introduce GLTexture::clear and use it from paintredirector

also work around broken fbo texture clearing on fglrx

so far supports FBO/glClear and resorts to glTexSubImage2D

if the fbo cannot be created or is (in case of fglrx)
known to break, resort to glTexImage2D loading of an
argb array of zeros

BUG: 323065
FIXED-IN: 4.11.2
REVIEW: 112526

libkwineffects/kwingltexture.cpp

@@ -46,7 +46,10 @@ namespace KWin
 bool GLTexturePrivate::sNPOTTextureSupported = false;
 bool GLTexturePrivate::sFramebufferObjectSupported = false;
 bool GLTexturePrivate::sSaturationSupported = false;
-bool GLTexturePrivate::sTextureFormatBGRA = false;
+GLenum GLTexturePrivate::sTextureFormat = GL_RGBA; // custom dummy, GL_BGRA is not present on GLES
+uint GLTexturePrivate::s_textureObjectCounter = 0;
+uint GLTexturePrivate::s_fbo = 0;
+
 
 GLTexture::GLTexture()
     : d_ptr(new GLTexturePrivate())
@@ -97,11 +100,8 @@ GLTexture::GLTexture(int width, int height)
         glGenTextures(1, &d->m_texture);
         bind();
 #ifdef KWIN_HAVE_OPENGLES
-        if (GLTexturePrivate::sTextureFormatBGRA) {
-            glTexImage2D(d->m_target, 0, GL_BGRA_EXT, width, height, 0, GL_BGRA_EXT, GL_UNSIGNED_BYTE, 0);
-        } else {
-            glTexImage2D(d->m_target, 0, GL_RGBA, width, height, 0, GL_RGBA, GL_UNSIGNED_BYTE, 0);
-        }
+        glTexImage2D(d->m_target, 0, GLTexturePrivate::sTextureFormat, width, height,
+                     0, GLTexturePrivate::sTextureFormat, GL_UNSIGNED_BYTE, 0);
 #else
         glTexImage2D(d->m_target, 0, GL_RGBA8, width, height, 0, GL_BGRA, GL_UNSIGNED_BYTE, 0);
 #endif
@@ -133,6 +133,7 @@ GLTexturePrivate::GLTexturePrivate()
     m_vbo = 0;
     m_filterChanged = true;
     m_wrapModeChanged = false;
+    ++s_textureObjectCounter;
 }
 
 GLTexturePrivate::~GLTexturePrivate()
@@ -143,6 +144,11 @@ GLTexturePrivate::~GLTexturePrivate()
     if (m_texture != 0) {
         glDeleteTextures(1, &m_texture);
     }
+    // Delete the FBO if this is the last Texture
+    if (--s_textureObjectCounter == 0 && s_fbo) {
+        glDeleteFramebuffers(1, &s_fbo);
+        s_fbo = 0;
+    }
 }
 
 void GLTexturePrivate::initStatic()
@@ -151,14 +157,17 @@ void GLTexturePrivate::initStatic()
     sNPOTTextureSupported = true;
     sFramebufferObjectSupported = true;
     sSaturationSupported = true;
-    sTextureFormatBGRA = hasGLExtension("GL_EXT_texture_format_BGRA8888");
+    if (hasGLExtension("GL_EXT_texture_format_BGRA8888"))
+        sTextureFormat = GL_BGRA_EXT;
+    else
+        sTextureFormat = GL_RGBA;
 #else
     sNPOTTextureSupported = hasGLExtension("GL_ARB_texture_non_power_of_two");
     sFramebufferObjectSupported = hasGLExtension("GL_EXT_framebuffer_object");
     sSaturationSupported = ((hasGLExtension("GL_ARB_texture_env_crossbar")
                              && hasGLExtension("GL_ARB_texture_env_dot3")) || hasGLVersion(1, 4))
                            && (glTextureUnitsCount >= 4) && glActiveTexture != NULL;
-    sTextureFormatBGRA = true;
+    sTextureFormat = GL_BGRA;
 #endif
 }
 
