Replace QGLDrawable with a new QGLPaintDevice

This patch adds a new abstract base class which inherits from
QPaintDevice called QGLPaintDevice. This base class will contain
everything the GL paint engines need to know about the surface they are
drawing onto. As such, new surfaces can be targeted by the GL paint
engines without having to modify QtOpenGL. This is very useful for
plugins, specifically QGraphicsSystem plugins.

To unify things a little, the GL paint engines will use the same
QGLPaintDevice API to render into existing target surfaces (QGLWidget,
QGLPixelBuffer & QGLFrameBufferObject). Ideally we'd make QGLPaintDevice
a common ancestor for these surfaces, but obviously that wil break B/C.

This patch only implements QGLWidget using the new interface. Rendering
to other surfaces will be fixed in following patches.

1 files changed, 64 insertions, 49 deletions

diff --git a/src/opengl/qpaintengine_opengl.cpp b/src/opengl/qpaintengine_opengl.cpp
index bf4d4b9..634067d 100644
--- a/src/opengl/qpaintengine_opengl.cpp
+++ b/src/opengl/qpaintengine_opengl.cpp
@@ -49,6 +49,7 @@
 #include "qbrush.h"
 #include "qgl.h"
 #include <private/qgl_p.h>
+#include <private/qglpaintdevice_p.h>
 #include <private/qpainter_p.h>
 #include "qmap.h"
 #include <private/qpaintengine_opengl_p.h>
@@ -75,7 +76,7 @@
 #include "qgl_cl_p.h"
 #endif
 
-#define QGL_FUNC_CONTEXT QGLContext *ctx = const_cast<QGLContext *>(drawable.context());
+#define QGL_FUNC_CONTEXT QGLContext *ctx = const_cast<QGLContext *>(device->context());
 
 #include <stdlib.h>
 #include "qpaintengine_opengl_p.h"
@@ -286,7 +287,8 @@ public Q_SLOTS:
     }
 
 private:
-    QGLDrawable drawable;
+//    QGLDrawable drawable;
+    QGLPaintDevice* device;
 
     QGLFramebufferObject *offscreen;
     QGLContext *ctx;
@@ -305,7 +307,13 @@ private:
 
 inline void QGLOffscreen::setDevice(QPaintDevice *pdev)
 {
-    drawable.setDevice(pdev);
+    if (pdev->devType() == QInternal::OpenGL)
+        device = static_cast<QGLPaintDevice*>(pdev);
+    else
+        device = QGLPaintDevice::getDevice(pdev);
+
+    if (!device)
+        return;
 
     drawable_fbo = (pdev->devType() == QInternal::FramebufferObject);
 }
@@ -329,12 +337,12 @@ void QGLOffscreen::initialize()
     activated = true;
     initialized = true;
 
-    int dim = qMax(2048, static_cast<int>(qt_next_power_of_two(qMax(drawable.size().width(), drawable.size().height()))));
+    int dim = qMax(2048, static_cast<int>(qt_next_power_of_two(qMax(device->size().width(), device->size().height()))));
 
-    bool shared_context = qgl_share_reg()->checkSharing(drawable.context(), ctx);
+    bool shared_context = qgl_share_reg()->checkSharing(device->context(), ctx);
     bool would_fail = last_failed_size.isValid() &&
-                      (drawable.size().width() >= last_failed_size.width() ||
-                       drawable.size().height() >= last_failed_size.height());
+                      (device->size().width() >= last_failed_size.width() ||
+                       device->size().height() >= last_failed_size.height());
     bool needs_refresh = dim > mask_dim || !shared_context;
 
     if (needs_refresh && !would_fail) {
@@ -348,13 +356,13 @@ void QGLOffscreen::initialize()
             delete offscreen;
             offscreen = 0;
             mask_dim = 0;
-            last_failed_size = drawable.size();
+            last_failed_size = device->size();
         }
     }
 
     qt_mask_texture_cache()->setOffscreenSize(offscreenSize());
-    qt_mask_texture_cache()->setDrawableSize(drawable.size());
-    ctx = drawable.context();
+    qt_mask_texture_cache()->setDrawableSize(device->size());
+    ctx = device->context();
 #endif
 }
 
