Use a single distance-field cache instance for all sizes of a given font.

Previously we had a different cache instance for each font size, but
they all shared the same textures and positions. Only the glyph metrics
were specific to each font size.
The metrics for each font sizes are now calculated by scaling the metrics
of the distance-field size (54px).

Change-Id: I0d9016990dedd93318893506afb1dba7a5249e2e
Reviewed-by: Eskil Abrahamsen Blomfeldt <eskil.abrahamsen-blomfeldt@nokia.com>

1 files changed, 62 insertions, 45 deletions

diff --git a/src/quick/scenegraph/qsgdefaultdistancefieldglyphcache.cpp b/src/quick/scenegraph/qsgdefaultdistancefieldglyphcache.cpp
index 5864f35060..2b2ccfe317 100644
--- a/src/quick/scenegraph/qsgdefaultdistancefieldglyphcache.cpp
+++ b/src/quick/scenegraph/qsgdefaultdistancefieldglyphcache.cpp
@@ -47,24 +47,41 @@
 
 QT_BEGIN_NAMESPACE
 
-QHash<QString, QOpenGLMultiGroupSharedResource> QSGDefaultDistanceFieldGlyphCache::m_textures_data;
-
-QSGDefaultDistanceFieldGlyphCache::DistanceFieldTextureData *QSGDefaultDistanceFieldGlyphCache::textureData(QOpenGLContext *c)
-{
-    QString key = QString::fromLatin1("%1_%2_%3_%4")
-            .arg(font().familyName())
-            .arg(font().styleName())
-            .arg(font().weight())
-            .arg(font().style());
-    return m_textures_data[key].value<QSGDefaultDistanceFieldGlyphCache::DistanceFieldTextureData>(c);
-}
 
 QSGDefaultDistanceFieldGlyphCache::QSGDefaultDistanceFieldGlyphCache(QSGDistanceFieldGlyphCacheManager *man, QOpenGLContext *c, const QRawFont &font)
     : QSGDistanceFieldGlyphCache(man, c, font)
     , m_maxTextureSize(0)
     , m_maxTextureCount(3)
+    , m_fbo(0)
+    , m_blitProgram(0)
+{
+    m_currentTexture = createTextureInfo();
+
+    m_blitVertexCoordinateArray[0] = -1.0f;
+    m_blitVertexCoordinateArray[1] = -1.0f;
+    m_blitVertexCoordinateArray[2] =  1.0f;
+    m_blitVertexCoordinateArray[3] = -1.0f;
+    m_blitVertexCoordinateArray[4] =  1.0f;
+    m_blitVertexCoordinateArray[5] =  1.0f;
+    m_blitVertexCoordinateArray[6] = -1.0f;
+    m_blitVertexCoordinateArray[7] =  1.0f;
+
+    m_blitTextureCoordinateArray[0] = 0.0f;
+    m_blitTextureCoordinateArray[1] = 0.0f;
+    m_blitTextureCoordinateArray[2] = 1.0f;
+    m_blitTextureCoordinateArray[3] = 0.0f;
+    m_blitTextureCoordinateArray[4] = 1.0f;
+    m_blitTextureCoordinateArray[5] = 1.0f;
+    m_blitTextureCoordinateArray[6] = 0.0f;
+    m_blitTextureCoordinateArray[7] = 1.0f;
+}
+
+QSGDefaultDistanceFieldGlyphCache::~QSGDefaultDistanceFieldGlyphCache()
 {
-    m_textureData = textureData(c);
+    for (int i = 0; i < m_textures.count(); ++i)
+        glDeleteTextures(1, &m_textures[i].texture);
+    ctx->functions()->glDeleteFramebuffers(1, &m_fbo);
+    delete m_blitProgram;
 }
 
 void QSGDefaultDistanceFieldGlyphCache::requestGlyphs(const QSet<glyph_t> &glyphs)
@@ -75,15 +92,15 @@ void QSGDefaultDistanceFieldGlyphCache::requestGlyphs(const QSet<glyph_t> &glyph
     for (QSet<glyph_t>::const_iterator it = glyphs.constBegin(); it != glyphs.constEnd() ; ++it) {
         glyph_t glyphIndex = *it;
 
-        if (cacheIsFull() && m_textureData->unusedGlyphs.isEmpty())
+        if (cacheIsFull() && m_unusedGlyphs.isEmpty())
             continue;
 
-        if (textureIsFull(m_textureData->currentTexture) && m_textureData->textures.count() < m_maxTextureCount)
-            m_textureData->currentTexture = m_textureData->addTexture();
+        if (textureIsFull(m_currentTexture) && m_textures.count() < m_maxTextureCount)
+            m_currentTexture = createTextureInfo();
 
