rt: abstract framebuffer scaling into common code

librashader-runtime-d3d11/src/filter_chain.rs

@@ -25,7 +25,9 @@ use crate::util::d3d11_compile_bound_shader;
 use crate::{error, util, D3D11OutputView};
 use librashader_reflect::reflect::presets::{CompilePresetTarget, ShaderPassArtifact};
 use librashader_runtime::binding::{BindingUtil, TextureInput};
+use librashader_runtime::filter_pass::FilterPassMeta;
 use librashader_runtime::quad::{QuadType, IDENTITY_MVP};
+use librashader_runtime::scaling::{scale_framebuffers, scale_framebuffers_with_context_callback};
 use librashader_runtime::uniforms::UniformStorage;
 use rayon::prelude::*;
 use windows::Win32::Graphics::Direct3D11::{
@@ -445,34 +447,16 @@ impl FilterChainD3D11 {
         };
 
         let mut source = original.clone();
-        let mut iterator = passes.iter_mut().enumerate().peekable();
 
         // rescale render buffers to ensure all bindings are valid.
-        let mut source_size = source.size();
+        scale_framebuffers::<(), _, _, _>(
-        while let Some((index, pass)) = iterator.next() {
+            source.size(),
-            let should_mipmap = iterator
+            viewport.output.size,
-                .peek()
+            &mut self.output_framebuffers,
-                .map_or(false, |(_, p)| p.config.mipmap_input);
+            &mut self.feedback_framebuffers,
-
+            &passes,
-            let next_size = self.output_framebuffers[index].scale(
-                pass.config.scaling.clone(),
-                pass.get_format(),
-                &viewport.output.size,
-                &source_size,
-                should_mipmap,
         )?;
 
-            self.feedback_framebuffers[index].scale(
-                pass.config.scaling.clone(),
-                pass.get_format(),
-                &viewport.output.size,
-                &source_size,
-                should_mipmap,
-            )?;
-
-            source_size = next_size;
-        }
-
         let passes_len = passes.len();
         let (pass, last) = passes.split_at_mut(passes_len - 1);
 

librashader-runtime-d3d11/src/filter_pass.rs

@@ -10,6 +10,7 @@ use librashader_reflect::reflect::ShaderReflection;
 use rustc_hash::FxHashMap;
 
 use librashader_runtime::binding::{BindSemantics, TextureInput};
+use librashader_runtime::filter_pass::FilterPassMeta;
 use librashader_runtime::quad::QuadType;
 use windows::Win32::Graphics::Direct3D11::{
     ID3D11Buffer, ID3D11InputLayout, ID3D11PixelShader, ID3D11SamplerState,
@@ -80,19 +81,18 @@ impl BindSemantics for FilterPass {
     }
 }
 
-// slang_process.cpp 229
+impl FilterPassMeta for FilterPass {
-impl FilterPass {
+    fn source_format(&self) -> ImageFormat {
-    pub fn get_format(&self) -> ImageFormat {
+        self.source.format
-        let fb_format = self.source.format;
+    }
-        if let Some(format) = self.config.get_format_override() {
+
-            format
+    fn config(&self) -> &ShaderPassConfig {
-        } else if fb_format == ImageFormat::Unknown {
+        &self.config
-            ImageFormat::R8G8B8A8Unorm
-        } else {
-            fb_format
     }
 }
 
+// slang_process.cpp 229
+impl FilterPass {
     // framecount should be pre-modded
     fn build_semantics<'a>(
         &mut self,

librashader-runtime-d3d11/src/framebuffer.rs

@@ -1,10 +1,10 @@
 use crate::error;
-use crate::error::assume_d3d11_init;
+use crate::error::{assume_d3d11_init, FilterChainError};
 use crate::texture::D3D11InputView;
 use crate::util::d3d11_get_closest_format;
 use librashader_common::{ImageFormat, Size};
 use librashader_presets::Scale2D;
-use librashader_runtime::scaling::{MipmapSize, ViewportSize};
+use librashader_runtime::scaling::{MipmapSize, ScaleableFramebuffer, ViewportSize};
 use windows::core::Interface;
 use windows::Win32::Graphics::Direct3D::D3D_SRV_DIMENSION_TEXTURE2D;
 use windows::Win32::Graphics::Direct3D11::{
@@ -251,3 +251,20 @@ pub const fn default_viewport(size: Size<u32>) -> D3D11_VIEWPORT {
         MaxDepth: 1.0,
     }
 }
+
+impl<T> ScaleableFramebuffer<T> for OwnedFramebuffer {
+    type Error = FilterChainError;
+    type Context = ();
+
+    fn scale(
+        &mut self,
+        scaling: Scale2D,
+        format: ImageFormat,
+        viewport_size: &Size<u32>,
+        source_size: &Size<u32>,
+        should_mipmap: bool,
+        _context: Self::Context,
+    ) -> Result<Size<u32>, Self::Error> {
+        self.scale(scaling, format, viewport_size, source_size, should_mipmap)
+    }
+}

