Client: Added GLTextComposer, utility for drawing GL text

doomsday/client/include/ui/widgets/gltextcomposer.h

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+/** @file gltextcomposer.h
+ *
+ * @authors Copyright (c) 2013 Jaakko Keränen <jaakko.keranen@iki.fi>
+ *
+ * @par License
+ * GPL: http://www.gnu.org/licenses/gpl.html
+ *
+ * <small>This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2 of the License, or (at your
+ * option) any later version. This program is distributed in the hope that it
+ * will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty
+ * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
+ * Public License for more details. You should have received a copy of the GNU
+ * General Public License along with this program; if not, see:
+ * http://www.gnu.org/licenses</small> 
+ */
+
+#ifndef DENG_CLIENT_GLTEXTCOMPOSER_H
+#define DENG_CLIENT_GLTEXTCOMPOSER_H
+
+#include <QVector>
+#include <de/Font>
+#include <de/Atlas>
+#include <de/GLBuffer>
+
+#include "fontlinewrapping.h"
+
+/**
+ * Manages lines of text on an atlas and produces geometry for drawing the
+ * text.
+ */
+class GLTextComposer
+{
+public:
+    typedef de::Vertex2TexRgba    Vertex;
+    typedef de::GLBufferT<Vertex> VertexBuf;
+    typedef VertexBuf::Vertices   Vertices;
+
+    /**
+     * Flags for specifying alignment.
+     */
+    enum AlignmentFlag
+    {
+        AlignTop    = 0x1,
+        AlignBottom = 0x2,
+        AlignLeft   = 0x4,
+        AlignRight  = 0x8,
+
+        AlignCenter = 0,
+
+        DefaultAlignment = AlignCenter
+    };
+    Q_DECLARE_FLAGS(Alignment, AlignmentFlag)
+
+public:
+    GLTextComposer();
+
+    void setAtlas(de::Atlas &atlas);
+    void setText(de::String const &text, FontLineWrapping const &wrappedLines);
+
+    /**
+     * Makes sure all the lines are allocated on the atlas.
+     */
+    void update();
+
+    /**
+     * Releases all the allocations from the atlas.
+     */
+    void release();
+
+    /**
+     * Generates vertices for all the text lines and concatenates them
+     * onto the existing triangle strip in @a triStrip.
+     *
+     * @param triStrip  Vertices for a triangle strip.
+     */
+    void makeVertices(Vertices &triStrip,
+                      de::Rectanglei const &rect,
+                      Alignment const &alignInRect,
+                      Alignment const &lineAlign);
+
+private:
+    DENG2_PRIVATE(d)
+};
+
+Q_DECLARE_OPERATORS_FOR_FLAGS(GLTextComposer::Alignment)
+
+#endif // DENG_CLIENT_GLTEXTCOMPOSER_H

