED_REPEAT,
+        }
+    }
+}
+
 #[derive(Debug)]
 pub struct PainterError(String);
 
@@ -555,12 +569,12 @@ impl Painter {
             self.gl.tex_parameter_i32(
                 glow::TEXTURE_2D,
                 glow::TEXTURE_WRAP_S,
-                glow::CLAMP_TO_EDGE as i32,
+                options.wrap_mode.glow_code() as i32,
             );
             self.gl.tex_parameter_i32(
                 glow::TEXTURE_2D,
                 glow::TEXTURE_WRAP_T,
-                glow::CLAMP_TO_EDGE as i32,
+                options.wrap_mode.glow_code() as i32,
             );
             check_for_gl_error!(&self.gl, "tex_parameter");
 

crates/epaint/src/textures.rs

@@ -156,6 +156,9 @@ pub struct TextureOptions {
 
     /// How to filter when minifying (when texels are smaller than pixels).
     pub minification: TextureFilter,
+
+    /// How to wrap the texture when the texture coordinates are outside the [0, 1] range.
+    pub wrap_mode: TextureWrapMode,
 }
 
 impl TextureOptions {
@@ -163,12 +166,42 @@ impl TextureOptions {
     pub const LINEAR: Self = Self {
         magnification: TextureFilter::Linear,
         minification: TextureFilter::Linear,
+        wrap_mode: TextureWrapMode::ClampToEdge,
     };
 
     /// Nearest magnification and minification.
     pub const NEAREST: Self = Self {
         magnification: TextureFilter::Nearest,
         minification: TextureFilter::Nearest,
+        wrap_mode: TextureWrapMode::ClampToEdge,
+    };
+
+    /// Linear magnification and minification, but with the texture repeated.
+    pub const LINEAR_REPEAT: Self = Self {
+        magnification: TextureFilter::Linear,
+        minification: TextureFilter::Linear,
+        wrap_mode: TextureWrapMode::Repeat,
+    };
+
+    /// Linear magnification and minification, but with the texture mirrored and repeated.
+    pub const LINEAR_MIRRORED_REPEAT: Self = Self {
+        magnification: TextureFilter::Linear,
+        minification: TextureFilter::Linear,
+        wrap_mode: TextureWrapMode::MirroredRepeat,
+    };
+
+    /// Nearest magnification and minification, but with the texture repeated.
+    pub const NEAREST_REPEAT: Self = Self {
+        magnification: TextureFilter::Nearest,
+        minification: TextureFilter::Nearest,
+        wrap_mode: TextureWrapMode::Repeat,
+    };
+
+    /// Nearest magnification and minification, but with the texture mirrored and repeated.
+    pub const NEAREST_MIRRORED_REPEAT: Self = Self {
+        magnification: TextureFilter::Nearest,
+        minification: TextureFilter::Nearest,
+        wrap_mode: TextureWrapMode::MirroredRepeat,
     };
 }
 
@@ -193,6 +226,23 @@ pub enum TextureFilter {
     Linear,
 }
 
+/// Defines how textures are wrapped around objects when texture coordinates fall outside the [0, 1] range.
+#[derive(Copy, Clone, Debug, Default, PartialEq, Eq, Hash)]
+#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
+pub enum TextureWrapMode {
+    /// Stretches the edge pixels to fill beyond the texture's bounds.
+    ///
+    /// This is what you want to use for a normal image in a GUI.
+    #[default]
+    ClampToEdge,
+
+    /// Tiles the texture across the surface, repeating it horizontally and vertically.
+    Repeat,
+
+    /// Mirrors the texture with each repetition, creating symmetrical tiling.
+    MirroredRepeat,
+}
+
 // ----------------------------------------------------------------------------
 
 /// What has been allocated and freed during the last period.