Use a VAO in the texture glyph cache

Task-number: QTBUG-36993
Change-Id: Icc77035b582c804ed809ea3cd99c0048b34d41d2
Reviewed-by: Gunnar Sletta <gunnar.sletta@jollamobile.com>
Reviewed-by: Sean Harmer <sean.harmer@kdab.com>

2 files changed, 33 insertions, 10 deletions

diff --git a/src/gui/opengl/qopengltextureglyphcache.cpp b/src/gui/opengl/qopengltextureglyphcache.cpp
index c3c04000a9..3524c1cb1a 100644
--- a/src/gui/opengl/qopengltextureglyphcache.cpp
+++ b/src/gui/opengl/qopengltextureglyphcache.cpp
@@ -164,6 +164,19 @@ void QOpenGLTextureGlyphCache::createTextureData(int width, int height)
         m_buffer.allocate(buf, sizeof(buf));
         m_buffer.release();
     }
+
+    if (!m_vao.isCreated())
+        m_vao.create();
+}
+
+void QOpenGLTextureGlyphCache::setupVertexAttribs()
+{
+    m_buffer.bind();
+    m_blitProgram->setAttributeBuffer(int(QT_VERTEX_COORDS_ATTR), GL_FLOAT, 0, 2);
+    m_blitProgram->setAttributeBuffer(int(QT_TEXTURE_COORDS_ATTR), GL_FLOAT, sizeof(m_vertexCoordinateArray), 2);
+    m_blitProgram->enableAttributeArray(int(QT_VERTEX_COORDS_ATTR));
+    m_blitProgram->enableAttributeArray(int(QT_TEXTURE_COORDS_ATTR));
+    m_buffer.release();
 }
 
 void QOpenGLTextureGlyphCache::resizeTextureData(int width, int height)
@@ -262,16 +275,19 @@ void QOpenGLTextureGlyphCache::resizeTextureData(int width, int height)
             m_blitProgram->bindAttributeLocation("textureCoordArray", QT_TEXTURE_COORDS_ATTR);
 
             m_blitProgram->link();
+
+            if (m_vao.isCreated()) {
+                m_vao.bind();
+                setupVertexAttribs();
+            }
         }
 
-        m_buffer.bind();
-        m_blitProgram->bind();
-        m_blitProgram->setAttributeBuffer(int(QT_VERTEX_COORDS_ATTR), GL_FLOAT, 0, 2);
-        m_blitProgram->setAttributeBuffer(int(QT_TEXTURE_COORDS_ATTR), GL_FLOAT, sizeof(m_vertexCoordinateArray), 2);
-        m_blitProgram->enableAttributeArray(int(QT_VERTEX_COORDS_ATTR));
-        m_blitProgram->enableAttributeArray(int(QT_TEXTURE_COORDS_ATTR));
-        m_blitProgram->disableAttributeArray(int(QT_OPACITY_ATTR));
+        if (m_vao.isCreated())
+            m_vao.bind();
+        else
+            setupVertexAttribs();
 
+        m_blitProgram->bind();
         blitProgram = m_blitProgram;
 
     } else {
@@ -301,9 +317,12 @@ void QOpenGLTextureGlyphCache::resizeTextureData(int width, int height)
         glViewport(0, 0, pex->width, pex->height);
         pex->updateClipScissorTest();
     } else {
-        m_blitProgram->disableAttributeArray(int(QT_VERTEX_COORDS_ATTR));
-        m_blitProgram->disableAttributeArray(int(QT_TEXTURE_COORDS_ATTR));
-        m_buffer.release();
+        if (m_vao.isCreated()) {
+            m_vao.release();
+        } else {
+            m_blitProgram->disableAttributeArray(int(QT_VERTEX_COORDS_ATTR));
+            m_blitProgram->disableAttributeArray(int(QT_TEXTURE_COORDS_ATTR));
+        }
     }
 }
 
diff --git a/src/gui/opengl/qopengltextureglyphcache_p.h b/src/gui/opengl/qopengltextureglyphcache_p.h
index 394c28f7ff..1e2c031018 100644
--- a/src/gui/opengl/qopengltextureglyphcache_p.h
+++ b/src/gui/opengl/qopengltextureglyphcache_p.h
@@ -58,6 +58,7 @@
 #include <qopenglshaderprogram.h>
 #include <qopenglfunctions.h>
 #include <qopenglbuffer.h>
+#include <qopenglvertexarrayobject.h>
 
 // #define QT_GL_TEXTURE_GLYPH_CACHE_DEBUG
 
@@ -153,6 +154,8 @@ public:
     void clear();
 
 private:
+    void setupVertexAttribs();
+
     QOpenGLGlyphTexture *m_textureResource;
 
     QOpenGL2PaintEngineExPrivate *pex;
@@ -165,6 +168,7 @@ private:
     int m_serialNumber;
 
     QOpenGLBuffer m_buffer;
+    QOpenGLVertexArrayObject m_vao;
 };
 
 QT_END_NAMESPACE