Make QGLWidget::renderText() desktop only

The renderText() function is only for legacy desktop systems,
so revert the previous attempts to port it to OpenGL/ES.
Documentation note added to direct users to QPainter::drawText()
for the correct way to render text onto an OpenGL paint device.

Reviewed-by: trustme

1 files changed, 72 insertions, 175 deletions

diff --git a/src/opengl/qgl.cpp b/src/opengl/qgl.cpp
index 9148456..fcb3510 100644
--- a/src/opengl/qgl.cpp
+++ b/src/opengl/qgl.cpp
@@ -63,7 +63,6 @@
 
 #include "qpixmap.h"
 #include "qimage.h"
-#include "qmatrix4x4.h"
 #include "qgl_p.h"
 
 #if !defined(QT_OPENGL_ES_1) && !defined(QT_OPENGL_ES_1_CL)
@@ -320,26 +319,52 @@ void QGL::setPreferredPaintEngine(QPaintEngine::Type engineType)
     \sa QGLContext, QGLWidget
 */
 
-static inline void qgluProject
-    (qreal objx, qreal objy, qreal objz,
-     const QMatrix4x4& model, const QMatrix4x4& proj, const GLint viewport[4],
-     GLfloat *winx, GLfloat *winy, GLfloat* winz)
+#ifndef QT_OPENGL_ES
+
+static inline void transform_point(GLdouble out[4], const GLdouble m[16], const GLdouble in[4])
+{
+#define M(row,col)  m[col*4+row]
+    out[0] =
+        M(0, 0) * in[0] + M(0, 1) * in[1] + M(0, 2) * in[2] + M(0, 3) * in[3];
+    out[1] =
+        M(1, 0) * in[0] + M(1, 1) * in[1] + M(1, 2) * in[2] + M(1, 3) * in[3];
+    out[2] =
+        M(2, 0) * in[0] + M(2, 1) * in[1] + M(2, 2) * in[2] + M(2, 3) * in[3];
+    out[3] =
+        M(3, 0) * in[0] + M(3, 1) * in[1] + M(3, 2) * in[2] + M(3, 3) * in[3];
+#undef M
+}
+
+static inline GLint qgluProject(GLdouble objx, GLdouble objy, GLdouble objz,
+           const GLdouble model[16], const GLdouble proj[16],
+           const GLint viewport[4],
+           GLdouble * winx, GLdouble * winy, GLdouble * winz)
 {
-    QVector4D transformed = proj.map(model.map(QVector4D(objx, objy, objz, 1)));
+   GLdouble in[4], out[4];
+
+   in[0] = objx;
+   in[1] = objy;
+   in[2] = objz;
+   in[3] = 1.0;
+   transform_point(out, model, in);
+   transform_point(in, proj, out);
 
-    qreal w = transformed.w();
-    if (w == 0.0f)
-        w = 1.0f; // Just in case!
+   if (in[3] == 0.0)
+      return GL_FALSE;
 
-    qreal x = transformed.x() / w;
-    qreal y = transformed.y() / w;
+   in[0] /= in[3];
+   in[1] /= in[3];
+   in[2] /= in[3];
 
-    *winx = viewport[0] + (1 + x) * viewport[2] / 2;
-    *winy = viewport[1] + (1 + y) * viewport[3] / 2;
+   *winx = viewport[0] + (1 + in[0]) * viewport[2] / 2;
+   *winy = viewport[1] + (1 + in[1]) * viewport[3] / 2;
 
-    *winz = (1 + transformed.z() / w) / 2;
+   *winz = (1 + in[2]) / 2;
+   return GL_TRUE;
 }
 
+#endif // !QT_OPENGL_ES
+
 /*!
     Constructs a QGLFormat object with the following default settings:
     \list
@@ -4131,13 +4156,12 @@ int QGLWidget::fontDisplayListBase(const QFont & font, int listBase)
     return base;
 }
 
