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39
40#include <QtGui/QOffscreenSurface>
41#include "qeglpbuffer_p.h"
42#include "qeglconvenience_p.h"
43
44QT_BEGIN_NAMESPACE
45
46/*!
47 \class QEGLPbuffer
48 \brief A pbuffer-based implementation of QPlatformOffscreenSurface for EGL.
49 \since 5.2
50 \internal
51 \ingroup qpa
52
53 To use this implementation in the platform plugin simply
54 reimplement QPlatformIntegration::createPlatformOffscreenSurface()
55 and return a new instance of this class.
56*/
57
58QEGLPbuffer::QEGLPbuffer(EGLDisplay display, const QSurfaceFormat &format, QOffscreenSurface *offscreenSurface,
59 QEGLPlatformContext::Flags flags)
60 : QPlatformOffscreenSurface(offscreenSurface)
61 , m_format(format)
62 , m_display(display)
63 , m_pbuffer(EGL_NO_SURFACE)
64{
65 m_hasSurfaceless = !flags.testFlag(flag: QEGLPlatformContext::NoSurfaceless)
66 && q_hasEglExtension(display, extensionName: "EGL_KHR_surfaceless_context");
67
68 // Disable surfaceless contexts on Mesa for now. As of 10.6.0 and Intel at least, some
69 // operations (glReadPixels) are unable to work without a surface since they at some
70 // point temporarily unbind the current FBO and then later blow up in some seemingly
71 // safe operations, like setting the viewport, that apparently need access to the
72 // read/draw surface in the Intel backend.
73 const char *vendor = eglQueryString(dpy: display, EGL_VENDOR); // hard to check for GL_ strings here, so blacklist all Mesa
74 if (vendor && strstr(haystack: vendor, needle: "Mesa"))
75 m_hasSurfaceless = false;
76
77 if (m_hasSurfaceless)
78 return;
79
80 EGLConfig config = q_configFromGLFormat(display: m_display, format: m_format, highestPixelFormat: false, EGL_PBUFFER_BIT);
81
82 if (config) {
83 const EGLint attributes[] = {
84 EGL_WIDTH, offscreenSurface->size().width(),
85 EGL_HEIGHT, offscreenSurface->size().height(),
86 EGL_LARGEST_PBUFFER, EGL_FALSE,
87 EGL_NONE
88 };
89
90 m_pbuffer = eglCreatePbufferSurface(dpy: m_display, config, attrib_list: attributes);
91
92 if (m_pbuffer != EGL_NO_SURFACE)
93 m_format = q_glFormatFromConfig(display: m_display, config);
94 }
95}
96
97QEGLPbuffer::~QEGLPbuffer()
98{
99 if (m_pbuffer != EGL_NO_SURFACE)
100 eglDestroySurface(dpy: m_display, surface: m_pbuffer);
101}
102
103bool QEGLPbuffer::isValid() const
104{
105 return m_pbuffer != EGL_NO_SURFACE || m_hasSurfaceless;
106}
107
108QT_END_NAMESPACE
109

source code of qtbase/src/platformsupport/eglconvenience/qeglpbuffer.cpp