glBindTexture(GL_TEXTURE_2D, m_texture);
- foreach (const QRect &rect, m_dirty.rects()) {
- if (rect == m_image.rect()) {
- glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, rect.width(), rect.height(), GL_RGBA, GL_UNSIGNED_BYTE, m_image.constBits());
- } else {
- glTexSubImage2D(GL_TEXTURE_2D, 0, rect.x(), rect.y(), rect.width(), rect.height(), GL_RGBA, GL_UNSIGNED_BYTE,
- m_image.copy(rect).constBits());
+ if (!m_dirty.isNull()) {
+ QRect imageRect = m_image.rect();
+
+ QRegion fixed;
+ foreach (const QRect &rect, m_dirty.rects()) {
+ // intersect with image rect to be sure
+ QRect r = imageRect & rect;
+
+ // if the rect is wide enough it's cheaper to just
+ // extend it instead of doing an image copy
+ if (r.width() >= imageRect.width() / 2) {
+ r.setX(0);
+ r.setWidth(imageRect.width());
+ }
+
+ fixed |= r;
+ }
+
+ foreach (const QRect &rect, fixed.rects()) {
+ // if the sub-rect is full-width we can pass the image data directly to
+ // OpenGL instead of copying, since there's no gap between scanlines
+ if (rect.width() == imageRect.width()) {
+ glTexSubImage2D(GL_TEXTURE_2D, 0, 0, rect.y(), rect.width(), rect.height(), GL_RGBA, GL_UNSIGNED_BYTE, m_image.constScanLine(rect.y()));
+ } else {
+ glTexSubImage2D(GL_TEXTURE_2D, 0, rect.x(), rect.y(), rect.width(), rect.height(), GL_RGBA, GL_UNSIGNED_BYTE,
+ m_image.copy(rect).constBits());
+ }
}
- }
- m_dirty = QRegion();
+ m_dirty = QRegion();
+ }
glDrawArrays(GL_TRIANGLE_FAN, 0, 4);