Saving Bandwidth and Memory with WebGL and Crunch - HTML5 Game Development Insights - page 339

extern "C" {
unsigned int crn_get_width(void *src, unsigned int src_size);
unsigned int crn_get_height(void *src, unsigned int src_size);
unsigned int crn_get_levels(void *src, unsigned int src_size);
unsigned int crn_get_dxt_format(void *src, unsigned int src_size);
unsigned int crn_get_bytes_per_block(void *src, unsigned int src_size);
unsigned int crn_get_uncompressed_size(void *p, unsigned int size, unsigned int level);
void crn_decompress(void *src, unsigned int src_size, void *dst, unsigned int dst_size,
unsigned int firstLevel, unsigned int levelCount);
}
unsigned int crn_get_width(void *src, unsigned int src_size) {
crnd::crn_texture_info tex_info;
crnd::crnd_get_texture_info(static_cast<crn_uint8*>(src), src_size, &tex_info);
return tex_info.m_width;
}
unsigned int crn_get_height(void *src, unsigned int src_size) {
crnd::crn_texture_info tex_info;
crnd::crnd_get_texture_info(static_cast<crn_uint8*>(src), src_size, &tex_info);
return tex_info.m_height;
}
unsigned int crn_get_levels(void *src, unsigned int src_size) {
crnd::crn_texture_info tex_info;
crnd::crnd_get_texture_info(static_cast<crn_uint8*>(src), src_size, &tex_info);
return tex_info.m_levels;
}
unsigned int crn_get_dxt_format(void *src, unsigned int src_size) {
crnd::crn_texture_info tex_info;
crnd::crnd_get_texture_info(static_cast<crn_uint8*>(src), src_size, &tex_info);
return tex_info.m_format;
}
unsigned int crn_get_bytes_per_block(void *src, unsigned int src_size) {
crnd::crn_texture_info tex_info;
crnd::crnd_get_texture_info(static_cast<crn_uint8*>(src), src_size, &tex_info);
return crnd::crnd_get_bytes_per_dxt_block(tex_info.m_format);
}
unsigned int crn_get_uncompressed_size(void *src, unsigned int src_size, unsigned int level) {
crnd::crn_texture_info tex_info;
crnd::crnd_get_texture_info(static_cast<crn_uint8*>(src), src_size, &tex_info);
const crn_uint32 width = tex_info.m_width >> level;
const crn_uint32 height = tex_info.m_height >> level;
const crn_uint32 blocks_x = (width + 3) >> 2;
const crn_uint32 blocks_y = (height + 3) >> 2;
const crn_uint32 row_pitch = blocks_x * crnd::crnd_get_bytes_per_dxt_block(tex_info.m_format);
const crn_uint32 total_face_size = row_pitch * blocks_y;
return total_face_size;
}