@@ -428,11 +436,11 @@ inline void QGLOffscreen::release()
     DEBUG_ONCE_STR("QGLOffscreen: releasing offscreen");
 
     if (drawable_fbo)
-        drawable.makeCurrent();
+        device->context()->makeCurrent(); //###
     else
         offscreen->release();
 
-    QSize sz(drawable.size());
+    QSize sz(device->size());
     glViewport(0, 0, sz.width(), sz.height());
 
     glMatrixMode(GL_PROJECTION);
@@ -455,7 +463,7 @@ inline bool QGLOffscreen::isBound() const
 
 inline QSize QGLOffscreen::drawableSize() const
 {
-    return drawable.size();
+    return device->size();
 }
 
 inline QSize QGLOffscreen::offscreenSize() const
@@ -757,7 +765,8 @@ public:
     GLubyte pen_color[4];
     GLubyte brush_color[4];
     QTransform::TransformationType txop;
-    QGLDrawable drawable;
+//    QGLDrawable drawable;
+    QGLPaintDevice* device;
     QGLOffscreen offscreen;
 
     qreal inverseScale;
@@ -1167,7 +1176,7 @@ void QOpenGLPaintEnginePrivate::createGradientPaletteTexture(const QGradient& g)
 #ifdef QT_OPENGL_ES //###
     Q_UNUSED(g);
 #else
-    GLuint texId = qt_opengl_gradient_cache()->getBuffer(g, opacity, drawable.context());
+    GLuint texId = qt_opengl_gradient_cache()->getBuffer(g, opacity, device->context());
     glBindTexture(GL_TEXTURE_1D, texId);
     grad_palette = texId;
     if (g.spread() == QGradient::RepeatSpread || g.type() == QGradient::ConicalGradient)
@@ -1236,12 +1245,19 @@ bool QOpenGLPaintEngine::begin(QPaintDevice *pdev)
 {
     Q_D(QOpenGLPaintEngine);
 
-    d->drawable.setDevice(pdev);
+    if (pdev->devType() == QInternal::OpenGL)
+        d->device = static_cast<QGLPaintDevice*>(pdev);
+    else
+        d->device = QGLPaintDevice::getDevice(pdev);
+
+    if (!d->device)
+        return false;
+
     d->offscreen.setDevice(pdev);
     d->has_fast_pen = false;
     d->inverseScale = 1;
     d->opacity = 1;
-    d->drawable.makeCurrent();
+    d->device->beginPaint();
     d->matrix = QTransform();
     d->has_antialiasing = false;
     d->high_quality_antialiasing = false;
@@ -1256,7 +1272,7 @@ bool QOpenGLPaintEngine::begin(QPaintDevice *pdev)
     bool has_frag_program = (QGLExtensions::glExtensions & QGLExtensions::FragmentProgram)
                             && (pdev->devType() != QInternal::Pixmap);
 
-    QGLContext *ctx = const_cast<QGLContext *>(d->drawable.context());
+    QGLContext *ctx = const_cast<QGLContext *>(d->device->context());
     if (!ctx) {
         qWarning() << "QOpenGLPaintEngine: paint device doesn't have a valid GL context.";
         return false;
@@ -1265,9 +1281,9 @@ bool QOpenGLPaintEngine::begin(QPaintDevice *pdev)
     if (has_frag_program)
         has_frag_program = qt_resolve_frag_program_extensions(ctx) && qt_resolve_version_1_3_functions(ctx);
 
-    d->use_stencil_method = d->drawable.format().stencil()
+    d->use_stencil_method = d->device->format().stencil()
                             && (QGLExtensions::glExtensions & QGLExtensions::StencilWrap);
-    if (d->drawable.format().directRendering()
+    if (d->device->format().directRendering()
         && (d->use_stencil_method && QGLExtensions::glExtensions & QGLExtensions::StencilTwoSide))
         d->has_stencil_face_ext = qt_resolve_stencil_face_extension(ctx);
 