librashader-runtime-d3d11/src/lib.rs

@@ -40,7 +40,7 @@ mod tests {
     // "../test/null.slangp",
     // const FILTER_PATH: &str = "../test/slang-shaders/scalefx/scalefx-9x.slangp";
 
-    const FILTER_PATH: &str = "../test/slang-shaders/crt/zfast-crt.slangp";
+    const FILTER_PATH: &str = "../test/slang-shaders/crt/crt-royale.slangp";
     const IMAGE_PATH: &str = "../test/finalfightlong.png";
     // #[test]
     // fn triangle_d3d11_args() {

librashader-runtime-d3d12/src/filter_chain.rs

@@ -46,7 +46,8 @@ use windows::Win32::Graphics::Dxgi::Common::DXGI_FORMAT_UNKNOWN;
 use windows::Win32::System::Threading::{CreateEventA, ResetEvent, WaitForSingleObject};
 use windows::Win32::System::WindowsProgramming::INFINITE;
 
-use librashader_runtime::scaling::MipmapSize;
+use librashader_runtime::filter_pass::FilterPassMeta;
+use librashader_runtime::scaling::{scale_framebuffers_with_context_callback, MipmapSize};
 use rayon::prelude::*;
 
 const MIPMAP_RESERVED_WORKHEAP_DESCRIPTORS: usize = 1024;
@@ -593,46 +594,29 @@ impl FilterChainD3D12 {
         );
 
         // rescale render buffers to ensure all bindings are valid.
-        let mut source_size = source.size();
+        scale_framebuffers_with_context_callback::<(), _, _, _, _>(
-        let mut iterator = passes.iter_mut().enumerate().peekable();
+            source.size(),
-        while let Some((index, pass)) = iterator.next() {
+            viewport.output.size,
-            let should_mipmap = iterator
+            &mut self.output_framebuffers,
-                .peek()
+            &mut self.feedback_framebuffers,
-                .map_or(false, |(_, p)| p.config.mipmap_input);
+            &passes,
-
+            (),
-            let next_size = self.output_framebuffers[index].scale(
+            |index: usize, pass: &FilterPass, output: &OwnedImage, feedback: &OwnedImage| {
-                pass.config.scaling.clone(),
-                pass.get_format(),
-                &viewport.output.size,
-                &source_size,
-                should_mipmap,
-            )?;
-
-            self.feedback_framebuffers[index].scale(
-                pass.config.scaling.clone(),
-                pass.get_format(),
-                &viewport.output.size,
-                &source_size,
-                should_mipmap,
-            )?;
-
-            source_size = next_size;
-
                 // refresh inputs
-            self.common.feedback_textures[index] = Some(
+                self.common.feedback_textures[index] = Some(feedback.create_shader_resource_view(
-                self.feedback_framebuffers[index].create_shader_resource_view(
-                    &mut self.staging_heap,
-                    pass.config.filter,
-                    pass.config.wrap_mode,
-                )?,
-            );
-            self.common.output_textures[index] =
-                Some(self.output_framebuffers[index].create_shader_resource_view(
                     &mut self.staging_heap,
                     pass.config.filter,
                     pass.config.wrap_mode,
                 )?);
-        }
+                self.common.output_textures[index] = Some(output.create_shader_resource_view(
+                    &mut self.staging_heap,
+                    pass.config.filter,
+                    pass.config.wrap_mode,
+                )?);
+
+                Ok(())
+            },
+        )?;
 
         let passes_len = passes.len();
         let (pass, last) = passes.split_at_mut(passes_len - 1);

