rhi: gl: Fix multisample texture specification

...so that MSAA is actually effective.

Pick-to: 6.7 6.6
Change-Id: I4bf85df1312773ec29154a51c9c8464912e6ef8a
Reviewed-by: Andy Nichols <andy.nichols@qt.io>

1 files changed, 13 insertions, 2 deletions

diff --git a/src/gui/rhi/qrhigles2.cpp b/src/gui/rhi/qrhigles2.cpp
index 29b6e60386..154ace305b 100644
--- a/src/gui/rhi/qrhigles2.cpp
+++ b/src/gui/rhi/qrhigles2.cpp
@@ -5470,8 +5470,16 @@ bool QGles2Texture::create()
                     }
                 }
             } else {
-                rhiD->f->glTexImage2D(target, 0, GLint(glintformat), size.width(), size.height(),
-                                      0, glformat, gltype, nullptr);
+                // 2D texture. For multisample textures the GLES 3.1
+                // glStorage2DMultisample must be used for portability.
+                if (m_sampleCount > 1 && rhiD->caps.multisampledTexture) {
+                    // internal format must be sized
+                    rhiD->f->glTexStorage2DMultisample(target, m_sampleCount, glsizedintformat,
+                                                       size.width(), size.height(), GL_TRUE);
+                } else {
+                    rhiD->f->glTexImage2D(target, 0, GLint(glintformat), size.width(), size.height(),
+                                          0, glformat, gltype, nullptr);
+                }
             }
         } else {
             // Must be specified with immutable storage functions otherwise
@@ -5482,6 +5490,9 @@ bool QGles2Texture::create()
             else if (!is1D && (is3D || isArray))
                 rhiD->f->glTexStorage3D(target, mipLevelCount, glsizedintformat, size.width(), size.height(),
                                         is3D ? qMax(1, m_depth) : qMax(0, m_arraySize));
+            else if (m_sampleCount > 1)
+                rhiD->f->glTexStorage2DMultisample(target, m_sampleCount, glsizedintformat,
+                                                   size.width(), size.height(), GL_TRUE);
             else
                 rhiD->f->glTexStorage2D(target, mipLevelCount, glsizedintformat, size.width(),
                                         is1D ? qMax(0, m_arraySize) : size.height());