Expose new LambertHillshader

breki · May 26, 2024 · 2b6f508 · 2b6f508
1 parent c381db4
commit 2b6f508
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Showing 10 changed files with 93 additions and 39 deletions.
diff --git a/Demeton.Tests/Aw3d/AW3D experiments.fs b/Demeton.Tests/Aw3d/AW3D experiments.fs
@@ -93,7 +93,6 @@ let ``Generate hillshading from AW3D`` () =
     let pixelShader =
         IgorHillshader.shadePixel
             { SunAzimuth = IgorHillshader.DefaultSunAzimuth |> degToRad
-              SunAltitude = IgorHillshader.DefaultSunAltitude |> degToRad
               ShadingColor = 0u
               Intensity = 1.
               HeightsArrayIndex = 0 }

diff --git a/Demeton.Tests/Commands tests/TileShadeCommand/Calculating geo area needed.fs b/Demeton.Tests/Commands tests/TileShadeCommand/Calculating geo area needed.fs
@@ -20,7 +20,7 @@ let ``Geo area needed is calculated correctly`` () =
           IgorHillshadingIntensity = 1.
           SlopeShadingIntensity = 1.
           SunAzimuth = IgorHillshader.DefaultSunAzimuth |> degToRad
-          SunAltitude = IgorHillshader.DefaultSunAltitude |> degToRad
+          SunAltitude = LambertHillshader.DefaultSunAltitude |> degToRad
           WaterBodiesColor = "#49C8FF" |> Png.Rgba8Bit.parseColorHexValue
           LocalCacheDir = TileShadeCommand.DefaultLocalCacheDir
           OutputDir = TileShadeCommand.DefaultOutputDir

diff --git a/Demeton.Tests/Commands tests/TileShadeCommand/Creating map projection.fs b/Demeton.Tests/Commands tests/TileShadeCommand/Creating map projection.fs
@@ -18,7 +18,7 @@ let ``Projection is created`` () =
           IgorHillshadingIntensity = 1.
           SlopeShadingIntensity = 1.
           SunAzimuth = IgorHillshader.DefaultSunAzimuth |> degToRad
-          SunAltitude = IgorHillshader.DefaultSunAltitude |> degToRad
+          SunAltitude = LambertHillshader.DefaultSunAltitude |> degToRad
           WaterBodiesColor = "#49C8FF" |> Png.Rgba8Bit.parseColorHexValue
           LocalCacheDir = TileShadeCommand.DefaultLocalCacheDir
           OutputDir = TileShadeCommand.DefaultOutputDir

diff --git a/Demeton.Tests/Shaders/Building igor hillshading step.fs b/Demeton.Tests/Shaders/Building igor hillshading step.fs
@@ -1,6 +1,5 @@
 module Tests.Shaders.``Building igor hillshading step``
 
-open Demeton.Shaders
 open Demeton.Shaders.Pipeline.Common
 open Demeton.Shaders.Pipeline.Parsing
 open Demeton.Shaders.Pipeline.BuildingIgorHillshading
@@ -26,7 +25,6 @@ let ``Can parse step without parameters`` () =
             step = Ok(
                 IgorHillshading(
                     { SunAzimuth = degToRad -45.
-                      SunAltitude = IgorHillshader.DefaultSunAltitude
                       ShadingColor = 0u
                       Intensity = 1.
                       HeightsArrayIndex = 0 }
@@ -49,7 +47,6 @@ let ``Can parse step with valid parameters`` () =
             step = Ok(
                 IgorHillshading(
                     { SunAzimuth = degToRad -90.
-                      SunAltitude = IgorHillshader.DefaultSunAltitude
                       ShadingColor = 0x333333ffu
                       Intensity = 1.
                       HeightsArrayIndex = 0 }

diff --git a/Demeton.Tests/Shaders/Hillshading/Igor's shading method.fs b/Demeton.Tests/Shaders/Hillshading/Igor's shading method.fs
@@ -86,7 +86,6 @@ let ``Igor shading properties test`` () =
             col: Rgba8Bit.RgbaColor
         ) : IgorHillshader.ShaderParameters =
         { SunAzimuth = az
-          SunAltitude = IgorHillshader.DefaultSunAltitude
           ShadingColor = col
           Intensity = 1.
           HeightsArrayIndex = 0 }

diff --git a/Demeton/Commands/TileShadeCommand.fs b/Demeton/Commands/TileShadeCommand.fs
@@ -163,7 +163,7 @@ let supportedParameters: CommandParameter[] =
        Option.build SunAltitudeParameter
        |> Option.desc
            "The altitude of the sun in degrees, 0° representing the horizon (default is 45°)."
-       |> Option.defaultValue IgorHillshader.DefaultSunAltitude
+       |> Option.defaultValue LambertHillshader.DefaultSunAltitude
        |> Option.asFloat
        |> Option.toPar
 
