feat(volumeMapper): add a first interaction render quality setting

The setting "initialInteractionScale" set the quality of the rendering when interacting

Author: bruyeret

Sources/Rendering/Core/VolumeMapper/index.d.ts

@@ -68,6 +68,14 @@ export interface vtkVolumeMapper extends vtkAbstractMapper {
 	 */
 	getAutoAdjustSampleDistances(): boolean;
 
+	/**
+	 * Get at what scale the quality is reduced when interacting for the first time with the volume
+	 * It should should be set before any call to render for this volume
+	 * The higher the scale is, the lower the quality of rendering is during interaction
+	 * @default 4
+	 */
+	getInitialInteractionScale(): number;
+
 	/**
 	 *
 	 */
@@ -188,6 +196,12 @@ export interface vtkVolumeMapper extends vtkAbstractMapper {
 	 */
 	setAutoAdjustSampleDistances(autoAdjustSampleDistances: boolean): boolean;
 
+	/**
+	 *
+	 * @param initialInteractionScale
+	 */
+	setInitialInteractionScale(initialInteractionScale: number): boolean;
+
 	/**
 	 * Set the normal computation to be dependent on the transfer function.
 	 * By default, the mapper relies on the scalar gradient for computing normals at sample locations

Sources/Rendering/Core/VolumeMapper/index.js

@@ -147,6 +147,7 @@ const DEFAULT_VALUES = {
   imageSampleDistance: 1.0,
   maximumSamplesPerRay: 1000,
   autoAdjustSampleDistances: true,
+  initialInteractionScale: 100.0,
   blendMode: BlendMode.COMPOSITE_BLEND,
   ipScalarRange: [-1000000.0, 1000000.0],
   filterMode: FilterMode.OFF, // ignored by WebGL so no behavior change
@@ -175,6 +176,7 @@ export function extend(publicAPI, model, initialValues = {}) {
     'imageSampleDistance',
     'maximumSamplesPerRay',
     'autoAdjustSampleDistances',
+    'initialInteractionScale',
     'blendMode',
     'filterMode',
     'preferSizeOverAccuracy',

Sources/Rendering/OpenGL/VolumeMapper/index.js

@@ -1136,6 +1136,9 @@ function vtkOpenGLVolumeMapper(publicAPI, model) {
   publicAPI.renderPieceStart = (ren, actor) => {
     const rwi = ren.getVTKWindow().getInteractor();
 
+    if (!model._lastScale) {
+      model._lastScale = model.renderable.getInitialInteractionScale();
+    }
     model._useSmallViewport = false;
     if (rwi.isAnimating() && model._lastScale > 1.5) {
       model._useSmallViewport = true;
@@ -1166,19 +1169,15 @@ function vtkOpenGLVolumeMapper(publicAPI, model) {
             model.renderable.getImageSampleDistance() *
             model.renderable.getImageSampleDistance();
         }
-        const size = model._openGLRenderWindow.getFramebufferSize();
-        model._smallViewportWidth = Math.ceil(
-          size[0] / Math.sqrt(model._lastScale)
-        );
-        model._smallViewportHeight = Math.ceil(
-          size[1] / Math.sqrt(model._lastScale)
-        );
       });
     }
 
     // use/create/resize framebuffer if needed
     if (model._useSmallViewport) {
       const size = model._openGLRenderWindow.getFramebufferSize();
+      const scaleFactor = 1 / Math.sqrt(model._lastScale);
+      model._smallViewportWidth = Math.ceil(scaleFactor * size[0]);
+      model._smallViewportHeight = Math.ceil(scaleFactor * size[1]);
 
       // adjust viewportSize to always be at most the dest fo size
       if (model._smallViewportHeight > size[1]) {
@@ -1662,8 +1661,6 @@ export function extend(publicAPI, model, initialValues = {}) {
   model.projectionToView = mat4.identity(new Float64Array(16));
   model.projectionToWorld = mat4.identity(new Float64Array(16));
 
-  model._lastScale = 1.0;
-
   // Build VTK API
   macro.setGet(publicAPI, model, ['context']);
 

Sources/Rendering/WebGPU/VolumePass/index.js

@@ -262,18 +262,14 @@ function vtkWebGPUVolumePass(publicAPI, model) {
   }, publicAPI.delete);
 
   publicAPI.computeTiming = (viewNode) => {
-    model._useSmallViewport = false;
     const rwi = viewNode.getRenderable().getInteractor();
 
+    if (model._lastScale == null) {
+      const firstMapper = model.volumes[0].getRenderable().getMapper();
+      model._lastScale = firstMapper.getInitialInteractionScale() || 1.0;
+    }
+    model._useSmallViewport = false;
     if (rwi.isAnimating() && model._lastScale > 1.5) {
-      if (!model._smallViewportHeight) {
-        model._smallViewportWidth = Math.ceil(
-          viewNode.getCanvas().width / Math.sqrt(model._lastScale)
-        );
-        model._smallViewportHeight = Math.ceil(
-          viewNode.getCanvas().height / Math.sqrt(model._lastScale)
-        );
-      }
       model._useSmallViewport = true;
     }
 
@@ -305,13 +301,6 @@ function vtkWebGPUVolumePass(publicAPI, model) {
         }
         if (model._lastScale < 1.5) {
           model._lastScale = 1.5;
-        } else {
-          model._smallViewportWidth = Math.ceil(
-            viewNode.getCanvas().width / Math.sqrt(model._lastScale)
-          );
-          model._smallViewportHeight = Math.ceil(
-            viewNode.getCanvas().height / Math.sqrt(model._lastScale)
-          );
         }
       });
     }
@@ -326,6 +315,10 @@ function vtkWebGPUVolumePass(publicAPI, model) {
     let width = model._colorTextureView.getTexture().getWidth();
     let height = model._colorTextureView.getTexture().getHeight();
     if (model._useSmallViewport) {
+      const canvas = viewNode.getCanvas();
+      const scaleFactor = 1 / Math.sqrt(model._lastScale);
+      model._smallViewportWidth = Math.ceil(scaleFactor * canvas.width);
+      model._smallViewportHeight = Math.ceil(scaleFactor * canvas.height);
       width = model._smallViewportWidth;
       height = model._smallViewportHeight;
     }
@@ -723,7 +716,6 @@ export function extend(publicAPI, model, initialValues = {}) {
   // Build VTK API
   vtkRenderPass.extend(publicAPI, model, initialValues);
 
-  model._lastScale = 2.0;
   model._mapper = vtkWebGPUSimpleMapper.newInstance();
   model._mapper.setFragmentShaderTemplate(DepthBoundsFS);
   model._mapper