void GGLAssembler::extract(component_t& d, const pixel_t& s, int component)
{
integer_t r(d.reg, 32, d.flags);
extract(r, s.reg,
s.format.c[component].h,
s.format.c[component].l,
s.size());
d = component_t(r);
}
void GGLAssembler::build_blendOneMinusFF(
component_t& temp,
const integer_t& factor,
const integer_t& fragment,
const integer_t& fb)
{
// R = S*f + D*(1-f) = (S-D)*f + D
Scratch scratches(registerFile());
// compute D-S
integer_t diff(fb.flags & CORRUPTIBLE ?
fb.reg : scratches.obtain(), fb.size(), CORRUPTIBLE);
const int shift = fragment.size() - fb.size();
if (shift>0) SUB(AL, 0, diff.reg, fb.reg, reg_imm(fragment.reg, LSR, shift));
else if (shift<0) SUB(AL, 0, diff.reg, fb.reg, reg_imm(fragment.reg, LSL,-shift));
else SUB(AL, 0, diff.reg, fb.reg, fragment.reg);
mul_factor_add(temp, diff, factor, component_t(fragment));
}
void GGLAssembler::build_blending(
component_t& temp, // incomming fragment / output
const pixel_t& pixel, // framebuffer
int component,
Scratch& regs)
{
if (!mInfo[component].blend)
return;
int fs = component==GGLFormat::ALPHA ? mBlendSrcA : mBlendSrc;
int fd = component==GGLFormat::ALPHA ? mBlendDstA : mBlendDst;
if (fs==GGL_SRC_ALPHA_SATURATE && component==GGLFormat::ALPHA)
fs = GGL_ONE;
const int blending = blending_codes(fs, fd);
if (!temp.size()) {
// here, blending will produce something which doesn't depend on
// that component (eg: GL_ZERO:GL_*), so the register has not been
// allocated yet. Will never be used as a source.
temp = component_t(regs.obtain(), CORRUPTIBLE);
}
// we are doing real blending...
// fb: extracted dst
// fragment: extracted src
// temp: component_t(fragment) and result
// scoped register allocator
Scratch scratches(registerFile());
comment("blending");
// we can optimize these cases a bit...
// (1) saturation is not needed
// (2) we can use only one multiply instead of 2
// (3) we can reduce the register pressure
// R = S*f + D*(1-f) = (S-D)*f + D
// R = S*(1-f) + D*f = (D-S)*f + S
const bool same_factor_opt1 =
(fs==GGL_DST_COLOR && fd==GGL_ONE_MINUS_DST_COLOR) ||
(fs==GGL_SRC_COLOR && fd==GGL_ONE_MINUS_SRC_COLOR) ||
(fs==GGL_DST_ALPHA && fd==GGL_ONE_MINUS_DST_ALPHA) ||
(fs==GGL_SRC_ALPHA && fd==GGL_ONE_MINUS_SRC_ALPHA);
const bool same_factor_opt2 =
(fs==GGL_ONE_MINUS_DST_COLOR && fd==GGL_DST_COLOR) ||
(fs==GGL_ONE_MINUS_SRC_COLOR && fd==GGL_SRC_COLOR) ||
(fs==GGL_ONE_MINUS_DST_ALPHA && fd==GGL_DST_ALPHA) ||
(fs==GGL_ONE_MINUS_SRC_ALPHA && fd==GGL_SRC_ALPHA);
// XXX: we could also optimize these cases:
// R = S*f + D*f = (S+D)*f
// R = S*(1-f) + D*(1-f) = (S+D)*(1-f)
// R = S*D + D*S = 2*S*D
// see if we need to extract 'component' from the destination (fb)
integer_t fb;
if (blending & (BLEND_DST|FACTOR_DST)) {
fb.setTo(scratches.obtain(), 32);
extract(fb, pixel, component);
if (mDithering) {
// XXX: maybe what we should do instead, is simply
// expand fb -or- fragment to the larger of the two
if (fb.size() < temp.size()) {
// for now we expand 'fb' to min(fragment, 8)
int new_size = temp.size() < 8 ? temp.size() : 8;
expand(fb, fb, new_size);
}
}
}
// convert input fragment to integer_t
if (temp.l && (temp.flags & CORRUPTIBLE)) {
MOV(AL, 0, temp.reg, reg_imm(temp.reg, LSR, temp.l));
temp.h -= temp.l;
temp.l = 0;
}
integer_t fragment(temp.reg, temp.size(), temp.flags);
// if not done yet, convert input fragment to integer_t
if (temp.l) {
// here we know temp is not CORRUPTIBLE
fragment.reg = scratches.obtain();
MOV(AL, 0, fragment.reg, reg_imm(temp.reg, LSR, temp.l));
fragment.flags |= CORRUPTIBLE;
}
if (!(temp.flags & CORRUPTIBLE)) {
// temp is not corruptible, but since it's the destination it
// will be modified, so we need to allocate a new register.
