Enhance msaa and blitframebuffer on ES with vendor extensions

The support already in place for ANGLE is now extended for NV.

On ES 2.0 the only way to get multisampled renderbuffers and blitframebuffer
is through vendor-specific extensions. QOpenGLFunctions is updated to resolve
the related functions for both ANGLE and NV, in addition to EXT.

Task-number: QTBUG-39187
Change-Id: I1aab805ced3d06dde3dc547221bbf833ff8e06c2
Reviewed-by: Andrew Knight <andrew.knight@digia.com>
Reviewed-by: Gunnar Sletta <gunnar.sletta@jollamobile.com>

1 files changed, 11 insertions, 10 deletions

diff --git a/src/gui/opengl/qopenglframebufferobject.cpp b/src/gui/opengl/qopenglframebufferobject.cpp
index 75f5a9fbfb..2651c23665 100644
--- a/src/gui/opengl/qopenglframebufferobject.cpp
+++ b/src/gui/opengl/qopenglframebufferobject.cpp
@@ -427,18 +427,21 @@ void QOpenGLFramebufferObjectPrivate::init(QOpenGLFramebufferObject *, const QSi
     if (!funcs.hasOpenGLFeature(QOpenGLFunctions::Framebuffers))
         return;
 
-
     // Fall back to using a normal non-msaa FBO if we don't have support for MSAA
     if (!funcs.hasOpenGLExtension(QOpenGLExtensions::FramebufferMultisample)
             || !funcs.hasOpenGLExtension(QOpenGLExtensions::FramebufferBlit)) {
         samples = 0;
     }
 
-#ifndef QT_OPENGL_ES_2
-    GLint maxSamples;
-    funcs.glGetIntegerv(GL_MAX_SAMPLES, &maxSamples);
-    samples = qBound(0, int(samples), int(maxSamples));
-#endif
+    // On GLES 2.0 multisampled framebuffers are available through vendor-specific extensions
+    const bool msaaES2 = ctx->isOpenGLES() && (ctx->hasExtension("GL_ANGLE_framebuffer_multisample")
+                                               || ctx->hasExtension("GL_NV_framebuffer_multisample"));
+
+    if (!ctx->isOpenGLES() || msaaES2) {
+        GLint maxSamples;
+        funcs.glGetIntegerv(GL_MAX_SAMPLES, &maxSamples);
+        samples = qBound(0, int(samples), int(maxSamples));
+    }
 
     size = sz;
     target = texture_target;
@@ -459,11 +462,9 @@ void QOpenGLFramebufferObjectPrivate::init(QOpenGLFramebufferObject *, const QSi
     } else {
         GLenum storageFormat = internal_format;
 #ifdef GL_RGBA8_OES
-        // Correct the internal format used by the render buffer when using ANGLE
-        if (QOpenGLContext::openGLModuleType() == QOpenGLContext::LibGLES && internal_format == GL_RGBA
-                && strstr((const char *)funcs.glGetString(GL_RENDERER), "ANGLE") != 0) {
+        // Correct the internal format used by the render buffer when using ES with extensions
+        if (msaaES2 && internal_format == GL_RGBA)
             storageFormat = GL_RGBA8_OES;
-        }
 #endif
 
         mipmap = false;