Switch to using R8 on all GL implementations.

Fixes #2134.
Fixes #788.

webrender/examples/basic.rs

@@ -212,7 +212,7 @@ impl Example for App {
         let image_mask_key = api.generate_image_key();
         resources.add_image(
             image_mask_key,
-            ImageDescriptor::new(2, 2, ImageFormat::A8, true),
+            ImageDescriptor::new(2, 2, ImageFormat::R8, true),
             ImageData::new(vec![0, 80, 180, 255]),
             None,
         );

webrender/examples/blob.rs

@@ -85,7 +85,7 @@ fn render_blob(
                     texels.push(color.r * checker + tc);
                     texels.push(color.a * checker + tc);
                 }
-                api::ImageFormat::A8 => {
+                api::ImageFormat::R8 => {
                     texels.push(color.a * checker + tc);
                 }
                 _ => {

webrender/examples/yuv.rs

@@ -192,7 +192,7 @@ impl Example for App {
         let yuv_chanel3 = api.generate_image_key();
         resources.add_image(
             yuv_chanel1,
-            ImageDescriptor::new(100, 100, ImageFormat::A8, true),
+            ImageDescriptor::new(100, 100, ImageFormat::R8, true),
             ImageData::new(vec![127; 100 * 100]),
             None,
         );
@@ -204,13 +204,13 @@ impl Example for App {
         );
         resources.add_image(
             yuv_chanel2_1,
-            ImageDescriptor::new(100, 100, ImageFormat::A8, true),
+            ImageDescriptor::new(100, 100, ImageFormat::R8, true),
             ImageData::new(vec![127; 100 * 100]),
             None,
         );
         resources.add_image(
             yuv_chanel3,
-            ImageDescriptor::new(100, 100, ImageFormat::A8, true),
+            ImageDescriptor::new(100, 100, ImageFormat::R8, true),
             ImageData::new(vec![127; 100 * 100]),
             None,
         );

webrender/src/debug_render.rs

@@ -121,7 +121,7 @@ impl DebugRenderer {
             &mut font_texture,
             debug_font_data::BMP_WIDTH,
             debug_font_data::BMP_HEIGHT,
-            ImageFormat::A8,
+            ImageFormat::R8,
             TextureFilter::Linear,
             None,
             1,

webrender/src/device.rs

@@ -12,7 +12,6 @@ use smallvec::SmallVec;
 use std::cell::RefCell;
 use std::fs::File;
 use std::io::Read;
-use std::iter::repeat;
 use std::marker::PhantomData;
 use std::mem;
 use std::ops::Add;
@@ -38,12 +37,6 @@ impl Add<usize> for FrameId {
     }
 }
 
-#[cfg(not(any(target_arch = "arm", target_arch = "aarch64")))]
-const GL_FORMAT_A: gl::GLuint = gl::RED;
-
-#[cfg(any(target_arch = "arm", target_arch = "aarch64"))]
-const GL_FORMAT_A: gl::GLuint = gl::ALPHA;
-
 const GL_FORMAT_BGRA_GL: gl::GLuint = gl::BGRA;
 
 const GL_FORMAT_BGRA_GLES: gl::GLuint = gl::BGRA_EXT;
@@ -457,7 +450,7 @@ impl Texture {
 
     pub fn get_bpp(&self) -> u32 {
         match self.format {
-            ImageFormat::A8 => 1,
+            ImageFormat::R8 => 1,
             ImageFormat::BGRA8 => 4,
             ImageFormat::RG8 => 2,
             ImageFormat::RGBAF32 => 16,
@@ -1011,20 +1004,6 @@ impl Device {
                 let (internal_format, gl_format) = gl_texture_formats_for_image_format(self.gl(), format);
                 let type_ = gl_type_for_texture_format(format);
 
