Remove duplicated code for handling OpenGL extensions in QtOpenGL

We now re-use QOpenGLExtensions/Functions from QtGui in the same way
as QtGui uses these classes. There is still some duplicated logic
in qglfunctions.cpp, but this code now at least uses the shared
QOpenGLExtensionMatcher class.

Change-Id: Ie04008c43d430ae805e6ec1c45e7e363deeb3b8f
Reviewed-by: Tor Arne Vestbø <tor.arne.vestbo@digia.com>

1 files changed, 61 insertions, 223 deletions

diff --git a/src/opengl/qgl.cpp b/src/opengl/qgl.cpp
index 402fdfa33f..f9ed294cca 100644
--- a/src/opengl/qgl.cpp
+++ b/src/opengl/qgl.cpp
@@ -59,6 +59,7 @@
 
 #include <qglpixelbuffer.h>
 #include <qglframebufferobject.h>
+#include <private/qopenglextensions_p.h>
 
 #include <private/qimage_p.h>
 #include <qpa/qplatformpixmap.h>
@@ -73,7 +74,52 @@
 
 QT_BEGIN_NAMESPACE
 
-QGLExtensionFuncs QGLContextPrivate::qt_extensionFuncs;
+class QGLDefaultExtensions
+{
+public:
+    QGLDefaultExtensions() : extensions(0) {
+        QGLTemporaryContext tempContext;
+        Q_ASSERT(QOpenGLContext::currentContext());
+        QOpenGLExtensions *ext = qgl_extensions();
+        Q_ASSERT(ext);
+        extensions = ext->openGLExtensions();
+        features = ext->openGLFeatures();
+    }
+
+    QOpenGLFunctions::OpenGLFeatures features;
+    QOpenGLExtensions::OpenGLExtensions extensions;
+};
+
+Q_GLOBAL_STATIC(QGLDefaultExtensions, qtDefaultExtensions)
+
+bool qgl_hasFeature(QOpenGLFunctions::OpenGLFeature feature)
+{
+    if (QOpenGLContext::currentContext())
+        return QOpenGLContext::currentContext()->functions()->hasOpenGLFeature(feature);
+    return qtDefaultExtensions()->features & feature;
+}
+
+bool qgl_hasExtension(QOpenGLExtensions::OpenGLExtension extension)
+{
+    if (QOpenGLContext::currentContext())
+        return qgl_extensions()->hasOpenGLExtension(extension);
+    return qtDefaultExtensions()->extensions & extension;
+}
+
+QOpenGLExtensions::OpenGLExtensions extensions;
+/*
+    Returns the GL extensions for the current QOpenGLContext. If there is no
+    current QOpenGLContext, a default context will be created and the extensions
+    for that context will be returned instead.
+*/
+QOpenGLExtensions* qgl_extensions()
+{
+    if (QOpenGLContext *context = QOpenGLContext::currentContext())
+        return static_cast<QOpenGLExtensions *>(context->functions());
+
+    Q_ASSERT(false);
+    return 0;
+}
 
 struct QGLThreadContext {
     ~QGLThreadContext() {
@@ -1567,8 +1613,6 @@ void QGLContextPrivate::init(QPaintDevice *dev, const QGLFormat &format)
     max_texture_size = -1;
     version_flags_cached = false;
     version_flags = QGLFormat::OpenGL_Version_None;
-    extension_flags_cached = false;
-    extension_flags = 0;
     current_fbo = 0;
     default_fbo = 0;
     active_engine = 0;
@@ -1956,30 +2000,32 @@ void QGLContextPrivate::cleanup()
 #define ctx q_ptr
 void QGLContextPrivate::setVertexAttribArrayEnabled(int arrayIndex, bool enabled)
 {
+    Q_Q(QGLContext);
     Q_ASSERT(arrayIndex < QT_GL_VERTEX_ARRAY_TRACKED_COUNT);
 #ifdef glEnableVertexAttribArray
     Q_ASSERT(glEnableVertexAttribArray);
 #endif
 
     if (vertexAttributeArraysEnabledState[arrayIndex] && !enabled)
-        glDisableVertexAttribArray(arrayIndex);
+        q->functions()->glDisableVertexAttribArray(arrayIndex);
 
     if (!vertexAttributeArraysEnabledState[arrayIndex] && enabled)
-        glEnableVertexAttribArray(arrayIndex);
+        q->functions()->glEnableVertexAttribArray(arrayIndex);
 
     vertexAttributeArraysEnabledState[arrayIndex] = enabled;
 }
 
 void QGLContextPrivate::syncGlState()
 {
+    Q_Q(QGLContext);
 #ifdef glEnableVertexAttribArray
     Q_ASSERT(glEnableVertexAttribArray);
 #endif
     for (int i = 0; i < QT_GL_VERTEX_ARRAY_TRACKED_COUNT; ++i) {
         if (vertexAttributeArraysEnabledState[i])
-            glEnableVertexAttribArray(i);
+            q->functions()->glEnableVertexAttribArray(i);
         else
-            glDisableVertexAttribArray(i);
+            q->functions()->glDisableVertexAttribArray(i);
     }
 
