151 lines
5.7 KiB
C
151 lines
5.7 KiB
C
/* -----------------------------------------------------------------------------
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*
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* Copyright (c) 2014-2017 Alexis Naveros.
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* Portions developed under contract to the SURVICE Engineering Company.
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*
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* This software is provided 'as-is', without any express or implied
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* warranty. In no event will the authors be held liable for any damages
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* arising from the use of this software.
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*
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* Permission is granted to anyone to use this software for any purpose,
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* including commercial applications, and to alter it and redistribute it
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* freely, subject to the following restrictions:
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*
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* 1. The origin of this software must not be misrepresented; you must not
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* claim that you wrote the original software. If you use this software
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* in a product, an acknowledgment in the product documentation would be
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* appreciated but is not required.
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* 2. Altered source versions must be plainly marked as such, and must not be
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* misrepresented as being the original software.
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* 3. This notice may not be removed or altered from any source distribution.
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*
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* -----------------------------------------------------------------------------
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*/
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#ifndef IMGRESIZE_H
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#define IMGRESIZE_H
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typedef struct
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{
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/* Specify filter type, from the IM_REDUCE_FILTER_* list */
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int filter;
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/* High quality, a little slow: hopcount=3; */
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/* Good quality, much faster: hopcount=2; */
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int hopcount;
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/* Strong preservation/amplification of details: alpha=2.0f; */
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/* Mild preservation/amplification of details: alpha=6.0f; */
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float alpha;
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/* NORMALMAP filters: factor to amyplify normals on X and Y before normalization */
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float amplifynormal;
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/* NORMALMAP_SUSTAIN filters: Preserve a factor of deviation "energy" as calculated by sqrtf(x*x+y*y) */
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float normalsustainfactor;
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} imReduceOptions;
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static inline void imReduceSetOptions( imReduceOptions *options, int filter, int hopcount, float alpha, float amplifynormal, float normalsustainfactor )
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{
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options->filter = filter;
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options->hopcount = hopcount;
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options->alpha = alpha;
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options->amplifynormal = amplifynormal;
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options->normalsustainfactor = normalsustainfactor;
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return;
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}
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/* Reduce the image's dimensions by an integer divisor ~ this is fairly fast */
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int imReduceImageKaiserDataDivisor( unsigned char *dstdata, unsigned char *srcdata, int width, int height, int bytesperpixel, int bytesperline, int sizedivisor, imReduceOptions *options );
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/* Same as imReduceImageKaiserDataDivisor(), but imgdst is allocated */
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int imReduceImageKaiserDivisor( imgImage *imgdst, imgImage *imgsrc, int sizedivisor, imReduceOptions *options );
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/* Reduce the image's dimensions to match the newwidth and newheight ~ this is a little slower */
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int imReduceImageKaiserData( unsigned char *dstdata, unsigned char *srcdata, int width, int height, int bytesperpixel, int bytesperline, int newwidth, int newheight, imReduceOptions *options );
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/* Same as imReduceImageKaiserData(), but imgdst is allocated */
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int imReduceImageKaiser( imgImage *imgdst, imgImage *imgsrc, int newwidth, int newheight, imReduceOptions *options );
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/* Resize by half with a dumb box filter ~ don't use that except for the smallest mipmaps */
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/* Filters with ALPHANORM and/or SUSTAIN keywords are processed as the regular base filter only */
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int imReduceImageHalfBoxData( unsigned char *dstdata, unsigned char *srcdata, int width, int height, int bytesperpixel, int bytesperline, imReduceOptions *options );
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int imReduceImageHalfBox( imgImage *imgdst, imgImage *imgsrc, imReduceOptions *options );
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/*
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Keywords for image reduction filters
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LINEAR: Data is linear, note that this is *not* the format of typical diffuse textures
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SRGB: Color is in sRGB space, any alpha is presumed linear
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NORMALMAP: RGB represents a XYZ vector as (2.0*RGB)-1.0f, any alpha is presumed linear
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ALPHANORM: Alpha normalization, the weight of pixels is proportional to their alpha values
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(do you have "black" fully transparent pixels? please use an ALPHANORM filter)
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SUSTAIN: The "energy" of the normal map is sustained, amplified to preserve the level of details
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Note that this filter is rather slow (set options->normalsustainfactor to 0.75 or so)
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*/
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enum
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{
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/* Linear space */
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IM_REDUCE_FILTER_LINEAR,
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IM_REDUCE_FILTER_LINEAR_ALPHANORM,
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/* sRGB space (probably what you want for diffuse textures) */
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IM_REDUCE_FILTER_SRGB,
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IM_REDUCE_FILTER_SRGB_ALPHANORM,
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/* RGB represents a XYZ vector as (2.0*RGB)-1.0f, any alpha is presumed linear */
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IM_REDUCE_FILTER_NORMALMAP,
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IM_REDUCE_FILTER_NORMALMAP_ALPHANORM,
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IM_REDUCE_FILTER_NORMALMAP_SUSTAIN,
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IM_REDUCE_FILTER_NORMALMAP_SUSTAIN_ALPHANORM,
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/* Custom specialized filters */
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IM_REDUCE_FILTER_WATERMAP,
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IM_REDUCE_FILTER_PLANTMAP,
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IM_REDUCE_FILTER_FOLLIAGE,
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IM_REDUCE_FILTER_SKY,
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IM_REDUCE_FILTER_FOG
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};
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////
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#define IM_MIPMAP_CASCADE_MAX (16)
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typedef struct
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{
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int width;
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int height;
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int layercount;
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int bytesperpixel;
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int bytesperline;
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imReduceOptions *options;
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void *mipmap[IM_MIPMAP_CASCADE_MAX];
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} imMipmapCascade;
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int imBuildMipmapCascade( imMipmapCascade *cascade, void *imagedata, int width, int height, int layercount, int bytesperpixel, int bytesperline, imReduceOptions *options, int cascadeflags );
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void imFreeMipmapCascade( imMipmapCascade *cascade );
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/* For base texture, propagate RGB channels to neighbors if they are fully transparent (ignored if bytesperpixel != 4 ) */
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#define IM_CASCADE_FLAGS_COLOR_BORDER_BASE (0x1)
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/* For generated mipmaps, propagate RGB channels to neighbors if they are fully transparent (ignored if bytesperpixel != 4 ) */
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#define IM_CASCADE_FLAGS_COLOR_BORDER_MIPMAPS (0x2)
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////
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void imPropagateAlphaBorder( unsigned char *imagedata, int width, int height, int bytesperpixel, int bytesperline );
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////
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#endif
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