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desktop-main.cpp: further improve the GL version detection

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First, attempt to use glGetString(GL_VERSION), which works
on legacy profiles but has to be parsed (unsafe and vendor specific?).
If the above fails attempt to use the newer version API from
glGetIntegerv().

If both fail, fall back to a software renderer or exit.

If GLES is detected from glGetString() (for some odd reason -
e.g. emulated driver) show a warning and return early as we don't
handle it's versioning.

Signed-off-by: Lubomir I. Ivanov <neolit123@gmail.com>
This commit is contained in:
Lubomir I. Ivanov 2017-11-01 14:31:04 +02:00
parent cb34b33a64
commit 31e11bc4e8
1 changed files with 30 additions and 4 deletions
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34
subsurface-desktop-main.cpp
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@ -152,11 +152,13 @@ void validateGL()
}
return;
}
GLint verMajor, verMinor;
GLint verMajor = -1, verMinor;
const char *glError = NULL;
QOpenGLContext ctx;
QOffscreenSurface surface;
QOpenGLFunctions *func;
const char *verChar;
float verFloat;
surface.setFormat(ctx.format());
surface.create();
@ -174,8 +176,32 @@ void validateGL()
}
if (verbose)
qDebug() << QStringLiteral(VALIDATE_GL_PREFIX "obtained QOpenGLFunctions.").toUtf8().data();
func->glGetIntegerv(GL_MAJOR_VERSION, &verMajor);
func->glGetIntegerv(GL_MINOR_VERSION, &verMinor);
// detect version for legacy profiles
verChar = (const char *)func->glGetString(GL_VERSION);
if (verChar) {
// detect GLES, show a warning and return early as we don't handle it's versioning
if (strstr(verChar, " ES ") != NULL) {
qWarning() << QStringLiteral(VALIDATE_GL_PREFIX "WARNING: Detected OpenGL ES!\n"
"Attempting to run with the available profile!\n"
"If this fails try manually setting the environment variable\n"
"'QT_QUICK_BACKEND' with the value of 'software'\n"
"before running Subsurface!\n").toUtf8().data();
return;
}
if (sscanf(verChar, "%f", &verFloat) == 1) {
verMajor = (GLint)verFloat;
verMinor = (GLint)((verFloat - verMajor) * 10.f);
}
}
// attempt to detect version using the newer API
if (verMajor == -1) {
func->glGetIntegerv(GL_MAJOR_VERSION, &verMajor);
func->glGetIntegerv(GL_MINOR_VERSION, &verMinor);
}
if (verMajor == -1) {
glError = "Cannot detect OpenGL version";
goto exit;
}
if (verbose)
qDebug() << QStringLiteral(VALIDATE_GL_PREFIX "detected OpenGL version %1.%2.").arg(verMajor).arg(verMinor).toUtf8().data();
if (verMajor * 10 + verMinor < 21) { // set 2.1 as the minimal version
@ -191,7 +217,7 @@ exit:
qWarning() << QStringLiteral(VALIDATE_GL_PREFIX "ERROR: %1.\n"
"Cannot automatically fallback to a software renderer!\n"
"Set the environment variable 'QT_QUICK_BACKEND' with the value of 'software'\n"
"before running Subsurface!").arg(glError).toUtf8().data();
"before running Subsurface!\n").arg(glError).toUtf8().data();
exit(0);
#else
qWarning() << QStringLiteral(VALIDATE_GL_PREFIX "WARNING: %1. Using a software renderer!").arg(glError).toUtf8().data();