 }
@@ -2129,11 +2175,6 @@ static void convertToGLFormatHelper(QImage &dst, const QImage &img, GLenum textu
     }
 }
 
-QGLExtensionFuncs& QGLContextPrivate::extensionFuncs(const QGLContext *)
-{
-    return qt_extensionFuncs;
-}
-
 /*! \internal */
 QGLTexture *QGLContextPrivate::bindTexture(const QImage &image, GLenum target, GLint format,
                                            QGLContext::BindOptions options)
@@ -2221,7 +2262,7 @@ QGLTexture* QGLContextPrivate::bindTexture(const QImage &image, GLenum target, G
 
     QImage img = image;
 
-    if (!(QGLExtensions::glExtensions() & QGLExtensions::NPOTTextures)
+    if (!qgl_extensions()->hasOpenGLFeature(QOpenGLFunctions::NPOTTextures)
         && !(QGLFormat::openGLVersionFlags() & QGLFormat::OpenGL_ES_Version_2_0)
         && (target == GL_TEXTURE_2D && (tx_w != image.width() || tx_h != image.height())))
     {
@@ -2243,7 +2284,7 @@ QGLTexture* QGLContextPrivate::bindTexture(const QImage &image, GLenum target, G
     bool genMipmap = false;
 #endif
     if (glFormat.directRendering()
-        && (QGLExtensions::glExtensions() & QGLExtensions::GenerateMipmap)
+        && (qgl_extensions()->hasOpenGLExtension(QOpenGLExtensions::GenerateMipmap))
         && target == GL_TEXTURE_2D
         && (options & QGLContext::MipmapBindOption))
     {
@@ -2267,7 +2308,7 @@ QGLTexture* QGLContextPrivate::bindTexture(const QImage &image, GLenum target, G
     bool premul = options & QGLContext::PremultipliedAlphaBindOption;
     GLenum externalFormat;
     GLuint pixel_type;
-    if (QGLExtensions::glExtensions() & QGLExtensions::BGRATextureFormat) {
+    if (qgl_extensions()->hasOpenGLExtension(QOpenGLExtensions::BGRATextureFormat)) {
         externalFormat = GL_BGRA;
         if (QGLFormat::openGLVersionFlags() & QGLFormat::OpenGL_Version_1_2)
             pixel_type = GL_UNSIGNED_INT_8_8_8_8_REV;
@@ -4651,192 +4692,6 @@ QPaintEngine *QGLWidget::paintEngine() const
     return qt_qgl_paint_engine();
 }
 
