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scenewalker-libretro/rpng.cpp
Themaister e49bff005c Fixup RPNG to work better for GL purposes. 
Avoids having to flip Y texture coordinate.
Also avoids having to use GLES2 extension to load textures.
2013-05-12 23:58:35 +02:00

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/* RetroArch - A frontend for libretro.
* Copyright (C) 2010-2013 - Hans-Kristian Arntzen
*
* RetroArch is free software: you can redistribute it and/or modify it under the terms
* of the GNU General Public License as published by the Free Software Found-
* ation, either version 3 of the License, or (at your option) any later version.
*
* RetroArch is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
* without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
* PURPOSE. See the GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License along with RetroArch.
* If not, see <http://www.gnu.org/licenses/>.
*/
#include "rpng.h"
#ifdef WANT_MINIZ
#include "../../deps/miniz/zlib.h"
#else
#include <zlib.h>
#endif
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
// Decodes a subset of PNG standard.
// Does not handle much outside 24/32-bit RGB(A) images.
//
// Missing: Adam7 interlace, 16 bpp, various color formats.
#undef GOTO_END_ERROR
#define GOTO_END_ERROR() do { \
fprintf(stderr, "[RPNG]: Error in line %d.\n", __LINE__); \
ret = false; \
goto end; \
} while(0)
static const uint8_t png_magic[8] = {
0x89, 'P', 'N', 'G', 0x0d, 0x0a, 0x1a, 0x0a,
};
struct png_chunk
{
uint32_t size;
char type[4];
uint8_t *data;
};
struct png_ihdr
{
uint32_t width;
uint32_t height;
uint8_t depth;
uint8_t color_type;
uint8_t compression;
uint8_t filter;
uint8_t interlace;
};
enum png_chunk_type
{
PNG_CHUNK_NOOP = 0,
PNG_CHUNK_ERROR,
PNG_CHUNK_IHDR,
PNG_CHUNK_IDAT,
PNG_CHUNK_IEND
};
static uint32_t dword_be(const uint8_t *buf)
{
return (buf[0] << 24) | (buf[1] << 16) | (buf[2] << 8) | (buf[3] << 0);
}
static bool read_chunk_header(FILE *file, struct png_chunk *chunk)
{
uint8_t dword[4] = {0};
if (fread(dword, 1, 4, file) != 4)
return false;
chunk->size = dword_be(dword);
if (fread(chunk->type, 1, 4, file) != 4)
return false;
return true;
}
struct
{
const char *id;
enum png_chunk_type type;
} static const chunk_map[] = {
{ "IHDR", PNG_CHUNK_IHDR },
{ "IDAT", PNG_CHUNK_IDAT },
{ "IEND", PNG_CHUNK_IEND },
};
struct idat_buffer
{
uint8_t *data;
size_t size;
};
static enum png_chunk_type png_chunk_type(const struct png_chunk *chunk)
{
for (unsigned i = 0; i < sizeof(chunk_map) / sizeof(chunk_map[0]); i++)
{
if (memcmp(chunk->type, chunk_map[i].id, 4) == 0)
return chunk_map[i].type;
}
return PNG_CHUNK_NOOP;
}
static bool png_read_chunk(FILE *file, struct png_chunk *chunk)
{
free(chunk->data);
chunk->data = (uint8_t*)calloc(1, chunk->size + sizeof(uint32_t)); // CRC32
if (!chunk->data)
return false;
if (fread(chunk->data, 1, chunk->size + sizeof(uint32_t), file) != (chunk->size + sizeof(uint32_t)))
{
free(chunk->data);
return false;
}
// Ignore CRC.
return true;
}
static void png_free_chunk(struct png_chunk *chunk)
{
free(chunk->data);
chunk->data = NULL;
}
static bool png_parse_ihdr(FILE *file, struct png_chunk *chunk, struct png_ihdr *ihdr)
{
bool ret = true;
if (!png_read_chunk(file, chunk))
return false;
if (chunk->size != 13)
GOTO_END_ERROR();
ihdr->width = dword_be(chunk->data + 0);
ihdr->height = dword_be(chunk->data + 4);
ihdr->depth = chunk->data[8];
ihdr->color_type = chunk->data[9];
ihdr->compression = chunk->data[10];
ihdr->filter = chunk->data[11];
ihdr->interlace = chunk->data[12];
if (ihdr->width == 0 || ihdr->height == 0)
GOTO_END_ERROR();
if (ihdr->depth != 8) // Only 8bpc supported.