@@ -215,11 +224,8 @@ bool GLTexture::load(const QImage& image, GLenum target)
     }
     bind();
 #ifdef KWIN_HAVE_OPENGLES
-    if (GLTexturePrivate::sTextureFormatBGRA) {
-        glTexImage2D(d->m_target, 0, GL_BGRA_EXT, img.width(), img.height(), 0, GL_BGRA_EXT, GL_UNSIGNED_BYTE, img.bits());
-    } else {
-        glTexImage2D(d->m_target, 0, GL_RGBA, img.width(), img.height(), 0, GL_RGBA, GL_UNSIGNED_BYTE, img.bits());
-    }
+    glTexImage2D(d->m_target, 0, GLTexturePrivate::sTextureFormat, img.width(), img.height(),
+                 0, GLTexturePrivate::sTextureFormat, GL_UNSIGNED_BYTE, img.bits());
 #else
     glTexImage2D(d->m_target, 0, GL_RGBA8, img.width(), img.height(), 0,
                  GL_BGRA, GL_UNSIGNED_BYTE, img.bits());
@@ -258,15 +264,8 @@ void GLTexture::update(const QImage &image, const QPoint &offset, const QRect &s
     const QImage &img = d->convertToGLFormat(tmpImage.isNull() ? image : tmpImage);
 
     bind();
-#ifdef KWIN_HAVE_OPENGLES
-    if (GLTexturePrivate::sTextureFormatBGRA) {
-        glTexSubImage2D(d->m_target, 0, offset.x(), offset.y(), width, height, GL_BGRA_EXT, GL_UNSIGNED_BYTE, img.bits());
-    } else {
-        glTexSubImage2D(d->m_target, 0, offset.x(), offset.y(), width, height, GL_RGBA, GL_UNSIGNED_BYTE, img.bits());
-    }
-#else
-    glTexSubImage2D(d->m_target, 0, offset.x(), offset.y(), width, height, GL_BGRA, GL_UNSIGNED_BYTE, img.bits());
-#endif
+    glTexSubImage2D(d->m_target, 0, offset.x(), offset.y(), width, height,
+                    GLTexturePrivate::sTextureFormat, GL_UNSIGNED_BYTE, img.bits());
     checkGLError("update texture");
     unbind();
     setDirty();
@@ -428,6 +427,33 @@ GLenum GLTexture::filter() const
     return d->m_filter;
 }
 
+void GLTexture::clear()
+{
+    Q_D(GLTexture);
+    if (!GLTexturePrivate::s_fbo && GLRenderTarget::supported() &&
+        GLPlatform::instance()->driver() != Driver_Catalyst) // fail. -> bug #323065
+        glGenFramebuffers(1, &GLTexturePrivate::s_fbo);
+
+    if (GLTexturePrivate::s_fbo) {
+        // Clear the texture
+        glBindFramebuffer(GL_FRAMEBUFFER, GLTexturePrivate::s_fbo);
+        glClearColor(0, 0, 0, 0);
+        glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, d->m_texture, 0);
+        glClear(GL_COLOR_BUFFER_BIT);
+        glBindFramebuffer(GL_FRAMEBUFFER, 0);
+    } else {
+        if (const int size = width()*height()) {
+            uint32_t *buffer = new uint32_t[size];
+            memset(buffer, 0, size*sizeof(uint32_t));
+            bind();
+            glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, width(), height(),
+                            GLTexturePrivate::sTextureFormat, GL_UNSIGNED_BYTE, buffer);
+            unbind();
+            delete[] buffer;
+        }
+    }
+}
+
 bool GLTexture::isDirty() const
 {
     Q_D(const GLTexture);
@@ -470,7 +496,7 @@ QImage GLTexturePrivate::convertToGLFormat(const QImage& img) const
     // Copied from Qt's QGLWidget::convertToGLFormat()
     QImage res;
 
