From 4e038031c1f8c94b520a95fce6403e4888b64d36 Mon Sep 17 00:00:00 2001
From: Paul Connelly <22944042+pmconne@users.noreply.github.com>
Date: Tue, 8 Mar 2022 09:58:02 -0500
Subject: [PATCH 1/2] u_texturesPresent is a lie.

---
 core/frontend/src/render/webgl/RealityMesh.ts      | 2 ++
 core/frontend/src/render/webgl/glsl/RealityMesh.ts | 3 +--
 2 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/core/frontend/src/render/webgl/RealityMesh.ts b/core/frontend/src/render/webgl/RealityMesh.ts
index 66b589674149..1e562d612512 100644
--- a/core/frontend/src/render/webgl/RealityMesh.ts
+++ b/core/frontend/src/render/webgl/RealityMesh.ts
@@ -218,6 +218,7 @@ export class RealityMeshGeometryParams extends IndexedGeometryParams {
 
 /** @internal */
 export class RealityMeshGeometry extends IndexedGeometry implements IDisposable, RenderMemory.Consumer {
+  public readonly hasTextures: boolean;
   public override get asRealityMesh(): RealityMeshGeometry | undefined { return this; }
   public override get isDisposed(): boolean { return this._realityMeshParams.isDisposed; }
   public get uvQParams() { return this._realityMeshParams.uvParams.params; }
@@ -228,6 +229,7 @@ export class RealityMeshGeometry extends IndexedGeometry implements IDisposable,
 
   private constructor(private _realityMeshParams: RealityMeshGeometryParams, public textureParams: RealityTextureParams | undefined, private readonly _transform: Transform | undefined, public readonly baseColor: ColorDef | undefined, private _baseIsTransparent: boolean, private _isTerrain: boolean) {
     super(_realityMeshParams);
+    this.hasTextures = undefined !== textureParams && textureParams.params.some((x) => undefined !== x.texture);
   }
 
   public override dispose() {
diff --git a/core/frontend/src/render/webgl/glsl/RealityMesh.ts b/core/frontend/src/render/webgl/glsl/RealityMesh.ts
index 2a7022297764..b48f885df6c8 100644
--- a/core/frontend/src/render/webgl/glsl/RealityMesh.ts
+++ b/core/frontend/src/render/webgl/glsl/RealityMesh.ts
@@ -130,8 +130,7 @@ function addTextures(builder: ProgramBuilder, maxTexturesPerMesh: number) {
 
   builder.frag.addUniform("u_texturesPresent", VariableType.Boolean, (program) => {
     program.addGraphicUniform("u_texturesPresent", (uniform, params) => {
-      const textureCount = params.geometry.asRealityMesh!.textureParams?.params.length;
-      uniform.setUniform1i(textureCount ? 1 : 0);
+      uniform.setUniform1i(params.geometry.asRealityMesh!.hasTextures ? 1 : 0);
     });
   });
 

From a6ca1cf1bab2bc6eb020a17af42f4f3587d05e20 Mon Sep 17 00:00:00 2001
From: Paul Connelly <22944042+pmconne@users.noreply.github.com>
Date: Tue, 8 Mar 2022 09:58:02 -0500
Subject: [PATCH 2/2] u_texturesPresent is a lie.

---
 .../fix-background-base-color_2022-03-08-15-02.json    | 10 ++++++++++
 core/frontend/src/render/webgl/RealityMesh.ts          |  2 ++
 core/frontend/src/render/webgl/glsl/RealityMesh.ts     |  3 +--
 3 files changed, 13 insertions(+), 2 deletions(-)
 create mode 100644 common/changes/@itwin/core-frontend/fix-background-base-color_2022-03-08-15-02.json

diff --git a/common/changes/@itwin/core-frontend/fix-background-base-color_2022-03-08-15-02.json b/common/changes/@itwin/core-frontend/fix-background-base-color_2022-03-08-15-02.json
new file mode 100644
index 000000000000..88adbed5edb6
--- /dev/null
+++ b/common/changes/@itwin/core-frontend/fix-background-base-color_2022-03-08-15-02.json
@@ -0,0 +1,10 @@
+{
+  "changes": [
+    {
+      "packageName": "@itwin/core-frontend",
+      "comment": "Fix regression that caused solid color background map base to fail to display.",
+      "type": "none"
+    }
+  ],
+  "packageName": "@itwin/core-frontend"
+}
\ No newline at end of file
diff --git a/core/frontend/src/render/webgl/RealityMesh.ts b/core/frontend/src/render/webgl/RealityMesh.ts
index 66b589674149..1e562d612512 100644
--- a/core/frontend/src/render/webgl/RealityMesh.ts
+++ b/core/frontend/src/render/webgl/RealityMesh.ts
@@ -218,6 +218,7 @@ export class RealityMeshGeometryParams extends IndexedGeometryParams {
 
 /** @internal */
 export class RealityMeshGeometry extends IndexedGeometry implements IDisposable, RenderMemory.Consumer {
+  public readonly hasTextures: boolean;
   public override get asRealityMesh(): RealityMeshGeometry | undefined { return this; }
   public override get isDisposed(): boolean { return this._realityMeshParams.isDisposed; }
   public get uvQParams() { return this._realityMeshParams.uvParams.params; }
@@ -228,6 +229,7 @@ export class RealityMeshGeometry extends IndexedGeometry implements IDisposable,
 
   private constructor(private _realityMeshParams: RealityMeshGeometryParams, public textureParams: RealityTextureParams | undefined, private readonly _transform: Transform | undefined, public readonly baseColor: ColorDef | undefined, private _baseIsTransparent: boolean, private _isTerrain: boolean) {
     super(_realityMeshParams);
+    this.hasTextures = undefined !== textureParams && textureParams.params.some((x) => undefined !== x.texture);
   }
 
   public override dispose() {
diff --git a/core/frontend/src/render/webgl/glsl/RealityMesh.ts b/core/frontend/src/render/webgl/glsl/RealityMesh.ts
index 2a7022297764..b48f885df6c8 100644
--- a/core/frontend/src/render/webgl/glsl/RealityMesh.ts
+++ b/core/frontend/src/render/webgl/glsl/RealityMesh.ts
@@ -130,8 +130,7 @@ function addTextures(builder: ProgramBuilder, maxTexturesPerMesh: number) {
 
   builder.frag.addUniform("u_texturesPresent", VariableType.Boolean, (program) => {
     program.addGraphicUniform("u_texturesPresent", (uniform, params) => {
-      const textureCount = params.geometry.asRealityMesh!.textureParams?.params.length;
-      uniform.setUniform1i(textureCount ? 1 : 0);
+      uniform.setUniform1i(params.geometry.asRealityMesh!.hasTextures ? 1 : 0);
     });
   });