GOTO_END_ERROR();
if (ihdr->color_type != 2 && ihdr->color_type != 6) // Only RGB/RGBA supported.
GOTO_END_ERROR();
if (ihdr->compression != 0)
GOTO_END_ERROR();
if (ihdr->interlace != 0) // No Adam7 supported.
GOTO_END_ERROR();
end:
png_free_chunk(chunk);
return ret;
}
// Paeth prediction filter.
static inline int paeth(int a, int b, int c)
{
int p = a + b - c;
int pa = abs(p - a);
int pb = abs(p - b);
int pc = abs(p - c);
if (pa <= pb && pa <= pc)
return a;
else if (pb <= pc)
return b;
else
return c;
}
static inline void copy_line_rgb(uint8_t *data, const uint8_t *decoded, unsigned width)
{
for (unsigned i = 0; i < width; i++)
{
*data++ = *decoded++;
*data++ = *decoded++;
*data++ = *decoded++;
*data++ = 0xff;
}
}
static inline void copy_line_rgba(uint8_t *data, const uint8_t *decoded, unsigned width)
{
memcpy(data, decoded, width * sizeof(uint32_t));
}
static bool png_reverse_filter(uint8_t *data, const struct png_ihdr *ihdr,
const uint8_t *inflate_buf, size_t inflate_buf_size)
{
bool ret = true;
unsigned bpp = ihdr->color_type == 2 ? 3 : 4;
if (inflate_buf_size < (ihdr->width * bpp + 1) * ihdr->height)
return false;
unsigned pitch = ihdr->width * bpp;
uint8_t *prev_scanline = (uint8_t*)calloc(1, pitch);
uint8_t *decoded_scanline = (uint8_t*)calloc(1, pitch);
if (!decoded_scanline || !decoded_scanline)
GOTO_END_ERROR();
// Top-left origin to bottom-left origin for OpenGL.
data += (ihdr->height - 1) * ihdr->width * sizeof(uint32_t);
for (unsigned h = 0; h < ihdr->height;
h++, inflate_buf += pitch, data -= ihdr->width * sizeof(uint32_t))
{
unsigned filter = *inflate_buf++;
switch (filter)
{
case 0: // None
memcpy(decoded_scanline, inflate_buf, pitch);
break;
case 1: // Sub
for (unsigned i = 0; i < bpp; i++)
decoded_scanline[i] = inflate_buf[i];
for (unsigned i = bpp; i < pitch; i++)
decoded_scanline[i] = decoded_scanline[i - bpp] + inflate_buf[i];
break;
case 2: // Up
for (unsigned i = 0; i < pitch; i++)
decoded_scanline[i] = prev_scanline[i] + inflate_buf[i];
break;
case 3: // Average
for (unsigned i = 0; i < bpp; i++)
{
uint8_t avg = prev_scanline[i] >> 1;
decoded_scanline[i] = avg + inflate_buf[i];
}
for (unsigned i = bpp; i < pitch; i++)
{
uint8_t avg = (decoded_scanline[i - bpp] + prev_scanline[i]) >> 1;
decoded_scanline[i] = avg + inflate_buf[i];
}
break;
case 4: // Paeth
for (unsigned i = 0; i < bpp; i++)
decoded_scanline[i] = paeth(0, prev_scanline[i], 0) + inflate_buf[i];
for (unsigned i = bpp; i < pitch; i++)
decoded_scanline[i] = paeth(decoded_scanline[i - bpp], prev_scanline[i], prev_scanline[i - bpp]) + inflate_buf[i];
break;
default:
GOTO_END_ERROR();
}
if (bpp == 3)
copy_line_rgb(data, decoded_scanline, ihdr->width);
else
copy_line_rgba(data, decoded_scanline, ihdr->width);
memcpy(prev_scanline, decoded_scanline, pitch);
}
end:
free(decoded_scanline);
free(prev_scanline);
return ret;
}
