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#include <u.h>
#include <libc.h>
#include <thread.h>
#include <draw.h>
#include <memdraw.h>
#include <geometry.h>
#include "libobj/obj.h"
#include "graphics.h"
#include "internal.h"
enum {
CUBEMAP_FACE_LEFT, /* -x */
CUBEMAP_FACE_RIGHT, /* +x */
CUBEMAP_FACE_BOTTOM, /* -y */
CUBEMAP_FACE_TOP, /* +y */
CUBEMAP_FACE_FRONT, /* -z */
CUBEMAP_FACE_BACK, /* +z */
};
/*
* uv-coords belong to the 1st quadrant (v grows bottom-up),
* hence the need to reverse the v coord.
*/
static Point
uv2tp(Point2 uv, Texture *t)
{
assert(uv.x >= 0 && uv.x <= 1 && uv.y >= 0 && uv.y <= 1);
return Pt(uv.x*Dx(t->image->r), (1 - uv.y)*Dy(t->image->r));
}
static Color
cbuf2col(uchar b[4])
{
Color c;
c.a = b[0] / 255.0;
c.b = b[1] / 255.0;
c.g = b[2] / 255.0;
c.r = b[3] / 255.0;
return c;
}
static Color
_memreadcolor(Texture *t, Point sp)
{
Color c;
uchar cbuf[4];
switch(t->image->chan){
case RGB24:
unloadmemimage(t->image, rectaddpt(UR, sp), cbuf+1, sizeof cbuf - 1);
cbuf[0] = 0xFF;
break;
case RGBA32:
unloadmemimage(t->image, rectaddpt(UR, sp), cbuf, sizeof cbuf);
break;
case XRGB32:
unloadmemimage(t->image, rectaddpt(UR, sp), cbuf, sizeof cbuf);
memmove(cbuf+1, cbuf, 3);
cbuf[0] = 0xFF;
break;
}
c = cbuf2col(cbuf);
switch(t->type){
case sRGBTexture: c = srgb2linear(c); break;
}
return c;
}
/*
* nearest-neighbour sampler
*/
Color
neartexsampler(Texture *t, Point2 uv)
{
return _memreadcolor(t, uv2tp(uv, t));
}
/*
* bilinear sampler
*/
Color
bilitexsampler(Texture *t, Point2 uv)
{
Rectangle r;
Color c1, c2;
r = rectaddpt(UR, uv2tp(uv, t));
if(r.min.x < t->image->r.min.x){
r.min.x++;
r.max.x++;
}if(r.min.y < t->image->r.min.y){
r.min.y++;
r.max.y++;
}if(r.max.x >= t->image->r.max.x){
r.min.x--;
r.max.x--;
}if(r.max.y >= t->image->r.max.y){
r.min.y--;
r.max.y--;
}
c1 = lerp3(_memreadcolor(t, r.min), _memreadcolor(t, Pt(r.max.x, r.min.y)), 0.5);
c2 = lerp3(_memreadcolor(t, Pt(r.min.x, r.max.y)), _memreadcolor(t, r.max), 0.5);
return lerp3(c1, c2, 0.5);
}
Color
sampletexture(Texture *t, Point2 uv, Color(*sampler)(Texture*,Point2))
{
return sampler(t, uv);
}
Texture *
alloctexture(int type, Memimage *i)
{
Texture *t;
t = emalloc(sizeof *t);
t->image = i;
t->type = type;
return t;
}
Texture *
duptexture(Texture *t)
{
if(t == nil)
return nil;
return alloctexture(t->type, dupmemimage(t->image));
}
void
freetexture(Texture *t)
{
if(t == nil)
return;
freememimage(t->image);
free(t);
}
/* cubemap sampling */
Cubemap *
readcubemap(char *paths[6])
{
Cubemap *cm;
Memimage *i;
char **p;
int fd;
cm = emalloc(sizeof *cm);
memset(cm, 0, sizeof *cm);
for(p = paths; p < paths+6; p++){
assert(*p != nil);
fd = open(*p, OREAD);
if(fd < 0)
sysfatal("open: %r");
i = readmemimage(fd);
if(i == nil)
sysfatal("readmemimage: %r");
cm->faces[p-paths] = alloctexture(sRGBTexture, i);
close(fd);
}
return cm;
}
Cubemap *
dupcubemap(Cubemap *cm)
{
Cubemap *ncm;
int i;
if(cm == nil)
return nil;
ncm = emalloc(sizeof *ncm);
memset(ncm, 0, sizeof *ncm);
if(cm->name != nil)
ncm->name = strdup(cm->name);
for(i = 0; i < 6; i++)
ncm->faces[i] = duptexture(cm->faces[i]);
return ncm;
}
void
freecubemap(Cubemap *cm)
{
int i;
if(cm == nil)
return;
for(i = 0; i < 6; i++)
freetexture(cm->faces[i]);
free(cm->name);
free(cm);
}
/*
* references:
* - https://github.com/zauonlok/renderer/blob/9ed5082f0eda453f0b2a0d5ec37cf5a60f0207f6/renderer/core/texture.c#L206
* - “Cubemap Texture Selection”, OpenGL ES 2.0 § 3.7.5, November 2010
*/
Color
samplecubemap(Cubemap *cm, Point3 d, Color(*sampler)(Texture*,Point2))
{
Point2 uv;
double ax, ay, az, ma, sc, tc;
int face;
ax = fabs(d.x);
ay = fabs(d.y);
az = fabs(d.z);
if(ax > ay && ax > az){
ma = ax;
if(d.x > 0){
face = CUBEMAP_FACE_RIGHT;
sc = -d.z;
tc = -d.y;
}else{
face = CUBEMAP_FACE_LEFT;
sc = d.z;
tc = -d.y;
}
}else if(ay > az){
ma = ay;
if(d.y > 0){
face = CUBEMAP_FACE_TOP;
sc = d.x;
tc = d.z;
}else{
face = CUBEMAP_FACE_BOTTOM;
sc = d.x;
tc = -d.z;
}
}else{
ma = az;
if(d.z > 0){
face = CUBEMAP_FACE_BACK;
sc = d.x;
tc = -d.y;
}else{
face = CUBEMAP_FACE_FRONT;
sc = -d.x;
tc = -d.y;
}
}
uv.x = (sc/ma + 1)/2;
uv.y = 1 - (tc/ma + 1)/2;
uv.w = 1;
return sampler(cm->faces[face], uv);
}
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