Add Classic Icons toggle to Graphics Settings

Adds a "Classic icons" toggle in the structure-icons section of the
Graphics Settings modal. Off (default) keeps today's renderer look;
on switches to a classic style — lighter player-colored shape behind
a dark icon glyph, with 0.75 alpha for a subtle translucent feel.

Exposes the underlying tuning as new render-settings knobs
(`structure.fillDarken`, `borderDarken`, `iconAlpha`, `iconR/G/B`) and
threads them through the structure shader as uniforms, replacing the
previously hardcoded `darken(_, 0.65)` / `darken(_, 0.35)` calls and
the hardcoded white `vec3(1.0)` icon color. The `classicIcons` boolean
in the override schema is the single user-facing knob; the generator
derives the five underlying field values from it. Extends the
ClientGameRunner live-apply path to copy the `structure` slice too,
and adds tests covering the schema and preset derivation.

src/client/render/gl/GraphicsOverrides.ts

@@ -9,6 +9,11 @@ export const GraphicsOverridesSchema = z
         darkNames: z.boolean(),
       })
       .partial(),
+    structure: z
+      .object({
+        classicIcons: z.boolean(),
+      })
+      .partial(),
   })
   .partial();
 

src/client/render/gl/RenderSettings.ts

@@ -102,6 +102,16 @@ export interface RenderSettings {
     shapes: Record<string, { scale: number; iconFill: number }>;
     highlightOutlineWidth: number;
     highlightDimAlpha: number;
+    /** HSV value multiplier applied to the icon fill (interior). 1.0 = no darkening. */
+    fillDarken: number;
+    /** HSV value multiplier applied to the icon border (outer ring). 1.0 = no darkening. */
+    borderDarken: number;
+    /** Multiplier on final icon alpha. 1.0 = opaque. */
+    iconAlpha: number;
+    /** RGB color of the inner icon glyph */
+    iconR: number;
+    iconG: number;
+    iconB: number;
   };
   structureLevel: {
     scale: number;
@@ -279,6 +289,16 @@ export function generateRenderSettings(
   if (overrides.name?.cullThreshold !== undefined) {
     settings.name.cullThreshold = overrides.name.cullThreshold;
   }
+  if (overrides.structure?.classicIcons === true) {
+    // Classic look: lighter player-colored shape behind a dark icon glyph,
+    // with a touch of translucency.
+    settings.structure.borderDarken = 0.7;
+    settings.structure.fillDarken = 1.0;
+    settings.structure.iconR = 0;
+    settings.structure.iconG = 0;
+    settings.structure.iconB = 0;
+    settings.structure.iconAlpha = 0.75;
+  }
   if (overrides.name?.darkNames !== undefined) {
     const dark = overrides.name.darkNames;
     // Dark: black fill + player-colored outline. Force outline RGB to black

src/client/render/gl/passes/StructurePass.ts

@@ -85,6 +85,10 @@ export class StructurePass {
   private uHighlightMask: WebGLUniformLocation;
   private uHighlightOutlineW: WebGLUniformLocation;
   private uHighlightDimAlpha: WebGLUniformLocation;
+  private uFillDarken: WebGLUniformLocation;
+  private uBorderDarken: WebGLUniformLocation;
+  private uIconAlpha: WebGLUniformLocation;
+  private uIconColor: WebGLUniformLocation;
 
   private vao: WebGLVertexArrayObject;
   private instanceBuf: DynamicInstanceBuffer;
@@ -166,6 +170,10 @@ export class StructurePass {
       this.program,
       "uHighlightDimAlpha",
     )!;
+    this.uFillDarken = gl.getUniformLocation(this.program, "uFillDarken")!;
+    this.uBorderDarken = gl.getUniformLocation(this.program, "uBorderDarken")!;
+    this.uIconAlpha = gl.getUniformLocation(this.program, "uIconAlpha")!;
+    this.uIconColor = gl.getUniformLocation(this.program, "uIconColor")!;
 