@@ -1333,12 +1349,12 @@ bool QOpenGLPaintEngine::begin(QPaintDevice *pdev)
 
     d->offscreen.begin();
 
-    if (d->drawable.context()->d_func()->clear_on_painter_begin && d->drawable.autoFillBackground()) {
+    if (d->device->context()->d_func()->clear_on_painter_begin && d->device->autoFillBackground()) {
 
-        if (d->drawable.hasTransparentBackground())
+        if (d->device->hasTransparentBackground())
             glClearColor(0.0, 0.0, 0.0, 0.0);
         else {
-            const QColor &c = d->drawable.backgroundColor();
+            const QColor &c = d->device->backgroundColor();
             glClearColor(c.redF(), c.greenF(), c.blueF(), 1.0);
         }
 
@@ -1349,7 +1365,7 @@ bool QOpenGLPaintEngine::begin(QPaintDevice *pdev)
         glClear(clearBits);
     }
 
-    QSize sz(d->drawable.size());
+    QSize sz(d->device->size());
     glViewport(0, 0, sz.width(), sz.height()); // XXX (Embedded): We need a solution for GLWidgets that draw in a part or a bigger surface...
     glMatrixMode(GL_PROJECTION);
     glLoadIdentity();
@@ -1366,7 +1382,7 @@ bool QOpenGLPaintEngine::begin(QPaintDevice *pdev)
 #ifdef QT_OPENGL_ES
     d->max_texture_size = ctx->d_func()->maxTextureSize();
 #else
-    bool shared_ctx = qgl_share_reg()->checkSharing(d->drawable.context(), d->shader_ctx);
+    bool shared_ctx = qgl_share_reg()->checkSharing(d->device->context(), d->shader_ctx);
 
     if (shared_ctx) {
         d->max_texture_size = d->shader_ctx->d_func()->maxTextureSize();
@@ -1382,7 +1398,7 @@ bool QOpenGLPaintEngine::begin(QPaintDevice *pdev)
                 glDeleteTextures(1, &d->drawable_texture);
             ctx->makeCurrent();
         }
-        d->shader_ctx = d->drawable.context();
+        d->shader_ctx = d->device->context();
         glGenTextures(1, &d->grad_palette);
 
         qt_mask_texture_cache()->clearCache();
@@ -1417,7 +1433,7 @@ bool QOpenGLPaintEngine::end()
     Q_D(QOpenGLPaintEngine);
     d->flushDrawQueue();
     d->offscreen.end();
-    QGLContext *ctx = const_cast<QGLContext *>(d->drawable.context());
+    QGLContext *ctx = const_cast<QGLContext *>(d->device->context());
     if (!ctx->d_ptr->internal_context) {
         glMatrixMode(GL_TEXTURE);
         glPopMatrix();
@@ -1434,8 +1450,7 @@ bool QOpenGLPaintEngine::end()
         glPopClientAttrib();
     }
 #endif
-    d->drawable.swapBuffers();
-    d->drawable.doneCurrent();
+    d->device->endPaint();
     qt_mask_texture_cache()->maintainCache();
 
     return true;
@@ -1961,7 +1976,7 @@ void QOpenGLPaintEnginePrivate::fillVertexArray(Qt::FillRule fillRule)
 
             const int left = rect.left();
             const int width = rect.width();
-            const int bottom = drawable.size().height() - (rect.bottom() + 1);
+            const int bottom = device->size().height() - (rect.bottom() + 1);
             const int height = rect.height();
 
             glScissor(left, bottom, width, height);
@@ -2242,7 +2257,7 @@ void QOpenGLPaintEnginePrivate::updateDepthClip()
 
         const int left = fastClip.left();
         const int width = fastClip.width();
-        const int bottom = drawable.size().height() - (fastClip.bottom() + 1);
+        const int bottom = device->size().height() - (fastClip.bottom() + 1);
         const int height = fastClip.height();
 
         glScissor(left, bottom, width, height);
@@ -2325,7 +2340,7 @@ void QOpenGLPaintEngine::updateClipRegion(const QRegion &clipRegion, Qt::ClipOpe
 