@@ -205,7 +205,7 @@ let fillOptions parsedParameters =
           IgorHillshadingIntensity = 1.
           SlopeShadingIntensity = 1.
           SunAzimuth = IgorHillshader.DefaultSunAzimuth |> degToRad
-          SunAltitude = IgorHillshader.DefaultSunAltitude |> degToRad
+          SunAltitude = LambertHillshader.DefaultSunAltitude |> degToRad
           WaterBodiesColor = defaultWaterBodiesColor
           LocalCacheDir = DefaultLocalCacheDir
           OutputDir = DefaultOutputDir
@@ -462,6 +462,13 @@ let run (options: Options) : Result<unit, string> =
 
     let igorHillshadingStep =
         ShadingStep.IgorHillshading
+            { SunAzimuth = options.SunAzimuth
+              ShadingColor = 0u
+              Intensity = options.IgorHillshadingIntensity
+              HeightsArrayIndex = 0 }
+
+    let lambertHillshadingStep =
+        ShadingStep.LambertHillshading
             { SunAzimuth = options.SunAzimuth
               SunAltitude = options.SunAltitude
               ShadingColor = 0u
@@ -477,7 +484,7 @@ let run (options: Options) : Result<unit, string> =
 
     let hillshadingStep =
         Compositing(
-            igorHillshadingStep,
+            lambertHillshadingStep,
             slopeShadingStep,
             CompositingFuncIdAlphaDarken
         )

diff --git a/Demeton/Demeton.fsproj b/Demeton/Demeton.fsproj
@@ -80,6 +80,7 @@
         <Compile Include="Shaders\SlopeShader.fs"/>
         <Compile Include="Shaders\AspectShader.fs"/>
         <Compile Include="Shaders\IgorHillshader.fs"/>
+        <Compile Include="Shaders\LambertHillshader.fs"/>
         <Compile Include="Shaders\Pipeline\Common.fs"/>
         <Compile Include="Shaders\Pipeline\Parsing.fs"/>
         <Compile Include="Shaders\Pipeline\Building.fs"/>

diff --git a/Demeton/Shaders/IgorHillshader.fs b/Demeton/Shaders/IgorHillshader.fs
@@ -11,20 +11,15 @@ type ShaderParameters =
     {
       // https://en.wikipedia.org/wiki/Azimuth
       SunAzimuth: float
-      SunAltitude: float
       ShadingColor: Rgba8Bit.RgbaColor
       Intensity: float
       HeightsArrayIndex: int }
 
 [<Literal>]
 let DefaultSunAzimuth = -45.
 
-[<Literal>]
-let DefaultSunAltitude = 45.
-
 let defaultParameters =
-    { SunAzimuth = DefaultSunAzimuth |> degToRad
-      SunAltitude = DefaultSunAltitude |> degToRad
+    { SunAzimuth = degToRad DefaultSunAzimuth
       ShadingColor = 0u
       Intensity = 1.
       HeightsArrayIndex = 0 }
@@ -34,29 +29,15 @@ let shadePixel parameters : Hillshading.PixelHillshader =
         match Double.IsNaN(aspect) with
         | true -> Rgba8Bit.TransparentColor
         | false ->
-            // let aspectDiff =
-            //     differenceBetweenAngles
-            //         aspect
-            //         parameters.SunAzimuth
-            //         (Math.PI * 2.)
-            //
-            // // "darkness" is a value from 0 (bright) to 1 (dark)
-            // let slopeDarkness = slope / (Math.PI / 2.)
-            // let aspectDarkness = aspectDiff / Math.PI
-            // let darkness = slopeDarkness * aspectDarkness * parameters.Intensity
-
-            let cosSolarElevation = sin parameters.SunAltitude
-            let sinSolarElevation = cos parameters.SunAltitude
-            let cosAspectMinusAzimuth = cos (aspect - parameters.SunAzimuth)
-            let sinSlope = sin slope
-
-            let darkness =
-                (cosSolarElevation * cos slope)
-                + (sinSolarElevation * sinSlope * cosAspectMinusAzimuth)
-                |> max 0.0
-                |> min 1.0 // Ensure positive values
-
-            let darkness = 1. - darkness
+            let aspectDiff =
+                differenceBetweenAngles
+                    aspect
+                    parameters.SunAzimuth
+                    (Math.PI * 2.)
+
+            let slopeDarkness = slope / (Math.PI / 2.)
+            let aspectDarkness = aspectDiff / Math.PI
+            let darkness = slopeDarkness * aspectDarkness * parameters.Intensity
 
