Implement 16bit color decoding

aardvark-platform · Jan 10, 2023 · 2f2b94d · 2f2b94d
1 parent 5692b05
commit 2f2b94d
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Showing 2 changed files with 121 additions and 15 deletions.
diff --git a/src/Aardvark.PixImage.Pfim.Tests/Dds.fs b/src/Aardvark.PixImage.Pfim.Tests/Dds.fs
@@ -43,16 +43,16 @@ module DdsTests =
                     [| 0; 28; 74 |]
                     [| 189; 0; 16 |]
                     [| 16; 174; 0 |]
-                    [| 172; 161; 0 |]
+                    [| 173; 162; 0 |]
                 |]
                 |> Array.map (Array.map uint8)
 
             let rgb5a1 =
                 [|
-                    [| 0; 32; 74; 255 |]
+                    [| 0; 33; 74; 255 |]
                     [| 189; 0; 16; 255 |]
-                    [| 16; 172; 0; 255 |]
-                    [| 172; 164; 0; 255 |]
+                    [| 16; 173; 0; 255 |]
+                    [| 173; 165; 0; 255 |]
                 |]
                 |> Array.map (Array.map uint8)
 
@@ -252,11 +252,9 @@ module DdsTests =
             // Broken: Pfim parses as grayscale
             // testCase "Dds.R3G3B2 mipmapped"                 Cases.r3g3b2Mipmapped
 
-            // TODO: Implement us!
-            //testCase "Dds.R5G6B5 mipmapped"                 Cases.r5g6b5Mipmapped
-            //testCase "Dds.RGB5A1 mipmapped"                 Cases.rgb5a1Mipmapped
-            //testCase "Dds.RGBA4 mipmapped"                  Cases.rgba4Mipmapped
-
+            testCase "Dds.R5G6B5 mipmapped"                 Cases.r5g6b5Mipmapped
+            testCase "Dds.RGB5A1 mipmapped"                 Cases.rgb5a1Mipmapped
+            testCase "Dds.RGBA4 mipmapped"                  Cases.rgba4Mipmapped
             testCase "Dds.L8 mipmapped"                     Cases.l8Mipmapped
 
             // Broken: Pfim parses as r5g5b5a1

diff --git a/src/Aardvark.PixImage.Pfim/PixImagePfim.fs b/src/Aardvark.PixImage.Pfim/PixImagePfim.fs
@@ -2,6 +2,7 @@
 
 open System
 open System.IO
+open FSharp.NativeInterop
 open Pfim
 
 #nowarn "9"
@@ -21,10 +22,41 @@ module private PixImagePfimImpl =
             if isNull x.MipMaps then 1
             else x.MipMaps.Length + 1
 
+    [<AutoOpen>]
+    module private ColorUtilities =
+
+        module Bits =
+
+            module Tables =
+
+                let expand1 =
+                    Array.init 2 (fun i -> uint8 (i * 255))
+
+                let expand4 =
+                    Array.init 16 (fun i -> uint8 (i * 17))
+
+                let expand5 =
+                    Array.init 32 (fun i -> uint8 ((i <<< 3) ||| (i >>> 2)))
+
+                let expand6 =
+                    Array.init 64 (fun i -> uint8 ((i <<< 2) ||| (i >>> 4)))
+
+            let inline expand1 x =
+                Tables.expand1.[int x]
+
+            let inline expand4 x =
+                Tables.expand4.[int x]
+
+            let inline expand5 x =
+                Tables.expand5.[int x]
+
+            let inline expand6 x =
+                Tables.expand6.[int x]
+
     // Note: The default allocator of Pfim just allocates a new array, so
     // we can just use it without worrying about it being reused when the original
     // IImage is disposed.
-    let private of8Bit (format : Col.Format) (info : MipMapOffset) (src : uint8[]) =
+    let private of8Bit (format : Col.Format) (info : MipMapOffset) (src : uint8[]) : PixImage =
         let channels =
             format.ChannelCount()
 
