Prevent bogus warning message flood on nVidia driver related to mipmaps

When using QtQuick2 Text elements on nVidia with the KHR_debug extension
active we get flooded by messages of the form:

"Texture state usage warning: Waste of memory: Texture 0 has mipmaps,
while its min filter is inconsistent with mipmaps."

This is totally bogus as there really aren't any mipmaps created here.
However, it is very annoying and hides genuine errors. Setting the
mipmap max level to 0 works around the issue. nVidia seem unwilling
to fix it in the driver.

Change-Id: I56632ba1ee777fb54fc8d17e1828669baa183a55
Reviewed-by: Giuseppe D'Angelo <giuseppe.dangelo@kdab.com>
Reviewed-by: James Turner <james.turner@kdab.com>
Reviewed-by: Gunnar Sletta <gunnar.sletta@digia.com>

1 files changed, 9 insertions, 3 deletions

diff --git a/src/quick/scenegraph/qsgdefaultdistancefieldglyphcache.cpp b/src/quick/scenegraph/qsgdefaultdistancefieldglyphcache.cpp
index 8a1a87cdc0..bc09ed83d7 100644
--- a/src/quick/scenegraph/qsgdefaultdistancefieldglyphcache.cpp
+++ b/src/quick/scenegraph/qsgdefaultdistancefieldglyphcache.cpp
@@ -212,11 +212,14 @@ void QSGDefaultDistanceFieldGlyphCache::createTexture(TextureInfo *texInfo, int
     glGenTextures(1, &texInfo->texture);
     glBindTexture(GL_TEXTURE_2D, texInfo->texture);
 
-    glTexImage2D(GL_TEXTURE_2D, 0, GL_ALPHA, width, height, 0, GL_ALPHA, GL_UNSIGNED_BYTE, 0);
     glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
     glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
     glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
     glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
+#if !defined(QT_OPENGL_ES_2)
+    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAX_LEVEL, 0);
+#endif
+    glTexImage2D(GL_TEXTURE_2D, 0, GL_ALPHA, width, height, 0, GL_ALPHA, GL_UNSIGNED_BYTE, 0);
 
     texInfo->size = QSize(width, height);
 
@@ -278,12 +281,15 @@ void QSGDefaultDistanceFieldGlyphCache::resizeTexture(TextureInfo *texInfo, int
     GLuint tmp_texture;
     glGenTextures(1, &tmp_texture);
     glBindTexture(GL_TEXTURE_2D, tmp_texture);
-    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, oldWidth, oldHeight, 0,
-                 GL_RGBA, GL_UNSIGNED_BYTE, NULL);
     glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
     glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
     glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
     glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
+#if !defined(QT_OPENGL_ES_2)
+    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAX_LEVEL, 0);
+#endif
+    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, oldWidth, oldHeight, 0,
+                 GL_RGBA, GL_UNSIGNED_BYTE, NULL);
     glBindTexture(GL_TEXTURE_2D, 0);
     ctx->functions()->glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0,
                                              GL_TEXTURE_2D, tmp_texture, 0);