             let alpha = Hillshading.colorComponentRatioToByte darkness
 

diff --git a/Demeton/Shaders/LambertHillshader.fs b/Demeton/Shaders/LambertHillshader.fs
@@ -0,0 +1,63 @@
+[<RequireQualifiedAccess>]
+module Demeton.Shaders.LambertHillshader
+
+open Demeton.Shaders
+open Demeton.Geometry.Common
+open Png
+
+open System
+
+type ShaderParameters =
+    {
+      // https://en.wikipedia.org/wiki/Azimuth
+      SunAzimuth: float
+      SunAltitude: float
+      ShadingColor: Rgba8Bit.RgbaColor
+      Intensity: float
+      HeightsArrayIndex: int }
+
+[<Literal>]
+let DefaultSunAzimuth = -45.
+
+[<Literal>]
+let DefaultSunAltitude = 45.
+
+let defaultParameters =
+    { SunAzimuth = DefaultSunAzimuth |> degToRad
+      SunAltitude = DefaultSunAltitude |> degToRad
+      ShadingColor = 0u
+      Intensity = 1.
+      HeightsArrayIndex = 0 }
+
+let shadePixel parameters : Hillshading.PixelHillshader =
+    fun _ slope aspect ->
+        match Double.IsNaN(aspect) with
+        | true -> Rgba8Bit.TransparentColor
+        | false ->
+            // let aspectDiff =
+            //     differenceBetweenAngles
+            //         aspect
+            //         parameters.SunAzimuth
+            //         (Math.PI * 2.)
+            //
+            // // "darkness" is a value from 0 (bright) to 1 (dark)
+            // let slopeDarkness = slope / (Math.PI / 2.)
+            // let aspectDarkness = aspectDiff / Math.PI
+            // let darkness = slopeDarkness * aspectDarkness * parameters.Intensity
+
+            let cosSolarElevation = sin parameters.SunAltitude
+            let sinSolarElevation = cos parameters.SunAltitude
+            let cosAspectMinusAzimuth = cos (aspect - parameters.SunAzimuth)
+            let sinSlope = sin slope
+
+            let darkness =
+                (cosSolarElevation * cos slope)
+                + (sinSolarElevation * sinSlope * cosAspectMinusAzimuth)
+                |> max 0.0
+                |> min 1.0 // Ensure positive values
+
+            let darkness = 1. - darkness
+
+            let alpha = Hillshading.colorComponentRatioToByte darkness
+
+            parameters.ShadingColor |> Rgba8Bit.withAlpha alpha
diff --git a/Demeton/Shaders/Pipeline/Common.fs b/Demeton/Shaders/Pipeline/Common.fs
@@ -21,6 +21,7 @@ type ShadingStep =
     | SolidBackground of SolidBackground.Parameters
     | ElevationColoring of ElevationColoring.Parameters
     | IgorHillshading of IgorHillshader.ShaderParameters
+    | LambertHillshading of LambertHillshader.ShaderParameters
     | SlopeShading of SlopeShader.ShaderParameters
     | AspectShading of AspectShader.ShaderParameters
     | CustomShading of ShadingFuncId
@@ -127,6 +128,12 @@ let rec executeShadingStep
                 Hillshading.shadeRaster
                     parameters.HeightsArrayIndex
                     (IgorHillshader.shadePixel parameters)
+            | LambertHillshading parameters ->
+                Log.info "Running lambert hillshading step..."
+
+                Hillshading.shadeRaster
+                    parameters.HeightsArrayIndex
+                    (LambertHillshader.shadePixel parameters)
             | SlopeShading parameters ->
                 Log.info "Running slope shading step..."