librashader-runtime-d3d12/src/filter_pass.rs

@@ -12,6 +12,7 @@ use librashader_presets::ShaderPassConfig;
 use librashader_reflect::reflect::semantics::{MemberOffset, TextureBinding, UniformBinding};
 use librashader_reflect::reflect::ShaderReflection;
 use librashader_runtime::binding::{BindSemantics, TextureInput};
+use librashader_runtime::filter_pass::FilterPassMeta;
 use librashader_runtime::quad::QuadType;
 use librashader_runtime::uniforms::{NoUniformBinder, UniformStorage};
 use rustc_hash::FxHashMap;
@@ -74,18 +75,17 @@ impl BindSemantics<NoUniformBinder, Option<()>, RawD3D12Buffer, RawD3D12Buffer>
     }
 }
 
-impl FilterPass {
+impl FilterPassMeta for FilterPass {
-    pub fn get_format(&self) -> ImageFormat {
+    fn source_format(&self) -> ImageFormat {
-        let fb_format = self.source.format;
+        self.source.format
-        if let Some(format) = self.config.get_format_override() {
+    }
-            format
+
-        } else if fb_format == ImageFormat::Unknown {
+    fn config(&self) -> &ShaderPassConfig {
-            ImageFormat::R8G8B8A8Unorm
+        &self.config
-        } else {
-            fb_format
     }
 }
 
+impl FilterPass {
     // framecount should be pre-modded
     fn build_semantics<'a>(
         &mut self,

librashader-runtime-d3d12/src/framebuffer.rs

@@ -1,11 +1,11 @@
 use crate::descriptor_heap::{CpuStagingHeap, D3D12DescriptorHeap, RenderTargetHeap};
-use crate::error::assume_d3d12_init;
+use crate::error::{assume_d3d12_init, FilterChainError};
 use crate::texture::{D3D12OutputView, InputTexture};
 use crate::util::d3d12_get_closest_format;
 use crate::{error, util};
 use librashader_common::{FilterMode, ImageFormat, Size, WrapMode};
 use librashader_presets::Scale2D;
-use librashader_runtime::scaling::{MipmapSize, ViewportSize};
+use librashader_runtime::scaling::{MipmapSize, ScaleableFramebuffer, ViewportSize};
 use std::ops::Deref;
 use windows::Win32::Foundation::RECT;
 use windows::Win32::Graphics::Direct3D12::{
@@ -305,3 +305,20 @@ impl OwnedImage {
         Ok(size)
     }
 }
+
+impl<T> ScaleableFramebuffer<T> for OwnedImage {
+    type Error = FilterChainError;
+    type Context = ();
+
+    fn scale(
+        &mut self,
+        scaling: Scale2D,
+        format: ImageFormat,
+        viewport_size: &Size<u32>,
+        source_size: &Size<u32>,
+        should_mipmap: bool,
+        _context: Self::Context,
+    ) -> Result<Size<u32>, Self::Error> {
+        self.scale(scaling, format, viewport_size, source_size, should_mipmap)
+    }
+}

librashader-runtime-gl/src/filter_chain/filter_impl.rs

@@ -21,6 +21,8 @@ use librashader_reflect::reflect::semantics::{BindingMeta, ShaderSemantics, Unif
 use librashader_reflect::reflect::presets::{CompilePresetTarget, ShaderPassArtifact};
 use librashader_reflect::reflect::ReflectShader;
 use librashader_runtime::binding::BindingUtil;
+use librashader_runtime::filter_pass::FilterPassMeta;
+use librashader_runtime::scaling::scale_framebuffers;
 use rustc_hash::FxHashMap;
 use spirv_cross::spirv::Decoration;
 use std::collections::VecDeque;
@@ -378,33 +380,15 @@ impl<T: GLInterface> FilterChainImpl<T> {
 
         let mut source = original;
 
-        let mut source_size = source.image.size;
         // rescale render buffers to ensure all bindings are valid.
-        let mut iterator = passes.iter_mut().enumerate().peekable();
+        scale_framebuffers::<T::FramebufferInterface, _, _, _>(
-        while let Some((index, pass)) = iterator.next() {
+            source.image.size,
-            let should_mipmap = iterator
+            viewport.output.size,
-                .peek()
+            &mut self.output_framebuffers,
-                .map_or(false, |(_, p)| p.config.mipmap_input);
+            &mut self.feedback_framebuffers,
-
+            &passes,
-            let next_size = self.output_framebuffers[index].scale::<T::FramebufferInterface>(
-                pass.config.scaling.clone(),
-                pass.get_format(),
-                viewport,
-                &source_size,
-                should_mipmap,
         )?;
 
