astc: Hard code bit depth changes to 8 and use fast replicate

This commit is contained in:
ReinUsesLisp 2020-04-09 05:47:34 -03:00
parent bd2c1ab8a0
commit 6bf5d2b011

View File

@ -759,10 +759,10 @@ public:
// significant bits when going from larger to smaller bit depth
// or by repeating the most significant bits when going from
// smaller to larger bit depths.
void ChangeBitDepth(const u8 (&depth)[4]) {
void ChangeBitDepth() {
for (u32 i = 0; i < 4; i++) {
Component(i) = ChangeBitDepth(Component(i), m_BitDepth[i], depth[i]);
m_BitDepth[i] = depth[i];
Component(i) = ChangeBitDepth(Component(i), m_BitDepth[i]);
m_BitDepth[i] = 8;
}
}
@ -774,29 +774,24 @@ public:
// Changes the bit depth of a single component. See the comment
// above for how we do this.
static ChannelType ChangeBitDepth(Pixel::ChannelType val, u8 oldDepth, u8 newDepth) {
assert(newDepth <= 8);
static ChannelType ChangeBitDepth(Pixel::ChannelType val, u8 oldDepth) {
assert(oldDepth <= 8);
if (oldDepth == newDepth) {
if (oldDepth == 8) {
// Do nothing
return val;
} else if (oldDepth == 0 && newDepth != 0) {
return static_cast<ChannelType>((1 << newDepth) - 1);
} else if (newDepth > oldDepth) {
return Replicate(val, oldDepth, newDepth);
} else if (oldDepth == 0) {
return static_cast<ChannelType>((1 << 8) - 1);
} else if (8 > oldDepth) {
return static_cast<ChannelType>(FastReplicateTo8(static_cast<u32>(val), oldDepth));
} else {
// oldDepth > newDepth
if (newDepth == 0) {
return 0xFF;
} else {
u8 bitsWasted = static_cast<u8>(oldDepth - newDepth);
const u8 bitsWasted = static_cast<u8>(oldDepth - 8);
u16 v = static_cast<u16>(val);
v = static_cast<u16>((v + (1 << (bitsWasted - 1))) >> bitsWasted);
v = ::std::min<u16>(::std::max<u16>(0, v), static_cast<u16>((1 << newDepth) - 1));
v = ::std::min<u16>(::std::max<u16>(0, v), static_cast<u16>((1 << 8) - 1));
return static_cast<u8>(v);
}
}
assert(false && "We shouldn't get here.");
return 0;
@ -845,8 +840,7 @@ public:
// up in the most-significant byte.
u32 Pack() const {
Pixel eightBit(*this);
const u8 eightBitDepth[4] = {8, 8, 8, 8};
eightBit.ChangeBitDepth(eightBitDepth);
eightBit.ChangeBitDepth();
u32 r = 0;
r |= eightBit.A();