From 27a8b3c17baf3952f74948b7842c2350144c8ef2 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Camilla=20L=C3=B6wy?= <elmindreda@glfw.org>
Date: Wed, 15 Mar 2017 17:37:33 +0100
Subject: [PATCH] EGL: Add support for EGL_KHR_context_flush_control

---
 README.md         |  1 +
 src/egl_context.c | 28 +++++++++++++++++++---------
 src/egl_context.h |  4 ++++
 3 files changed, 24 insertions(+), 9 deletions(-)

diff --git a/README.md b/README.md
index 60e8dce5..939aba18 100644
--- a/README.md
+++ b/README.md
@@ -188,6 +188,7 @@ information on what to include when reporting a bug.
 - [Cocoa] Bugfix: Iconified full screen windows could not be restored (#848)
 - [X11] Moved to XI2 `XI_RawMotion` for disable cursor mode motion input (#125)
 - [EGL] Added support for `EGL_KHR_get_all_proc_addresses` (#871)
+- [EGL] Added support for `EGL_KHR_context_flush_control`
 - [EGL] Bugfix: The test for `EGL_RGB_BUFFER` was invalid
 
 
diff --git a/src/egl_context.c b/src/egl_context.c
index 80e9bca0..e73fc0b4 100644
--- a/src/egl_context.c
+++ b/src/egl_context.c
@@ -403,6 +403,8 @@ GLFWbool _glfwInitEGL(void)
         extensionSupportedEGL("EGL_KHR_gl_colorspace");
     _glfw.egl.KHR_get_all_proc_addresses =
         extensionSupportedEGL("EGL_KHR_get_all_proc_addresses");
+    _glfw.egl.KHR_context_flush_control =
+        extensionSupportedEGL("EGL_KHR_context_flush_control");
 
     return GLFW_TRUE;
 }
@@ -440,6 +442,7 @@ GLFWbool _glfwCreateContextEGL(_GLFWwindow* window,
     EGLint attribs[40];
     EGLConfig config;
     EGLContext share = NULL;
+    int index = 0;
 
     if (!_glfw.egl.display)
     {
@@ -480,7 +483,7 @@ GLFWbool _glfwCreateContextEGL(_GLFWwindow* window,
 
     if (_glfw.egl.KHR_create_context)
     {
-        int index = 0, mask = 0, flags = 0;
+        int mask = 0, flags = 0;
 
         if (ctxconfig->client == GLFW_OPENGL_API)
         {
@@ -529,21 +532,28 @@ GLFWbool _glfwCreateContextEGL(_GLFWwindow* window,
 
         if (flags)
             setEGLattrib(EGL_CONTEXT_FLAGS_KHR, flags);
-
-        setEGLattrib(EGL_NONE, EGL_NONE);
     }
     else
     {
-        int index = 0;
-
         if (ctxconfig->client == GLFW_OPENGL_ES_API)
             setEGLattrib(EGL_CONTEXT_CLIENT_VERSION, ctxconfig->major);
-
-        setEGLattrib(EGL_NONE, EGL_NONE);
     }
 
-    // Context release behaviors (GL_KHR_context_flush_control) are not yet
-    // supported on EGL but are not a hard constraint, so ignore and continue
+    if (_glfw.egl.KHR_context_flush_control)
+    {
+        if (ctxconfig->release == GLFW_RELEASE_BEHAVIOR_NONE)
+        {
+            setEGLattrib(EGL_CONTEXT_RELEASE_BEHAVIOR_KHR,
+                         EGL_CONTEXT_RELEASE_BEHAVIOR_NONE_KHR);
+        }
+        else if (ctxconfig->release == GLFW_RELEASE_BEHAVIOR_FLUSH)
+        {
+            setEGLattrib(EGL_CONTEXT_RELEASE_BEHAVIOR_KHR,
+                         EGL_CONTEXT_RELEASE_BEHAVIOR_FLUSH_KHR);
+        }
+    }
+
+    setEGLattrib(EGL_NONE, EGL_NONE);
 
     window->context.egl.handle = eglCreateContext(_glfw.egl.display,
                                                   config, share, attribs);
diff --git a/src/egl_context.h b/src/egl_context.h
index e1040acd..f8393a49 100644
--- a/src/egl_context.h
+++ b/src/egl_context.h
@@ -110,6 +110,9 @@ typedef MirEGLNativeWindowType EGLNativeWindowType;
 #define EGL_CONTEXT_OPENGL_NO_ERROR_KHR 0x31b3
 #define EGL_GL_COLORSPACE_KHR 0x309d
 #define EGL_GL_COLORSPACE_SRGB_KHR 0x3089
+#define EGL_CONTEXT_RELEASE_BEHAVIOR_KHR 0x2097
+#define EGL_CONTEXT_RELEASE_BEHAVIOR_NONE_KHR 0
+#define EGL_CONTEXT_RELEASE_BEHAVIOR_FLUSH_KHR 0x2098
 
 typedef int EGLint;
 typedef unsigned int EGLBoolean;
@@ -181,6 +184,7 @@ typedef struct _GLFWlibraryEGL
     GLFWbool        KHR_create_context_no_error;
     GLFWbool        KHR_gl_colorspace;
     GLFWbool        KHR_get_all_proc_addresses;
+    GLFWbool        KHR_context_flush_control;
 
     void*           handle;