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diff --git a/src/egl.h b/src/egl.h
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+// Copyright 2021 Benjamin Barenblat
+//
+// Licensed under the Apache License, Version 2.0 (the "License"); you may not
+// use this file except in compliance with the License. You may obtain a copy of
+// the License at
+//
+//     https://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+// WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+// License for the specific language governing permissions and limitations under
+// the License.
+
+// An idiomatic C++ interface to EGL 1.5.
+
+#ifndef GLPLANET_SRC_EGL_H_
+#define GLPLANET_SRC_EGL_H_
+
+#include <EGL/egl.h>
+#include <X11/Xlib.h>
+
+#include <utility>
+#include <vector>
+
+#include "src/undo_xlib_dot_h_namespace_pollution.h"
+//
+
+#include "src/util.h"
+#include "third_party/abseil/absl/types/optional.h"
+
+namespace egl {
+
+class Context;
+class Display;
+class Surface;
+
+// Makes a Context active in the current thread.
+void BindContext(Surface&, Context&);
+
+// Configuration attributes.
+enum Attribute : EGLint {
+  kBufferSize = EGL_BUFFER_SIZE,
+
+  kRedSize = EGL_RED_SIZE,
+  kGreenSize = EGL_GREEN_SIZE,
+  kBlueSize = EGL_BLUE_SIZE,
+  kLuminanceSize = EGL_LUMINANCE_SIZE,
+  kAlphaSize = EGL_ALPHA_SIZE,
+  kAlphaMaskSize = EGL_ALPHA_MASK_SIZE,
+
+  kBindToTextureRgb = EGL_BIND_TO_TEXTURE_RGB,
+  kBindToTextureRgba = EGL_BIND_TO_TEXTURE_RGBA,
+  kColorBufferType = EGL_COLOR_BUFFER_TYPE,
+  kConfigCaveat = EGL_CONFIG_CAVEAT,
+  kConfigId = EGL_CONFIG_ID,
+  kConformantMask = EGL_CONFORMANT,
+  kDepthSize = EGL_DEPTH_SIZE,
+  kLevel = EGL_LEVEL,
+  kMatchNativePixmap = EGL_MATCH_NATIVE_PIXMAP,
+  kMaxSwapInterval = EGL_MAX_SWAP_INTERVAL,
+  kMinSwapInterval = EGL_MIN_SWAP_INTERVAL,
+  kNativeRenderable = EGL_NATIVE_RENDERABLE,
+  kNativeVisualId = EGL_NATIVE_VISUAL_ID,
+  kNativeVisualType = EGL_NATIVE_VISUAL_TYPE,
+  kSampleBuffers = EGL_SAMPLE_BUFFERS,
+  kSamples = EGL_SAMPLES,
+  kStencilSize = EGL_STENCIL_SIZE,
+  kSurfaceTypeMask = EGL_SURFACE_TYPE,
+  kTransparentType = EGL_TRANSPARENT_TYPE,
+  kTransparentRedValue = EGL_TRANSPARENT_RED_VALUE,
+  kTransparentGreenValue = EGL_TRANSPARENT_GREEN_VALUE,
+  kTransparentBlueValue = EGL_TRANSPARENT_BLUE_VALUE,
+
+  kRenderableTypeMask = EGL_RENDERABLE_TYPE,
+};
+
+// A "don't care" value for use in attribute lists.
+constexpr int kDontCare = EGL_DONT_CARE;
+
+enum class Api : EGLenum {
+  kOpenglEs = EGL_OPENGL_ES_API,
+  kOpenvg = EGL_OPENVG_API,
+  kOpengl = EGL_OPENGL_API,
+};
+
+enum ApiMask : EGLint {
+  kOpenglEsBit = EGL_OPENGL_ES_BIT,
+  kOpenVgBit = EGL_OPENVG_BIT,
+  kOpenglEs2Bit = EGL_OPENGL_ES2_BIT,
+  kOpenglBit = EGL_OPENGL_BIT,
+};
+
+// The format, type, and size of the buffers for a drawable.
+//
+// This class is thread-safe.
+class Configuration final {
+ public:
+  Configuration(const Configuration&) = default;
+  Configuration& operator=(const Configuration&) = default;
+  Configuration(Configuration&&) noexcept = default;
+  Configuration& operator=(Configuration&&) noexcept = default;
+
+  int Get(Attribute attribute) const;
+
+ private:
+  friend class Display;
+
+  explicit Configuration(EGLDisplay display, EGLConfig config) noexcept
+      : display_(display), config_(config) {}
+
+  EGLDisplay display_;
+  EGLConfig config_;
+};
+
+// A rendering surface.
+//
+// This class inherits the thread-safety properties of the Display that
+// constructed it.
+class Surface final {
+ public:
+  Surface(const Surface&) = default;
+  Surface& operator=(const Surface&) = default;
+  Surface(Surface&&) noexcept = default;
+  Surface& operator=(Surface&&) noexcept = default;
+
+  void SwapBuffers();
+
+ private:
+  friend class Display;
+  friend void BindContext(Surface&, Context&);
+
+  explicit Surface(EGLDisplay display, EGLSurface surface) noexcept
+      : display_(display), surface_(surface) {}
+
+  EGLDisplay display_;
+  EGLSurface surface_;
+};
+
+// A rendering context.
+//
+// This class inherits the thread-safety properties of the Display that
+// constructed it.
+class Context final {
+ public:
+  Context(Context&&) noexcept = default;
+  Context& operator=(Context&&) noexcept = default;
+
+  ~Context() noexcept {
+    // This should always succeed, since display_ and context_ are guaranteed
+    // valid.
+    DCHECK(eglDestroyContext(display_, context_));
+  }
+
+ private:
+  friend class Display;
+  friend void BindContext(Surface&, Context&);
+
+  explicit Context(EGLDisplay display, EGLContext context) noexcept
+      : display_(display), context_(context) {}
+
+  EGLDisplay display_;
+  EGLContext context_;
+};
+
+// The abstract display on which graphics are drawn.
+//
+// This class inherits the thread-safety properties of the underlying Xlib
+// Display with which it is constructed.
+class Display final {
+ public:
+  explicit Display(::Display* xlib_display);
+
+  Display(Display&&) noexcept = default;
+  Display& operator=(Display&&) noexcept = default;
+
+  ~Display() noexcept;
+
+  // Gets Configurations that match the specified attributes. If a limit is
+  // specified, no more than that many Configurations will be returned.
+  //
+  // The returned Configurations hold references into this object and must not
+  // outlive it.
+  std::vector<Configuration> GetConfigurations(
+      const std::vector<std::pair<Attribute, int>>& filter_attributes,
+      absl::optional<int> limit = absl::nullopt) const;
+
+  // Creates a rendering surface on a window.
+  //
+  // The returned Surface holds a reference into this Display and must not
+  // outlive it.
+  Surface CreateWindowSurface(const Configuration& config, ::Window window);
+
+  // Creates an OpenGL context.
+  //
+  // The returned Context holds a reference into this Display and must not
+  // outlive it.
+  Context CreateContext(const Configuration& config, Api api, int major,
+                        int minor);
+
+ private:
+  EGLDisplay display_;
+};
+
+}  // namespace egl
+
+#endif  // GLPLANET_SRC_EGL_H_