feat(RenderWindow): cache cull-face mode and route raw calls through it

Extend the vtkOpenGLRenderWindow cull cache to mirror vtkOpenGLState in
VTK C++: alongside the existing cullFaceEnabled flag, add cullFaceMode
and a setCullFaceMode method that is no-op-on-match.

Migrate the four raw gl.cullFace(X) call sites in PolyDataMapper,
Glyph3DMapper, SurfaceLICMapper, and PolyDataMapper2D, as well as the
raw gl.enable/gl.disable(CULL_FACE) call sites in SurfaceLICMapper's
popState and post-LIC cleanup, and the raw restore in
OrderIndependentTranslucentPass. After this commit the cache fully
tracks cull state, so a stale cache cannot silently no-op a later cull
write against a divergent real GL state.

Pure infrastructure: no behavioral change.

Author: PaulHax

Sources/Rendering/OpenGL/Glyph3DMapper/index.js

@@ -77,10 +77,10 @@ function vtkOpenGLGlyph3DMapper(publicAPI, model) {
       model._openGLRenderWindow.disableCullFace();
     } else if (frontfaceCulling) {
       model._openGLRenderWindow.enableCullFace();
-      gl.cullFace(gl.FRONT);
+      model._openGLRenderWindow.setCullFaceMode(gl.FRONT);
     } else {
       model._openGLRenderWindow.enableCullFace();
-      gl.cullFace(gl.BACK);
+      model._openGLRenderWindow.setCullFaceMode(gl.BACK);
     }
 
     publicAPI.renderPieceStart(ren, actor);

Sources/Rendering/OpenGL/OrderIndependentTranslucentPass/index.js

@@ -333,7 +333,7 @@ function vtkOpenGLOrderIndependentTranslucentPass(publicAPI, model) {
     gl.depthFunc(gl.LEQUAL);
     if (cullFaceEnabled) {
       viewNode.enableCullFace();
-      gl.cullFace(cullFaceMode);
+      viewNode.setCullFaceMode(cullFaceMode);
     }
     model.translucentRGBATexture.deactivate();
     model.translucentRTexture.deactivate();

Sources/Rendering/OpenGL/PolyDataMapper/index.js

@@ -1743,10 +1743,10 @@ function vtkOpenGLPolyDataMapper(publicAPI, model) {
       model._openGLRenderWindow.disableCullFace();
     } else if (frontfaceCulling) {
       model._openGLRenderWindow.enableCullFace();
-      gl.cullFace(gl.FRONT);
+      model._openGLRenderWindow.setCullFaceMode(gl.FRONT);
     } else {
       model._openGLRenderWindow.enableCullFace();
-      gl.cullFace(gl.BACK);
+      model._openGLRenderWindow.setCullFaceMode(gl.BACK);
     }
 
     publicAPI.renderPieceStart(ren, actor);

Sources/Rendering/OpenGL/PolyDataMapper2D/index.js

@@ -96,7 +96,7 @@ function vtkOpenGLPolyDataMapper2D(publicAPI, model) {
     // cull back face to avoid double drawing
     const gl = model.context;
     model._openGLRenderWindow.enableCullFace();
-    gl.cullFace(gl.BACK);
+    model._openGLRenderWindow.setCullFaceMode(gl.BACK);
 
     publicAPI.renderPieceStart(ren, actor);
     publicAPI.renderPieceDraw(ren, actor);

Sources/Rendering/OpenGL/RenderWindow/index.d.ts

@@ -16,6 +16,7 @@ import vtkViewStream from '../../../IO/Core/ImageStream/ViewStream';
  */
 export interface IOpenGLRenderWindowInitialValues {
   cullFaceEnabled?: boolean;
+  cullFaceMode?: number | null;
   shaderCache?: null;
   initialized?: boolean;
   context?: WebGLRenderingContext | WebGL2RenderingContext;
@@ -376,6 +377,13 @@ export interface vtkOpenGLRenderWindow extends vtkViewNode {
    */
   enableCullFace(): void;
 
+  /**
+   * Set the cull face mode (gl.FRONT, gl.BACK, or gl.FRONT_AND_BACK).
+   * Caches the value to avoid redundant gl.cullFace() calls.
+   * @param mode A WebGL cull face mode constant.
+   */
+  setCullFaceMode(mode: number): void;
+
   /**
    *
    * @param {vtkViewStream} stream The vtkViewStream instance.

Sources/Rendering/OpenGL/RenderWindow/index.js

@@ -27,6 +27,7 @@ const parentMethodsToProxy = [
   'deactivateTexture',
   'disableCullFace',
   'enableCullFace',
+  'setCullFaceMode',
   'get3DContext',
   'getActiveFramebuffer',
   'getContext',
@@ -1143,6 +1144,13 @@ function vtkOpenGLRenderWindow(publicAPI, model) {
     }
   };
 
+  publicAPI.setCullFaceMode = (mode) => {
+    if (model.cullFaceMode !== mode) {
+      model.context.cullFace(mode);
+      model.cullFaceMode = mode;
+    }
+  };
+
   publicAPI.setViewStream = (stream) => {
     if (model.viewStream === stream) {
       return false;
@@ -1302,6 +1310,7 @@ function vtkOpenGLRenderWindow(publicAPI, model) {
 
 const DEFAULT_VALUES = {
   cullFaceEnabled: false,
+  cullFaceMode: null,
   shaderCache: null,
   initialized: false,
   context: null,

Sources/Rendering/OpenGL/SurfaceLIC/SurfaceLICMapper/index.js

@@ -134,7 +134,11 @@ function vtkOpenGLSurfaceLICMapper(publicAPI, model) {
     apply(gl.BLEND);
     apply(gl.DEPTH_TEST);
     apply(gl.SCISSOR_TEST);
-    apply(gl.CULL_FACE);
+    if (model.stateCache[gl.CULL_FACE]) {
+      model._openGLRenderWindow.enableCullFace();
+    } else {
+      model._openGLRenderWindow.disableCullFace();
+    }
   };
 
   publicAPI.renderPiece = (ren, actor) => {
@@ -211,10 +215,10 @@ function vtkOpenGLSurfaceLICMapper(publicAPI, model) {
       model._openGLRenderWindow.disableCullFace();
     } else if (frontfaceCulling) {
       model._openGLRenderWindow.enableCullFace();
-      gl.cullFace(gl.FRONT);
+      model._openGLRenderWindow.setCullFaceMode(gl.FRONT);
     } else {
       model._openGLRenderWindow.enableCullFace();
-      gl.cullFace(gl.BACK);
+      model._openGLRenderWindow.setCullFaceMode(gl.BACK);
     }
 
     const windowSize = model._openGLRenderWindow.getSize();
@@ -241,7 +245,7 @@ function vtkOpenGLSurfaceLICMapper(publicAPI, model) {
     publicAPI.pushState(model.context);
     model.VBOBuildTime.modified();
     model.openGLLicInterface.completedGeometry();
-    model.context.disable(model.context.CULL_FACE);
+    model._openGLRenderWindow.disableCullFace();
     model.openGLLicInterface.applyLIC();
     model.openGLLicInterface.combineColorsAndLIC();
     model.openGLLicInterface.copyToScreen(windowSize);