From 0541516907da117c391b6c8d9820209673fcd9cd Mon Sep 17 00:00:00 2001
From: Laszlo Agocs <laszlo.agocs@digia.com>
Date: Wed, 2 Jul 2014 16:33:15 +0200
Subject: Use the standard functions in GLES3 builds in VAOs

There is no guarantee that the OES extension is present and the standard
functions are not required to be dynamically resolvable on ES.

By performing the ARB-style lookup for the suffixless function names we
can also support ES3 compatible contexts on desktop GL.

This also fixes the problem of picking up the APPLE extension functions
instead of ARB when both are available. vaoFuncsType was set to ARB correctly
but the helper has to take the preference of ARB into account too.

Task-number: QTBUG-38168
Change-Id: If7402320e8f96891017674f3c43bc57c4b5d29f3
Reviewed-by: Sean Harmer <sean.harmer@kdab.com>
---
 src/gui/opengl/qopenglvertexarrayobject.cpp | 42 +++++++++++++++++++----------
 1 file changed, 28 insertions(+), 14 deletions(-)

(limited to 'src/gui/opengl/qopenglvertexarrayobject.cpp')

diff --git a/src/gui/opengl/qopenglvertexarrayobject.cpp b/src/gui/opengl/qopenglvertexarrayobject.cpp
index 5ebfc9a9c82..d9b9385751a 100644
--- a/src/gui/opengl/qopenglvertexarrayobject.cpp
+++ b/src/gui/opengl/qopenglvertexarrayobject.cpp
@@ -60,20 +60,34 @@ public:
     QVertexArrayObjectHelper(QOpenGLContext *context)
     {
         Q_ASSERT(context);
+        bool tryARB = true;
+
         if (context->isOpenGLES()) {
-            GenVertexArrays = reinterpret_cast<void (QOPENGLF_APIENTRYP)(GLsizei , GLuint *)>(context->getProcAddress(QByteArrayLiteral("glGenVertexArraysOES")));
-            DeleteVertexArrays = reinterpret_cast<void (QOPENGLF_APIENTRYP)(GLsizei , const GLuint *)>(context->getProcAddress(QByteArrayLiteral("glDeleteVertexArraysOES")));
-            BindVertexArray = reinterpret_cast<void (QOPENGLF_APIENTRYP)(GLuint )>(context->getProcAddress(QByteArrayLiteral("glBindVertexArrayOES")));
-        } else {
-            if (context->hasExtension(QByteArrayLiteral("GL_APPLE_vertex_array_object"))) {
-                GenVertexArrays = reinterpret_cast<void (QOPENGLF_APIENTRYP)(GLsizei , GLuint *)>(context->getProcAddress(QByteArrayLiteral("glGenVertexArraysAPPLE")));
-                DeleteVertexArrays = reinterpret_cast<void (QOPENGLF_APIENTRYP)(GLsizei , const GLuint *)>(context->getProcAddress(QByteArrayLiteral("glDeleteVertexArraysAPPLE")));
-                BindVertexArray = reinterpret_cast<void (QOPENGLF_APIENTRYP)(GLuint )>(context->getProcAddress(QByteArrayLiteral("glBindVertexArrayAPPLE")));
-            } else {
-                GenVertexArrays = reinterpret_cast<void (QOPENGLF_APIENTRYP)(GLsizei , GLuint *)>(context->getProcAddress(QByteArrayLiteral("glGenVertexArrays")));
-                DeleteVertexArrays = reinterpret_cast<void (QOPENGLF_APIENTRYP)(GLsizei , const GLuint *)>(context->getProcAddress(QByteArrayLiteral("glDeleteVertexArrays")));
-                BindVertexArray = reinterpret_cast<void (QOPENGLF_APIENTRYP)(GLuint )>(context->getProcAddress(QByteArrayLiteral("glBindVertexArray")));
+#ifdef QT_OPENGL_ES_3
+            GenVertexArrays = ::glGenVertexArrays;
+            DeleteVertexArrays = ::glDeleteVertexArrays;
+            BindVertexArray = ::glBindVertexArray;
+            tryARB = false;
+#else
+            if (context->hasExtension(QByteArrayLiteral("GL_OES_vertex_array_object"))) {
+                GenVertexArrays = reinterpret_cast<void (QOPENGLF_APIENTRYP)(GLsizei , GLuint *)>(context->getProcAddress(QByteArrayLiteral("glGenVertexArraysOES")));
+                DeleteVertexArrays = reinterpret_cast<void (QOPENGLF_APIENTRYP)(GLsizei , const GLuint *)>(context->getProcAddress(QByteArrayLiteral("glDeleteVertexArraysOES")));
+                BindVertexArray = reinterpret_cast<void (QOPENGLF_APIENTRYP)(GLuint )>(context->getProcAddress(QByteArrayLiteral("glBindVertexArrayOES")));
+                tryARB = false;
             }
+#endif
+        } else if (!context->hasExtension(QByteArrayLiteral("GL_ARB_vertex_array_object"))
+                   && context->hasExtension(QByteArrayLiteral("GL_APPLE_vertex_array_object"))) {
+            GenVertexArrays = reinterpret_cast<void (QOPENGLF_APIENTRYP)(GLsizei , GLuint *)>(context->getProcAddress(QByteArrayLiteral("glGenVertexArraysAPPLE")));
+            DeleteVertexArrays = reinterpret_cast<void (QOPENGLF_APIENTRYP)(GLsizei , const GLuint *)>(context->getProcAddress(QByteArrayLiteral("glDeleteVertexArraysAPPLE")));
+            BindVertexArray = reinterpret_cast<void (QOPENGLF_APIENTRYP)(GLuint )>(context->getProcAddress(QByteArrayLiteral("glBindVertexArrayAPPLE")));
+            tryARB = false;
+        }
+
+        if (tryARB) {
+            GenVertexArrays = reinterpret_cast<void (QOPENGLF_APIENTRYP)(GLsizei , GLuint *)>(context->getProcAddress(QByteArrayLiteral("glGenVertexArrays")));
+            DeleteVertexArrays = reinterpret_cast<void (QOPENGLF_APIENTRYP)(GLsizei , const GLuint *)>(context->getProcAddress(QByteArrayLiteral("glDeleteVertexArrays")));
+            BindVertexArray = reinterpret_cast<void (QOPENGLF_APIENTRYP)(GLuint )>(context->getProcAddress(QByteArrayLiteral("glBindVertexArray")));
         }
     }
 