-                let expanded_data: Vec<u8>;
-                let actual_pixels = if pixels.is_some() && format == ImageFormat::A8 &&
-                    cfg!(any(target_arch = "arm", target_arch = "aarch64"))
-                {
-                    expanded_data = pixels
-                        .unwrap()
-                        .iter()
-                        .flat_map(|&byte| repeat(byte).take(4))
-                        .collect();
-                    Some(expanded_data.as_slice())
-                } else {
-                    pixels
-                };
-
                 match texture.target {
                     gl::TEXTURE_2D_ARRAY => {
                         self.gl.tex_image_3d(
@@ -1037,7 +1016,7 @@ impl Device {
                             0,
                             gl_format,
                             type_,
-                            actual_pixels,
+                            pixels,
                         );
                     }
                     gl::TEXTURE_2D | gl::TEXTURE_RECTANGLE | gl::TEXTURE_EXTERNAL_OES => {
@@ -1050,7 +1029,7 @@ impl Device {
                             0,
                             gl_format,
                             type_,
-                            actual_pixels,
+                            pixels,
                         );
                     }
                     _ => panic!("BUG: Unexpected texture target!"),
@@ -1924,11 +1903,7 @@ fn gl_texture_formats_for_image_format(
     format: ImageFormat,
 ) -> (gl::GLint, gl::GLuint) {
     match format {
-        ImageFormat::A8 => if cfg!(any(target_arch = "arm", target_arch = "aarch64")) {
-            (get_gl_format_bgra(gl) as gl::GLint, get_gl_format_bgra(gl))
-        } else {
-            (GL_FORMAT_A as gl::GLint, GL_FORMAT_A)
-        },
+        ImageFormat::R8 => (gl::RED as gl::GLint, gl::RED),
         ImageFormat::BGRA8 => match gl.get_type() {
             gl::GlType::Gl => (gl::RGBA as gl::GLint, get_gl_format_bgra(gl)),
             gl::GlType::Gles => (get_gl_format_bgra(gl) as gl::GLint, get_gl_format_bgra(gl)),
@@ -2053,7 +2028,7 @@ impl<'a, T> TextureUploader<'a, T> {
 impl<'a> UploadTarget<'a> {
     fn update_impl(&mut self, chunk: UploadChunk) {
         let (gl_format, bpp, data_type) = match self.texture.format {
-            ImageFormat::A8 => (GL_FORMAT_A, 1, gl::UNSIGNED_BYTE),
+            ImageFormat::R8 => (gl::RED, 1, gl::UNSIGNED_BYTE),
             ImageFormat::BGRA8 => (get_gl_format_bgra(self.gl), 4, gl::UNSIGNED_BYTE),
             ImageFormat::RG8 => (gl::RG, 2, gl::UNSIGNED_BYTE),
             ImageFormat::RGBAF32 => (gl::RGBA, 16, gl::FLOAT),

webrender/src/renderer.rs

@@ -2099,7 +2099,7 @@ impl Renderer {
                 &mut texture,
                 8,
                 8,
-                ImageFormat::A8,
+                ImageFormat::R8,
                 TextureFilter::Nearest,
                 None,
                 1,

webrender/src/texture_cache.rs

@@ -206,7 +206,7 @@ impl TextureCache {
         TextureCache {
             max_texture_size,
             array_a8_linear: TextureArray::new(
-                ImageFormat::A8,
+                ImageFormat::R8,
                 TextureFilter::Linear,
                 TEXTURE_ARRAY_LAYERS_LINEAR,
             ),
@@ -365,13 +365,13 @@ impl TextureCache {
         region_index: u16
     ) -> &mut TextureRegion {
         let texture_array = match (format, filter) {
-            (ImageFormat::A8, TextureFilter::Linear) => &mut self.array_a8_linear,
+            (ImageFormat::R8, TextureFilter::Linear) => &mut self.array_a8_linear,
             (ImageFormat::BGRA8, TextureFilter::Linear) => &mut self.array_rgba8_linear,
             (ImageFormat::BGRA8, TextureFilter::Nearest) => &mut self.array_rgba8_nearest,
             (ImageFormat::Invalid, _) |
             (ImageFormat::RGBAF32, _) |
             (ImageFormat::RG8, _) |
-            (ImageFormat::A8, TextureFilter::Nearest) => unreachable!(),
+            (ImageFormat::R8, TextureFilter::Nearest) => unreachable!(),
         };
 