+#ifndef QT_OPENGL_ES
+
 static void qt_save_gl_state()
 {
-#ifndef QT_OPENGL_ES
     glPushClientAttrib(GL_CLIENT_ALL_ATTRIB_BITS);
     glPushAttrib(GL_ALL_ATTRIB_BITS);
-#endif
-#if !defined(QT_OPENGL_ES_2)
     glMatrixMode(GL_TEXTURE);
     glPushMatrix();
     glLoadIdentity();
@@ -4152,32 +4176,25 @@ static void qt_save_gl_state()
     glDisable(GL_STENCIL_TEST);
     glEnable(GL_BLEND);
     glBlendFunc(GL_ONE, GL_ONE_MINUS_SRC_ALPHA);
-#endif // !defined(QT_OPENGL_ES_2)
 }
 
 static void qt_restore_gl_state()
 {
-#if !defined(QT_OPENGL_ES_2)
     glMatrixMode(GL_TEXTURE);
     glPopMatrix();
     glMatrixMode(GL_PROJECTION);
     glPopMatrix();
     glMatrixMode(GL_MODELVIEW);
     glPopMatrix();
-#endif // !defined(QT_OPENGL_ES_2)
-#ifndef QT_OPENGL_ES
     glPopAttrib();
     glPopClientAttrib();
-#endif
 }
 
 static void qt_gl_draw_text(QPainter *p, int x, int y, const QString &str,
                             const QFont &font)
 {
     GLfloat color[4];
-#ifndef QT_OPENGL_ES
     glGetFloatv(GL_CURRENT_COLOR, &color[0]);
-#endif
 
     QColor col;
     col.setRgbF(color[0], color[1], color[2],color[3]);
@@ -4192,29 +4209,7 @@ static void qt_gl_draw_text(QPainter *p, int x, int y, const QString &str,
     p->setFont(old_font);
 }
 
-#if defined(GL_OES_VERSION_1_0) && !defined(GL_OES_VERSION_1_1)
-
-// OpenGL/ES 1.0 cannot fetch viewports from the GL server.
-// We therefore create a default viewport to simulate the fetch.
-
-static void qt_gl_get_viewport(GLint *view, int deviceWidth, int deviceHeight)
-{
-    view[0] = 0;
-    view[1] = 0;
-    view[2] = deviceWidth;
-    view[3] = deviceHeight;
-}
-
-#else
-
-static void qt_gl_get_viewport(GLint *view, int deviceWidth, int deviceHeight)
-{
-    Q_UNUSED(deviceWidth);
-    Q_UNUSED(deviceHeight);
-    glGetIntegerv(GL_VIEWPORT, view);
-}
-
-#endif
+#endif // !QT_OPENGL_ES
 
 /*!
    Renders the string \a str into the GL context of this widget.
@@ -4230,37 +4225,29 @@ static void qt_gl_get_viewport(GLint *view, int deviceWidth, int deviceHeight)
    future version of Qt.
 
    \note This function clears the stencil buffer.
+
+   \note This function is not supported on OpenGL/ES systems.
+   \l{Overpainting Example}{Overpaint} with QPainter::drawText() instead.
 */
 
 void QGLWidget::renderText(int x, int y, const QString &str, const QFont &font, int)
 {
+#ifndef QT_OPENGL_ES
     Q_D(QGLWidget);
     if (str.isEmpty() || !isValid())
         return;
 
     GLint view[4];
-#ifndef QT_OPENGL_ES
     bool use_scissor_testing = glIsEnabled(GL_SCISSOR_TEST);
-#else
-    bool use_scissor_testing = false;
-#endif
+    if (!use_scissor_testing)
+        glGetIntegerv(GL_VIEWPORT, &view[0]);
     int width = d->glcx->device()->width();
     int height = d->glcx->device()->height();
-    if (!use_scissor_testing) {
-        qt_gl_get_viewport(&view[0], width, height);
-    } else {
-        view[0] = 0;
-        view[1] = 0;
-        view[2] = width;
-        view[3] = height;
-    }
     bool auto_swap = autoBufferSwap();
 
     QPaintEngine *engine = paintEngine();
-#ifndef QT_OPENGL_ES
     if (engine->type() == QPaintEngine::OpenGL2)
         static_cast<QGL2PaintEngineEx *>(engine)->setRenderTextActive(true);
-#endif
     QPainter *p;
     bool reuse_painter = false;
     if (engine->isActive()) {
@@ -4268,30 +4255,22 @@ void QGLWidget::renderText(int x, int y, const QString &str, const QFont &font,
         p = engine->painter();
         qt_save_gl_state();
 