doomsday/client/src/ui/widgets/gltextcomposer.cpp

@@ -0,0 +1,169 @@
+/** @file gltextcomposer.cpp
+ *
+ * @authors Copyright (c) 2013 Jaakko Keränen <jaakko.keranen@iki.fi>
+ *
+ * @par License
+ * GPL: http://www.gnu.org/licenses/gpl.html
+ *
+ * <small>This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2 of the License, or (at your
+ * option) any later version. This program is distributed in the hope that it
+ * will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty
+ * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
+ * Public License for more details. You should have received a copy of the GNU
+ * General Public License along with this program; if not, see:
+ * http://www.gnu.org/licenses</small> 
+ */
+
+#include "ui/widgets/gltextcomposer.h"
+
+#include <QList>
+
+using namespace de;
+
+DENG2_PIMPL(GLTextComposer)
+{
+    Font const *font;
+    Atlas *atlas;
+    String text;
+    FontLineWrapping const *wraps;
+    bool needRaster;
+
+    typedef QList<Id> Lines;
+    Lines lines;
+
+    Instance(Public *i) : Base(i), font(0), atlas(0), wraps(0), needRaster(false)
+    {}
+
+    ~Instance()
+    {
+        releaseLines();
+    }
+
+    void releaseLines()
+    {
+        DENG2_ASSERT(atlas != 0);
+
+        foreach(Id const &id, lines)
+        {
+            atlas->release(id);
+        }
+        lines.clear();
+    }
+
+    void allocLines()
+    {
+        /// @todo Could check which lines have actually changed.
+
+        // Release the old lines.
+        releaseLines();
+
+        qDebug() << "allocLines for" << text << wraps->height();
+
+        for(int i = 0; i < wraps->height(); ++i)
+        {
+            shell::WrappedLine const span = wraps->line(i);
+            String part = text.substr(span.range.start, span.range.size());
+            lines.append(atlas->alloc(font->rasterize(part)));
+
+            qDebug() << lines.back().asText() << part;
+        }
+    }
+};
+
+GLTextComposer::GLTextComposer() : d(new Instance(this))
+{}
+
+void GLTextComposer::release()
+{
+    d->releaseLines();
+}
+
+void GLTextComposer::setAtlas(Atlas &atlas)
+{
+    d->atlas = &atlas;
+}
+
+void GLTextComposer::setText(String const &text, FontLineWrapping const &wrappedLines)
+{
+    d->text = text;
+    d->wraps = &wrappedLines;
+    d->font = &d->wraps->font();
+    d->needRaster = true;
+}
+
+void GLTextComposer::update()
+{
+    if(d->needRaster)
+    {
+        d->needRaster = false;
+        d->allocLines();
+    }
+
+    DENG2_ASSERT(d->wraps->height() == d->lines.size());
+}
+
+void GLTextComposer::makeVertices(Vertices &triStrip,
+                                  Rectanglei const &rect,
+                                  Alignment const &alignInRect,
+                                  Alignment const &lineAlign)
+{
+    // Top left corner.
+    Vector2f p = rect.topLeft;
+
+    Vector2i const contentSize(d->wraps->width(), d->wraps->totalHeightInPixels());
+
+    // Apply alignment within the provided rectangle.
+    if(alignInRect.testFlag(AlignRight))
+    {
+        p.x += rect.width() - contentSize.x;
+    }
+    else if(!alignInRect.testFlag(AlignLeft))
+    {
+        p.x += (rect.width() - contentSize.x) / 2;
+    }
+    if(alignInRect.testFlag(AlignBottom))
+    {
+        p.y += rect.height() - contentSize.y;
+    }
+    else
+    {
+        p.y += (rect.height() - contentSize.y) / 2;
+    }
+
+    DENG2_ASSERT(d->wraps->height() == d->lines.size());
+
+    // Generate vertices for each line.
+    for(int i = 0; i < d->wraps->height(); ++i)
+    {
+        Vector2ui const size = d->atlas->imageRect(d->lines[i]).size();
+        Rectanglef const uv  = d->atlas->imageRectf(d->lines[i]);
+
+        Vertex v;
+        Vertices quad;
+
+        v.rgba = Vector4f(1, 1, 1, 1); // should be a param
+
+        Vector2f linePos = p;
+
+        // Align the line.
+        if(lineAlign.testFlag(AlignRight))
+        {
+            linePos.x += rect.width() - size.x;
+        }
+        else if(!lineAlign.testFlag(AlignLeft))
+        {
+            linePos.x += (rect.width() - size.x) / 2;
+        }
+
+        v.pos = linePos;                            v.texCoord = uv.topLeft;      quad << v;
+        v.pos = linePos + Vector2f(size.x, 0);      v.texCoord = uv.topRight();   quad << v;
+        v.pos = linePos + Vector2f(0, size.y);      v.texCoord = uv.bottomLeft(); quad << v;
+        v.pos = linePos + Vector2f(size.x, size.y); v.texCoord = uv.bottomRight;  quad << v;
+
+        VertexBuf::concatenate(quad, triStrip);
+
+        p.y += d->font->lineSpacing().value();
+    }
+}