LibWeb/WebGL: Implement WEBGL_compressed_texture_s3tc extension

Author: https://github.com/Lubrsi
Commit: 958938655d
Pull-request: https://github.com/LadybirdBrowser/ladybird/pull/3385

Libraries/LibWeb/WebGL/Extensions/WebGLCompressedTextureS3tc.cpp

@@ -0,0 +1,43 @@
+/*
+ * Copyright (c) 2025, Luke Wilde <luke@ladybird.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#include <LibJS/Runtime/Realm.h>
+#include <LibWeb/Bindings/Intrinsics.h>
+#include <LibWeb/Bindings/WebGLCompressedTextureS3tcPrototype.h>
+#include <LibWeb/WebGL/Extensions/WebGLCompressedTextureS3tc.h>
+#include <LibWeb/WebGL/OpenGLContext.h>
+
+namespace Web::WebGL::Extensions {
+
+GC_DEFINE_ALLOCATOR(WebGLCompressedTextureS3tc);
+
+JS::ThrowCompletionOr<GC::Ptr<WebGLCompressedTextureS3tc>> WebGLCompressedTextureS3tc::create(JS::Realm& realm, WebGLRenderingContextBase* context)
+{
+    return realm.create<WebGLCompressedTextureS3tc>(realm, context);
+}
+
+WebGLCompressedTextureS3tc::WebGLCompressedTextureS3tc(JS::Realm& realm, WebGLRenderingContextBase* context)
+    : PlatformObject(realm)
+    , m_context(context)
+{
+    m_context->context().request_extension("GL_EXT_texture_compression_dxt1");
+    m_context->context().request_extension("GL_ANGLE_texture_compression_dxt3");
+    m_context->context().request_extension("GL_ANGLE_texture_compression_dxt5");
+}
+
+void WebGLCompressedTextureS3tc::initialize(JS::Realm& realm)
+{
+    Base::initialize(realm);
+    WEB_SET_PROTOTYPE_FOR_INTERFACE(WebGLCompressedTextureS3tc);
+}
+
+void WebGLCompressedTextureS3tc::visit_edges(Visitor& visitor)
+{
+    Base::visit_edges(visitor);
+    visitor.visit(m_context->gc_cell());
+}
+
+}

Libraries/LibWeb/WebGL/Extensions/WebGLCompressedTextureS3tc.h

@@ -0,0 +1,33 @@
+/*
+ * Copyright (c) 2025, Luke Wilde <luke@ladybird.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#pragma once
+
+#include <LibWeb/Bindings/PlatformObject.h>
+#include <LibWeb/Forward.h>
+#include <LibWeb/WebGL/WebGLRenderingContextBase.h>
+
+namespace Web::WebGL::Extensions {
+
+class WebGLCompressedTextureS3tc : public Bindings::PlatformObject {
+    WEB_PLATFORM_OBJECT(WebGLCompressedTextureS3tc, Bindings::PlatformObject);
+    GC_DECLARE_ALLOCATOR(WebGLCompressedTextureS3tc);
+
+public:
+    static JS::ThrowCompletionOr<GC::Ptr<WebGLCompressedTextureS3tc>> create(JS::Realm&, WebGLRenderingContextBase*);
+
+protected:
+    void initialize(JS::Realm&) override;
+    void visit_edges(Visitor&) override;
+
+private:
+    WebGLCompressedTextureS3tc(JS::Realm&, WebGLRenderingContextBase*);
+
+    // FIXME: It should be GC::Ptr instead of raw pointer, but we need to make WebGLRenderingContextBase inherit from PlatformObject first.
+    WebGLRenderingContextBase* m_context;
+};
+
+}

Libraries/LibWeb/WebGL/Extensions/WebGLCompressedTextureS3tc.idl

@@ -0,0 +1,16 @@
+#import <WebGL/Types.idl>
+
+// https://registry.khronos.org/webgl/extensions/WEBGL_compressed_texture_s3tc/
+// NOTE: Original WEBGL_compressed_texture_s3tc name is changed to title case,
+//       so it matches corresponding C++ class name, and does not require
+//       IDL generator to handle snake_case to TitleCase conversion.
+//       Having a different name is totally fine, because LegacyNoInterfaceObject
+//       prevents the name from being exposed to JavaScript.
+[Exposed=(Window,Worker), LegacyNoInterfaceObject]
+interface WebGLCompressedTextureS3tc {
+    // Compressed Texture Formats
+    const GLenum COMPRESSED_RGB_S3TC_DXT1_EXT = 0x83F0;
+    const GLenum COMPRESSED_RGBA_S3TC_DXT1_EXT = 0x83F1;
+    const GLenum COMPRESSED_RGBA_S3TC_DXT3_EXT = 0x83F2;
+    const GLenum COMPRESSED_RGBA_S3TC_DXT5_EXT = 0x83F3;
+};