depth to color map filters as a part of kinect common support

orx-kinect-common/src/main/kotlin/Kinect.kt

@@ -2,6 +2,7 @@ package org.openrndr.extra.kinect
 
 import org.openrndr.Extension
 import org.openrndr.draw.*
+import org.openrndr.resourceUrl
 import java.lang.RuntimeException
 
 /**
@@ -10,11 +11,13 @@ import java.lang.RuntimeException
  * @param <CTX> data needed to make low level kinect support calls.
  */
 interface Kinects<CTX> {
+
     fun countDevices(): Int
 
     /**
      * Starts kinect device of a given number.
      *
+     * @param num the kinect device index.
      * @throws KinectException if device of such a number does not exist,
      *          better to count them first.
      * @see countDevices
@@ -24,7 +27,8 @@ interface Kinects<CTX> {
     /**
      * Executes low level Kinect commands in the kinect thread.
      */
-    fun execute(commands: (CTX) -> Any) : Any
+    fun <T> execute(commands: (CTX) -> T) : T
+
 }
 
 /**
@@ -38,7 +42,7 @@ interface KinectDevice<CTX> : Extension {
     /**
      * Executes low level Kinect commands in the kinect thread in the context of this device.
      */
-    fun execute(commands: (CTX) -> Any): Any
+    fun <T> execute(commands: (CTX) -> T): T
 }
 
 interface KinectCamera {
@@ -55,3 +59,31 @@ interface KinectDepthCamera : KinectCamera {
 }
 
 class KinectException(msg: String) : RuntimeException(msg)
+
+/**
+ * Maps depth values to grayscale.
+ */
+class DepthToGrayscaleMapper : Filter(
+        filterShaderFromUrl(resourceUrl("depth-to-grayscale.frag", Kinects::class.java))
+)
+
+/**
+ * Maps depth values to color map according to natural light dispersion as described
+ * by Alan Zucconi in the
+ * <a href="https://www.alanzucconi.com/2017/07/15/improving-the-rainbow/">Improving the Rainbow</a>
+ * article.
+ */
+class DepthToColorsZucconi6Mapper : Filter(
+        filterShaderFromUrl(resourceUrl("depth-to-colors-zucconi6.frag", Kinects::class.java))
+)
+
+/**
+ * Maps depth values to color map according to
+ * <a href="https://ai.googleblog.com/2019/08/turbo-improved-rainbow-colormap-for.html">
+ *     Turbo, An Improved Rainbow Colormap for Visualization
+ * </a>
+ * by Google.
+ */
+class DepthToColorsTurboMapper : Filter(
+        filterShaderFromUrl(resourceUrl("depth-to-colors-turbo.frag", Kinects::class.java))
+)

orx-kinect-common/src/main/resources/org/openrndr/extra/kinect/depth-to-colors-turbo.frag

@@ -0,0 +1,41 @@
+#version 330
+
+uniform sampler2D tex0;
+out     vec3 color;
+
+float saturate(in float x) {
+    return max(0, min(1, x));
+}
+
+// Copyright 2019 Google LLC.
+// SPDX-License-Identifier: Apache-2.0
+
+// Polynomial approximation in GLSL for the Turbo colormap
+// Original LUT: https://gist.github.com/mikhailov-work/ee72ba4191942acecc03fe6da94fc73f
+
+// Authors:
+//   Colormap Design: Anton Mikhailov (mikhailov@google.com)
+//   GLSL Approximation: Ruofei Du (ruofei@google.com)
+
+vec3 TurboColormap(in float x) {
+    const vec4 kRedVec4 = vec4(0.13572138, 4.61539260, -42.66032258, 132.13108234);
+    const vec4 kGreenVec4 = vec4(0.09140261, 2.19418839, 4.84296658, -14.18503333);
+    const vec4 kBlueVec4 = vec4(0.10667330, 12.64194608, -60.58204836, 110.36276771);
+    const vec2 kRedVec2 = vec2(-152.94239396, 59.28637943);
+    const vec2 kGreenVec2 = vec2(4.27729857, 2.82956604);
+    const vec2 kBlueVec2 = vec2(-89.90310912, 27.34824973);
+
+    x = saturate(x);
+    vec4 v4 = vec4( 1.0, x, x * x, x * x * x);
+    vec2 v2 = v4.zw * v4.z;
+    return vec3(
+    dot(v4, kRedVec4)   + dot(v2, kRedVec2),
+    dot(v4, kGreenVec4) + dot(v2, kGreenVec2),
+    dot(v4, kBlueVec4)  + dot(v2, kBlueVec2)
+    );
+}
+
+void main() {
+    float depth = texelFetch(tex0, ivec2(int(gl_FragCoord.x), int(gl_FragCoord.y)), 0).r;
+    color = (depth >= .999) ? vec3(0) : TurboColormap(depth);
+}