     // Texture unit bindings + ghost defaults
     gl.useProgram(this.program);
@@ -358,6 +366,10 @@ export class StructurePass {
     gl.uniform1i(this.uHighlightMask, this.highlightMask);
     gl.uniform1f(this.uHighlightOutlineW, ss.highlightOutlineWidth);
     gl.uniform1f(this.uHighlightDimAlpha, ss.highlightDimAlpha);
+    gl.uniform1f(this.uFillDarken, ss.fillDarken);
+    gl.uniform1f(this.uBorderDarken, ss.borderDarken);
+    gl.uniform1f(this.uIconAlpha, ss.iconAlpha);
+    gl.uniform3f(this.uIconColor, ss.iconR, ss.iconG, ss.iconB);
 
     gl.activeTexture(gl.TEXTURE0);
     gl.bindTexture(gl.TEXTURE_2D, this.paletteTex);

src/client/render/gl/render-settings.json

@@ -116,7 +116,13 @@
       }
     },
     "highlightOutlineWidth": 0.04,
-    "highlightDimAlpha": 0.3
+    "highlightDimAlpha": 0.3,
+    "fillDarken": 0.65,
+    "borderDarken": 0.35,
+    "iconAlpha": 1.0,
+    "iconR": 1.0,
+    "iconG": 1.0,
+    "iconB": 1.0
   },
   "structureLevel": {
     "scale": 1.2,

src/client/render/gl/shaders/structure/structure.frag.glsl

@@ -11,6 +11,10 @@ uniform int   uAltView;
 uniform int   uHighlightMask;   // bitmask of atlas columns to highlight (0 = off)
 uniform float uHighlightOutlineW; // outline width for highlighted structures
 uniform float uHighlightDimAlpha; // alpha multiplier for non-highlighted structures
+uniform float uFillDarken;      // HSV value multiplier on icon fill
+uniform float uBorderDarken;    // HSV value multiplier on icon border
+uniform float uIconAlpha;       // global multiplier on final icon alpha
+uniform vec3  uIconColor;       // color of the inner icon glyph (was white)
 
 in vec2  vLocalPos;
 in vec2  vAtlasUV;
@@ -91,8 +95,8 @@ void main() {
 
   if (uAltView != 0 && vUnderConstruction < 0.5) {
     vec3 ac = texelFetch(uAffiliation, ivec2(int(vOwnerID), 1), 0).rgb;
-    fillColor = vec4(darken(ac, 0.65), 1.0);
-    borderColor = vec4(darken(ac, 0.35), 1.0);
+    fillColor = vec4(darken(ac, uFillDarken), 1.0);
+    borderColor = vec4(darken(ac, uBorderDarken), 1.0);
   } else if (vUnderConstruction > 0.5) {
     fillColor = vec4(198.0/255.0, 198.0/255.0, 198.0/255.0, 1.0);
     borderColor = vec4(127.0/255.0, 127.0/255.0, 127.0/255.0, 1.0);
@@ -102,8 +106,8 @@ void main() {
     borderColor = texture(uPalette, vec2(u, 0.75));
     // Darken via HSV value so hue/saturation stay intact
     // vScale < 1.0 = darker, > 1.0 = brighter
-    fillColor.rgb = darken(fillColor.rgb, 0.65);
-    borderColor.rgb = darken(borderColor.rgb, 0.35);
+    fillColor.rgb = darken(fillColor.rgb, uFillDarken);
+    borderColor.rgb = darken(borderColor.rgb, uBorderDarken);
     fillColor.a = 1.0;
     borderColor.a = 1.0;
   }
@@ -127,8 +131,8 @@ void main() {
     iconAlpha = iconSample.a * borderMask * inBounds;
   }
 
-  // Composite: white icon over player-colored shape
-  vec3 finalRGB = mix(bgColor.rgb, vec3(1.0), iconAlpha);
+  // Composite: tinted icon over player-colored shape
+  vec3 finalRGB = mix(bgColor.rgb, uIconColor, iconAlpha);
 
   // Red X overlay for units marked for deletion
   if (vMarkedForDeletion > 0.5) {
@@ -147,7 +151,7 @@ void main() {
   float tintActive = step(0.01, dot(uOutlineColor, uOutlineColor));
   finalRGB = mix(finalRGB, uOutlineColor, tintActive * 0.5);
 
-  float finalAlpha = bgColor.a * outerAlpha * uGhostAlpha;
+  float finalAlpha = bgColor.a * outerAlpha * uGhostAlpha * uIconAlpha;
 
   // Build-button hover highlight: white outline on matching types, dim the rest
   if (uHighlightMask != 0) {