perf(WebGPU): reduce ImageMapper UBO array allocations

Author: daker

Sources/Rendering/WebGPU/ImageMapper/Constants.js

@@ -0,0 +1,18 @@
+export const TextureChannelMode = {
+  SINGLE: 'single',
+  DEPENDENT_LA: 'dependent-la',
+  DEPENDENT_RGB: 'dependent-rgb',
+  DEPENDENT_RGBA: 'dependent-rgba',
+  INDEPENDENT_1: 'independent-1',
+  INDEPENDENT_2: 'independent-2',
+  INDEPENDENT_3: 'independent-3',
+  INDEPENDENT_4: 'independent-4',
+};
+
+export const TextureSlot = {
+  IMAGE: 0,
+  COLOR_LUT: 1,
+  OPACITY_LUT: 2,
+  LABEL_OUTLINE_THICKNESS: 3,
+  LABEL_OUTLINE_OPACITY: 4,
+};