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Stop decoding BC1 punchthrough alpha in BC2&3 #2

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14 changes: 7 additions & 7 deletions src/bcndecode.c
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Original file line number Diff line number Diff line change
Expand Up @@ -85,7 +85,7 @@ static rgba decode_565(uint16_t x)
return c;
}

static void decode_bc1_color(rgba *dst, const uint8_t *src)
static void decode_bc1_color(rgba *dst, const uint8_t *src, int separate_alpha)
{
bc1_color col;
rgba p[4];
Expand All @@ -101,7 +101,7 @@ static void decode_bc1_color(rgba *dst, const uint8_t *src)
r1 = p[1].r;
g1 = p[1].g;
b1 = p[1].b;
if (col.c0 > col.c1)
if (col.c0 > col.c1 || separate_alpha)
{
p[2].r = (2 * r0 + 1 * r1) / 3;
p[2].g = (2 * g0 + 1 * g1) / 3;
Expand Down Expand Up @@ -176,13 +176,13 @@ static void decode_bc3_alpha(char *dst, const uint8_t *src, int stride, int o)

static void decode_bc1_block(rgba *col, const uint8_t *src)
{
decode_bc1_color(col, src);
decode_bc1_color(col, src, 0);
}

static void decode_bc2_block(rgba *col, const uint8_t *src)
{
int n, bitI, byI, av;
decode_bc1_color(col, src + 8);
decode_bc1_color(col, src + 8, 1);
for (n = 0; n < 16; n++)
{
bitI = n * 4;
Expand All @@ -195,7 +195,7 @@ static void decode_bc2_block(rgba *col, const uint8_t *src)

static void decode_bc3_block(rgba *col, const uint8_t *src)
{
decode_bc1_color(col, src + 8);
decode_bc1_color(col, src + 8, 1);
decode_bc3_alpha((char *)col, src, sizeof(col[0]), 3);
}

Expand Down Expand Up @@ -1119,7 +1119,7 @@ int main(int argc, char **argv) {
case 5: flip = v; break;
}
}

int src_size = 4 * width * height;
int dst_size = src_size;
if (N == 1 || N == 4) {
Expand All @@ -1146,4 +1146,4 @@ int main(int argc, char **argv) {
}
}*/

#endif
#endif
10 changes: 5 additions & 5 deletions src/decode.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -336,11 +336,11 @@ fn swizzle_copy(swizzle: u8, dst: &mut [u8], src: &[u8], mut block_size: usize)
}

fn decode_bc1_block(col: &mut [RGBA], source: &[u8]) {
decode_bc1_color(col, source);
decode_bc1_color(col, source, false);
}

fn decode_bc2_block(col: &mut [RGBA], source: &[u8]) {
decode_bc1_color(col, &source[8..]);
decode_bc1_color(col, &source[8..], true);
for n in 0..16 {
let bit_i: usize = n * 4;
let by_i: usize = bit_i >> 3;
Expand All @@ -351,7 +351,7 @@ fn decode_bc2_block(col: &mut [RGBA], source: &[u8]) {
}

fn decode_bc3_block(col: &mut [RGBA], source: &[u8]) {
decode_bc1_color(col, &source[8..]);
decode_bc1_color(col, &source[8..], true);
unsafe {
decode_bc3_alpha(to_byte_ptr_mut(col), source, mem::size_of::<RGBA>(), 3);
}
Expand Down Expand Up @@ -2210,7 +2210,7 @@ fn decode_565(x: u16) -> RGBA {
};
}

fn decode_bc1_color(dst: &mut [RGBA], source: &[u8]) {
fn decode_bc1_color(dst: &mut [RGBA], source: &[u8], separate_alpha: bool) {
let mut col = Bc1Color::default();
let mut p = [RGBA::default(); 4];

Expand All @@ -2226,7 +2226,7 @@ fn decode_bc1_color(dst: &mut [RGBA], source: &[u8]) {
let g1: u16 = p[1].g as u16;
let b1: u16 = p[1].b as u16;

if col.c0 > col.c1 {
if col.c0 > col.c1 || separate_alpha {
p[2].r = ((2 * r0 + 1 * r1) / 3) as u8;
p[2].g = ((2 * g0 + 1 * g1) / 3) as u8;
p[2].b = ((2 * b0 + 1 * b1) / 3) as u8;
Expand Down