libgui|GLState: Normalized scissor

The normalized scissor is relative to the viewport, so it can be used with downscaled viewports.
skyjake · Jun 15, 2013 · 8b36057 · 8b36057
1 parent 3f1aae2
commit 8b36057
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diff --git a/doomsday/libgui/include/de/gui/glstate.h b/doomsday/libgui/include/de/gui/glstate.h
@@ -111,6 +111,7 @@ class LIBGUI_PUBLIC GLState
     GLState &setViewport(Rectangleui const &viewportRect);
     GLState &setScissor(Rectanglei const &scissorRect);
     GLState &setScissor(Rectangleui const &scissorRect);
+    GLState &setNormalizedScissor(Rectanglef const &normScissorRect);
     GLState &clearScissor();
 
     gl::Cull cull() const;

diff --git a/doomsday/libgui/src/glstate.cpp b/doomsday/libgui/src/glstate.cpp
@@ -369,6 +369,16 @@ GLState &GLState::setScissor(Rectangleui const &scissorRect)
     return *this;
 }
 
+GLState &GLState::setNormalizedScissor(Rectanglef const &normScissorRect)
+{
+    Rectangleui vp = viewport();
+    Rectangleui scis(Vector2ui(normScissorRect.left()   * vp.width(),
+                               normScissorRect.top()    * vp.height()),
+                     Vector2ui(std::ceil(normScissorRect.right()  * vp.width()),
+                               std::ceil(normScissorRect.bottom() * vp.height())));
+    return setScissor(scis);
+}
+
 GLState &GLState::clearScissor()
 {
     d->props.set(Scissor,       false);