     // clipping is only supported when a stencil or depth buffer is
     // available
-    if (!d->drawable.format().depth())
+    if (!d->device->format().depth())
         return;
 
     d->use_system_clip = false;
@@ -2362,7 +2377,7 @@ void QOpenGLPaintEngine::updateClipRegion(const QRegion &clipRegion, Qt::ClipOpe
             path.addRect(untransformedRects[0]);
             path = d->matrix.map(path);
 
-            if (path.contains(QRectF(QPointF(), d->drawable.size())))
+            if (path.contains(QRectF(QPointF(), d->device->size())))
                 isScreenClip = true;
         }
     }
@@ -3369,7 +3384,7 @@ void QOpenGLPaintEnginePrivate::drawOffscreenPath(const QPainterPath &path)
 
     disableClipping();
 
-    GLuint program = qt_gl_program_cache()->getProgram(drawable.context(),
+    GLuint program = qt_gl_program_cache()->getProgram(device->context(),
                                                        FRAGMENT_PROGRAM_MASK_TRAPEZOID_AA, 0, true);
     QGLPathMaskGenerator maskGenerator(path, matrix, offscreen, program);
     addItem(qt_mask_texture_cache()->getMask(maskGenerator, this));
@@ -3506,7 +3521,7 @@ void QOpenGLPaintEngine::drawRects(const QRectF *rects, int rectCount)
 
             if (d->has_brush) {
                 d->disableClipping();
-                GLuint program = qt_gl_program_cache()->getProgram(d->drawable.context(),
+                GLuint program = qt_gl_program_cache()->getProgram(d->device->context(),
                                                                    FRAGMENT_PROGRAM_MASK_TRAPEZOID_AA, 0, true);
 
                 if (d->matrix.type() >= QTransform::TxProject) {
@@ -3916,7 +3931,7 @@ void QOpenGLPaintEnginePrivate::strokeLines(const QPainterPath &path)
 
     qreal penWidth = cpen.widthF();
 
-    GLuint program = qt_gl_program_cache()->getProgram(drawable.context(),
+    GLuint program = qt_gl_program_cache()->getProgram(device->context(),
                                                        FRAGMENT_PROGRAM_MASK_TRAPEZOID_AA, 0, true);
     QGLLineMaskGenerator maskGenerator(path, matrix, penWidth == 0 ? 1.0 : penWidth,
                                        offscreen, program);
@@ -4302,7 +4317,7 @@ void QOpenGLPaintEngine::drawPixmap(const QRectF &r, const QPixmap &pm, const QR
     else {
         GLenum target = qt_gl_preferredTextureTarget();
         d->flushDrawQueue();
-        d->drawable.bindTexture(pm, target);
+        d->device->context()->bindTexture(pm, target);
         drawTextureRect(pm.width(), pm.height(), r, sr, target);
     }
 }
@@ -4336,9 +4351,9 @@ void QOpenGLPaintEngine::drawTiledPixmap(const QRectF &r, const QPixmap &pm, con
         d->flushDrawQueue();
 
         if (scaled.isNull())
-            d->drawable.bindTexture(pm);
+            d->device->context()->bindTexture(pm);
         else
-            d->drawable.bindTexture(scaled);
+            d->device->context()->bindTexture(scaled);
         updateTextureFilter(GL_TEXTURE_2D, GL_REPEAT, d->use_smooth_pixmap_transform);
 
 #ifndef QT_OPENGL_ES
@@ -4404,7 +4419,7 @@ void QOpenGLPaintEngine::drawImage(const QRectF &r, const QImage &image, const Q
     else {
         GLenum target = qt_gl_preferredTextureTarget();
         d->flushDrawQueue();
-        d->drawable.bindTexture(image, target);
+        d->device->context()->bindTexture(image, target);
         drawTextureRect(image.width(), image.height(), r, sr, target);
     }
 }
@@ -4871,7 +4886,7 @@ void QOpenGLPaintEngine::drawTextItem(const QPointF &p, const QTextItem &textIte
     ti.fontEngine->getGlyphPositions(ti.glyphs, matrix, ti.flags, glyphs, positions);
 