@@ -93,7 +107,7 @@ public:
     }
 
 private:
-    // Function signatures are equivalent between desktop core, ARB, APPLE and ES 2 extensions
+    // Function signatures are equivalent between desktop core, ARB, APPLE, ES3 and ES 2 extensions
     void (QOPENGLF_APIENTRYP GenVertexArrays)(GLsizei n, GLuint *arrays);
     void (QOPENGLF_APIENTRYP DeleteVertexArrays)(GLsizei n, const GLuint *arrays);
     void (QOPENGLF_APIENTRYP BindVertexArray)(GLuint array);
@@ -160,7 +174,7 @@ bool QOpenGLVertexArrayObjectPrivate::create()
     QObject::connect(context, SIGNAL(aboutToBeDestroyed()), q, SLOT(_q_contextAboutToBeDestroyed()));
 
     if (ctx->isOpenGLES()) {
-        if (ctx->hasExtension(QByteArrayLiteral("GL_OES_vertex_array_object"))) {
+        if (ctx->format().majorVersion() >= 3 || ctx->hasExtension(QByteArrayLiteral("GL_OES_vertex_array_object"))) {
             vaoFuncs.helper = new QVertexArrayObjectHelper(ctx);
             vaoFuncsType = OES;
             vaoFuncs.helper->glGenVertexArrays(1, &vao);
-- 
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