@@ -38,17 +70,93 @@ module private PixImagePfimImpl =
                 )
             )
 
-        PixImage<uint8>(format, volume) :> PixImage
+        PixImage<uint8>(format, volume)
+
+    let private of16Bit (format : Col.Format) (decode : uint16 -> C4b) (info : MipMapOffset) (src : uint8[]) : PixImage =
+        if info.Stride % 2 <> 0 then
+            failwith $"Stride is odd ({info.Stride})."
+
+        let pi = PixImage<uint8>(format, int64 info.Width, int64 info.Height)
+
+        pinned src (fun src ->
+            let srcVolume =
+                NativeVolume<uint16>(
+                    NativePtr.ofNativeInt (src + nativeint info.DataOffset),
+                    VolumeInfo(
+                        0L,
+                        V3l(info.Width, info.Height, 1),
+                        V3l(1, info.Stride / 2, 1)
+                    )
+                )
+
+            PixImage.pin pi (fun dst ->
+                let dstVolume =
+                    NativeVolume<uint8>(
+                        dst.Pointer,
+                        VolumeInfo(dst.Origin, dst.Size.XYI, dst.Delta)
+                    )
+
+                (srcVolume, dstVolume) ||> NativeVolume.iterPtr2 (fun _ src dst ->
+                    let color = decode <| NativePtr.read src
+                    NativePtr.set dst 0 color.B
+                    NativePtr.set dst 1 color.G
+                    NativePtr.set dst 2 color.R
+                    NativePtr.set dst 3 color.A
+                )
+            )
+        )
+
+        pi
+
+    let private ofRGBA16 =
+        of16Bit Col.Format.BGRA (fun pixel ->
+            let b = pixel &&& 0xFus
+            let g = (pixel >>> 4) &&& 0xFus
+            let r = (pixel >>> 8) &&& 0xFus
+            let a = (pixel >>> 12) &&& 0xFus
+            C4b(
+                Bits.expand4 r,
+                Bits.expand4 g,
+                Bits.expand4 b,
+                Bits.expand4 a
+            )
+        )
+
+    let private ofR5G5B5A1 (withAlpha : bool) =
+        of16Bit Col.Format.BGRA (fun pixel ->
+            let b = pixel &&& 0x1Fus
+            let g = (pixel >>> 5) &&& 0x1Fus
+            let r = (pixel >>> 10) &&& 0x1Fus
+            let a = (pixel >>> 15) &&& 0x1us
+            C4b(
+                Bits.expand5 r,
+                Bits.expand5 g,
+                Bits.expand5 b,
+                if withAlpha then Bits.expand1 a else 255uy
+            )
+        )
+
+    let private ofR5G6B5 =
+        of16Bit Col.Format.BGR (fun pixel ->
+            let b = pixel &&& 0x1Fus
+            let g = (pixel >>> 5) &&& 0x3Fus
+            let r = (pixel >>> 11) &&& 0x1Fus
+            C4b(
+                Bits.expand5 r,
+                Bits.expand6 g,
+                Bits.expand5 b
+            )
+        )
 
-    // TODO: Implement missing formats
     let private levelToPixImageTable : (ImageFormat -> (MipMapOffset -> uint8[] -> PixImage) option) =
         LookupTable.lookupTable' [
             ImageFormat.Rgb8,     of8Bit Col.Format.Gray
             ImageFormat.Rgb24,    of8Bit Col.Format.BGR
             ImageFormat.Rgba32,   of8Bit Col.Format.BGRA
-            //ImageFormat.R5g5b5
-            //ImageFormat.R5g6b5
-            //ImageFormat.R5g5b5a1
+            ImageFormat.Rgba16,   ofRGBA16
+            ImageFormat.R5g5b5,   ofR5G5B5A1 false
+            ImageFormat.R5g6b5,   ofR5G6B5
+            ImageFormat.R5g5b5a1, ofR5G5B5A1 true
         ]
 
     let private levelToPixImage (format : ImageFormat) =