-            self.feedback_framebuffers[index].scale::<T::FramebufferInterface>(
-                pass.config.scaling.clone(),
-                pass.get_format(),
-                viewport,
-                &source_size,
-                should_mipmap,
-            )?;
-
-            source_size = next_size
-        }
-
         let passes_len = passes.len();
         let (pass, last) = passes.split_at_mut(passes_len - 1);
 

librashader-runtime-gl/src/filter_pass.rs

@@ -8,6 +8,7 @@ use librashader_preprocess::ShaderSource;
 use librashader_presets::ShaderPassConfig;
 use librashader_reflect::reflect::semantics::{MemberOffset, TextureBinding, UniformBinding};
 use librashader_runtime::binding::{BindSemantics, ContextOffset, TextureInput};
+use librashader_runtime::filter_pass::FilterPassMeta;
 use rustc_hash::FxHashMap;
 
 use crate::binding::{GlUniformBinder, GlUniformStorage, UniformLocation, VariableLocation};
@@ -147,18 +148,17 @@ impl<T: GLInterface> FilterPass<T> {
     }
 }
 
-impl<T: GLInterface> FilterPass<T> {
+impl<T: GLInterface> FilterPassMeta for FilterPass<T> {
-    pub fn get_format(&self) -> ImageFormat {
+    fn source_format(&self) -> ImageFormat {
-        let fb_format = self.source.format;
+        self.source.format
-        if let Some(format) = self.config.get_format_override() {
+    }
-            format
+
-        } else if fb_format == ImageFormat::Unknown {
+    fn config(&self) -> &ShaderPassConfig {
-            ImageFormat::R8G8B8A8Unorm
+        &self.config
-        } else {
-            fb_format
     }
 }
 
+impl<T: GLInterface> FilterPass<T> {
     // framecount should be pre-modded
     fn build_semantics(
         &mut self,

librashader-runtime-gl/src/gl/framebuffer.rs

@@ -1,10 +1,11 @@
-use crate::error::Result;
+use crate::error::{FilterChainError, Result};
 use crate::framebuffer::GLImage;
 use crate::gl::FramebufferInterface;
 use crate::texture::InputTexture;
 use gl::types::{GLenum, GLuint};
 use librashader_common::{FilterMode, ImageFormat, Size, Viewport, WrapMode};
 use librashader_presets::Scale2D;
+use librashader_runtime::scaling::ScaleableFramebuffer;
 
 /// A handle to an OpenGL FBO and its backing texture with format and size information.
 ///
@@ -50,7 +51,7 @@ impl Framebuffer {
         &mut self,
         scaling: Scale2D,
         format: ImageFormat,
-        viewport: &Viewport<&Framebuffer>,
+        viewport: &Size<u32>,
         source_size: &Size<u32>,
         mipmap: bool,
     ) -> Result<Size<u32>> {
@@ -92,3 +93,20 @@ impl Drop for Framebuffer {
         }
     }
 }
+//
+impl<T: FramebufferInterface> ScaleableFramebuffer<T> for Framebuffer {
+    type Error = FilterChainError;
+    type Context = ();
+
+    fn scale(
+        &mut self,
+        scaling: Scale2D,
+        format: ImageFormat,
+        viewport_size: &Size<u32>,
+        source_size: &Size<u32>,
+        should_mipmap: bool,
+        _context: Self::Context,
+    ) -> Result<Size<u32>> {
+        self.scale::<T>(scaling, format, viewport_size, source_size, should_mipmap)
+    }
+}

librashader-runtime-gl/src/gl/gl3/framebuffer.rs

@@ -37,7 +37,7 @@ impl FramebufferInterface for Gl3Framebuffer {
         fb: &mut Framebuffer,
         scaling: Scale2D,
         format: ImageFormat,
-        viewport: &Viewport<&Framebuffer>,
+        viewport_size: &Size<u32>,
         source_size: &Size<u32>,
         mipmap: bool,
     ) -> Result<Size<u32>> {
@@ -45,7 +45,7 @@ impl FramebufferInterface for Gl3Framebuffer {
             return Ok(fb.size);
         }
 