orx-kinect-common/src/main/resources/org/openrndr/extra/kinect/depth-to-colors-zucconi6.frag

@@ -0,0 +1,68 @@
+#version 330
+
+uniform sampler2D tex0;             // kinect raw
+out     vec3 color;
+
+// Spectral Colour Schemes
+// By Alan Zucconi
+// Website: www.alanzucconi.com
+// Twitter: @AlanZucconi
+
+// Example of different spectral colour schemes
+// to convert visible wavelengths of light (400-700 nm) to RGB colours.
+
+// The function "spectral_zucconi6" provides the best approximation
+// without including any branching.
+// Its faster version, "spectral_zucconi", is advised for mobile applications.
+
+
+// Read "Improving the Rainbow" for more information
+// http://www.alanzucconi.com/?p=6703
+
+
+
+float saturate (float x)
+{
+    return min(1.0, max(0.0,x));
+}
+vec3 saturate (vec3 x)
+{
+    return min(vec3(1.,1.,1.), max(vec3(0.,0.,0.),x));
+}
+
+// --- Spectral Zucconi --------------------------------------------
+// By Alan Zucconi
+// Based on GPU Gems: https://developer.nvidia.com/sites/all/modules/custom/gpugems/books/GPUGems/gpugems_ch08.html
+// But with values optimised to match as close as possible the visible spectrum
+// Fits this: https://commons.wikimedia.org/wiki/File:Linear_visible_spectrum.svg
+// With weighter MSE (RGB weights: 0.3, 0.59, 0.11)
+vec3 bump3y (vec3 x, vec3 yoffset)
+{
+    vec3 y = vec3(1.,1.,1.) - x * x;
+    y = saturate(y-yoffset);
+    return y;
+}
+
+// --- Spectral Zucconi 6 --------------------------------------------
+
+// Based on GPU Gems
+// Optimised by Alan Zucconi
+vec3 spectral_zucconi6 (float x)
+{
+    const vec3 c1 = vec3(3.54585104, 2.93225262, 2.41593945);
+    const vec3 x1 = vec3(0.69549072, 0.49228336, 0.27699880);
+    const vec3 y1 = vec3(0.02312639, 0.15225084, 0.52607955);
+
+    const vec3 c2 = vec3(3.90307140, 3.21182957, 3.96587128);
+    const vec3 x2 = vec3(0.11748627, 0.86755042, 0.66077860);
+    const vec3 y2 = vec3(0.84897130, 0.88445281, 0.73949448);
+
+    return
+    bump3y(c1 * (x - x1), y1) +
+    bump3y(c2 * (x - x2), y2) ;
+}
+
+void main() {
+    float depth = texelFetch(tex0, ivec2(int(gl_FragCoord.x), int(gl_FragCoord.y)), 0).r;
+    color = (depth >= .999) ? vec3(0) : spectral_zucconi6(depth);
+}

orx-kinect-common/src/main/resources/org/openrndr/extra/kinect/depth-to-grayscale.frag

@@ -0,0 +1,9 @@
+#version 330
+
+uniform sampler2D tex0;
+out     vec3 color;
+
+void main() {
+    float depth = texelFetch(tex0, ivec2(int(gl_FragCoord.x), int(gl_FragCoord.y)), 0).r;
+    color = (depth >= .999) ? vec3(0) : vec3(depth);
+}