     // make sure the glyphs we want to draw are in the cache
-    qt_glyph_cache()->cacheGlyphs(d->drawable.context(), ti, glyphs);
+    qt_glyph_cache()->cacheGlyphs(d->device->context(), ti, glyphs);
 
     d->setGradientOps(Qt::SolidPattern, QRectF()); // turns off gradient ops
     qt_glColor4ubv(d->pen_color);
@@ -4949,7 +4964,7 @@ void QOpenGLPaintEngine::drawEllipse(const QRectF &rect)
             glPushMatrix();
             glLoadIdentity();
 
-            GLuint program = qt_gl_program_cache()->getProgram(d->drawable.context(),
+            GLuint program = qt_gl_program_cache()->getProgram(d->device->context(),
                                                                FRAGMENT_PROGRAM_MASK_ELLIPSE_AA, 0, true);
             QGLEllipseMaskGenerator maskGenerator(rect,
                                                   d->matrix,
@@ -5084,10 +5099,10 @@ void QOpenGLPaintEnginePrivate::copyDrawable(const QRectF &rect)
     QRectF screen_rect = rect.adjusted(-1, -1, 1, 1);
 
     int left = qMax(0, static_cast<int>(screen_rect.left()));
-    int width = qMin(drawable.size().width() - left, static_cast<int>(screen_rect.width()) + 1);
+    int width = qMin(device->size().width() - left, static_cast<int>(screen_rect.width()) + 1);
 
-    int bottom = qMax(0, static_cast<int>(drawable.size().height() - screen_rect.bottom()));
-    int height = qMin(drawable.size().height() - bottom, static_cast<int>(screen_rect.height()) + 1);
+    int bottom = qMax(0, static_cast<int>(device->size().height() - screen_rect.bottom()));
+    int height = qMin(device->size().height() - bottom, static_cast<int>(screen_rect.height()) + 1);
 
     glBindTexture(GL_TEXTURE_2D, drawable_texture);
     glCopyTexSubImage2D(GL_TEXTURE_2D, 0, left, bottom, left, bottom, width, height);
@@ -5181,9 +5196,9 @@ void QOpenGLPaintEnginePrivate::composite(GLuint primitive, const q_vertexType *
         glActiveTexture(GL_TEXTURE0 + brush_texture_location);
 
         if (current_style == Qt::TexturePattern)
-            drawable.bindTexture(cbrush.textureImage());
+            device->context()->bindTexture(cbrush.textureImage());
         else
-            drawable.bindTexture(qt_imageForBrush(current_style, true));
+            device->context()->bindTexture(qt_imageForBrush(current_style, true));
 
         updateTextureFilter(GL_TEXTURE_2D, GL_REPEAT, use_smooth_pixmap_transform);
     }
@@ -5191,7 +5206,7 @@ void QOpenGLPaintEnginePrivate::composite(GLuint primitive, const q_vertexType *
     glEnableClientState(GL_VERTEX_ARRAY);
     glVertexPointer(2, q_vertexTypeEnum, 0, vertexArray);
     glEnable(GL_FRAGMENT_PROGRAM_ARB);
-    GLuint program = qt_gl_program_cache()->getProgram(drawable.context(),
+    GLuint program = qt_gl_program_cache()->getProgram(device->context(),
                                                        fragment_brush,
                                                        fragment_composition_mode, false);
     glBindProgramARB(GL_FRAGMENT_PROGRAM_ARB, program);
@@ -5263,7 +5278,7 @@ void QOpenGLPaintEnginePrivate::drawItem(const QDrawQueueItem &item)
     setGradientOps(item.brush, item.location.screen_rect);
 
     composite(item.location.screen_rect, item.location.rect.topLeft() - item.location.screen_rect.topLeft()
-                                         - QPoint(0, offscreen.offscreenSize().height() - drawable.size().height()));
+                                         - QPoint(0, offscreen.offscreenSize().height() - device->size().height()));
 }
 
 void QOpenGLPaintEnginePrivate::flushDrawQueue()