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bemaniutils/bemani/format/afp/blendaltimpl.cxx
2021-05-19 20:16:51 +00:00

233 lines
8.0 KiB
C++

#include <stdio.h>
#include <math.h>
extern "C"
{
typedef struct intcolor {
unsigned char r;
unsigned char g;
unsigned char b;
unsigned char a;
} intcolor_t;
typedef struct floatcolor {
float r;
float g;
float b;
float a;
} floatcolor_t;
typedef struct point {
float x;
float y;
struct point add(struct point other) {
return (struct point){
x + other.x,
y + other.y,
};
};
} point_t;
typedef struct matrix {
float a;
float b;
float c;
float d;
float tx;
float ty;
point_t multiply_point(point_t point) {
return (point_t){
(a * point.x) + (c * point.y) + tx,
(b * point.x) + (d * point.y) + ty,
};
}
} matrix_t;
inline unsigned char clamp(float color) {
return fmin(fmax(0.0, roundf(color)), 255.0);
}
intcolor_t blend_normal(
intcolor_t dest,
intcolor_t src
) {
// "Normal" blend mode, which is just alpha blending. Various games use the DX
// equation Src * As + Dst * (1 - As). We premultiply Dst by Ad as well, since
// we are blitting onto a destination that could have transparency. Once we are
// done, we divide out the premultiplied Ad in order to put the pixes back to
// their full blended values since we are not setting the destination alpha to 1.0.
// This enables partial transparent backgrounds to work properly.
// Short circuit for speed.
if (src.a == 0) {
return dest;
}
if (src.a == 255) {
return src;
}
// Calculate alpha blending.
float srcpercent = src.a / 255.0;
float destpercent = dest.a / 255.0;
float srcremaineder = 1.0 - srcpercent;
float new_alpha = (srcpercent + destpercent * srcremaineder);
return (intcolor_t){
clamp(((dest.r * destpercent * srcremaineder) + (src.r * srcpercent)) / new_alpha),
clamp(((dest.g * destpercent * srcremaineder) + (src.g * srcpercent)) / new_alpha),
clamp(((dest.b * destpercent * srcremaineder) + (src.b * srcpercent)) / new_alpha),
clamp(255 * new_alpha)
};
}
intcolor_t blend_addition(
intcolor_t dest,
intcolor_t src
) {
// "Addition" blend mode, which is used for fog/clouds/etc. Various games use the DX
// equation Src * As + Dst * 1. It appears jubeat does not premultiply the source
// by its alpha component.
// Short circuit for speed.
if (src.a == 0) {
return dest;
}
// Calculate final color blending.
float srcpercent = src.a / 255.0;
return (intcolor_t){
clamp(dest.r + (src.r * srcpercent)),
clamp(dest.g + (src.g * srcpercent)),
clamp(dest.b + (src.b * srcpercent)),
dest.a,
};
}
intcolor_t blend_subtraction(
intcolor_t dest,
intcolor_t src
) {
// "Subtraction" blend mode, used for darkening an image. Various games use the DX
// equation Dst * 1 - Src * As. It appears jubeat does not premultiply the source
// by its alpha component much like the "additive" blend above..
// Short circuit for speed.
if (src.a == 0) {
return dest;
}
// Calculate final color blending.
float srcpercent = src.a / 255.0;
return (intcolor_t){
clamp(dest.r - (src.r * srcpercent)),
clamp(dest.g - (src.g * srcpercent)),
clamp(dest.b - (src.b * srcpercent)),
dest.a,
};
}
intcolor_t blend_multiply(
intcolor_t dest,
intcolor_t src
) {
// "Multiply" blend mode, used for darkening an image. Various games use the DX
// equation Src * 0 + Dst * Src. It appears jubeat uses the alternative formula
// Src * Dst + Dst * (1 - As) which reduces to the first equation as long as the
// source alpha is always 255.
// Calculate final color blending.
return (intcolor_t){
clamp(255 * ((dest.r / 255.0) * (src.r / 255.0))),
clamp(255 * ((dest.g / 255.0) * (src.g / 255.0))),
clamp(255 * ((dest.b / 255.0) * (src.b / 255.0))),
dest.a,
};
}
intcolor_t blend_point(
intcolor_t add_color,
floatcolor_t mult_color,
intcolor_t src_color,
intcolor_t dest_color,
int blendfunc
) {
// Calculate multiplicative and additive colors against the source.
src_color = (intcolor_t){
clamp((src_color.r * mult_color.r) + add_color.r),
clamp((src_color.g * mult_color.g) + add_color.g),
clamp((src_color.b * mult_color.b) + add_color.b),
clamp((src_color.a * mult_color.a) + add_color.a),
};
if (blendfunc == 3) {
return blend_multiply(dest_color, src_color);
}
// TODO: blend mode 4, which is "screen" blending according to SWF references. I've only seen this
// in Jubeat and it implements it using OpenGL equation Src * (1 - Dst) + Dst * 1.
// TODO: blend mode 5, which is "lighten" blending according to SWF references. Jubeat does not
// premultiply by alpha, but the GL/DX equation is max(Src * As, Dst * 1).
// TODO: blend mode 6, which is "darken" blending according to SWF references. Jubeat does not
// premultiply by alpha, but the GL/DX equation is min(Src * As, Dst * 1).
// TODO: blend mode 10, which is "invert" according to SWF references. The only game I could find
// that implemented this had equation Src * (1 - Dst) + Dst * (1 - As).
// TODO: blend mode 13, which is "overlay" according to SWF references. The equation seems to be
// Src * Dst + Dst * Src but Jubeat thinks it should be Src * Dst + Dst * (1 - As).
if (blendfunc == 8) {
return blend_addition(dest_color, src_color);
}
if (blendfunc == 9 || blendfunc == 70) {
return blend_subtraction(dest_color, src_color);
}
// TODO: blend mode 75, which is not in the SWF spec and appears to have the equation
// Src * (1 - Dst) + Dst * (1 - Src).
return blend_normal(dest_color, src_color);
}
int affine_composite_fast(
unsigned char *imgbytes,
unsigned int imgwidth,
unsigned int imgheight,
unsigned int minx,
unsigned int maxx,
unsigned int miny,
unsigned int maxy,
intcolor_t add_color,
floatcolor_t mult_color,
matrix_t inverse,
point_t origin,
int blendfunc,
unsigned char *texbytes,
unsigned int texwidth,
unsigned int texheight,
int single_threaded
) {
// Cast to a usable type.
intcolor_t *imgdata = (intcolor_t *)imgbytes;
intcolor_t *texdata = (intcolor_t *)texbytes;
for (unsigned int imgy = miny; imgy < maxy; imgy++) {
for (unsigned int imgx = minx; imgx < maxx; imgx++) {
// Determine offset.
unsigned int imgoff = imgx + (imgy * imgwidth);
// Calculate what texture pixel data goes here.
point_t texloc = inverse.multiply_point((point_t){(float)imgx, (float)imgy}).add(origin);
int texx = roundf(texloc.x);
int texy = roundf(texloc.y);
// If we're out of bounds, don't update.
if (texx < 0 or texy < 0 or texx >= (int)texwidth or texy >= (int)texheight) {
continue;
}
// Blend it.
unsigned int texoff = texx + (texy * texwidth);
imgdata[imgoff] = blend_point(add_color, mult_color, texdata[texoff], imgdata[imgoff], blendfunc);
}
}
return 0;
}
}