-        let size = source_size.scale_viewport(scaling, viewport.output.size);
+        let size = source_size.scale_viewport(scaling, *viewport_size);
 
         if fb.size != size || (mipmap && fb.max_levels == 1) || (!mipmap && fb.max_levels != 1) {
             fb.size = size;

librashader-runtime-gl/src/gl/gl46/framebuffer.rs

@@ -35,7 +35,7 @@ impl FramebufferInterface for Gl46Framebuffer {
         fb: &mut Framebuffer,
         scaling: Scale2D,
         format: ImageFormat,
-        viewport: &Viewport<&Framebuffer>,
+        viewport_size: &Size<u32>,
         source_size: &Size<u32>,
         mipmap: bool,
     ) -> Result<Size<u32>> {
@@ -43,7 +43,7 @@ impl FramebufferInterface for Gl46Framebuffer {
             return Ok(fb.size);
         }
 
-        let size = source_size.scale_viewport(scaling, viewport.output.size);
+        let size = source_size.scale_viewport(scaling, *viewport_size);
 
         if fb.size != size || (mipmap && fb.max_levels == 1) || (!mipmap && fb.max_levels != 1) {
             fb.size = size;

librashader-runtime-gl/src/gl/mod.rs

@@ -41,7 +41,7 @@ pub trait FramebufferInterface {
         fb: &mut Framebuffer,
         scaling: Scale2D,
         format: ImageFormat,
-        viewport: &Viewport<&Framebuffer>,
+        viewport_size: &Size<u32>,
         source_size: &Size<u32>,
         mipmap: bool,
     ) -> Result<Size<u32>>;

librashader-runtime-vk/src/filter_chain.rs

@@ -31,7 +31,10 @@ use std::collections::VecDeque;
 use std::path::Path;
 use std::sync::Arc;
 
+use librashader_runtime::filter_pass::FilterPassMeta;
+use librashader_runtime::scaling::scale_framebuffers_with_context_callback;
 use rayon::prelude::*;
+
 /// A Vulkan device and metadata that is required by the shader runtime.
 pub struct VulkanObjects {
     pub(crate) device: Arc<ash::Device>,
@@ -613,25 +616,12 @@ impl FilterChainVulkan {
         );
 
         // rescale render buffers to ensure all bindings are valid.
-        let mut source_size = source.image.size;
+        scale_framebuffers_with_context_callback::<(), _, _, _, _>(
-        let mut iterator = passes.iter_mut().enumerate().peekable();
+            source.image.size,
-        while let Some((index, pass)) = iterator.next() {
+            viewport.output.size,
-            let should_mipmap = iterator
+            &mut self.output_framebuffers,
-                .peek()
+            &mut self.feedback_framebuffers,
-                .map_or(false, |(_, p)| p.config.mipmap_input);
+            &passes,
-
-            // needs a barrier to SHADER_READ_ONLY_OPTIMAL otherwise any non-filled in output framebuffers
-            // (like the final one which is just held there and not ever written to, but needs to be
-            // there for indexing) will always stay in UNDEFINED.
-            //
-            // since scaling is hopefully a rare occurrence (since it's tested for if the output size
-            // requires changing) it should be ok.
-            let next_size = self.output_framebuffers[index].scale(
-                pass.config.scaling.clone(),
-                pass.get_format(),
-                &viewport.output.size,
-                &source_size,
-                should_mipmap,
             Some(OwnedImageLayout {
                 dst_layout: vk::ImageLayout::SHADER_READ_ONLY_OPTIMAL,
                 dst_access: vk::AccessFlags::SHADER_READ,
@@ -639,33 +629,15 @@ impl FilterChainVulkan {
                 dst_stage: vk::PipelineStageFlags::FRAGMENT_SHADER,
                 cmd,
             }),
-            )?;
+            |index: usize, pass: &FilterPass, output: &OwnedImage, feedback: &OwnedImage| {
-
-            self.feedback_framebuffers[index].scale(
-                pass.config.scaling.clone(),
-                pass.get_format(),
-                &viewport.output.size,
-                &source_size,
-                should_mipmap,
-                Some(OwnedImageLayout {
-                    dst_layout: vk::ImageLayout::SHADER_READ_ONLY_OPTIMAL,
-                    dst_access: vk::AccessFlags::SHADER_READ,
-                    src_stage: vk::PipelineStageFlags::TOP_OF_PIPE,
-                    dst_stage: vk::PipelineStageFlags::FRAGMENT_SHADER,
-                    cmd,
-                }),
-            )?;
-
-            source_size = next_size;
                 // refresh inputs
-            self.common.feedback_inputs[index] = Some(
+                self.common.feedback_inputs[index] =
-                self.feedback_framebuffers[index]
+                    Some(feedback.as_input(pass.config.filter, pass.config.wrap_mode));
-                    .as_input(pass.config.filter, pass.config.wrap_mode),
+                self.common.output_inputs[index] =
-            );
+                    Some(output.as_input(pass.config.filter, pass.config.wrap_mode));
-            self.common.output_inputs[index] = Some(
+                Ok(())
-                self.output_framebuffers[index].as_input(pass.config.filter, pass.config.wrap_mode),
+            },
-            );
+        )?;
-        }
 
