Prevent crashing on ES2 SDK - ES3 device scenarios with Android

Making a build with an older NDK having only gl2.h results in crashing
QOpenGLTexture on devices that provide ES 3.0 or 3.1. This is because
immutable storage is supported (based on runtime checks) but the function
pointers are not there (due to ifdef checks).

Fix this like we did in other places: get rid of the ifdef and dlsym the
ES3-only symbols.

Task-number: QTBUG-44397
Change-Id: Ief518ec8c7d532aeea0075ba166baf8d22e66ec5
Reviewed-by: Sean Harmer <sean.harmer@kdab.com>

3 files changed, 17 insertions, 8 deletions

diff --git a/src/gui/opengl/qopenglextensions_p.h b/src/gui/opengl/qopenglextensions_p.h
index aa712f51a3..aa2f784d86 100644
--- a/src/gui/opengl/qopenglextensions_p.h
+++ b/src/gui/opengl/qopenglextensions_p.h
@@ -72,6 +72,9 @@ public:
     void (QOPENGLF_APIENTRYP CompressedTexImage3D)(GLenum target, GLint level, GLenum internalFormat, GLsizei width, GLsizei height, GLsizei depth, GLint border, GLsizei imageSize, const GLvoid *data);
     void (QOPENGLF_APIENTRYP CompressedTexSubImage3D)(GLenum target, GLint level, GLint xoffset, GLint yoffset, GLint zoffset, GLsizei width, GLsizei height, GLsizei depth, GLenum format, GLsizei imageSize, const GLvoid *data);
 
+    void (QOPENGLF_APIENTRYP TexStorage3D)(GLenum target, GLsizei levels, GLenum internalFormat, GLsizei width, GLsizei height, GLsizei depth);
+    void (QOPENGLF_APIENTRYP TexStorage2D)(GLenum target, GLsizei levels, GLenum internalFormat, GLsizei width, GLsizei height);
+
 private:
     QLibrary m_gl;
 };
diff --git a/src/gui/opengl/qopenglfunctions.cpp b/src/gui/opengl/qopenglfunctions.cpp
index aefea9a0e9..587995515d 100644
--- a/src/gui/opengl/qopenglfunctions.cpp
+++ b/src/gui/opengl/qopenglfunctions.cpp
@@ -3229,7 +3229,10 @@ QOpenGLES3Helper::QOpenGLES3Helper()
         CompressedTexImage3D = (void (QOPENGLF_APIENTRYP)(GLenum, GLint, GLenum, GLsizei, GLsizei, GLsizei, GLint, GLsizei, const GLvoid *)) m_gl.resolve("glCompressedTexImage3D");
         CompressedTexSubImage3D = (void (QOPENGLF_APIENTRYP)(GLenum, GLint, GLint, GLint, GLint, GLsizei, GLsizei, GLsizei, GLenum, GLsizei, const GLvoid *)) m_gl.resolve("glCompressedTexSubImage3D");
 
-        if (!MapBufferRange || !GenVertexArrays || !TexImage3D)
+        TexStorage3D = (void (QOPENGLF_APIENTRYP)(GLenum, GLsizei, GLenum, GLsizei, GLsizei, GLsizei)) m_gl.resolve("glTexStorage3D");
+        TexStorage2D = (void (QOPENGLF_APIENTRYP)(GLenum, GLsizei, GLenum, GLsizei, GLsizei)) m_gl.resolve("glTexStorage2D");
+
+        if (!MapBufferRange || !GenVertexArrays || !TexImage3D || !TexStorage3D)
             qFatal("OpenGL ES 3.0 entry points not found");
     } else {
         qFatal("Failed to load libGLESv2");
diff --git a/src/gui/opengl/qopengltexturehelper.cpp b/src/gui/opengl/qopengltexturehelper.cpp
index 3f55dfdba7..386c4af232 100644
--- a/src/gui/opengl/qopengltexturehelper.cpp
+++ b/src/gui/opengl/qopengltexturehelper.cpp
@@ -201,13 +201,16 @@ QOpenGLTextureHelper::QOpenGLTextureHelper(QOpenGLContext *context)
     TexImage2DMultisample = 0;
 
     // OpenGL 4.2
-#ifdef QT_OPENGL_ES_3
-    TexStorage3D = ::glTexStorage3D;
-    TexStorage2D = ::glTexStorage2D;
-#else
-    TexStorage3D = 0;
-    TexStorage2D = 0;
-#endif
+    QOpenGLContext *ctx = QOpenGLContext::currentContext();
+    if (ctx->format().majorVersion() >= 3) {
+        // OpenGL ES 3.0+ has immutable storage for 2D and 3D at least.
+        QOpenGLES3Helper *es3 = static_cast<QOpenGLExtensions *>(ctx->functions())->gles3Helper();
+        TexStorage3D = es3->TexStorage3D;
+        TexStorage2D = es3->TexStorage2D;
+    } else {
+        TexStorage3D = 0;
+        TexStorage2D = 0;
+    }
     TexStorage1D = 0;
 
     // OpenGL 4.3