static bool png_append_idat(FILE *file, const struct png_chunk *chunk, struct idat_buffer *buf)
{
uint8_t *new_buffer = (uint8_t*)realloc(buf->data, buf->size + chunk->size);
if (!new_buffer)
return false;
buf->data = new_buffer;
if (fread(buf->data + buf->size, 1, chunk->size, file) != chunk->size)
return false;
if (fseek(file, sizeof(uint32_t), SEEK_CUR) < 0)
return false;
buf->size += chunk->size;
return true;
}
bool rpng_load_image_rgba(const char *path, uint8_t **data, unsigned *width, unsigned *height)
{
*data = NULL;
*width = 0;
*height = 0;
bool ret = true;
FILE *file = fopen(path, "rb");
if (!file)
return false;
fseek(file, 0, SEEK_END);
long file_len = ftell(file);
rewind(file);
bool has_ihdr = false;
bool has_idat = false;
bool has_iend = false;
uint8_t *inflate_buf = NULL;
size_t inflate_buf_size = 0;
z_stream stream = {0};
struct idat_buffer idat_buf = {0};
struct png_ihdr ihdr = {0};
char header[8];
if (fread(header, 1, sizeof(header), file) != sizeof(header))
GOTO_END_ERROR();
if (memcmp(header, png_magic, sizeof(png_magic)) != 0)
GOTO_END_ERROR();
// feof() apparently isn't triggered after a seek (IEND).
for (long pos = ftell(file); pos < file_len && pos >= 0; pos = ftell(file))
{
struct png_chunk chunk = {0};
if (!read_chunk_header(file, &chunk))
GOTO_END_ERROR();
switch (png_chunk_type(&chunk))
{
case PNG_CHUNK_NOOP:
default:
if (fseek(file, chunk.size + sizeof(uint32_t), SEEK_CUR) < 0)
GOTO_END_ERROR();
break;
case PNG_CHUNK_ERROR:
GOTO_END_ERROR();
case PNG_CHUNK_IHDR:
if (has_ihdr || has_idat || has_iend)
GOTO_END_ERROR();
if (!png_parse_ihdr(file, &chunk, &ihdr))
GOTO_END_ERROR();
has_ihdr = true;
break;
case PNG_CHUNK_IDAT:
if (!has_ihdr || has_iend)
GOTO_END_ERROR();
if (!png_append_idat(file, &chunk, &idat_buf))
GOTO_END_ERROR();
has_idat = true;
break;
case PNG_CHUNK_IEND:
if (!has_ihdr || !has_idat)
GOTO_END_ERROR();
if (fseek(file, sizeof(uint32_t), SEEK_CUR) < 0)
GOTO_END_ERROR();
has_iend = true;
break;
}
}
if (!has_ihdr || !has_idat || !has_iend)
GOTO_END_ERROR();
if (inflateInit(&stream) != Z_OK)
GOTO_END_ERROR();
inflate_buf_size = (ihdr.width + 1) * ihdr.height * sizeof(uint32_t);
inflate_buf = (uint8_t*)malloc(inflate_buf_size);
if (!inflate_buf)
GOTO_END_ERROR();
stream.next_in = idat_buf.data;
stream.avail_in = idat_buf.size;
stream.avail_out = inflate_buf_size;
stream.next_out = inflate_buf;
if (inflate(&stream, Z_FINISH) != Z_STREAM_END)
{
inflateEnd(&stream);
GOTO_END_ERROR();
}
inflateEnd(&stream);
*width = ihdr.width;
*height = ihdr.height;
*data = (uint8_t*)malloc(ihdr.width * ihdr.height * sizeof(uint32_t));
if (!*data)
GOTO_END_ERROR();
if (!png_reverse_filter(*data, &ihdr, inflate_buf, stream.total_out))
GOTO_END_ERROR();
end:
if (file)
fclose(file);
if (!ret)
free(*data);
free(idat_buf.data);
free(inflate_buf);
return ret;
}
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