Add the often requested Texture->Image conversion method

git-svn-id: svn://svn.code.sf.net/p/irrlicht/code/trunk@2498 dfc29bdd-3216-0410-991c-e03cc46cb475

include/IVideoDriver.h

@@ -1016,7 +1016,7 @@ namespace video
 
 		//! Creates a software image from a part of another image.
 		/**
-		\param imageToCopy Image to copy the the new image in part.
+		\param imageToCopy Image to copy to the new image in part.
 		\param pos Position of rectangle to copy.
 		\param size Extents of rectangle to copy.
 		\return The created image.
@@ -1026,6 +1026,18 @@ namespace video
 				const core::position2d<s32>& pos,
 				const core::dimension2d<u32>& size) =0;
 
+		//! Creates a software image from a part of a texture.
+		/**
+		\param texture Texture to copy to the new image in part.
+		\param pos Position of rectangle to copy.
+		\param size Extents of rectangle to copy.
+		\return The created image.
+		If you no longer need the image, you should call IImage::drop().
+		See IReferenceCounted::drop() for more information. */
+		virtual IImage* createImage(ITexture* texture,
+				const core::position2d<s32>& pos,
+				const core::dimension2d<u32>& size) =0;
+
 		//! Event handler for resize events. Only used by the engine internally.
 		/** Used to notify the driver that the window was resized.
 		Usually, there is no need to call this method. */

source/Irrlicht/CNullDriver.cpp

@@ -12,6 +12,7 @@
 #include "IImageWriter.h"
 #include "IMaterialRenderer.h"
 #include "CMeshManipulator.h"
+#include "CColorConverter.h"
 
 
 namespace irr
@@ -1370,6 +1371,38 @@ IImage* CNullDriver::createImage(IImage* imageToCopy, const core::position2d<s32
 }
 
 
+//! Creates a software image from part of a texture.
+IImage* CNullDriver::createImage(ITexture* texture, const core::position2d<s32>& pos, const core::dimension2d<u32>& size)
+{
+	if (pos==core::position2di(0,0) && size == texture->getSize())
+	{
+		IImage* image = new CImage(texture->getColorFormat(), size, texture->lock(true), false);
+		texture->unlock();
+		return image;
+	}
+	else
+	{
+		// make sure to avoid buffer overruns
+		const core::rect<u32> clamped(core::vector2d<u32>(core::clamp(static_cast<u32>(pos.X), 0u, texture->getSize().Width),
+					core::clamp(static_cast<u32>(pos.Y), 0u, texture->getSize().Height)),
+					core::dimension2du(core::clamp(static_cast<u32>(size.Width), 0u, texture->getSize().Width),
+					core::clamp(static_cast<u32>(size.Height), 0u, texture->getSize().Height)));
+		if (!clamped.isValid())
+			return 0;
+		IImage* image = new CImage(texture->getColorFormat(), clamped.getSize());
+		void* src = texture->lock(true);
+		void* dst = image->lock();
+		for (u32 i=clamped.UpperLeftCorner.X; i<clamped.getHeight(); ++i)
+		{
+			video::CColorConverter::convert_viaFormat(src, texture->getColorFormat(), clamped.getWidth(), dst, image->getColorFormat());
+		}
+		image->unlock();
+		texture->unlock();
+		return image;
+	}
+}
+
+
 //! Sets the fog mode.
 void CNullDriver::setFog(SColor color, E_FOG_TYPE fogType, f32 start, f32 end,
 		f32 density, bool pixelFog, bool rangeFog)

source/Irrlicht/CNullDriver.h

@@ -343,6 +343,11 @@ namespace video
 				const core::position2d<s32>& pos,
 				const core::dimension2d<u32>& size);
 
+		//! Creates a software image from part of a texture.
+		virtual IImage* createImage(ITexture* texture,
+				const core::position2d<s32>& pos,
+				const core::dimension2d<u32>& size);
+
 		//! Draws a mesh buffer
 		virtual void drawMeshBuffer(const scene::IMeshBuffer* mb);