Resolve GLES3 functions from the shared lib

Unfortunately the few functions that are part of the OpenGL ES 3.0
standard and are used by QtGui have to have special handling after all.
Just directly calling the functions causes issues when building on a
GLES3 capable system and deploying somewhere where only GLES2 is available.

Using eglGetProcAddress and such is not an option because the ES spec does
not guarantee that standard functions are resolvable via that mechanism.

Task-number: QTBUG-43318
Change-Id: I72f985d75ca669835839016573cbb8e4a3fb41db
Reviewed-by: Jørgen Lind <jorgen.lind@theqtcompany.com>

1 files changed, 18 insertions, 15 deletions

diff --git a/src/gui/opengl/qopengltexturehelper.cpp b/src/gui/opengl/qopengltexturehelper.cpp
index 29cecf0ea8..e1e3593f4f 100644
--- a/src/gui/opengl/qopengltexturehelper.cpp
+++ b/src/gui/opengl/qopengltexturehelper.cpp
@@ -34,6 +34,7 @@
 #include "qopengltexturehelper_p.h"
 
 #include <QOpenGLContext>
+#include <private/qopenglextensions_p.h>
 
 QT_BEGIN_NAMESPACE
 
@@ -242,21 +243,23 @@ QOpenGLTextureHelper::QOpenGLTextureHelper(QOpenGLContext *context)
         CompressedTexImage3D = reinterpret_cast<void (QOPENGLF_APIENTRYP)(GLenum, GLint, GLenum, GLsizei, GLsizei, GLsizei, GLint, GLsizei, const GLvoid*)>(context->getProcAddress(QByteArrayLiteral("glCompressedTexImage3DOES")));
         CompressedTexSubImage3D = reinterpret_cast<void (QOPENGLF_APIENTRYP)(GLenum, GLint, GLint, GLint, GLint, GLsizei, GLsizei, GLsizei, GLenum, GLsizei, const GLvoid*)>(context->getProcAddress(QByteArrayLiteral("glCompressedTexSubImage3DOES")));
     } else {
-#ifdef QT_OPENGL_ES_3
-        // OpenGL ES 3.0+ has glTexImage3D.
-        TexImage3D = ::glTexImage3D;
-        TexSubImage3D = ::glTexSubImage3D;
-        CompressedTexImage3D = ::glCompressedTexImage3D;
-        CompressedTexSubImage3D = ::glCompressedTexSubImage3D;
-#else
-        // OpenGL 1.2
-        TexImage3D = reinterpret_cast<void (QOPENGLF_APIENTRYP)(GLenum , GLint , GLint , GLsizei , GLsizei , GLsizei , GLint , GLenum , GLenum , const GLvoid *)>(context->getProcAddress(QByteArrayLiteral("glTexImage3D")));
-        TexSubImage3D = reinterpret_cast<void (QOPENGLF_APIENTRYP)(GLenum , GLint , GLint , GLint , GLint , GLsizei , GLsizei , GLsizei , GLenum , GLenum , const GLvoid *)>(context->getProcAddress(QByteArrayLiteral("glTexSubImage3D")));
-
-        // OpenGL 1.3
-        CompressedTexImage3D = reinterpret_cast<void (QOPENGLF_APIENTRYP)(GLenum , GLint , GLenum , GLsizei , GLsizei , GLsizei , GLint , GLsizei , const GLvoid *)>(context->getProcAddress(QByteArrayLiteral("glCompressedTexImage3D")));
-        CompressedTexSubImage3D = reinterpret_cast<void (QOPENGLF_APIENTRYP)(GLenum , GLint , GLint , GLint , GLint , GLsizei , GLsizei , GLsizei , GLenum , GLsizei , const GLvoid *)>(context->getProcAddress(QByteArrayLiteral("glCompressedTexSubImage3D")));
-#endif
+        QOpenGLContext *ctx = QOpenGLContext::currentContext();
+        if (ctx->isOpenGLES() && ctx->format().majorVersion() >= 3) {
+            // OpenGL ES 3.0+ has glTexImage3D.
+            QOpenGLES3Helper *es3 = static_cast<QOpenGLExtensions *>(ctx->functions())->gles3Helper();
+            TexImage3D = es3->TexImage3D;
+            TexSubImage3D = es3->TexSubImage3D;
+            CompressedTexImage3D = es3->CompressedTexImage3D;
+            CompressedTexSubImage3D = es3->CompressedTexSubImage3D;
+        } else {
+            // OpenGL 1.2
+            TexImage3D = reinterpret_cast<void (QOPENGLF_APIENTRYP)(GLenum , GLint , GLint , GLsizei , GLsizei , GLsizei , GLint , GLenum , GLenum , const GLvoid *)>(context->getProcAddress(QByteArrayLiteral("glTexImage3D")));
+            TexSubImage3D = reinterpret_cast<void (QOPENGLF_APIENTRYP)(GLenum , GLint , GLint , GLint , GLint , GLsizei , GLsizei , GLsizei , GLenum , GLenum , const GLvoid *)>(context->getProcAddress(QByteArrayLiteral("glTexSubImage3D")));
+
+            // OpenGL 1.3
+            CompressedTexImage3D = reinterpret_cast<void (QOPENGLF_APIENTRYP)(GLenum , GLint , GLenum , GLsizei , GLsizei , GLsizei , GLint , GLsizei , const GLvoid *)>(context->getProcAddress(QByteArrayLiteral("glCompressedTexImage3D")));
+            CompressedTexSubImage3D = reinterpret_cast<void (QOPENGLF_APIENTRYP)(GLenum , GLint , GLint , GLint , GLint , GLsizei , GLsizei , GLsizei , GLenum , GLsizei , const GLvoid *)>(context->getProcAddress(QByteArrayLiteral("glCompressedTexSubImage3D")));
+        }
     }
 
 #ifndef QT_OPENGL_ES_2