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Evas rg_etc2: Complete support for ETC2 with RGBA8_EAC 

Add support for alpha in the ETC2 decoder.
This commit is contained in:
Jean-Philippe Andre 2014-05-07 14:47:45 +09:00
parent 4e358a582e
commit 03505d1f81
1 changed files with 140 additions and 42 deletions
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182
src/static_libs/rg_etc/rg_etc2.c
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@ -51,6 +51,26 @@ static const int kSigned3bit[8] = {
0, 1, 2, 3, -4, -3, -2, -1
};
// For alpha support
static const int kAlphaModifiers[16][8] = {
{ -3, -6, -9, -15, 2, 5, 8, 14},
{ -3, -7, -10, -13, 2, 6, 9, 12},
{ -2, -5, -8, -13, 1, 4, 7, 12},
{ -2, -4, -6, -13, 1, 3, 5, 12},
{ -3, -6, -8, -12, 2, 5, 7, 11},
{ -3, -7, -9, -11, 2, 6, 8, 10},
{ -4, -7, -8, -11, 3, 6, 7, 10},
{ -3, -5, -8, -11, 2, 4, 7, 10},
{ -2, -6, -8, -10, 1, 5, 7, 9},
{ -2, -5, -8, -10, 1, 4, 7, 9},
{ -2, -4, -8, -10, 1, 3, 7, 9},
{ -2, -5, -7, -10, 1, 4, 6, 9},
{ -3, -4, -7, -10, 2, 3, 6, 9},
{ -1, -2, -3, -10, 0, 1, 2, 9},
{ -4, -6, -8, -9, 3, 5, 7, 8},
{ -3, -5, -7, -9, 2, 4, 6, 8}
};
// Use with static constants so the compiler can optimize everything
#define BITS(byteval, lowbit, highbit) \
(((byteval) >> (lowbit)) & ((1 << ((highbit) - (lowbit) + 1)) - 1))
@ -67,6 +87,9 @@ static const int kSigned3bit[8] = {
// Real clamp
#define CLAMP(a) ({ int _b = (a); (((_b) >= 0) ? (((_b) < 256) ? (_b) : 255) : 0); })
// Simple min
#define MIN(a,b) ({ int _z = (a), _y = (b); ((_z <= _y) ? _z : _y); })
// Write a BGRA value for output to Evas
#define BGRA(r,g,b,a) ((a << 24) | (r << 16) | (g << 8) | b)
@ -75,6 +98,20 @@ static const int kSigned3bit[8] = {
#define _6to8(a) ({ int _a = (a) & ((1 << 6) - 1); ((_a << 2) | ((_a >> 4) & 0x3)); })
#define _7to8(a) ({ int _a = (a) & ((1 << 7) - 1); ((_a << 1) | ((_a >> 6) & 0x1)); })
#ifndef WORDS_BIGENDIAN
/* x86 */
#define A_VAL(p) (((uint8_t *)(p))[3])
#define R_VAL(p) (((uint8_t *)(p))[2])
#define G_VAL(p) (((uint8_t *)(p))[1])
#define B_VAL(p) (((uint8_t *)(p))[0])
#else
/* ppc */
#define A_VAL(p) (((uint8_t *)(p))[0])
#define R_VAL(p) (((uint8_t *)(p))[1])
#define G_VAL(p) (((uint8_t *)(p))[2])
#define B_VAL(p) (((uint8_t *)(p))[3])
#endif
static inline void
_T_mode_color_read(const uint8_t *etc, uint32_t *paint_colors, int alpha)
@ -176,48 +213,9 @@ _planar_mode_color_read(const uint8_t *etc, uint32_t *bgra, int alpha)
}
}
void
rg_etc2_rgb8_decode_block(const uint8_t *etc, uint32_t *bgra)
static inline void
_TH_paint(const uint8_t *etc, uint32_t paint_colors[4], uint32_t *bgra)
{
// Check differential mode bit
if ((etc[3] & 0x2) == 0)
goto etc1;
// Read R,G,B
const int R = BITS(etc[0], 3, 7);
const int dR = kSigned3bit[BITS(etc[0], 0, 2)];
const int G = BITS(etc[1], 3, 7);
const int dG = kSigned3bit[BITS(etc[1], 0, 2)];
const int B = BITS(etc[2], 3, 7);
const int dB = kSigned3bit[BITS(etc[2], 0, 2)];
uint32_t paint_colors[4];
if ((R + dR) < 0 || (R + dR) >= 32)
{
// T mode
_T_mode_color_read(etc, paint_colors, 255);
goto th_mode;
}
if ((G + dG) < 0 || (G + dG) >= 32)
{
// H mode
_H_mode_color_read(etc, paint_colors, 255);
goto th_mode;
}
if ((B + dB) < 0 || (B + dB) >= 32)
{
// Planar mode
_planar_mode_color_read(etc, bgra, 255);
return;
}
etc1:
// Valid differential mode or individual mode: ETC1
if (!rg_etc1_unpack_block(etc, bgra, 0))
fprintf(stderr, "ETC2: Something very strange is happening here!\n");
return;
th_mode:
// Common code for modes T and H.