temp.reg = regs.obtain();
temp.flags &= ~CORRUPTIBLE;
fragment.flags &= ~CORRUPTIBLE;
}
if ((blending & BLEND_SRC) && !same_factor_opt1) {
// source (fragment) is needed for the blending stage
// so it's not CORRUPTIBLE (unless we're doing same_factor_opt1)
fragment.flags &= ~CORRUPTIBLE;
}
if (same_factor_opt1) {
// R = S*f + D*(1-f) = (S-D)*f + D
integer_t factor;
build_blend_factor(factor, fs,
component, pixel, fragment, fb, scratches);
// fb is always corruptible from this point
fb.flags |= CORRUPTIBLE;
build_blendFOneMinusF(temp, factor, fragment, fb);
} else if (same_factor_opt2) {
// R = S*(1-f) + D*f = (D-S)*f + S
integer_t factor;
// fb is always corrruptible here
fb.flags |= CORRUPTIBLE;
build_blend_factor(factor, fd,
component, pixel, fragment, fb, scratches);
build_blendOneMinusFF(temp, factor, fragment, fb);
} else {
integer_t src_factor;
integer_t dst_factor;
// if destination (fb) is not needed for the blending stage,
// then it can be marked as CORRUPTIBLE
if (!(blending & BLEND_DST)) {
fb.flags |= CORRUPTIBLE;
}
// XXX: try to mark some registers as CORRUPTIBLE
// in most case we could make those corruptible
// when we're processing the last component
// but not always, for instance
// when fragment is constant and not reloaded
// when fb is needed for logic-ops or masking
// when a register is aliased (for instance with mAlphaSource)
// blend away...
if (fs==GGL_ZERO) {
if (fd==GGL_ZERO) { // R = 0
// already taken care of
} else if (fd==GGL_ONE) { // R = D
// already taken care of
} else { // R = D*fd
// compute fd
build_blend_factor(dst_factor, fd,
component, pixel, fragment, fb, scratches);
mul_factor(temp, fb, dst_factor);
}
} else if (fs==GGL_ONE) {
if (fd==GGL_ZERO) { // R = S
// NOP, taken care of
} else if (fd==GGL_ONE) { // R = S + D
component_add(temp, fb, fragment); // args order matters
component_sat(temp);
} else { // R = S + D*fd
// compute fd
build_blend_factor(dst_factor, fd,
component, pixel, fragment, fb, scratches);
mul_factor_add(temp, fb, dst_factor, component_t(fragment));
component_sat(temp);
}
} else {
// compute fs
build_blend_factor(src_factor, fs,
component, pixel, fragment, fb, scratches);
if (fd==GGL_ZERO) { // R = S*fs
mul_factor(temp, fragment, src_factor);
} else if (fd==GGL_ONE) { // R = S*fs + D
mul_factor_add(temp, fragment, src_factor, component_t(fb));
component_sat(temp);
} else { // R = S*fs + D*fd
mul_factor(temp, fragment, src_factor);
if (scratches.isUsed(src_factor.reg))
scratches.recycle(src_factor.reg);
// compute fd
build_blend_factor(dst_factor, fd,
component, pixel, fragment, fb, scratches);
mul_factor_add(temp, fb, dst_factor, temp);
if (!same_factor_opt1 && !same_factor_opt2) {
component_sat(temp);
}
}
}
}
// now we can be corrupted (it's the dest)
temp.flags |= CORRUPTIBLE;
}
void GGLAssembler::expand(component_t& d, const component_t& s, int dbits)
{
integer_t r(d.reg, 32, d.flags);
expand(r, s, dbits);
d = component_t(r);
}
