bevy_render: Convert KTX2 R8_SRGB/R8G8_SRGB to Unorm for use with wgpu

bevyengine · Apr 25, 2022 · 99c4382 · 99c4382
1 parent 88b4b04
commit 99c4382
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Showing 2 changed files with 56 additions and 17 deletions.
diff --git a/crates/bevy_render/src/texture/image.rs b/crates/bevy_render/src/texture/image.rs
@@ -348,9 +348,13 @@ pub enum DataFormat {
 #[derive(Clone, Copy, Debug)]
 pub enum TranscodeFormat {
     Etc1s,
+    Uastc(DataFormat),
+    // Has to be transcoded to R8Unorm for use with `wgpu`
+    R8UnormSrgb,
+    // Has to be transcoded to R8G8Unorm for use with `wgpu`
+    Rg8UnormSrgb,
     // Has to be transcoded to Rgba8 for use with `wgpu`
     Rgb8,
-    Uastc(DataFormat),
 }
 
 /// An error that occurs when loading a texture

diff --git a/crates/bevy_render/src/texture/ktx2.rs b/crates/bevy_render/src/texture/ktx2.rs
@@ -1,6 +1,7 @@
 #[cfg(any(feature = "flate2", feature = "ruzstd"))]
 use std::io::Read;
 
+use crate::color::SrgbColorSpace;
 #[cfg(feature = "basis-universal")]
 use basis_universal::{
     DecodeFlags, LowLevelUastcTranscoder, SliceParametersUastc, TranscoderBlockFormat,
@@ -82,6 +83,44 @@ pub fn ktx2_buffer_to_image(
         TextureError::FormatRequiresTranscodingError(transcode_format) => {
             let mut transcoded = Vec::new();
             let texture_format = match transcode_format {
+                TranscodeFormat::R8UnormSrgb => {
+                    let (mut original_width, mut original_height) = (width, height);
+
+                    for level_data in levels.iter() {
+                        transcoded.push(
+                            level_data
+                                .iter()
+                                .copied()
+                                .map(|v| v.nonlinear_to_linear_srgb())
+                                .collect::<Vec<u8>>(),
+                        );
+
+                        // Next mip dimensions are half the current, minimum 1x1
+                        original_width = (original_width / 2).max(1);
+                        original_height = (original_height / 2).max(1);
+                    }
+
+                    TextureFormat::R8Unorm
+                }
+                TranscodeFormat::Rg8UnormSrgb => {
+                    let (mut original_width, mut original_height) = (width, height);
+
+                    for level_data in levels.iter() {
+                        transcoded.push(
+                            level_data
+                                .iter()
+                                .copied()
+                                .map(|v| v.nonlinear_to_linear_srgb())
+                                .collect::<Vec<u8>>(),
+                        );
+
+                        // Next mip dimensions are half the current, minimum 1x1
+                        original_width = (original_width / 2).max(1);
+                        original_height = (original_height / 2).max(1);
+                    }
+
+                    TextureFormat::Rg8Unorm
+                }
                 TranscodeFormat::Rgb8 => {
                     let (mut original_width, mut original_height) = (width, height);
 
@@ -1283,10 +1322,9 @@ pub fn ktx2_format_to_texture_format(
     Ok(match ktx2_format {
         ktx2::Format::R8_UNORM => {
             if is_srgb {
-                return Err(TextureError::UnsupportedTextureFormat(format!(
-                    "{:?}",
-                    ktx2_format
-                )));
+                return Err(TextureError::FormatRequiresTranscodingError(
+                    TranscodeFormat::R8UnormSrgb,
+                ));
             } else {
                 TextureFormat::R8Unorm
             }
@@ -1296,20 +1334,18 @@ pub fn ktx2_format_to_texture_format(
         ktx2::Format::R8_SINT => TextureFormat::R8Sint,
         ktx2::Format::R8_SRGB => {
             if is_srgb {
-                return Err(TextureError::UnsupportedTextureFormat(format!(
-                    "{:?}",
-                    ktx2_format
-                )));
+                return Err(TextureError::FormatRequiresTranscodingError(
+                    TranscodeFormat::R8UnormSrgb,
+                ));
             } else {
                 TextureFormat::R8Unorm
             }
         }
         ktx2::Format::R8G8_UNORM => {
             if is_srgb {
-                return Err(TextureError::UnsupportedTextureFormat(format!(
-                    "{:?}",
-                    ktx2_format
-                )));
+                return Err(TextureError::FormatRequiresTranscodingError(
+                    TranscodeFormat::Rg8UnormSrgb,
+                ));
             } else {
                 TextureFormat::Rg8Unorm
             }
@@ -1319,10 +1355,9 @@ pub fn ktx2_format_to_texture_format(
         ktx2::Format::R8G8_SINT => TextureFormat::Rg8Sint,
         ktx2::Format::R8G8_SRGB => {
             if is_srgb {
-                return Err(TextureError::UnsupportedTextureFormat(format!(
-                    "{:?}",
-                    ktx2_format
-                )));
+                return Err(TextureError::FormatRequiresTranscodingError(
+                    TranscodeFormat::Rg8UnormSrgb,
+                ));
             } else {
                 TextureFormat::Rg8Unorm
             }