Add new Filament Gradle plugin (#9694)

Author: bejado

android/buildSrc/README.md

@@ -0,0 +1,120 @@
+# Filament Tools Gradle Plugin
+
+## About
+
+The **Filament Tools Gradle Plugin** helps integrate Filament into your Android project. It
+automates the use of Filament's command-line tools (`matc`, `cmgen`, and `filamesh`).
+
+This plugin handles:
+- **Material Compilation**: Compiles `.mat` material definitions into `.filamat` binaries.
+- **IBL Generation**: Generates Image-Based Lighting assets from HDR environment maps.
+- **Mesh Compilation**: Converts models into Filament's efficient `.filamesh` binary format. *Note:
+  This tool is no longer recommended; instead, use glTF and Filament's `gltfio` library for model
+  loading.*
+
+The plugin hooks directly into the Android build lifecycle (via `preBuild`) and supports incremental
+builds, so assets are only recompiled when source files change.
+
+## Usage
+
+Apply the plugin in your module's `build.gradle` file and configure the `filament` block. You can
+specify inputs and outputs for any combination of materials, IBLs, or meshes. If a path is not
+configured, the corresponding task will be disabled.
+
+### Example Configuration
+
+```groovy
+plugins {
+    id 'filament-plugin'
+}
+
+filament {
+    materialInputDir = project.layout.projectDirectory.dir("src/main/materials")
+    materialOutputDir = project.layout.projectDirectory.dir("src/main/assets/materials")
+
+    iblInputFile = project.layout.projectDirectory.file("path/to/environment.hdr")
+    iblOutputDir = project.layout.projectDirectory.dir("src/main/assets/envs")
+
+    meshInputFile = project.layout.projectDirectory.file("path/to/model.obj")
+    meshOutputDir = project.layout.projectDirectory.dir("src/main/assets/models")
+}
+```
+
+### Configuration Details
+
+- **materialInputDir**: The directory containing your source material definitions (`.mat` files).
+- **materialOutputDir**: The directory where the compiled material files (`.filamat`) will be
+  generated.
+- **iblInputFile**: The source high-dynamic-range image file (e.g., `.hdr` or `.exr`) used to
+  generate Image Based Lighting assets.
+- **iblOutputDir**: The directory where the generated IBL assets (typically `.ktx` files) will be
+  placed.
+- **meshInputFile**: The source mesh file (e.g., `.obj`) to be compiled.
+- **meshOutputDir**: The directory where the compiled mesh file (`.filamesh`) will be generated.
+
+Automatically adds tasks to your Android build to compile materials, generate an IBL, and compile a
+mesh. The plugin hooks into `preBuild` to ensure assets are generated before the application is
+built.
+
+### Configuration Flags
+
+You can control specific compilation options using Gradle properties (e.g., in `gradle.properties`
+or via command line `-P`).
+
+- **`com.google.android.filament.exclude-vulkan`**  When set to `true`, the Vulkan backend is
+  excluded from the compiled materials. This can be useful to reduce the size of the generated
+  assets if your application does not target Vulkan.  *Default: `false` (Vulkan is included)*
+
+- **`com.google.android.filament.include-webgpu`**  When set to `true`, the WebGPU backend is
+  included in the compiled materials. Use this if you intend to use the materials in a context
+  supporting WebGPU.  *Default: `false`*
+
+## Tools Configuration
+
+The Filament Tools plugin requires some binary tools to be available: `matc`, `cmgen`, and
+`filamesh`.
+
+There are three ways to configure Filament tools:
+
+1. **Point to a local path directly**
+
+```groovy
+filament {
+    matc {
+        path = "/path/to/matc"
+    }
+
+    cmgen {
+        path = "/path/to/cmgen"
+    }
+
+    filamesh {
+        path = "/path/to/filamesh"
+    }
+}
+```
+
+2. **Point to a Maven artifact**
+
+```groovy
+filament {
+    matc {
+        // The minor version (the middle number) must match the Filament dependency's.
+        artifact = 'com.google.android.filament:matc:1.68.5'
+    }
+
+    cmgen {
+        artifact = 'com.google.android.filament:cmgen:1.68.5'
+    }
+}
+```
+
+*Note that the `filamesh` artifact is not hosted on Maven Central, so it must be provided locally or
+via another mechanism if needed.*
+
+Gradle will automatically handle downloading the tool appropriate for your machine (MacOS/Linux/Windows) from Maven.
+
+3. **Set the `com.google.android.filament.tools-dir` Gradle property**
+
+This will override any other configuration. Gradle will attempt to locate the tools under
+`<tools-dir>/bin` (e.g., `.../bin/matc`, `.../bin/cmgen`, `.../bin/filamesh`).

android/buildSrc/build.gradle

@@ -4,13 +4,18 @@ plugins {
 
 gradlePlugin {
     plugins {
-        create("filament-tools-plugin") {
-            id = "filament-tools-plugin"
-            implementationClass = "FilamentToolsPlugin"
+        create("filament-plugin") {
+            id = "filament-plugin"
+            implementationClass = "com.google.android.filament.gradle.FilamentPlugin"
         }
     }
 }
 
 repositories {
     mavenCentral()
+    gradlePluginPortal()
+}
+
+dependencies {
+    implementation "com.google.gradle:osdetector-gradle-plugin:1.7.3"
 }