Don't generate mipmaps in GLTexture::bind()

This code is broken in a number of different ways; firstly by assuming
that the mipmaps need to be regenerated when the texture filter has
changed. Secondly by preventing mipmaps from being specified by other
means.

This commit removes the code from bind() and adds a generateMipmaps()
method instead.

effects/logout/logout.cpp

@@ -357,6 +357,7 @@ void LogoutEffect::renderBlurTexture()
     glEnable(GL_BLEND);
     glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
     blurTexture->bind();
+    blurTexture->generateMipmaps();
     blurTexture->render(infiniteRegion(), effects->virtualScreenGeometry());
     blurTexture->unbind();
     glDisable(GL_BLEND);

effects/lookingglass/lookingglass.cpp

@@ -239,6 +239,7 @@ void LookingGlassEffect::postPaintScreen()
         assert(target == m_fbo);
         Q_UNUSED(target);
         m_texture->bind();
+        m_texture->generateMipmaps();
 
         // Use the shader
         ShaderBinder binder(m_shader);

libkwineffects/kwingltexture.cpp

@@ -283,7 +283,6 @@ void GLTexture::update(const QImage &image, const QPoint &offset, const QRect &s
     }
 
     unbind();
-    setDirty();
 
     if (useUnpack) {
         glPixelStorei(GL_UNPACK_ROW_LENGTH, 0);
@@ -312,7 +311,6 @@ void GLTexture::bind()
             if (d->s_supportsFramebufferObjects && d->m_canUseMipmaps) {
                 glTexParameteri(d->m_target, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_LINEAR);
                 glTexParameteri(d->m_target, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
-                glGenerateMipmap(d->m_target);
             } else {
                 // can't use trilinear, so use bilinear
                 d->m_filter = GL_LINEAR;
@@ -337,6 +335,14 @@ void GLTexture::bind()
     }
 }
 
+void GLTexture::generateMipmaps()
+{
+    Q_D(GLTexture);
+
+    if (d->m_canUseMipmaps && d->s_supportsFramebufferObjects)
+        glGenerateMipmap(d->m_target);
+}
+
 void GLTexture::unbind()
 {
     Q_D(GLTexture);
@@ -460,9 +466,7 @@ void GLTexture::setWrapMode(GLenum mode)
 
 void GLTexturePrivate::onDamage()
 {
-    if (m_filter == GL_LINEAR_MIPMAP_LINEAR && !m_filterChanged) {
-        glGenerateMipmap(m_target);
-    }
+    // No-op
 }
 
 void GLTexture::setDirty()

libkwineffects/kwingltexture.h

@@ -101,6 +101,8 @@ public:
     void setWrapMode(GLenum mode);
     void setDirty();
 
+    void generateMipmaps();
+
     static bool framebufferObjectSupported();
 
 protected: