LibWeb/WebGL: Implement WEBGL_draw_buffers extension

Author: https://github.com/Lubrsi
Commit: 55f7cb4f10
Pull-request: https://github.com/LadybirdBrowser/ladybird/pull/3239
Reviewed-by: https://github.com/awesomekling
Reviewed-by: https://github.com/kalenikaliaksandr

Libraries/LibWeb/WebGL/Extensions/WebGLDrawBuffers.cpp

@@ -0,0 +1,52 @@
+/*
+ * 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/WebGLDrawBuffersPrototype.h>
+#include <LibWeb/WebGL/Extensions/WebGLDrawBuffers.h>
+#include <LibWeb/WebGL/OpenGLContext.h>
+#include <LibWeb/WebGL/WebGLRenderingContext.h>
+
+#define GL_GLEXT_PROTOTYPES 1
+#include <GLES2/gl2.h>
+#include <GLES2/gl2ext.h>
+
+namespace Web::WebGL::Extensions {
+
+GC_DEFINE_ALLOCATOR(WebGLDrawBuffers);
+
+JS::ThrowCompletionOr<GC::Ptr<WebGLDrawBuffers>> WebGLDrawBuffers::create(JS::Realm& realm, GC::Ref<WebGLRenderingContext> context)
+{
+    return realm.create<WebGLDrawBuffers>(realm, context);
+}
+
+WebGLDrawBuffers::WebGLDrawBuffers(JS::Realm& realm, GC::Ref<WebGLRenderingContext> context)
+    : PlatformObject(realm)
+    , m_context(context)
+{
+    m_context->context().request_extension("GL_EXT_draw_buffers");
+}
+
+void WebGLDrawBuffers::draw_buffers_webgl(Vector<GLenum> buffers)
+{
+    m_context->context().make_current();
+    glDrawBuffersEXT(buffers.size(), buffers.data());
+}
+
+void WebGLDrawBuffers::initialize(JS::Realm& realm)
+{
+    Base::initialize(realm);
+    WEB_SET_PROTOTYPE_FOR_INTERFACE(WebGLDrawBuffers);
+}
+
+void WebGLDrawBuffers::visit_edges(Visitor& visitor)
+{
+    Base::visit_edges(visitor);
+    visitor.visit(m_context);
+}
+
+}

Libraries/LibWeb/WebGL/Extensions/WebGLDrawBuffers.h

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+/*
+ * 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/Types.h>
+
+namespace Web::WebGL::Extensions {
+
+class WebGLDrawBuffers : public Bindings::PlatformObject {
+    WEB_PLATFORM_OBJECT(WebGLDrawBuffers, Bindings::PlatformObject);
+    GC_DECLARE_ALLOCATOR(WebGLDrawBuffers);
+
+public:
+    static JS::ThrowCompletionOr<GC::Ptr<WebGLDrawBuffers>> create(JS::Realm&, GC::Ref<WebGLRenderingContext>);
+
+    void draw_buffers_webgl(Vector<GLenum> buffers);
+
+protected:
+    void initialize(JS::Realm&) override;
+    void visit_edges(Visitor&) override;
+
+private:
+    WebGLDrawBuffers(JS::Realm&, GC::Ref<WebGLRenderingContext>);
+
+    GC::Ref<WebGLRenderingContext> m_context;
+};
+
+}

Libraries/LibWeb/WebGL/Extensions/WebGLDrawBuffers.idl

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+#import <WebGL/Types.idl>
+
+// https://registry.khronos.org/webgl/extensions/WEBGL_draw_buffers/
+// NOTE: Original WEBGL_draw_buffers 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 WebGLDrawBuffers {
+    const GLenum COLOR_ATTACHMENT0_WEBGL     = 0x8CE0;
+    const GLenum COLOR_ATTACHMENT1_WEBGL     = 0x8CE1;
+    const GLenum COLOR_ATTACHMENT2_WEBGL     = 0x8CE2;
+    const GLenum COLOR_ATTACHMENT3_WEBGL     = 0x8CE3;
+    const GLenum COLOR_ATTACHMENT4_WEBGL     = 0x8CE4;
+    const GLenum COLOR_ATTACHMENT5_WEBGL     = 0x8CE5;
+    const GLenum COLOR_ATTACHMENT6_WEBGL     = 0x8CE6;
+    const GLenum COLOR_ATTACHMENT7_WEBGL     = 0x8CE7;
+    const GLenum COLOR_ATTACHMENT8_WEBGL     = 0x8CE8;
+    const GLenum COLOR_ATTACHMENT9_WEBGL     = 0x8CE9;
+    const GLenum COLOR_ATTACHMENT10_WEBGL    = 0x8CEA;
+    const GLenum COLOR_ATTACHMENT11_WEBGL    = 0x8CEB;
+    const GLenum COLOR_ATTACHMENT12_WEBGL    = 0x8CEC;
+    const GLenum COLOR_ATTACHMENT13_WEBGL    = 0x8CED;
+    const GLenum COLOR_ATTACHMENT14_WEBGL    = 0x8CEE;
+    const GLenum COLOR_ATTACHMENT15_WEBGL    = 0x8CEF;
+
+    const GLenum DRAW_BUFFER0_WEBGL          = 0x8825;
+    const GLenum DRAW_BUFFER1_WEBGL          = 0x8826;
+    const GLenum DRAW_BUFFER2_WEBGL          = 0x8827;
+    const GLenum DRAW_BUFFER3_WEBGL          = 0x8828;
+    const GLenum DRAW_BUFFER4_WEBGL          = 0x8829;
+    const GLenum DRAW_BUFFER5_WEBGL          = 0x882A;
+    const GLenum DRAW_BUFFER6_WEBGL          = 0x882B;
+    const GLenum DRAW_BUFFER7_WEBGL          = 0x882C;
+    const GLenum DRAW_BUFFER8_WEBGL          = 0x882D;
+    const GLenum DRAW_BUFFER9_WEBGL          = 0x882E;
+    const GLenum DRAW_BUFFER10_WEBGL         = 0x882F;
+    const GLenum DRAW_BUFFER11_WEBGL         = 0x8830;
+    const GLenum DRAW_BUFFER12_WEBGL         = 0x8831;
+    const GLenum DRAW_BUFFER13_WEBGL         = 0x8832;
+    const GLenum DRAW_BUFFER14_WEBGL         = 0x8833;
+    const GLenum DRAW_BUFFER15_WEBGL         = 0x8834;
+
+    const GLenum MAX_COLOR_ATTACHMENTS_WEBGL = 0x8CDF;
+    const GLenum MAX_DRAW_BUFFERS_WEBGL      = 0x8824;
+
+    undefined drawBuffersWEBGL(sequence<GLenum> buffers);
+};