-#if !defined(QT_OPENGL_ES_2)
         glDisable(GL_DEPTH_TEST);
         glViewport(0, 0, width, height);
         glMatrixMode(GL_PROJECTION);
         glLoadIdentity();
-#ifndef QT_OPENGL_ES
         glOrtho(0, width, height, 0, 0, 1);
-#else
-        glOrthof(0, width, height, 0, 0, 1);
-#endif
         glMatrixMode(GL_MODELVIEW);
 
         glLoadIdentity();
-#endif // !defined(QT_OPENGL_ES_2)
     } else {
         setAutoBufferSwap(false);
         // disable glClear() as a result of QPainter::begin()
         d->disable_clear_on_painter_begin = true;
         if (engine->type() == QPaintEngine::OpenGL2) {
             qt_save_gl_state();
-#ifndef QT_OPENGL_ES_2
             glMatrixMode(GL_MODELVIEW);
             glLoadIdentity();
-#endif
         }
         p = new QPainter(this);
     }
@@ -4319,75 +4298,17 @@ void QGLWidget::renderText(int x, int y, const QString &str, const QFont &font,
         if (engine->type() == QPaintEngine::OpenGL2)
             qt_restore_gl_state();
     }
-#ifndef QT_OPENGL_ES
     if (engine->type() == QPaintEngine::OpenGL2)
         static_cast<QGL2PaintEngineEx *>(engine)->setRenderTextActive(false);
+#else // QT_OPENGL_ES
+    Q_UNUSED(x);
+    Q_UNUSED(y);
+    Q_UNUSED(str);
+    Q_UNUSED(font);
+    qWarning("QGLWidget::renderText is not supported under OpenGL/ES");
 #endif
 }
 
-#if defined(QT_OPENGL_ES_2) || \
-        (defined(GL_OES_VERSION_1_0) && !defined(GL_OES_VERSION_1_1))
-
-// OpenGL/ES 1.0 cannot fetch matrices from the GL server.
-// OpenGL/ES 2.0 does not use fixed-function matrices at all.
-// We therefore create some default matrices to simulate the fetch.
-
-static QMatrix4x4 qt_gl_projection_matrix(int deviceWidth, int deviceHeight)
-{
-    QMatrix4x4 m;
-    m.ortho(0, deviceWidth, deviceHeight, 0, -1, 1);
-    return m;
-}
-
-static QMatrix4x4 qt_gl_modelview_matrix(void)
-{
-    return QMatrix4x4();
-}
-
-#else // !QT_OPENGL_ES_2
-
-static QMatrix4x4 qt_gl_fetch_matrix(GLenum type)
-{
-    QMatrix4x4 matrix;
-#if defined(QT_OPENGL_ES_1_CL)
-    GLfixed mat[16];
-    glGetFixedv(type, mat);
-    qreal *m = matrix.data();
-    for (int index = 0; index < 16; ++index)
-        m[index] = vt2f(mat[index]);
-#else
-    if (sizeof(qreal) == sizeof(GLfloat)) {
-        glGetFloatv(type, reinterpret_cast<GLfloat *>(matrix.data()));
-#if !defined(QT_OPENGL_ES)
-    } else if (sizeof(qreal) == sizeof(GLdouble)) {
-        glGetDoublev(type, reinterpret_cast<GLdouble *>(matrix.data()));
-#endif
-    } else {
-        GLfloat mat[16];
-        glGetFloatv(type, mat);
-        qreal *m = matrix.data();
-        for (int index = 0; index < 16; ++index)
-            m[index] = mat[index];
-    }
-#endif
-    matrix.inferSpecialType();
-    return matrix;
-}
-
-static QMatrix4x4 qt_gl_projection_matrix(int deviceWidth, int deviceHeight)
-{
-    Q_UNUSED(deviceWidth);
-    Q_UNUSED(deviceHeight);
-    return qt_gl_fetch_matrix(GL_PROJECTION_MATRIX);
-}
-
-static QMatrix4x4 qt_gl_modelview_matrix(void)
-{
-    return qt_gl_fetch_matrix(GL_MODELVIEW_MATRIX);
-}
-
-#endif // !QT_OPENGL_ES_2
-
 /*! \overload
 
     \a x, \a y and \a z are specified in scene or object coordinates
@@ -4395,28 +4316,12 @@ static QMatrix4x4 qt_gl_modelview_matrix(void)
     can be useful if you want to annotate models with text labels and
     have the labels move with the model as it is rotated etc.
 
