Minimize parameter changes on glyph cache textures

Cache the last set filtering mode on glyph textures and update only
when necessary.

Reviewed-by: Gunnar Sletta

3 files changed, 32 insertions, 5 deletions

diff --git a/src/opengl/gl2paintengineex/qpaintengineex_opengl2.cpp b/src/opengl/gl2paintengineex/qpaintengineex_opengl2.cpp
index 5dd66fe..cb1ca8e 100644
--- a/src/opengl/gl2paintengineex/qpaintengineex_opengl2.cpp
+++ b/src/opengl/gl2paintengineex/qpaintengineex_opengl2.cpp
@@ -1695,12 +1695,26 @@ void QGL2PaintEngineExPrivate::drawCachedGlyphs(QFontEngineGlyphCache::Type glyp
     }
     //### TODO: Gamma correction
 
-    glActiveTexture(GL_TEXTURE0 + QT_MASK_TEXTURE_UNIT);
-    if (lastMaskTextureUsed != cache->texture()) {
-        glBindTexture(GL_TEXTURE_2D, cache->texture());
-        lastMaskTextureUsed = cache->texture();
+    QGLTextureGlyphCache::FilterMode filterMode = (s->matrix.type() > QTransform::TxTranslate)?QGLTextureGlyphCache::Linear:QGLTextureGlyphCache::Nearest;
+    if (lastMaskTextureUsed != cache->texture() || cache->filterMode() != filterMode) {
+
+        glActiveTexture(GL_TEXTURE0 + QT_MASK_TEXTURE_UNIT);
+        if (lastMaskTextureUsed != cache->texture()) {
+            glBindTexture(GL_TEXTURE_2D, cache->texture());
+            lastMaskTextureUsed = cache->texture();
+        }
+
+        if (cache->filterMode() != filterMode) {
+            if (filterMode == QGLTextureGlyphCache::Linear) {
+                glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
+                glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
+            } else {
+                glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
+                glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
+            }
+            cache->setFilterMode(filterMode);
+        }
     }
-    updateTextureFilter(GL_TEXTURE_2D, GL_REPEAT, s->matrix.type() > QTransform::TxTranslate);
 
 #if defined(QT_OPENGL_DRAWCACHEDGLYPHS_INDEX_ARRAY_VBO)
     glDrawElements(GL_TRIANGLE_STRIP, 6 * staticTextItem->numGlyphs, GL_UNSIGNED_SHORT, 0);
diff --git a/src/opengl/gl2paintengineex/qtextureglyphcache_gl.cpp b/src/opengl/gl2paintengineex/qtextureglyphcache_gl.cpp
index f353995..9a5bac0 100644
--- a/src/opengl/gl2paintengineex/qtextureglyphcache_gl.cpp
+++ b/src/opengl/gl2paintengineex/qtextureglyphcache_gl.cpp
@@ -57,6 +57,7 @@ QGLTextureGlyphCache::QGLTextureGlyphCache(QGLContext *context, QFontEngineGlyph
     , ctx(context)
     , m_width(0)
     , m_height(0)
+    , m_filterMode(Nearest)
 {
     // broken FBO readback is a bug in the SGX 1.3 and 1.4 drivers for the N900 where
     // copying between FBO's is broken if the texture is either GL_ALPHA or POT. The
@@ -114,6 +115,9 @@ void QGLTextureGlyphCache::createTextureData(int width, int height)
 
     glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
     glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
+    glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
+    glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
+    m_filterMode = Nearest;
 }
 
 void QGLTextureGlyphCache::resizeTextureData(int width, int height)
@@ -152,6 +156,7 @@ void QGLTextureGlyphCache::resizeTextureData(int width, int height)
     glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
     glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
     glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
+    m_filterMode = Nearest;
     glBindTexture(GL_TEXTURE_2D, 0);
     glFramebufferTexture2D(GL_FRAMEBUFFER_EXT, GL_COLOR_ATTACHMENT0_EXT,
                            GL_TEXTURE_2D, tmp_texture, 0);
diff --git a/src/opengl/gl2paintengineex/qtextureglyphcache_gl_p.h b/src/opengl/gl2paintengineex/qtextureglyphcache_gl_p.h
index eb3693c..e22146d 100644
--- a/src/opengl/gl2paintengineex/qtextureglyphcache_gl_p.h
+++ b/src/opengl/gl2paintengineex/qtextureglyphcache_gl_p.h
@@ -83,6 +83,12 @@ public:
 
     inline void setPaintEnginePrivate(QGL2PaintEngineExPrivate *p) { pex = p; }
 
+    enum FilterMode {
+        Nearest,
+        Linear
+    };
+    FilterMode filterMode() const { return m_filterMode; }
+    void setFilterMode(FilterMode m) { m_filterMode = m; }
 
 public Q_SLOTS:
     void contextDestroyed(const QGLContext *context) {
@@ -117,6 +123,8 @@ private:
     int m_height;
 
     QGLShaderProgram *m_program;
+
+    FilterMode m_filterMode;
 };
 
 QT_END_NAMESPACE