Pass a sized format when creating multisampled renderbuffers on ES

Task-number: QTBUG-40921
Change-Id: I96b05442dd5928992dab06553b3d41feca89084d
Reviewed-by: BogDan Vatra <bogdan@kde.org>
Reviewed-by: Giuseppe D'Angelo <giuseppe.dangelo@kdab.com>

3 files changed, 18 insertions, 15 deletions

diff --git a/src/gui/opengl/qopenglextensions_p.h b/src/gui/opengl/qopenglextensions_p.h
index 72e32e939e..23cfe16467 100644
--- a/src/gui/opengl/qopenglextensions_p.h
+++ b/src/gui/opengl/qopenglextensions_p.h
@@ -80,7 +80,8 @@ public:
         SRGBFrameBuffer         = 0x00020000,
         MapBuffer               = 0x00040000,
         GeometryShaders         = 0x00080000,
-        MapBufferRange          = 0x00100000
+        MapBufferRange          = 0x00100000,
+        Sized8Formats           = 0x00200000
     };
     Q_DECLARE_FLAGS(OpenGLExtensions, OpenGLExtension)
 
diff --git a/src/gui/opengl/qopenglframebufferobject.cpp b/src/gui/opengl/qopenglframebufferobject.cpp
index f33d4df280..b185e332e6 100644
--- a/src/gui/opengl/qopenglframebufferobject.cpp
+++ b/src/gui/opengl/qopenglframebufferobject.cpp
@@ -452,13 +452,7 @@ void QOpenGLFramebufferObjectPrivate::init(QOpenGLFramebufferObject *, const QSi
     if (!funcs.hasOpenGLExtension(QOpenGLExtensions::FramebufferMultisample)
             || !funcs.hasOpenGLExtension(QOpenGLExtensions::FramebufferBlit)) {
         samples = 0;
-    }
-
-    // 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) {
+    } else if (!ctx->isOpenGLES() || ctx->format().majorVersion() >= 3) {
         GLint maxSamples;
         funcs.glGetIntegerv(GL_MAX_SAMPLES, &maxSamples);
         samples = qBound(0, int(samples), int(maxSamples));
@@ -483,11 +477,15 @@ void QOpenGLFramebufferObjectPrivate::init(QOpenGLFramebufferObject *, const QSi
         initTexture(texture_target, internal_format, size, mipmap);
     } else {
         GLenum storageFormat = internal_format;
+        // ES requires a sized format. The older desktop extension does not. Correct the format on ES.
+        if (ctx->isOpenGLES() && internal_format == GL_RGBA) {
 #ifdef GL_RGBA8_OES
-        // Correct the internal format used by the render buffer when using ES with extensions
-        if (msaaES2 && internal_format == GL_RGBA)
-            storageFormat = GL_RGBA8_OES;
+            if (funcs.hasOpenGLExtension(QOpenGLExtensions::Sized8Formats))
+                storageFormat = GL_RGBA8_OES;
+            else
 #endif
+                storageFormat = GL_RGBA4;
+        }
 
         mipmap = false;
         funcs.glGenRenderbuffers(1, &color_buffer);
diff --git a/src/gui/opengl/qopenglfunctions.cpp b/src/gui/opengl/qopenglfunctions.cpp
index 5ee72f54bf..44b56699df 100644
--- a/src/gui/opengl/qopenglfunctions.cpp
+++ b/src/gui/opengl/qopenglfunctions.cpp
@@ -385,7 +385,8 @@ static int qt_gl_resolve_extensions()
                 | QOpenGLExtensions::ElementIndexUint
                 | QOpenGLExtensions::MapBufferRange
                 | QOpenGLExtensions::FramebufferBlit
-                | QOpenGLExtensions::FramebufferMultisample;
+                | QOpenGLExtensions::FramebufferMultisample
+                | QOpenGLExtensions::Sized8Formats;
         } else {
             // Recognize features by extension name.
             if (extensionMatcher.match("GL_OES_packed_depth_stencil"))
@@ -400,6 +401,8 @@ static int qt_gl_resolve_extensions()
                 extensions |= QOpenGLExtensions::FramebufferBlit;
             if (extensionMatcher.match("GL_NV_framebuffer_multisample"))
                 extensions |= QOpenGLExtensions::FramebufferMultisample;
+            if (extensionMatcher.match("GL_OES_rgb8_rgba8"))
+                extensions |= QOpenGLExtensions::Sized8Formats;
         }
 
         if (extensionMatcher.match("GL_OES_mapbuffer"))
@@ -419,9 +422,10 @@ static int qt_gl_resolve_extensions()
             extensions |= QOpenGLExtensions::GenerateMipmap;
 
         if (format.majorVersion() >= 3 || extensionMatcher.match("GL_ARB_framebuffer_object")) {
-            extensions |= QOpenGLExtensions::FramebufferMultisample |
-                QOpenGLExtensions::FramebufferBlit |
-                QOpenGLExtensions::PackedDepthStencil;
+            extensions |= QOpenGLExtensions::FramebufferMultisample
+                | QOpenGLExtensions::FramebufferBlit
+                | QOpenGLExtensions::PackedDepthStencil
+                | QOpenGLExtensions::Sized8Formats;
         } else {
             // Recognize features by extension name.
             if (extensionMatcher.match("GL_EXT_framebuffer_multisample"))