Fix crash when expanding glyph cache beyond one texture

The textureInfo() function was returning pointers to the
m_textures array, which would then be stored in the
m_glyphTextures map and other places in the renderer.
Then the function then later resized it, the renderer
would be riddled with dangling pointers and crash pretty
quickly.

There is a preset maximum texture count, so we just make
sure the array is the correct size to begin with and
never resize it.

In addition, this contains a port of
46d72a117df642135718b38995346267312c4808 and
9a53834f1e7fce2fc3b1ecc2a311faedbc371d37 from Qt Quick.

Note: Glyph recycling does not seem to work, so you may end
up running out of cache space. However, it will no longer crash,
but glyphs will be missing instead.

Fixes: QT3DS-4235
Change-Id: I7d9707ff95ac0838e7e6574714a06ac1c23986fa
Reviewed-by: Janne Koskinen <janne.p.koskinen@qt.io>

1 files changed, 4 insertions, 4 deletions

diff --git a/src/runtimerender/Qt3DSDistanceFieldGlyphCache_p.h b/src/runtimerender/Qt3DSDistanceFieldGlyphCache_p.h
index fb4826e..2eca726 100644
--- a/src/runtimerender/Qt3DSDistanceFieldGlyphCache_p.h
+++ b/src/runtimerender/Qt3DSDistanceFieldGlyphCache_p.h
@@ -54,10 +54,10 @@ class Q3DSDistanceFieldGlyphCache : public QSGDistanceFieldGlyphCache
 {
 public:
     struct TextureInfo {
-        qt3ds::render::NVRenderTexture2D *texture;
+        qt3ds::render::NVRenderTexture2D *texture = nullptr;
         int padding = -1;
 
-        QRect allocatedArea;
+        QRect allocatedArea = QRect(0, 0, 1, 1);
         QImage copy;
     };
 
@@ -84,12 +84,12 @@ private:
     bool loadPregeneratedCache(const QRawFont &font);
     TextureInfo *textureInfo(int index) const;
 
-    int maxTextureSize() const;
     void resizeTexture(TextureInfo *info, int width, int height);
     void setTextureData(qt3ds::render::NVRenderTexture2D *texture, QImage &image);
 
     QSGAreaAllocator *m_areaAllocator = nullptr;
-    int m_maxTextureSize              = 0;
+    int m_maxTextureWidth             = 0;
+    int m_maxTextureHeight            = 0;
     int m_maxTextureCount             = 3;
 
     mutable QVector<TextureInfo> m_textures;