ImageLoaderParams LoadMipLevel(const hires_mip_level& item,
const std::function<u8*(size_t, bool)>& bufferdelegate,
bool cacheresult)
{
ImageLoaderParams imgInfo;
imgInfo.releaseresourcesonerror = cacheresult;
imgInfo.dst = nullptr;
imgInfo.Path = item.path.c_str();
imgInfo.request_buffer_delegate = bufferdelegate;
if (item.is_compressed)
{
ReadDDS(imgInfo);
}
else
{
ReadImageFile(imgInfo);
}
return imgInfo;
}
bool Texture::LoadDDS(const std::string & path, const TextureInfo & info, std::ostream & error)
{
std::ifstream file(path.c_str(), std::ifstream::in | std::ifstream::binary);
if (!file)
return false;
// test for dds magic value
char magic[4];
file.read(magic, 4);
if (!IsDDS(magic, 4))
return false;
// get length of file:
file.seekg (0, file.end);
const unsigned long length = file.tellg();
file.seekg (0, file.beg);
// read file into memory
std::vector<char> data(length);
file.read(&data[0], length);
// load dds
const char * texdata(0);
unsigned long texlen(0);
unsigned format(0), width(0), height(0), levels(0);
if (!ReadDDS(
(void*)&data[0], length,
(const void*&)texdata, texlen,
format, width, height, levels))
{
return false;
}
// set properties
m_w = width;
m_h = height;
m_scale = 1.0f;
m_alpha = (format != GL_BGR);
m_cube = false;
// gl3 renderer expects srgb
unsigned iformat = format;
if (info.srgb)
{
if (format == GL_BGR)
iformat = GL_SRGB8;
else if (format == GL_BGRA)
iformat = GL_SRGB8_ALPHA8;
else if (format == GL_COMPRESSED_RGBA_S3TC_DXT1_EXT)
iformat = GL_COMPRESSED_SRGB_ALPHA_S3TC_DXT1_EXT;
else if (format == GL_COMPRESSED_RGBA_S3TC_DXT3_EXT)
iformat = GL_COMPRESSED_SRGB_ALPHA_S3TC_DXT3_EXT;
else if (format == GL_COMPRESSED_RGBA_S3TC_DXT5_EXT)
iformat = GL_COMPRESSED_SRGB_ALPHA_S3TC_DXT5_EXT;
}
// load texture
assert(!m_id);
glGenTextures(1, &m_id);
CheckForOpenGLErrors("Texture ID generation", error);
glBindTexture(GL_TEXTURE_2D, m_id);
SetSampler(info, levels > 1);
const char * idata = texdata;
unsigned blocklen = 16 * texlen / (width * height);
unsigned ilen = texlen;
unsigned iw = width;
unsigned ih = height;
for (unsigned i = 0; i < levels; ++i)
{
if (format == GL_BGR || format == GL_BGRA)
{
// fixme: support compression here?
ilen = iw * ih * blocklen / 16;
glTexImage2D(GL_TEXTURE_2D, i, iformat, iw, ih, 0, format, GL_UNSIGNED_BYTE, idata);
}
else
{
ilen = std::max(1u, iw / 4) * std::max(1u, ih / 4) * blocklen;
glCompressedTexImage2D(GL_TEXTURE_2D, i, iformat, iw, ih, 0, ilen, idata);
}
CheckForOpenGLErrors("Texture creation", error);
idata += ilen;
iw = std::max(1u, iw / 2);
ih = std::max(1u, ih / 2);
}
// force mipmaps for GL3
if (levels == 1)
GenerateMipmap(GL_TEXTURE_2D);
return true;
}