         let passes_len = passes.len();
         let (pass, last) = passes.split_at_mut(passes_len - 1);

librashader-runtime-vk/src/filter_pass.rs

@@ -14,6 +14,7 @@ use librashader_reflect::reflect::semantics::{
 };
 use librashader_reflect::reflect::ShaderReflection;
 use librashader_runtime::binding::{BindSemantics, TextureInput};
+use librashader_runtime::filter_pass::FilterPassMeta;
 use librashader_runtime::quad::QuadType;
 use librashader_runtime::uniforms::{NoUniformBinder, UniformStorage, UniformStorageAccess};
 use rustc_hash::FxHashMap;
@@ -73,18 +74,17 @@ impl BindSemantics<NoUniformBinder, Option<()>, RawVulkanBuffer> for FilterPass
     }
 }
 
-impl FilterPass {
+impl FilterPassMeta for FilterPass {
-    pub fn get_format(&self) -> ImageFormat {
+    fn source_format(&self) -> ImageFormat {
-        let fb_format = self.source.format;
+        self.source.format
-        if let Some(format) = self.config.get_format_override() {
+    }
-            format
+
-        } else if fb_format == ImageFormat::Unknown {
+    fn config(&self) -> &ShaderPassConfig {
-            ImageFormat::R8G8B8A8Unorm
+        &self.config
-        } else {
-            fb_format
     }
 }
 
+impl FilterPass {
     pub(crate) fn draw(
         &mut self,
         cmd: vk::CommandBuffer,

librashader-runtime-vk/src/lib.rs

@@ -45,7 +45,7 @@ mod tests {
         dbg!("finished");
         let filter = FilterChainVulkan::load_from_path(
             &base,
-            "../test/slang-shaders/border/gameboy-player/gameboy-player-crt-royale.slangp",
+            "../test/slang-shaders/crt/crt-royale.slangp",
             // "../test/slang-shaders/bezel/Mega_Bezel/Presets/MBZ__2__ADV-NO-REFLECT.slangp",
             // "../test/basic.slangp",
             Some(&FilterChainOptionsVulkan {

librashader-runtime-vk/src/texture.rs

@@ -5,9 +5,10 @@ use crate::{error, util};
 use ash::vk;
 use std::sync::Arc;
 
+use crate::error::FilterChainError;
 use librashader_common::{FilterMode, ImageFormat, Size, WrapMode};
 use librashader_presets::Scale2D;
-use librashader_runtime::scaling::{MipmapSize, ViewportSize};
+use librashader_runtime::scaling::{MipmapSize, ScaleableFramebuffer, ViewportSize};
 
 pub struct OwnedImage {
     pub device: Arc<ash::Device>,
@@ -19,6 +20,7 @@ pub struct OwnedImage {
     pub levels: u32,
 }
 
+#[derive(Copy, Clone)]
 pub struct OwnedImageLayout {
     pub(crate) dst_layout: vk::ImageLayout,
     pub(crate) dst_access: vk::AccessFlags,
@@ -533,3 +535,27 @@ impl AsRef<InputImage> for InputImage {
         self
     }
 }
+
+impl<T> ScaleableFramebuffer<T> for OwnedImage {
+    type Error = FilterChainError;
+    type Context = Option<OwnedImageLayout>;
+
+    fn scale(
+        &mut self,
+        scaling: Scale2D,
+        format: ImageFormat,
+        viewport_size: &Size<u32>,
+        source_size: &Size<u32>,
+        should_mipmap: bool,
+        context: Self::Context,
+    ) -> Result<Size<u32>, Self::Error> {
+        self.scale(
+            scaling,
+            format,
+            viewport_size,
+            source_size,
+            should_mipmap,
+            context,
+        )
+    }
+}

