From f207997b59f1381cf3523521209cb435b1a73f25 Mon Sep 17 00:00:00 2001
From: Jani Hautakangas <jani.hautakangas@ixonos.com>
Date: Thu, 16 May 2013 09:52:07 +0300
Subject: [PATCH] QOpenGLPaintDevice sub-area support

Allows creating QOpenGLPaintDevice targetting sub-area
of binded framebuffer.

Upstream-Status: Pending

Change-Id: Ida2f079aa1ac0b87d36b54129e226399dbcdda80

Signed-off-by: Martin Jansa <Martin.Jansa@gmail.com>
---
 src/gui/opengl/qopenglpaintdevice.cpp       | 11 +++++++++++
 src/gui/opengl/qopenglpaintdevice.h         |  2 ++
 src/gui/opengl/qopenglpaintdevice_p.h       |  1 +
 src/gui/opengl/qopenglpaintengine.cpp       |  9 +++++++--
 src/gui/opengl/qopenglpaintengine_p.h       |  1 +
 src/gui/opengl/qopengltextureglyphcache.cpp |  2 +-
 6 files changed, 23 insertions(+), 3 deletions(-)

diff --git a/src/gui/opengl/qopenglpaintdevice.cpp b/src/gui/opengl/qopenglpaintdevice.cpp
index 75f09d6..17d7155 100644
--- a/src/gui/opengl/qopenglpaintdevice.cpp
+++ b/src/gui/opengl/qopenglpaintdevice.cpp
@@ -141,6 +141,12 @@ QOpenGLPaintDevice::QOpenGLPaintDevice(int width, int height)
 {
 }
 
+QOpenGLPaintDevice::QOpenGLPaintDevice(int x, int y, int width, int height)
+    : d_ptr(new QOpenGLPaintDevicePrivate(QSize(width, height)))
+{
+    d_ptr->offset = QPoint(x,y);
+}
+
 /*!
     \internal
  */
@@ -222,6 +228,11 @@ QOpenGLContext *QOpenGLPaintDevice::context() const
     return d_ptr->ctx;
 }
 
+QPoint QOpenGLPaintDevice::offset() const
+{
+    return d_ptr->offset;
+}
+
 /*!
     Returns the pixel size of the paint device.
 
diff --git a/src/gui/opengl/qopenglpaintdevice.h b/src/gui/opengl/qopenglpaintdevice.h
index dffa68c..66a1e3d 100644
--- a/src/gui/opengl/qopenglpaintdevice.h
+++ b/src/gui/opengl/qopenglpaintdevice.h
@@ -59,12 +59,14 @@ public:
     QOpenGLPaintDevice();
     explicit QOpenGLPaintDevice(const QSize &size);
     QOpenGLPaintDevice(int width, int height);
+    QOpenGLPaintDevice(int x, int y, int width, int height);
     virtual ~QOpenGLPaintDevice();
 
     int devType() const { return QInternal::OpenGL; }
     QPaintEngine *paintEngine() const;
 
     QOpenGLContext *context() const;
+    QPoint offset() const;
     QSize size() const;
     void setSize(const QSize &size);
     void setDevicePixelRatio(qreal devicePixelRatio);
diff --git a/src/gui/opengl/qopenglpaintdevice_p.h b/src/gui/opengl/qopenglpaintdevice_p.h
index 78e6b7a..6630461 100644
--- a/src/gui/opengl/qopenglpaintdevice_p.h
+++ b/src/gui/opengl/qopenglpaintdevice_p.h
@@ -71,6 +71,7 @@ public:
 
 public:
     QSize size;
+    QPoint offset;
     QOpenGLContext *ctx;
 
     qreal dpmx;
diff --git a/src/gui/opengl/qopenglpaintengine.cpp b/src/gui/opengl/qopenglpaintengine.cpp
index d93871c..be2bee9 100644
--- a/src/gui/opengl/qopenglpaintengine.cpp
+++ b/src/gui/opengl/qopenglpaintengine.cpp
@@ -2084,7 +2084,10 @@ bool QOpenGL2PaintEngineEx::begin(QPaintDevice *pdev)
     for (int i = 0; i < QT_GL_VERTEX_ARRAY_TRACKED_COUNT; ++i)
         d->vertexAttributeArraysEnabledState[i] = false;
 
+    const QPoint offset = d->device->offset();
     const QSize sz = d->device->size();
+    d->x = offset.x();
+    d->y = offset.y();
     d->width = sz.width();
     d->height = sz.height();
     d->mode = BrushDrawingMode;
@@ -2171,7 +2174,7 @@ void QOpenGL2PaintEngineEx::ensureActive()
         d->device->ensureActiveTarget();
 
         d->transferMode(BrushDrawingMode);
-        d->funcs.glViewport(0, 0, d->width, d->height);
+        d->funcs.glViewport(d->x, d->y, d->width, d->height);
         d->needsSync = false;
         d->shaderManager->setDirty();
         d->syncGlState();
@@ -2213,6 +2216,7 @@ void QOpenGL2PaintEngineExPrivate::updateClipScissorTest()
     if (bounds == QRect(0, 0, width, height)) {
         funcs.glDisable(GL_SCISSOR_TEST);
     } else {
+        bounds = QRect(bounds.x(), bounds.y(), bounds.width(), bounds.height());
         funcs.glEnable(GL_SCISSOR_TEST);
         setScissor(bounds);
     }
@@ -2221,12 +2225,13 @@ void QOpenGL2PaintEngineExPrivate::updateClipScissorTest()
 
 void QOpenGL2PaintEngineExPrivate::setScissor(const QRect &rect)
 {
-    const int left = rect.left();
+    const int left = rect.left() + x;
     const int width = rect.width();
     int bottom = height - (rect.top() + rect.height());
     if (device->paintFlipped()) {
         bottom = rect.top();
     }
+    bottom += y;
     const int height = rect.height();
 
     funcs.glScissor(left, bottom, width, height);
diff --git a/src/gui/opengl/qopenglpaintengine_p.h b/src/gui/opengl/qopenglpaintengine_p.h
index c9f3282..7c0616b 100644
--- a/src/gui/opengl/qopenglpaintengine_p.h
+++ b/src/gui/opengl/qopenglpaintengine_p.h
@@ -270,6 +270,7 @@ public:
     QOpenGL2PaintEngineEx* q;
     QOpenGLEngineShaderManager* shaderManager;
     QOpenGLPaintDevice* device;
+    int x, y;
     int width, height;
     QOpenGLContext *ctx;
     EngineMode mode;
diff --git a/src/gui/opengl/qopengltextureglyphcache.cpp b/src/gui/opengl/qopengltextureglyphcache.cpp
index 9a7b1eb..6f301f8 100644
--- a/src/gui/opengl/qopengltextureglyphcache.cpp
+++ b/src/gui/opengl/qopengltextureglyphcache.cpp
@@ -403,7 +403,7 @@ void QOpenGLTextureGlyphCache::resizeTextureData(int width, int height)
     funcs->glBindFramebuffer(GL_FRAMEBUFFER, (GLuint)oldFbo);
 
     if (pex != 0) {
-        funcs->glViewport(0, 0, pex->width, pex->height);
+        funcs->glViewport(pex->x, pex->y, pex->width, pex->height);
         pex->updateClipScissorTest();
     } else {
         if (m_vao.isCreated()) {