From 42c8c7e9dbf4c9e67b88bd16f0fe4e0d3c57857b Mon Sep 17 00:00:00 2001
From: James Turner <james.turner@kdab.com>
Date: Tue, 15 Oct 2013 18:32:02 +0100
Subject: Support APPLE VAO extension on Mac.

Since Mac lacks a compatibility profile, we often use the highest
supported compatible version, 2.1; this lacks vertex-array-object (VAO)
support in the API, but Apple provide a compatible extension. Extend
the helper object to detect this case and make VAO support work.

Change-Id: I75a74e048a0d188cec76bc5a4a9eafa4c9143740
Reviewed-by: Sean Harmer <sean.harmer@kdab.com>
---
 src/gui/opengl/qopenglvertexarrayobject.cpp | 40 +++++++++++++++++++----------
 1 file changed, 27 insertions(+), 13 deletions(-)

diff --git a/src/gui/opengl/qopenglvertexarrayobject.cpp b/src/gui/opengl/qopenglvertexarrayobject.cpp
index 16ed79ac10..1f039a8ca9 100644
--- a/src/gui/opengl/qopenglvertexarrayobject.cpp
+++ b/src/gui/opengl/qopenglvertexarrayobject.cpp
@@ -58,9 +58,15 @@ public:
     {
         Q_ASSERT(context);
 #if !defined(QT_OPENGL_ES_2)
-        GenVertexArrays = reinterpret_cast<void (QOPENGLF_APIENTRYP)(GLsizei , GLuint *)>(context->getProcAddress("glGenVertexArrays"));
-        DeleteVertexArrays = reinterpret_cast<void (QOPENGLF_APIENTRYP)(GLsizei , const GLuint *)>(context->getProcAddress("glDeleteVertexArrays"));
-        BindVertexArray = reinterpret_cast<void (QOPENGLF_APIENTRYP)(GLuint )>(context->getProcAddress("glBindVertexArray"));
+        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("glGenVertexArrays"));
+            DeleteVertexArrays = reinterpret_cast<void (QOPENGLF_APIENTRYP)(GLsizei , const GLuint *)>(context->getProcAddress("glDeleteVertexArrays"));
+            BindVertexArray = reinterpret_cast<void (QOPENGLF_APIENTRYP)(GLuint )>(context->getProcAddress("glBindVertexArray"));
+        }
 #else
         GenVertexArrays = reinterpret_cast<void (QOPENGLF_APIENTRYP)(GLsizei , GLuint *)>(context->getProcAddress("glGenVertexArraysOES"));
         DeleteVertexArrays = reinterpret_cast<void (QOPENGLF_APIENTRYP)(GLsizei , const GLuint *)>(context->getProcAddress("glDeleteVertexArraysOES"));
@@ -84,7 +90,7 @@ public:
     }
 
 private:
-    // Function signatures are equivalent between desktop core, ARB and ES 2 extensions
+    // Function signatures are equivalent between desktop core, ARB, APPLE 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);
@@ -109,8 +115,8 @@ public:
 #if defined(QT_OPENGL_ES_2)
         delete vaoFuncs;
 #else
-        if (vaoFuncsType == ARB)
-            delete vaoFuncs.arb;
+        if ((vaoFuncsType == ARB) || (vaoFuncsType == APPLE))
+            delete vaoFuncs.helper;
 #endif
     }
 
@@ -130,13 +136,14 @@ public:
     union {
         QOpenGLFunctions_3_0 *core_3_0;
         QOpenGLFunctions_3_2_Core *core_3_2;
-        QVertexArrayObjectHelper *arb;
+        QVertexArrayObjectHelper *helper;
     } vaoFuncs;
     enum {
         NotSupported,
         Core_3_0,
         Core_3_2,
-        ARB
+        ARB,
+        APPLE
     } vaoFuncsType;
 #endif
     QOpenGLContext *context;
@@ -181,9 +188,13 @@ bool QOpenGLVertexArrayObjectPrivate::create()
         vaoFuncs.core_3_0->initializeOpenGLFunctions();
         vaoFuncs.core_3_0->glGenVertexArrays(1, &vao);
     } else if (ctx->hasExtension("GL_ARB_vertex_array_object")) {
-        vaoFuncs.arb = new QVertexArrayObjectHelper(ctx);
+        vaoFuncs.helper = new QVertexArrayObjectHelper(ctx);
         vaoFuncsType = ARB;
-        vaoFuncs.arb->glGenVertexArrays(1, &vao);
+        vaoFuncs.helper->glGenVertexArrays(1, &vao);
+    } else if (ctx->hasExtension(QByteArrayLiteral("GL_APPLE_vertex_array_object"))) {
+        vaoFuncs.helper = new QVertexArrayObjectHelper(ctx);
+        vaoFuncsType = APPLE;
+        vaoFuncs.helper->glGenVertexArrays(1, &vao);
     }
 #endif
     return (vao != 0);
@@ -205,7 +216,8 @@ void QOpenGLVertexArrayObjectPrivate::destroy()
         vaoFuncs.core_3_0->glDeleteVertexArrays(1, &vao);
         break;
     case ARB:
-        vaoFuncs.arb->glDeleteVertexArrays(1, &vao);
+    case APPLE:
+        vaoFuncs.helper->glDeleteVertexArrays(1, &vao);
         break;
     case NotSupported:
         break;
@@ -236,7 +248,8 @@ void QOpenGLVertexArrayObjectPrivate::bind()
         vaoFuncs.core_3_0->glBindVertexArray(vao);
         break;
     case ARB:
-        vaoFuncs.arb->glBindVertexArray(vao);
+    case APPLE:
+        vaoFuncs.helper->glBindVertexArray(vao);
         break;
     case NotSupported:
         break;
@@ -258,7 +271,8 @@ void QOpenGLVertexArrayObjectPrivate::release()
         vaoFuncs.core_3_0->glBindVertexArray(0);
         break;
     case ARB:
-        vaoFuncs.arb->glBindVertexArray(0);
+    case APPLE:
+        vaoFuncs.helper->glBindVertexArray(0);
         break;
     case NotSupported:
         break;
-- 
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