/*
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Open Asset Import Library (ASSIMP)
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*/

/** @file aiTexture.h
 *  @brief Defines texture helper structures for the library
 *
 * Used for file formats which embed their textures into the model file.
 * Supported are both normal textures, which are stored as uncompressed
 * pixels, and "compressed" textures, which are stored in a file format
 * such as PNG or TGA.
 */

#ifndef AI_TEXTURE_H_INC
#define AI_TEXTURE_H_INC

#include "aiTypes.h"

#ifdef __cplusplus
extern "C" {
#endif


// --------------------------------------------------------------------------------
/** @def AI_MAKE_EMBEDDED_TEXNAME
 *  Used to build the reserved path name used by the material system to 
 *  reference textures that are embedded into their corresponding
 *  model files. The parameter specifies the index of the texture
 *  (zero-based, in the aiScene::mTextures array)
 */
#if (!defined AI_MAKE_EMBEDDED_TEXNAME)
#	define AI_MAKE_EMBEDDED_TEXNAME(_n_) "*" # _n_
#endif


#include "./Compiler/pushpack1.h"

// --------------------------------------------------------------------------------
/** @brief Helper structure to represent a texel in a ARGB8888 format
* 
*  Used by aiTexture.
*/
struct aiTexel
{
	unsigned char b,g,r,a;

#ifdef __cplusplus
	//! Comparison operator
	bool operator== (const aiTexel& other) const
	{
		return b == other.b && r == other.r &&
			   g == other.g && a == other.a;
	}

	//! Inverse comparison operator
	bool operator!= (const aiTexel& other) const
	{
		return b != other.b || r != other.r ||
			   g != other.g || a != other.a;
	}

	//! Conversion to a floating-point 4d color
	operator aiColor4D() const
	{
		return aiColor4D(r/255.f,g/255.f,b/255.f,a/255.f);
	}
#endif // __cplusplus

} PACK_STRUCT;

#include "./Compiler/poppack1.h"

// --------------------------------------------------------------------------------
/** Helper structure to describe an embedded texture
 * 
 * Normally textures are contained in external files but some file formats embed
 * them directly in the model file. There are two types of embedded textures: 
 * 1. Uncompressed textures. The color data is given in an uncompressed format. 
 * 2. Compressed textures stored in a file format like png or jpg. The raw file 
 * bytes are given so the application must utilize an image decoder (e.g. DevIL) to
 * get access to the actual color data.
 */
struct aiTexture
{
	/** Width of the texture, in pixels
	 *
	 * If mHeight is zero the texture is compressed in a format
	 * like JPEG. In this case mWidth specifies the size of the
	 * memory area pcData is pointing to, in bytes.
	 */
	unsigned int mWidth;

	/** Height of the texture, in pixels
	 *
	 * If this value is zero, pcData points to an compressed texture
	 * in any format (e.g. JPEG).
	 */
	unsigned int mHeight;

	/** A hint from the loader to make it easier for applications
	 *  to determine the type of embedded compressed textures.
	 *
	 * If mHeight != 0 this member is undefined. Otherwise it
	 * is set set to '\\0\\0\\0\\0' if the loader has no additional
	 * information about the texture file format used OR the
	 * file extension of the format without a trailing dot. If there 
	 * are multiple file extensions for a format, the shortest 
	 * extension is chosen (JPEG maps to 'jpg', not to 'jpeg').
	 * E.g. 'dds\\0', 'pcx\\0', 'jpg\\0'.  All characters are lower-case.
	 * The fourth character will always be '\\0'.
	 */
	char achFormatHint[4];

	/** Data of the texture.
	 *
	 * Points to an array of mWidth * mHeight aiTexel's.
	 * The format of the texture data is always ARGB8888 to
	 * make the implementation for user of the library as easy
	 * as possible. If mHeight = 0 this is a pointer to a memory
	 * buffer of size mWidth containing the compressed texture
	 * data. Good luck, have fun!
	 */
	C_STRUCT aiTexel* pcData;

#ifdef __cplusplus

	//! For compressed textures (mHeight == 0): compare the
	//! format hint against a given string.
	//! @param s Input string. 3 characters are maximally processed.
	//!        Example values: "jpg", "png"
	//! @return true if the given string matches the format hint
	bool CheckFormat(const char* s) const
	{
		ai_assert(s && !mHeight);
		return (0 == ::strncmp(achFormatHint,s,3));
	}

	// Construction
	aiTexture ()
		: mWidth  (0)
		, mHeight (0)
		, pcData  (NULL)
	{
		achFormatHint[0] = achFormatHint[1] = 0;
		achFormatHint[2] = achFormatHint[3] = 0;
	}

	// Destruction
	~aiTexture ()
	{
		delete[] pcData;
	}
#endif
};


#ifdef __cplusplus
}
#endif

#endif // AI_TEXTURE_H_INC