-typedef const GLubyte * (QGLF_APIENTRYP qt_glGetStringi)(GLenum, GLuint);
-
-#ifndef GL_NUM_EXTENSIONS
-#define GL_NUM_EXTENSIONS 0x821D
-#endif
-
-QGLExtensionMatcher::QGLExtensionMatcher(const char *str)
-{
-    init(str);
-}
-
-QGLExtensionMatcher::QGLExtensionMatcher()
-{
-    const char *extensionStr = reinterpret_cast<const char *>(glGetString(GL_EXTENSIONS));
-
-    if (extensionStr) {
-        init(extensionStr);
-    } else {
-        // clear error state
-        while (glGetError()) {}
-
-        const QGLContext *ctx = QGLContext::currentContext();
-        if (ctx) {
-            qt_glGetStringi glGetStringi = (qt_glGetStringi)ctx->getProcAddress(QLatin1String("glGetStringi"));
-
-            GLint numExtensions;
-            glGetIntegerv(GL_NUM_EXTENSIONS, &numExtensions);
-
-            for (int i = 0; i < numExtensions; ++i) {
-                const char *str = reinterpret_cast<const char *>(glGetStringi(GL_EXTENSIONS, i));
-
-                m_offsets << m_extensions.size();
-
-                while (*str != 0)
-                    m_extensions.append(*str++);
-                m_extensions.append(' ');
-            }
-        }
-    }
-}
-
-void QGLExtensionMatcher::init(const char *str)
-{
-    m_extensions = str;
-
-    // make sure extension string ends with a space
-    if (!m_extensions.endsWith(' '))
-        m_extensions.append(' ');
-
-    int index = 0;
-    int next = 0;
-    while ((next = m_extensions.indexOf(' ', index)) >= 0) {
-        m_offsets << index;
-        index = next + 1;
-    }
-}
-
-// ####TODO Properly #ifdef this class to use #define symbols actually defined
-// by OpenGL/ES includes
-#ifndef GL_FRAMEBUFFER_SRGB_CAPABLE_EXT
-#define GL_FRAMEBUFFER_SRGB_CAPABLE_EXT 0x8DBA
-#endif
-
-/*
-    Returns the GL extensions for the current context.
-*/
-QGLExtensions::Extensions QGLExtensions::currentContextExtensions()
-{
-    QGLExtensionMatcher extensions;
-    Extensions glExtensions;
-
-    if (extensions.match("GL_ARB_texture_rectangle"))
-        glExtensions |= TextureRectangle;
-    if (extensions.match("GL_ARB_multisample"))
-        glExtensions |= SampleBuffers;
-    if (extensions.match("GL_SGIS_generate_mipmap"))
-        glExtensions |= GenerateMipmap;
-    if (extensions.match("GL_ARB_texture_compression"))
-        glExtensions |= TextureCompression;
-    if (extensions.match("GL_EXT_texture_compression_s3tc"))
-        glExtensions |= DDSTextureCompression;
-    if (extensions.match("GL_OES_compressed_ETC1_RGB8_texture"))
-        glExtensions |= ETC1TextureCompression;
-    if (extensions.match("GL_IMG_texture_compression_pvrtc"))
-        glExtensions |= PVRTCTextureCompression;
-    if (extensions.match("GL_ARB_fragment_program"))
-        glExtensions |= FragmentProgram;
-    if (extensions.match("GL_ARB_fragment_shader"))
-        glExtensions |= FragmentShader;
-    if (extensions.match("GL_ARB_shader_objects"))
-        glExtensions |= FragmentShader;
-    if (extensions.match("GL_ARB_texture_mirrored_repeat"))
-        glExtensions |= MirroredRepeat;
-    if (extensions.match("GL_EXT_framebuffer_object"))
-        glExtensions |= FramebufferObject;
-    if (extensions.match("GL_EXT_stencil_two_side"))
-        glExtensions |= StencilTwoSide;
-    if (extensions.match("GL_EXT_stencil_wrap"))
-        glExtensions |= StencilWrap;
-    if (extensions.match("GL_EXT_packed_depth_stencil"))
-        glExtensions |= PackedDepthStencil;
-    if (extensions.match("GL_NV_float_buffer"))
-        glExtensions |= NVFloatBuffer;
-    if (extensions.match("GL_ARB_pixel_buffer_object"))
-        glExtensions |= PixelBufferObject;
-    if (extensions.match("GL_IMG_texture_format_BGRA8888"))
-        glExtensions |= BGRATextureFormat;
-#if defined(QT_OPENGL_ES_2)
-    glExtensions |= FramebufferObject;
-    glExtensions |= GenerateMipmap;
-    glExtensions |= FragmentShader;
-#endif
-#if defined(QT_OPENGL_ES)
-    if (extensions.match("GL_OES_packed_depth_stencil"))
-        glExtensions |= PackedDepthStencil;
-    if (extensions.match("GL_OES_element_index_uint"))
-        glExtensions |= ElementIndexUint;
-    if (extensions.match("GL_OES_depth24"))
-        glExtensions |= Depth24;
-#else
-    glExtensions |= ElementIndexUint;
-#endif
-    if (extensions.match("GL_ARB_framebuffer_object")) {
-        // ARB_framebuffer_object also includes EXT_framebuffer_blit.
-        glExtensions |= FramebufferObject;
-        glExtensions |= FramebufferBlit;
-    }
-
-    if (extensions.match("GL_EXT_framebuffer_blit"))
-        glExtensions |= FramebufferBlit;
-
-    if (extensions.match("GL_ARB_texture_non_power_of_two"))
-        glExtensions |= NPOTTextures;
-
-    if (extensions.match("GL_EXT_bgra"))
-        glExtensions |= BGRATextureFormat;
-
-#if !defined(QT_OPENGL_ES)
-    {
-        GLboolean srgbCapableFramebuffers = false;
-        glGetBooleanv(GL_FRAMEBUFFER_SRGB_CAPABLE_EXT, &srgbCapableFramebuffers);
-        if (srgbCapableFramebuffers)
-            glExtensions |= SRGBFrameBuffer;
-    }
-#endif
-
-    return glExtensions;
-}
-
-
-class QGLDefaultExtensions
-{
-public:
-    QGLDefaultExtensions() {
-        QGLTemporaryContext tempContext;
-        extensions = QGLExtensions::currentContextExtensions();
-    }
-
-    QGLExtensions::Extensions extensions;
-};
-
-Q_GLOBAL_STATIC(QGLDefaultExtensions, qtDefaultExtensions)
-
-/*
-    Returns the GL extensions for the current QGLContext. If there is no
-    current QGLContext, a default context will be created and the extensions
-    for that context will be returned instead.
-*/
-QGLExtensions::Extensions QGLExtensions::glExtensions()
-{
-    Extensions extensionFlags = 0;
-    QGLContext *currentCtx = const_cast<QGLContext *>(QGLContext::currentContext());
-
-    if (currentCtx && currentCtx->d_func()->extension_flags_cached)
-        return currentCtx->d_func()->extension_flags;
-
-    if (!currentCtx) {
-        extensionFlags = qtDefaultExtensions()->extensions;
-    } else {
-        extensionFlags = currentContextExtensions();
-        currentCtx->d_func()->extension_flags_cached = true;
-        currentCtx->d_func()->extension_flags = extensionFlags;
-    }
-    return extensionFlags;
-}
-
 /*
   This is the shared initialization for all platforms. Called from QGLWidgetPrivate::init()
 */
@@ -5023,21 +4878,6 @@ QSize QGLTexture::bindCompressedTexture
         // systems such as x86 and ARM at the moment.
         return QSize();
     }
-#if !defined(QT_OPENGL_ES)
-    if (!glCompressedTexImage2D) {
-        if (!(QGLExtensions::glExtensions() & QGLExtensions::TextureCompression)) {
-            qWarning("QGLContext::bindTexture(): The GL implementation does "
-                     "not support texture compression extensions.");
-            return QSize();
-        }
-        glCompressedTexImage2D = (_glCompressedTexImage2DARB) ctx->getProcAddress(QLatin1String("glCompressedTexImage2DARB"));
-        if (!glCompressedTexImage2D) {
-            qWarning("QGLContext::bindTexture(): could not resolve "
-                     "glCompressedTexImage2DARB.");
-            return QSize();
-        }
-    }
-#endif
     if (!format) {
         // Auto-detect the format from the header.
         if (len >= 4 && !qstrncmp(buf, "DDS ", 4))
@@ -5064,7 +4904,7 @@ QSize QGLTexture::bindCompressedTextureDDS(const char *buf, int len)
         return QSize();
 