-        m_textureData->unusedGlyphs.remove(glyphIndex);
+        m_unusedGlyphs.remove(glyphIndex);
 
-        DistanceFieldTextureData::TextureInfo *tex = m_textureData->currentTexture;
+        TextureInfo *tex = m_currentTexture;
 
         GlyphPosition p;
         p.glyph = glyphIndex;
@@ -97,13 +114,13 @@ void QSGDefaultDistanceFieldGlyphCache::requestGlyphs(const QSet<glyph_t> &glyph
             }
         } else {
             // Recycle glyphs
-            if (!m_textureData->unusedGlyphs.isEmpty()) {
-                glyph_t unusedGlyph = *m_textureData->unusedGlyphs.constBegin();
+            if (!m_unusedGlyphs.isEmpty()) {
+                glyph_t unusedGlyph = *m_unusedGlyphs.constBegin();
                 TexCoord unusedCoord = glyphTexCoord(unusedGlyph);
-                tex = m_textureData->glyphsTexture.value(unusedGlyph);
+                tex = m_glyphsTexture.value(unusedGlyph);
                 p.position = QPointF(unusedCoord.x, unusedCoord.y);
-                m_textureData->unusedGlyphs.remove(unusedGlyph);
-                m_textureData->glyphsTexture.remove(unusedGlyph);
+                m_unusedGlyphs.remove(unusedGlyph);
+                m_glyphsTexture.remove(unusedGlyph);
                 removeGlyph(unusedGlyph);
             }
         }
@@ -111,7 +128,7 @@ void QSGDefaultDistanceFieldGlyphCache::requestGlyphs(const QSet<glyph_t> &glyph
         if (p.position.y() < maxTextureSize()) {
             glyphPositions.append(p);
             glyphsToRender.append(glyphIndex);
-            m_textureData->glyphsTexture.insert(glyphIndex, tex);
+            m_glyphsTexture.insert(glyphIndex, tex);
         }
     }
 
@@ -124,13 +141,13 @@ void QSGDefaultDistanceFieldGlyphCache::storeGlyphs(const QHash<glyph_t, QImage>
     int requiredWidth = maxTextureSize();
     int rows = 128 / (requiredWidth / QT_DISTANCEFIELD_TILESIZE(doubleGlyphResolution())); // Enough rows to fill the latin1 set by default..
 
-    QHash<DistanceFieldTextureData::TextureInfo *, QVector<glyph_t> > glyphTextures;
+    QHash<TextureInfo *, QVector<glyph_t> > glyphTextures;
 
     QHash<glyph_t, QImage>::const_iterator it;
     for (it = glyphs.constBegin(); it != glyphs.constEnd(); ++it) {
         glyph_t glyphIndex = it.key();
         TexCoord c = glyphTexCoord(glyphIndex);
-        DistanceFieldTextureData::TextureInfo *texInfo = m_textureData->glyphsTexture.value(glyphIndex);
+        TextureInfo *texInfo = m_glyphsTexture.value(glyphIndex);
 
         int requiredHeight = qMin(maxTextureSize(),
                                   qMax(texInfo->currY + QT_DISTANCEFIELD_TILESIZE(doubleGlyphResolution()),
@@ -156,7 +173,7 @@ void QSGDefaultDistanceFieldGlyphCache::storeGlyphs(const QHash<glyph_t, QImage>
         glTexSubImage2D(GL_TEXTURE_2D, 0, c.x, c.y, glyph.width(), glyph.height(), GL_ALPHA, GL_UNSIGNED_BYTE, glyph.constBits());
     }
 
-    QHash<DistanceFieldTextureData::TextureInfo *, QVector<glyph_t> >::const_iterator i;
+    QHash<TextureInfo *, QVector<glyph_t> >::const_iterator i;
     for (i = glyphTextures.constBegin(); i != glyphTextures.constEnd(); ++i) {
         Texture t;
         t.textureId = i.key()->texture;
@@ -167,15 +184,15 @@ void QSGDefaultDistanceFieldGlyphCache::storeGlyphs(const QHash<glyph_t, QImage>
 
 void QSGDefaultDistanceFieldGlyphCache::referenceGlyphs(const QSet<glyph_t> &glyphs)
 {
-    m_textureData->unusedGlyphs -= glyphs;
+    m_unusedGlyphs -= glyphs;
 }
 
 void QSGDefaultDistanceFieldGlyphCache::releaseGlyphs(const QSet<glyph_t> &glyphs)
 {
-    m_textureData->unusedGlyphs += glyphs;
+    m_unusedGlyphs += glyphs;
 }
 