-    This function fetches the modelview matrix, projection matrix, and
-    current viewport from the GL server to map (\a x, \a y, \a z)
-    into window co-ordinates.  This entails several round-trips to the GL
-    server which will probably impact performance.
-
-    Fetching the modelview and projection matrices is not supported
-    under OpenGL/ES 1.0 and OpenGL/ES 2.0 so a default orthographic
-    projection will be used to map the co-ordinates on those platforms.
-    This probably will not give results that are consistent with desktop
-    and OpenGL/ES 1.1 systems.  Fetching the viewport is not supported
-    under OpenGL/ES 1.0, so the full device will be used as the viewport.
-
-    This function is deprecated because it is non-portable.  It is
-    recommended that the application map the co-ordinates itself using
-    application-provided matrix data that reflects the desired
-    transformation.  Then use QPainter::drawText() to draw \a str at
-    the mapped position.
-
-    \sa QMatrix4x4
+    \note This function is not supported on OpenGL/ES systems.
+    \l{Overpainting Example}{Overpaint} with QPainter::drawText() instead.
 */
 void QGLWidget::renderText(double x, double y, double z, const QString &str, const QFont &font, int)
 {
+#ifndef QT_OPENGL_ES
     Q_D(QGLWidget);
     if (str.isEmpty() || !isValid())
         return;
@@ -4425,31 +4330,23 @@ void QGLWidget::renderText(double x, double y, double z, const QString &str, con
 
     int width = d->glcx->device()->width();
     int height = d->glcx->device()->height();
-
-    QMatrix4x4 model = qt_gl_modelview_matrix();
-    QMatrix4x4 proj = qt_gl_projection_matrix(width, height);
+    GLdouble model[4][4], proj[4][4];
     GLint view[4];
-    qt_gl_get_viewport(view, width, height);
-
-    GLfloat win_x = 0, win_y = 0, win_z = 0;
-    qgluProject(qreal(x), qreal(y), qreal(z),
-                model, proj, &view[0], &win_x, &win_y, &win_z);
+    glGetDoublev(GL_MODELVIEW_MATRIX, &model[0][0]);
+    glGetDoublev(GL_PROJECTION_MATRIX, &proj[0][0]);
+    glGetIntegerv(GL_VIEWPORT, &view[0]);
+    GLdouble win_x = 0, win_y = 0, win_z = 0;
+    qgluProject(x, y, z, &model[0][0], &proj[0][0], &view[0],
+                &win_x, &win_y, &win_z);
     win_y = height - win_y; // y is inverted
 
     QPaintEngine *engine = paintEngine();
-#ifndef QT_OPENGL_ES
     if (engine->type() == QPaintEngine::OpenGL2)
         static_cast<QGL2PaintEngineEx *>(engine)->setRenderTextActive(true);
-#endif
     QPainter *p;
     bool reuse_painter = false;
-#ifndef QT_OPENGL_ES
     bool use_depth_testing = glIsEnabled(GL_DEPTH_TEST);
     bool use_scissor_testing = glIsEnabled(GL_SCISSOR_TEST);
-#else
-    bool use_depth_testing = false;
-    bool use_scissor_testing = false;
-#endif
 
     if (engine->isActive()) {
         reuse_painter = true;
@@ -4471,23 +4368,17 @@ void QGLWidget::renderText(double x, double y, double z, const QString &str, con
     } else if (use_scissor_testing) {
         glEnable(GL_SCISSOR_TEST);
     }
-#if !defined(QT_OPENGL_ES_2)
     glMatrixMode(GL_PROJECTION);
     glLoadIdentity();
     glViewport(0, 0, width, height);
-#ifndef QT_OPENGL_ES
     glOrtho(0, width, height, 0, 0, 1);
-#else
-    glOrthof(0, width, height, 0, 0, 1);
-#endif
     glMatrixMode(GL_MODELVIEW);
     glLoadIdentity();
     glAlphaFunc(GL_GREATER, 0.0);
     glEnable(GL_ALPHA_TEST);
     if (use_depth_testing)
         glEnable(GL_DEPTH_TEST);
-    glTranslatef(0, 0, -win_z);
-#endif // !defined(QT_OPENGL_ES_2)
+    glTranslated(0, 0, -win_z);
     qt_gl_draw_text(p, qRound(win_x), qRound(win_y), str, font);
 
     if (reuse_painter) {
@@ -4500,9 +4391,15 @@ void QGLWidget::renderText(double x, double y, double z, const QString &str, con
         setAutoBufferSwap(auto_swap);
         d->disable_clear_on_painter_begin = false;
     }
-#ifndef QT_OPENGL_ES
     if (engine->type() == QPaintEngine::OpenGL2)
         static_cast<QGL2PaintEngineEx *>(engine)->setRenderTextActive(false);
+#else // QT_OPENGL_ES
+    Q_UNUSED(x);
+    Q_UNUSED(y);
+    Q_UNUSED(z);
+    Q_UNUSED(str);
+    Q_UNUSED(font);
+    qWarning("QGLWidget::renderText is not supported under OpenGL/ES");
 #endif
 }