     // Bail out if the necessary extension is not present.
-    if (!(QGLExtensions::glExtensions() & QGLExtensions::DDSTextureCompression)) {
+    if (!qgl_extensions()->hasOpenGLExtension(QOpenGLExtensions::DDSTextureCompression)) {
         qWarning("QGLContext::bindTexture(): DDS texture compression is not supported.");
         return QSize();
     }
@@ -5116,7 +4956,7 @@ QSize QGLTexture::bindCompressedTextureDDS(const char *buf, int len)
         size = ((w+3)/4) * ((h+3)/4) * blockSize;
         if (size > available)
             break;
-        glCompressedTexImage2D(GL_TEXTURE_2D, i, format, w, h, 0,
+        qgl_extensions()->glCompressedTexImage2D(GL_TEXTURE_2D, i, format, w, h, 0,
                                size, pixels + offset);
         offset += size;
         available -= size;
@@ -5174,14 +5014,12 @@ QSize QGLTexture::bindCompressedTexturePVR(const char *buf, int len)
 
     // Bail out if the necessary extension is not present.
     if (textureFormat == GL_ETC1_RGB8_OES) {
-        if (!(QGLExtensions::glExtensions() &
-                    QGLExtensions::ETC1TextureCompression)) {
+        if (!qgl_extensions()->hasOpenGLExtension(QOpenGLExtensions::ETC1TextureCompression)) {
             qWarning("QGLContext::bindTexture(): ETC1 texture compression is not supported.");
             return QSize();
         }
     } else {
-        if (!(QGLExtensions::glExtensions() &
-                    QGLExtensions::PVRTCTextureCompression)) {
+        if (!qgl_extensions()->hasOpenGLExtension(QOpenGLExtensions::PVRTCTextureCompression)) {
             qWarning("QGLContext::bindTexture(): PVRTC texture compression is not supported.");
             return QSize();
         }
@@ -5227,7 +5065,7 @@ QSize QGLTexture::bindCompressedTexturePVR(const char *buf, int len)
              pvrHeader->bitsPerPixel) / 8;
         if (size > bufferSize)
             break;
-        glCompressedTexImage2D(GL_TEXTURE_2D, GLint(level), textureFormat,
+        qgl_extensions()->glCompressedTexImage2D(GL_TEXTURE_2D, GLint(level), textureFormat,
                                GLsizei(width), GLsizei(height), 0,
                                GLsizei(size), buffer);
         width /= 2;