Enable building Qt Quick module with QT_NO_OPENGL defined

Currently the Qt Quick module depends on either the OpenGL or OpenGLES
headers being available at build time.  Since we are adding support for
adaptations that do not depend on OpenGL, it should be possible to build
Qt Quick in environments that do not have OpenGL development headers.

This does present many challenges though because in some cases GL types,
and classes that require OpenGL are part of the public APIs.  However
since these classes were never available when QT_NO_OPENGL was defined,
it should be possible to redefine the function signatures under this
scenario, since it's not possible to break binary compatibility if there
never were any binaries to break compatibility with.

One of the bigger changes that was necessary to facilitate this change
is creating interfaces out of QSGContext and QSGRenderContext.  Here the
default behavior was usage of OpenGL directly, even though subclasses
could override all OpenGL usage. Making them interfaces should bring
QSGContext and QSGRenderContext more in line with the other classes
present in the adaptation layer.

Change-Id: Iaa54dc0f6cfd18d2da1d059548abf509bd71f200
Reviewed-by: Laszlo Agocs <laszlo.agocs@theqtcompany.com>

1 files changed, 21 insertions, 5 deletions

diff --git a/src/quick/scenegraph/util/qsgtexture.cpp b/src/quick/scenegraph/util/qsgtexture.cpp
index 74390334c4..751406f12c 100644
--- a/src/quick/scenegraph/util/qsgtexture.cpp
+++ b/src/quick/scenegraph/util/qsgtexture.cpp
@@ -38,7 +38,6 @@
 ****************************************************************************/
 
 #include "qsgtexture_p.h"
-#include <qopenglfunctions.h>
 #include <QtQuick/private/qsgcontext_p.h>
 #include <qthread.h>
 #include <qmath.h>
@@ -46,9 +45,12 @@
 #include <private/qqmlglobal_p.h>
 #include <QtGui/qguiapplication.h>
 #include <QtGui/qpa/qplatformnativeinterface.h>
-#include <QtGui/qopenglcontext.h>
-#include <QtGui/qopenglfunctions.h>
-
+#ifndef QT_NO_OPENGL
+# include <qopenglfunctions.h>
+# include <QtGui/qopenglcontext.h>
+# include <QtGui/qopenglfunctions.h>
+# include <private/qsgdefaultrendercontext_p.h>
+#endif
 #include <private/qsgmaterialshader_p.h>
 
 #if defined(Q_OS_LINUX) && !defined(Q_OS_ANDROID) && !defined(__UCLIBC__)
@@ -278,6 +280,7 @@ Q_GLOBAL_STATIC(QMutex, qsg_valid_texture_mutex)
 
 bool qsg_safeguard_texture(QSGTexture *texture)
 {
+#ifndef QT_NO_OPENGL
     QMutexLocker locker(qsg_valid_texture_mutex());
     if (!qsg_valid_texture_set()->contains(texture)) {
         qWarning() << "Invalid texture accessed:" << (void *) texture;
@@ -285,6 +288,7 @@ bool qsg_safeguard_texture(QSGTexture *texture)
         QOpenGLContext::currentContext()->functions()->glBindTexture(GL_TEXTURE_2D, 0);
         return false;
     }
+#endif
     return true;
 }
 #endif
@@ -517,6 +521,7 @@ QSGTexture::WrapMode QSGTexture::verticalWrapMode() const
  */
 void QSGTexture::updateBindOptions(bool force)
 {
+#ifndef QT_NO_OPENGL
     Q_D(QSGTexture);
     QOpenGLFunctions *funcs = QOpenGLContext::currentContext()->functions();
     force |= isAtlasTexture();
@@ -551,6 +556,9 @@ void QSGTexture::updateBindOptions(bool force)
         funcs->glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, d->verticalWrap == Repeat ? GL_REPEAT : GL_CLAMP_TO_EDGE);
         d->wrapChanged = false;
     }
+#else
+    Q_UNUSED(force)
+#endif
 }
 
 QSGPlainTexture::QSGPlainTexture()
@@ -568,8 +576,10 @@ QSGPlainTexture::QSGPlainTexture()
 
 QSGPlainTexture::~QSGPlainTexture()
 {
+#ifndef QT_NO_OPENGL
     if (m_texture_id && m_owns_texture && QOpenGLContext::currentContext())
         QOpenGLContext::currentContext()->functions()->glDeleteTextures(1, &m_texture_id);
+#endif
 }
 
 void qsg_swizzleBGRAToRGBA(QImage *image)
@@ -601,8 +611,10 @@ int QSGPlainTexture::textureId() const
             // or ~QSGPlainTexture so just keep it minimal here.
             return 0;
         } else if (m_texture_id == 0){
+#ifndef QT_NO_OPENGL
             // Generate a texture id for use later and return it.
             QOpenGLContext::currentContext()->functions()->glGenTextures(1, &const_cast<QSGPlainTexture *>(this)->m_texture_id);
+#endif
             return m_texture_id;
         }
     }
@@ -611,8 +623,10 @@ int QSGPlainTexture::textureId() const
 
 void QSGPlainTexture::setTextureId(int id)
 {
+#ifndef QT_NO_OPENGL
     if (m_texture_id && m_owns_texture)
         QOpenGLContext::currentContext()->functions()->glDeleteTextures(1, &m_texture_id);
+#endif
 
     m_texture_id = id;
     m_dirty_texture = false;
@@ -623,6 +637,7 @@ void QSGPlainTexture::setTextureId(int id)
 
 void QSGPlainTexture::bind()
 {
+#ifndef QT_NO_OPENGL
     QOpenGLContext *context = QOpenGLContext::currentContext();
     QOpenGLFunctions *funcs = context->functions();
     if (!m_dirty_texture) {
@@ -684,7 +699,7 @@ void QSGPlainTexture::bind()
     // based on QSGTexture::textureSize which is updated after this, so that
     // should be ok.
     int max;
-    if (QSGRenderContext *rc = QSGRenderContext::from(context))
+    if (auto rc = QSGDefaultRenderContext::from(context))
         max = rc->maxTextureSize();
     else
         funcs->glGetIntegerv(GL_MAX_TEXTURE_SIZE, &max);
@@ -789,6 +804,7 @@ void QSGPlainTexture::bind()
     m_dirty_bind_options = false;
     if (!m_retain_image)
         m_image = QImage();
+#endif
 }