-void QSGDefaultDistanceFieldGlyphCache::createTexture(DistanceFieldTextureData::TextureInfo *texInfo, int width, int height)
+void QSGDefaultDistanceFieldGlyphCache::createTexture(TextureInfo *texInfo, int width, int height)
 {
     if (useWorkaroundBrokenFBOReadback() && texInfo->image.isNull())
         texInfo->image = QImage(width, height, QImage::Format_Indexed8);
@@ -202,7 +219,7 @@ void QSGDefaultDistanceFieldGlyphCache::createTexture(DistanceFieldTextureData::
 
 }
 
-void QSGDefaultDistanceFieldGlyphCache::resizeTexture(DistanceFieldTextureData::TextureInfo *texInfo, int width, int height)
+void QSGDefaultDistanceFieldGlyphCache::resizeTexture(TextureInfo *texInfo, int width, int height)
 {
     int oldWidth = texInfo->size.width();
     int oldHeight = texInfo->size.height();
@@ -224,14 +241,14 @@ void QSGDefaultDistanceFieldGlyphCache::resizeTexture(DistanceFieldTextureData::
         return;
     }
 
-    if (!m_textureData->blitProgram)
-        m_textureData->createBlitProgram();
+    if (!m_blitProgram)
+        createBlitProgram();
 
-    Q_ASSERT(m_textureData->blitProgram);
+    Q_ASSERT(m_blitProgram);
 
-    if (!m_textureData->fbo)
-        ctx->functions()->glGenFramebuffers(1, &m_textureData->fbo);
-    ctx->functions()->glBindFramebuffer(GL_FRAMEBUFFER, m_textureData->fbo);
+    if (!m_fbo)
+        ctx->functions()->glGenFramebuffers(1, &m_fbo);
+    ctx->functions()->glBindFramebuffer(GL_FRAMEBUFFER, m_fbo);
 
     GLuint tmp_texture;
     glGenTextures(1, &tmp_texture);
@@ -270,14 +287,14 @@ void QSGDefaultDistanceFieldGlyphCache::resizeTexture(DistanceFieldTextureData::
 
     glViewport(0, 0, oldWidth, oldHeight);
 
-    ctx->functions()->glVertexAttribPointer(QT_VERTEX_COORDS_ATTR, 2, GL_FLOAT, GL_FALSE, 0, m_textureData->blitVertexCoordinateArray);
-    ctx->functions()->glVertexAttribPointer(QT_TEXTURE_COORDS_ATTR, 2, GL_FLOAT, GL_FALSE, 0, m_textureData->blitTextureCoordinateArray);
+    ctx->functions()->glVertexAttribPointer(QT_VERTEX_COORDS_ATTR, 2, GL_FLOAT, GL_FALSE, 0, m_blitVertexCoordinateArray);
+    ctx->functions()->glVertexAttribPointer(QT_TEXTURE_COORDS_ATTR, 2, GL_FLOAT, GL_FALSE, 0, m_blitTextureCoordinateArray);
 
-    m_textureData->blitProgram->bind();
-    m_textureData->blitProgram->enableAttributeArray(int(QT_VERTEX_COORDS_ATTR));
-    m_textureData->blitProgram->enableAttributeArray(int(QT_TEXTURE_COORDS_ATTR));
-    m_textureData->blitProgram->disableAttributeArray(int(QT_OPACITY_ATTR));
-    m_textureData->blitProgram->setUniformValue("imageTexture", GLuint(0));
+    m_blitProgram->bind();
+    m_blitProgram->enableAttributeArray(int(QT_VERTEX_COORDS_ATTR));
+    m_blitProgram->enableAttributeArray(int(QT_TEXTURE_COORDS_ATTR));
+    m_blitProgram->disableAttributeArray(int(QT_OPACITY_ATTR));
+    m_blitProgram->setUniformValue("imageTexture", GLuint(0));
 
     glDrawArrays(GL_TRIANGLE_FAN, 0, 4);
 
@@ -304,8 +321,8 @@ void QSGDefaultDistanceFieldGlyphCache::resizeTexture(DistanceFieldTextureData::
     glViewport(viewport[0], viewport[1], viewport[2], viewport[3]);
     ctx->functions()->glUseProgram(oldProgram);
 
-    m_textureData->blitProgram->disableAttributeArray(int(QT_VERTEX_COORDS_ATTR));
-    m_textureData->blitProgram->disableAttributeArray(int(QT_TEXTURE_COORDS_ATTR));
+    m_blitProgram->disableAttributeArray(int(QT_VERTEX_COORDS_ATTR));
+    m_blitProgram->disableAttributeArray(int(QT_TEXTURE_COORDS_ATTR));
 }
 
 bool QSGDefaultDistanceFieldGlyphCache::useWorkaroundBrokenFBOReadback() const