fix(imageOutline): fix the bug where outline was not showing without …

…filling
Kitware · Feb 16, 2024 · e7b0968 · e7b0968
1 parent d6a4380
commit e7b0968
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Showing 2 changed files with 52 additions and 43 deletions.
diff --git a/Sources/Rendering/OpenGL/ImageMapper/index.js b/Sources/Rendering/OpenGL/ImageMapper/index.js
@@ -346,37 +346,41 @@ function vtkOpenGLImageMapper(publicAPI, model) {
                   float textureValue = texture2D(labelOutlineTexture1, vec2(textureCoordinate, 0.5)).r;
                   int actualThickness = int(textureValue * 255.0);
 
+                  if (segmentIndex == 0){
+                    gl_FragData[0] = vec4(0.0, 1.0, 1.0, 0.0);
+                    return;
+                  }
+
                   if (actualThickness == 0) {
                     gl_FragData[0] = vec4(0.0, 0.0, 1.0, 1.0);
                     return;
                   }
-                  if (opacityToUse > 0.01) {
-                    for (int i = -actualThickness; i <= actualThickness; i++) {
-                      for (int j = -actualThickness; j <= actualThickness; j++) {
-                        if (i == 0 || j == 0) {
-                          continue;
-                        }
-                        vec4 neighborPixelCoord = vec4(gl_FragCoord.x + float(i),
-                          gl_FragCoord.y + float(j),
-                          gl_FragCoord.z, gl_FragCoord.w);
-                        vec3 neighborPosIS = fragCoordToIndexSpace(neighborPixelCoord);
-                        float value = texture2D(texture1, neighborPosIS.xy).r;
-                        if (value != centerValue) {
-                          pixelOnBorder = true;
-                          break;
-                        }
+
+                  for (int i = -actualThickness; i <= actualThickness; i++) {
+                    for (int j = -actualThickness; j <= actualThickness; j++) {
+                      if (i == 0 || j == 0) {
+                        continue;
                       }
-                      if (pixelOnBorder == true) {
+                      vec4 neighborPixelCoord = vec4(gl_FragCoord.x + float(i),
+                        gl_FragCoord.y + float(j),
+                        gl_FragCoord.z, gl_FragCoord.w);
+                      vec3 neighborPosIS = fragCoordToIndexSpace(neighborPixelCoord);
+                      float value = texture2D(texture1, neighborPosIS.xy).r;
+                      if (value != centerValue) {
+                        pixelOnBorder = true;
                         break;
                       }
                     }
                     if (pixelOnBorder == true) {
-                      gl_FragData[0] = vec4(tColor, outlineOpacity);
-                    }
-                    else {
-                      gl_FragData[0] = vec4(tColor, opacityToUse);
+                      break;
                     }
                   }
+                  if (pixelOnBorder == true) {
+                    gl_FragData[0] = vec4(tColor, outlineOpacity);
+                  }
+                  else {
+                    gl_FragData[0] = vec4(tColor, opacityToUse);
+                  }
                 #else
                   float intensity = texture2D(texture1, tcoordVCVSOutput).r;
                   vec3 tcolor = texture2D(colorTexture1, vec2(intensity * cscale0 + cshift0, 0.5)).rgb;

diff --git a/Sources/Rendering/OpenGL/glsl/vtkVolumeFS.glsl b/Sources/Rendering/OpenGL/glsl/vtkVolumeFS.glsl
@@ -988,43 +988,48 @@ vec4 getColorForValue(vec4 tValue, vec3 posIS, vec3 tstep)
     return vec4(0, 0, 1, 1);
   }
 
+  // If it is the background (segment index 0), we should quickly bail out. 
+  // Previously, this was determined by tColor.a, which was incorrect as it
+  // prevented the outline from appearing when the fill is 0.
+  if (segmentIndex == 0){
+    return vec4(0, 0, 0, 0);
+  }
+
   // Only perform outline check on fragments rendering voxels that aren't invisible.
   // Saves a bunch of needless checks on the background.
   // TODO define epsilon when building shader?
-  if (float(tColor.a) > 0.01) {
-    for (int i = -actualThickness; i <= actualThickness; i++) {
-      for (int j = -actualThickness; j <= actualThickness; j++) {
-        if (i == 0 || j == 0) {
-          continue;
-        }
-
-        vec4 neighborPixelCoord = vec4(gl_FragCoord.x + float(i),
-          gl_FragCoord.y + float(j),
-          gl_FragCoord.z, gl_FragCoord.w);
+  for (int i = -actualThickness; i <= actualThickness; i++) {
+    for (int j = -actualThickness; j <= actualThickness; j++) {
+      if (i == 0 || j == 0) {
+        continue;
+      }
 
-        vec3 neighborPosIS = fragCoordToIndexSpace(neighborPixelCoord);
-        vec4 value = getTextureValue(neighborPosIS);
+      vec4 neighborPixelCoord = vec4(gl_FragCoord.x + float(i),
+        gl_FragCoord.y + float(j),
+        gl_FragCoord.z, gl_FragCoord.w);
 
-        // If any of my neighbours are not the same value as I
-        // am, this means I am on the border of the segment.
-        // We can break the loops
-        if (any(notEqual(value, centerValue))) {
-          pixelOnBorder = true;
-          break;
-        }
-      }
+      vec3 neighborPosIS = fragCoordToIndexSpace(neighborPixelCoord);
+      vec4 value = getTextureValue(neighborPosIS);
 
-      if (pixelOnBorder == true) {
+      // If any of my neighbours are not the same value as I
+      // am, this means I am on the border of the segment.
+      // We can break the loops
+      if (any(notEqual(value, centerValue))) {
+        pixelOnBorder = true;
         break;
       }
     }
 
-    // If I am on the border, I am displayed at full opacity
     if (pixelOnBorder == true) {
-      tColor.a = outlineOpacity;
+      break;
     }
   }
 
+  // If I am on the border, I am displayed at full opacity
+  if (pixelOnBorder == true) {
+    tColor.a = outlineOpacity;
+  }
+
 #else
   // compute the normal and gradient magnitude if needed
   // We compute it as a vec4 if possible otherwise a mat4