BansheeEngine/CamelotGLRenderer/Include/CmGLPixelFormat.h

/*
-----------------------------------------------------------------------------
This source file is part of OGRE
    (Object-oriented Graphics Rendering Engine)
For the latest info, see http://www.ogre3d.org/

Copyright (c) 2000-2011 Torus Knot Software Ltd

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.
-----------------------------------------------------------------------------
*/
#ifndef __GLPIXELFORMAT_H__
#define __GLPIXELFORMAT_H__

#include "CmGLPrerequisites.h"
#include "CmPixelUtil.h"
namespace CamelotFramework {
    
	/**
	* Class to do pixel format mapping between GL and OGRE
	*/
	class CM_RSGL_EXPORT GLPixelUtil
	{
	public:
		/** Takes the engine pixel format and returns the appropriate GL one
			@returns a GLenum describing the format, or 0 if there is no exactly matching 
			one (and conversion is needed)
		*/
		static GLenum getGLOriginFormat(PixelFormat mFormat);
	
		/** Takes the engine pixel format and returns type that must be provided
			to GL as data type for reading it into the GPU
			@returns a GLenum describing the data type, or 0 if there is no exactly matching 
			one (and conversion is needed)
		*/
		static GLenum getGLOriginDataType(PixelFormat mFormat);
        
        /**	Takes the engine pixel format and returns the type that must be provided
			to GL as internal format. GL_NONE if no match exists.
		@param mFormat The pixel format
		@param hwGamma Whether a hardware gamma-corrected version is requested
		*/
		static GLenum getGLInternalFormat(PixelFormat mFormat, bool hwGamma = false);
	
		/**	Takes the OGRE pixel format and returns the type that must be provided
			to GL as internal format. If no match exists, returns the closest match.
		@param mFormat The pixel format
		@param hwGamma Whether a hardware gamma-corrected version is requested
		*/
		static GLenum getClosestGLInternalFormat(PixelFormat mFormat, bool hwGamma = false);
		
		/**
		 * @brief	Returns a valid type that should be used for creating a buffer for the specified
		 * 			depth/stencil format.
		 */
		static GLenum getDepthStencilTypeFromFormat(PixelFormat mFormat);

		/**	Function to get the closest matching engine format to an internal GL format. To be
			precise, the format will be chosen that is most efficient to transfer to the card 
			without losing precision.
			@remarks It is valid for this function to always return PF_A8R8G8B8.
		*/
		static PixelFormat getClosestEngineFormat(GLenum fmt);

		/**
		 * @brief	Gets OpenGL format based on a compressed OpenGL internal format.
		 * 			e.g. GL_COMPRESSED_RGBA_S3TC_DXT1_EXT will return GL_RGBA
		 *
		 */
		static GLenum getBaseFormatFromCompressedInternalFormat(GLenum internalFormat);
	
		/** Returns the maximum number of Mipmaps that can be generated until we reach
			the mininum format possible. This does not count the base level.
			@param width
				The width of the area
			@param height
				The height of the area
			@param depth
				The depth of the area
			@param format
				The format of the area
			@remarks
				In case that the format is non-compressed, this simply returns
				how many times we can divide this texture in 2 until we reach 1x1.
				For compressed formats, constraints apply on minimum size and alignment
				so this might differ.
		*/
		static UINT32 getMaxMipmaps(UINT32 width, UINT32 height, UINT32 depth, PixelFormat format);
        
        /** Returns next power-of-two size if required by render system, in case
            RSC_NON_POWER_OF_2_TEXTURES is supported it returns value as-is.
        */
        static UINT32 optionalPO2(UINT32 value);
	};
};

#endif