// a,b,c,d
@ -243,5 +241,105 @@ th_mode:
bgra[ 7] = paint_colors[(BIT(etc[4], 5) << 1) | (BIT(etc[6], 5))];
bgra[11] = paint_colors[(BIT(etc[4], 6) << 1) | (BIT(etc[6], 6))];
bgra[15] = paint_colors[(BIT(etc[4], 7) << 1) | (BIT(etc[6], 7))];
return;
}
void
rg_etc2_rgb8_decode_block(const uint8_t *etc, uint32_t *bgra)
{
// Check differential mode bit
if ((etc[3] & 0x2) == 0)
goto etc1;
// Read R,G,B
const int R = BITS(etc[0], 3, 7);
const int dR = kSigned3bit[BITS(etc[0], 0, 2)];
const int G = BITS(etc[1], 3, 7);
const int dG = kSigned3bit[BITS(etc[1], 0, 2)];
const int B = BITS(etc[2], 3, 7);
const int dB = kSigned3bit[BITS(etc[2], 0, 2)];
uint32_t paint_colors[4];
if ((R + dR) < 0 || (R + dR) >= 32)
{
// T mode
_T_mode_color_read(etc, paint_colors, 255);
_TH_paint(etc, paint_colors, bgra);
return;
}
if ((G + dG) < 0 || (G + dG) >= 32)
{
// H mode
_H_mode_color_read(etc, paint_colors, 255);
_TH_paint(etc, paint_colors, bgra);
return;
}
if ((B + dB) < 0 || (B + dB) >= 32)
{
// Planar mode
_planar_mode_color_read(etc, bgra, 255);
return;
}
etc1:
// Valid differential mode or individual mode: ETC1
if (!rg_etc1_unpack_block(etc, bgra, 0))
fprintf(stderr, "ETC2: Something very strange is happening here!\n");
}
void
rg_etc2_rgba8_decode_block(const uint8_t *etc, uint32_t *bgra)
{
const uint8_t zeros[7] = {0};
uint32_t table_index;
int base_codeword;
int multiplier;
base_codeword = etc[0];
// Fast path if alpha is the same for all pixels
if (!memcmp(etc + 1, zeros, 7))
{
if (!base_codeword)
memset(bgra, 0, 64);
else
{
rg_etc2_rgb8_decode_block(etc + 8, bgra);
if (base_codeword != 255)
for (int k = 0; k < 16; k++)
{
const uint32_t rgb = *bgra;
const int R = MIN(R_VAL(&rgb), base_codeword);
const int G = MIN(G_VAL(&rgb), base_codeword);
const int B = MIN(B_VAL(&rgb), base_codeword);
*bgra++ = BGRA(R, G, B, base_codeword);
}
}
return;
}
rg_etc2_rgb8_decode_block(etc + 8, bgra);
multiplier = BITS(etc[1], 4, 7);
table_index = BITS(etc[1], 0, 3);
for (int x = 0, k = 0; x < 4; x++)
for (int y = 0; y < 4; y++, k += 3)
{
const uint32_t byte = (k >> 3); // = [k/8]
const uint32_t bit = k - (byte << 3); // = k%8
const uint32_t rgb = bgra[(y << 2) + x];
uint32_t index, alpha, R, G, B;
if (bit < 6)
index = BITS(etc[byte + 2], 5 - bit, 7 - bit);
else if (bit == 6)
index = (BITS(etc[byte + 2], 0, 1) << 1) | BIT(etc[byte + 3], 7);
else // bit == 7
index = (BIT(etc[byte + 2], 0) << 2) | BITS(etc[byte + 3], 6, 7);
alpha = CLAMP(base_codeword + kAlphaModifiers[table_index][index] * multiplier);
R = MIN(R_VAL(&rgb), alpha);
G = MIN(G_VAL(&rgb), alpha);
B = MIN(B_VAL(&rgb), alpha);
bgra[(y << 2) + x] = BGRA(R, G, B, alpha);
}
}