librashader-runtime/src/filter_pass.rs

@@ -0,0 +1,18 @@
+use librashader_common::ImageFormat;
+use librashader_presets::ShaderPassConfig;
+
+pub trait FilterPassMeta {
+    fn source_format(&self) -> ImageFormat;
+    fn config(&self) -> &ShaderPassConfig;
+
+    fn get_format(&self) -> ImageFormat {
+        let fb_format = self.source_format();
+        if let Some(format) = self.config().get_format_override() {
+            format
+        } else if fb_format == ImageFormat::Unknown {
+            ImageFormat::R8G8B8A8Unorm
+        } else {
+            fb_format
+        }
+    }
+}

librashader-runtime/src/lib.rs

@@ -28,3 +28,5 @@ pub mod binding;
 
 /// VBO helper utilities
 pub mod quad;
+
+pub mod filter_pass;

librashader-runtime/src/scaling.rs

@@ -1,5 +1,6 @@
+use crate::filter_pass::FilterPassMeta;
 use crate::scaling;
-use librashader_common::Size;
+use librashader_common::{ImageFormat, Size};
 use librashader_presets::{Scale2D, ScaleFactor, ScaleType, Scaling};
 use num_traits::AsPrimitive;
 use std::ops::Mul;
@@ -93,3 +94,92 @@ where
         height: height.round().as_(),
     }
 }
+
+/// Trait for owned framebuffer objects that can be scaled.
+pub trait ScaleableFramebuffer<T> {
+    type Error;
+    type Context: Copy;
+    /// Scale the framebuffer according to the provided parameters, returning the new size.
+    fn scale(
+        &mut self,
+        scaling: Scale2D,
+        format: ImageFormat,
+        viewport_size: &Size<u32>,
+        source_size: &Size<u32>,
+        should_mipmap: bool,
+        context: Self::Context,
+    ) -> Result<Size<u32>, Self::Error>;
+}
+
+/// Scale framebuffers according to the pass configs, source and viewport size.
+pub fn scale_framebuffers<T, F, E, P>(
+    source_size: Size<u32>,
+    viewport_size: Size<u32>,
+    output: &mut [F],
+    feedback: &mut [F],
+    passes: &[P],
+) -> Result<(), E>
+where
+    F: ScaleableFramebuffer<T, Context = (), Error = E>,
+    P: FilterPassMeta,
+{
+    scale_framebuffers_with_context_callback(
+        source_size,
+        viewport_size,
+        output,
+        feedback,
+        passes,
+        (),
+        |_, _, _, _| Ok(()),
+    )
+}
+
+/// Scale framebuffers according to the pass configs, source and viewport size
+/// passing a context into the scale function and a callback for each framebuffer rescale.
+pub fn scale_framebuffers_with_context_callback<T, F, E, C, P>(
+    source_size: Size<u32>,
+    viewport_size: Size<u32>,
+    output: &mut [F],
+    feedback: &mut [F],
+    passes: &[P],
+    context: C,
+    mut callback: impl FnMut(usize, &P, &F, &F) -> Result<(), E>,
+) -> Result<(), E>
+where
+    F: ScaleableFramebuffer<T, Context = C, Error = E>,
+    C: Copy,
+    P: FilterPassMeta,
+{
+    assert_eq!(output.len(), feedback.len());
+    let mut iterator = passes.iter().enumerate().peekable();
+    let mut target_size = source_size;
+    while let Some((index, pass)) = iterator.next() {
+        let should_mipmap = iterator
+            .peek()
+            .map_or(false, |(_, p)| p.config().mipmap_input);
+
+        let next_size = output[index].scale(
+            pass.config().scaling.clone(),
+            pass.get_format(),
+            &viewport_size,
+            &target_size,
+            should_mipmap,
+            context,
+        )?;
+
+        feedback[index].scale(
+            pass.config().scaling.clone(),
+            pass.get_format(),
+            &viewport_size,
+            &target_size,
+            should_mipmap,
+            context,
+        )?;
+
+        target_size = next_size;
+
+        callback(index, &pass, &output[index], &feedback[index])?;
+    }
+
+    Ok(())
+}