-    if (sTextureFormatBGRA) {
+    if (sTextureFormat != GL_RGBA) {
         if (QSysInfo::ByteOrder == QSysInfo::BigEndian) {
             res = QImage(img.size(), QImage::Format_ARGB32);
             QImage imgARGB32 = img.convertToFormat(QImage::Format_ARGB32_Premultiplied);

libkwineffects/kwingltexture.h

@@ -93,6 +93,11 @@ public:
     GLuint texture() const;
     GLenum target() const;
     GLenum filter() const;
+    /** @short
+     * Make the texture fully transparent
+     * Warning: this clobbers the current framebuffer binding except on fglrx
+     */
+    void clear();
     bool isDirty() const;
     void setFilter(GLenum filter);
     void setWrapMode(GLenum mode);

libkwineffects/kwingltexture_p.h

@@ -73,7 +73,9 @@ public:
     static bool sNPOTTextureSupported;
     static bool sFramebufferObjectSupported;
     static bool sSaturationSupported;
-    static bool sTextureFormatBGRA;
+    static GLenum sTextureFormat;
+    static uint s_fbo;
+    static uint s_textureObjectCounter;
 private:
     Q_DISABLE_COPY(GLTexturePrivate)
 };

paintredirector.cpp

@@ -28,6 +28,7 @@ DEALINGS IN THE SOFTWARE.
 #include "client.h"
 #include "deleted.h"
 #include "effects.h"
+#include <kwinglplatform.h>
 #include <kwinglutils.h>
 #include <kwinxrenderutils.h>
 #include <kdebug.h>
@@ -310,21 +311,12 @@ void ImageBasedPaintRedirector::discardScratch()
 // ------------------------------------------------------------------
 
 
-
-unsigned int OpenGLPaintRedirector::s_count = 0;
-unsigned int OpenGLPaintRedirector::s_fbo = 0;
-
 OpenGLPaintRedirector::OpenGLPaintRedirector(Client *c, QWidget *widget)
     : ImageBasedPaintRedirector(c, widget)
 {
-    s_count++;
-
     for (int i = 0; i < TextureCount; ++i)
         m_textures[i] = NULL;
 
-    if (!s_fbo && GLRenderTarget::supported())
-        glGenFramebuffers(1, &s_fbo);
-
     PaintRedirector::resizePixmaps();
 }
 
@@ -332,12 +324,6 @@ OpenGLPaintRedirector::~OpenGLPaintRedirector()
 {
     for (int i = 0; i < TextureCount; ++i)
         delete m_textures[i];
-
-    // Delete the FBO if this is the last OpenGLPaintRedirector
-    if (--s_count == 0 && s_fbo) {
-        glDeleteFramebuffers(1, &s_fbo);
-        s_fbo = 0;
-    }
 }
 
 void OpenGLPaintRedirector::resizePixmaps(const QRect *rects)
@@ -355,8 +341,6 @@ void OpenGLPaintRedirector::resizePixmaps(const QRect *rects)
         }
     }
 
-    bool fbo_bound = false;
-
     for (int i = 0; i < 2; i++) {
         if (m_textures[i] && m_textures[i]->size() == size[i])
             continue;
@@ -370,22 +354,8 @@ void OpenGLPaintRedirector::resizePixmaps(const QRect *rects)
         m_textures[i] = new GLTexture(size[i].width(), size[i].height());
         m_textures[i]->setYInverted(true);
         m_textures[i]->setWrapMode(GL_CLAMP_TO_EDGE);
-
-        if (s_fbo) {
-            // Clear the texture
-            if (!fbo_bound) {
-                glBindFramebuffer(GL_FRAMEBUFFER, s_fbo);
-                glClearColor(0, 0, 0, 0);
-                fbo_bound = true;
-            }
-
-            glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, m_textures[i]->texture(), 0);
-            glClear(GL_COLOR_BUFFER_BIT);
-        }
+        m_textures[i]->clear();
     }
-
-    if (fbo_bound)
-        glBindFramebuffer(GL_FRAMEBUFFER, 0);
 }
 
 void OpenGLPaintRedirector::preparePaint(const QPixmap &pending)

paintredirector.h

@@ -157,9 +157,6 @@ protected:
 private:
     QImage m_tempImage;
     GLTexture *m_textures[2];
-
-    static unsigned int s_fbo;
-    static unsigned int s_count;
 };
 
 class NativeXRenderPaintRedirector : public PaintRedirector