         &mut texture_array.regions[region_index as usize]
@@ -537,12 +537,12 @@ impl TextureCache {
     ) -> Option<CacheEntry> {
         // Work out which cache it goes in, based on format.
         let texture_array = match (descriptor.format, filter) {
-            (ImageFormat::A8, TextureFilter::Linear) => &mut self.array_a8_linear,
+            (ImageFormat::R8, TextureFilter::Linear) => &mut self.array_a8_linear,
             (ImageFormat::BGRA8, TextureFilter::Linear) => &mut self.array_rgba8_linear,
             (ImageFormat::BGRA8, TextureFilter::Nearest) => &mut self.array_rgba8_nearest,
             (ImageFormat::Invalid, _) |
             (ImageFormat::RGBAF32, _) |
-            (ImageFormat::A8, TextureFilter::Nearest) |
+            (ImageFormat::R8, TextureFilter::Nearest) |
             (ImageFormat::RG8, _) => unreachable!(),
         };
 

webrender/src/tiling.rs

@@ -559,7 +559,7 @@ impl RenderPass {
         RenderPass {
             kind: RenderPassKind::OffScreen {
                 color: RenderTargetList::new(screen_size, ImageFormat::BGRA8),
-                alpha: RenderTargetList::new(screen_size, ImageFormat::A8),
+                alpha: RenderTargetList::new(screen_size, ImageFormat::R8),
             },
             tasks: vec![],
             dynamic_tasks: FastHashMap::default(),

webrender_api/src/image.rs

@@ -51,7 +51,7 @@ pub struct ExternalImageData {
 #[derive(Clone, Copy, Debug, Deserialize, Eq, Hash, PartialEq, Serialize)]
 pub enum ImageFormat {
     Invalid = 0,
-    A8 = 1,
+    R8 = 1,
     BGRA8 = 3,
     RGBAF32 = 4,
     RG8 = 5,
@@ -60,7 +60,7 @@ pub enum ImageFormat {
 impl ImageFormat {
     pub fn bytes_per_pixel(self) -> u32 {
         match self {
-            ImageFormat::A8 => 1,
+            ImageFormat::R8 => 1,
             ImageFormat::BGRA8 => 4,
             ImageFormat::RGBAF32 => 16,
             ImageFormat::RG8 => 2,

wrench/src/blob.rs

@@ -65,7 +65,7 @@ fn render_blob(
                     texels.push(color.r * checker + tc);
                     texels.push(color.a * checker + tc);
                 }
-                ImageFormat::A8 => {
+                ImageFormat::R8 => {
                     texels.push(color.a * checker + tc);
                 }
                 _ => {

wrench/src/json_frame_writer.rs

@@ -234,7 +234,7 @@ impl JsonFrameWriter {
             } else {
                 false
             },
-            ImageFormat::A8 => if data.stride == data.width {
+            ImageFormat::R8 => if data.stride == data.width {
                 save_buffer(
                     &path_file,
                     &bytes,

wrench/src/yaml_frame_reader.rs

@@ -169,7 +169,7 @@ fn is_image_opaque(format: ImageFormat, bytes: &[u8]) -> bool {
             is_opaque
         }
         ImageFormat::RG8 => true,
-        ImageFormat::A8 => false,
+        ImageFormat::R8 => false,
         ImageFormat::Invalid | ImageFormat::RGBAF32 => unreachable!(),
     }
 }
@@ -343,7 +343,7 @@ impl YamlFrameReader {
                 let image_dims = image.dimensions();
                 let (format, bytes) = match image {
                     image::ImageLuma8(_) => {
-                        (ImageFormat::A8, image.raw_pixels())
+                        (ImageFormat::R8, image.raw_pixels())
                     }
                     image::ImageRgba8(_) => {
                         let mut pixels = image.raw_pixels();

wrench/src/yaml_frame_writer.rs

@@ -555,7 +555,7 @@ impl YamlFrameWriter {
         assert!(data.stride > 0);
         let (color_type, bpp) = match data.format {
             ImageFormat::BGRA8 => (ColorType::RGBA(8), 4),
-            ImageFormat::A8 => (ColorType::Gray(8), 1),
+            ImageFormat::R8 => (ColorType::Gray(8), 1),
             _ => {
                 println!(
                     "Failed to write image with format {:?}, dimensions {}x{}, stride {}",