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metal: implement texture decoder

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This commit is contained in:
Samuliak
2025-03-11 08:11:39 +01:00
parent c59ee99364
commit 3a654b3609
11 changed files with 419 additions and 223 deletions
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58
src/core/renderer_mtl/mtl_texture.cpp
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@@ -99,35 +99,7 @@ namespace Metal {
}
}
// u and v are the UVs of the relevant texel
// Texture data is stored interleaved in Morton order, ie in a Z - order curve as shown here
// https://en.wikipedia.org/wiki/Z-order_curve
// Textures are split into 8x8 tiles.This function returns the in - tile offset depending on the u & v of the texel
// The in - tile offset is the sum of 2 offsets, one depending on the value of u % 8 and the other on the value of y % 8
// As documented in this picture https ://en.wikipedia.org/wiki/File:Moser%E2%80%93de_Bruijn_addition.svg
u32 Texture::mortonInterleave(u32 u, u32 v) {
static constexpr u32 xOffsets[] = {0, 1, 4, 5, 16, 17, 20, 21};
static constexpr u32 yOffsets[] = {0, 2, 8, 10, 32, 34, 40, 42};
return xOffsets[u & 7] + yOffsets[v & 7];
}
// Get the byte offset of texel (u, v) in the texture
u32 Texture::getSwizzledOffset(u32 u, u32 v, u32 width, u32 bytesPerPixel) {
u32 offset = ((u & ~7) * 8) + ((v & ~7) * width); // Offset of the 8x8 tile the texel belongs to
offset += mortonInterleave(u, v); // Add the in-tile offset of the texel
return offset * bytesPerPixel;
}
// Same as the above code except we need to divide by 2 because 4 bits is smaller than a byte
u32 Texture::getSwizzledOffset_4bpp(u32 u, u32 v, u32 width) {
u32 offset = ((u & ~7) * 8) + ((v & ~7) * width); // Offset of the 8x8 tile the texel belongs to
offset += mortonInterleave(u, v); // Add the in-tile offset of the texel
return offset / 2;
}
/*
u8 Texture::decodeTexelU8(u32 u, u32 v, PICA::TextureFmt fmt, std::span<const u8> data) {
switch (fmt) {
case PICA::TextureFmt::A4: {
@@ -331,32 +303,18 @@ namespace Metal {
default: Helpers::panic("[Texture::DecodeTexel] Unimplemented format = %d", static_cast<int>(fmt));
}
}
*/
void Texture::decodeTexture(std::span<const u8> data) {
std::vector<u8> decoded;
decoded.reserve(u64(size.u()) * u64(size.v()) * formatInfo.bytesPerTexel);
// Decode texels line by line
for (u32 v = 0; v < size.v(); v++) {
for (u32 u = 0; u < size.u(); u++) {
if (formatInfo.bytesPerTexel == 1) {
u8 texel = decodeTexelU8(u, v, format, data);
decoded.push_back(texel);
} else if (formatInfo.bytesPerTexel == 2) {
u16 texel = decodeTexelU16(u, v, format, data);
decoded.push_back((texel & 0x00ff) >> 0);
decoded.push_back((texel & 0xff00) >> 8);
} else if (formatInfo.bytesPerTexel == 4) {
u32 texel = decodeTexelU32(u, v, format, data);
decoded.push_back((texel & 0x000000ff) >> 0);
decoded.push_back((texel & 0x0000ff00) >> 8);
decoded.push_back((texel & 0x00ff0000) >> 16);
decoded.push_back((texel & 0xff000000) >> 24);
} else {
Helpers::panic("[Texture::decodeTexture] Unimplemented bytesPerTexel (%u)", formatInfo.bytesPerTexel);
}
}
}
// Decode texels line by line
for (u32 v = 0; v < size.v(); v++) {
for (u32 u = 0; u < size.u(); u++) {
formatInfo.decoder(size, u, v, data, decoded);
}
}
texture->replaceRegion(MTL::Region(0, 0, size.u(), size.v()), 0, 0, decoded.data(), formatInfo.bytesPerTexel * size.u(), 0);
}