fix(datasource/graphene) multicut tool no longer relies on showing segment zero in order to color it black (has the negative effect of giving it a highlight color when hovering above it, which is problematic for volume rendering)

Author: chrisj

src/datasource/graphene/frontend.ts

@@ -226,6 +226,7 @@ const RED_COLOR_SEGMENT_PACKED = BigInt(packColor(RED_COLOR_SEGMENT));
 const BLUE_COLOR_SEGMENT_PACKED = BigInt(packColor(BLUE_COLOR_SEGMENT));
 const TRANSPARENT_COLOR_PACKED = BigInt(packColor(TRANSPARENT_COLOR));
 const MULTICUT_OFF_COLOR = vec4.fromValues(0, 0, 0, 0.5);
+const MULTICUT_OFF_COLOR_PACKED = BigInt(packColor(MULTICUT_OFF_COLOR));
 const WHITE_COLOR = vec3.fromValues(1, 1, 1);
 
 class GrapheneMeshSource extends WithParameters(
@@ -2767,14 +2768,12 @@ class MulticutSegmentsTool extends LayerTool<SegmentationUserLayer> {
     const priorBaseSegmentHighlighting =
       displayState.baseSegmentHighlighting.value;
     const priorHighlightColor = displayState.highlightColor.value;
-    const priorHideSegmentZero = displayState.hideSegmentZero.value;
 
     activation.bindInputEventMap(MULTICUT_SEGMENTS_INPUT_EVENT_MAP);
     activation.registerDisposer(() => {
       resetMulticutDisplay();
       displayState.baseSegmentHighlighting.value = priorBaseSegmentHighlighting;
       displayState.highlightColor.value = priorHighlightColor;
-      displayState.hideSegmentZero.value = priorHideSegmentZero;
     });
     const resetMulticutDisplay = () => {
       resetTemporaryVisibleSegmentsState(segmentationGroupState);
@@ -2795,7 +2794,6 @@ class MulticutSegmentsTool extends LayerTool<SegmentationUserLayer> {
       displayState.highlightColor.value = multicutState.blueGroup.value
         ? BLUE_COLOR_HIGHTLIGHT
         : RED_COLOR_HIGHLIGHT;
-      displayState.hideSegmentZero.value = false;
       segmentsState.useTemporaryVisibleSegments.value = true;
       segmentsState.useTemporarySegmentEquivalences.value = true;
       // add focus segment and red/blue segments
@@ -2820,6 +2818,10 @@ class MulticutSegmentsTool extends LayerTool<SegmentationUserLayer> {
         focusSegment,
         TRANSPARENT_COLOR_PACKED,
       );
+      displayState.tempSegmentStatedColors2d.value.set(
+        0n,
+        MULTICUT_OFF_COLOR_PACKED,
+      );
       for (const segment of multicutState.redSegments) {
         displayState.tempSegmentStatedColors2d.value.set(
           segment,

src/sliceview/volume/segmentation_renderlayer.ts

@@ -267,9 +267,48 @@ uint64_t getMappedObjectId(uint64_t value) {
   float alpha = uSelectedAlpha;
   float saturation = uSaturation;
 `;
+
+    let getMappedIdColor = `vec4 getMappedIdColor(uint64_t value) {
+  `;
+    // If the value has a mapped color, use it; otherwise, compute the color.
+
+    // specific color, highlight ok
+    if (parameters.hasSegmentStatedColors) {
+      this.segmentStatedColorShaderManager.defineShader(builder);
+      getMappedIdColor += `
+    vec4 rgba;
+    if (${this.segmentStatedColorShaderManager.getFunctionName}(value, rgba)) {
+      return rgba;
+    }
+  `;
+    }
+    if (parameters.hasSegmentDefaultColor) {
+      builder.addUniform("highp vec4", "uSegmentDefaultColor");
+      getMappedIdColor += `  return uSegmentDefaultColor;
+  `;
+    } else {
+      this.segmentColorShaderManager.defineShader(builder);
+      getMappedIdColor += `  return vec4(segmentColorHash(value), 0.0);
+  `;
+    }
+    getMappedIdColor += `
+  }
+  `;
+    builder.addFragmentCode(getMappedIdColor);
+
     if (parameters.hideSegmentZero) {
       fragmentMain += `
-  if (value.value[0] == 0u && value.value[1] == 0u) {
+  if (value.value[0] == 0u && value.value[1] == 0u) {`;
+      if (parameters.hasSegmentStatedColors) {
+        fragmentMain += `
+    vec4 rgba;
+    if (${this.segmentStatedColorShaderManager.getFunctionName}(valueForColor, rgba)) {
+      emit(vec4(mix(vec3(1.0,1.0,1.0), vec3(rgba), saturation), alpha));
+      return;
+    }
+  `;
+      }
+      fragmentMain += `
     emit(vec4(vec4(0, 0, 0, 0)));
     return;
   }
@@ -297,32 +336,6 @@ uint64_t getMappedObjectId(uint64_t value) {
     alpha = uNotSelectedAlpha;
   }
 `;
-    let getMappedIdColor = `vec4 getMappedIdColor(uint64_t value) {
-`;
-    // If the value has a mapped color, use it; otherwise, compute the color.
-    if (parameters.hasSegmentStatedColors) {
-      this.segmentStatedColorShaderManager.defineShader(builder);
-      getMappedIdColor += `
-  vec4 rgba;
-  if (${this.segmentStatedColorShaderManager.getFunctionName}(value, rgba)) {
-    return rgba;
-  }
-`;
-    }
-    if (parameters.hasSegmentDefaultColor) {
-      builder.addUniform("highp vec4", "uSegmentDefaultColor");
-      getMappedIdColor += `  return uSegmentDefaultColor;
-`;
-    } else {
-      this.segmentColorShaderManager.defineShader(builder);
-      getMappedIdColor += `  return vec4(segmentColorHash(value), 0.0);
-`;
-    }
-    getMappedIdColor += `
-}
-`;
-    builder.addFragmentCode(getMappedIdColor);
-
     fragmentMain += `
   vec4 rgba = getMappedIdColor(valueForColor);
   if (rgba.a > 0.0) {