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Merged
merged 2 commits into from
May 19, 2025
Merged

Image: Fix detecting color channels #106486

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92cfd2b
Expand the imported texture channel count for remapping if necessary
BlueCube3310 May 15, 2025
0f99864
Image: Fix detecting color channels
BlueCube3310 May 16, 2025
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28 changes: 17 additions & 11 deletions core/io/image.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -3464,18 +3464,24 @@ Image::UsedChannels Image::detect_used_channels(CompressSource p_source) const {

UsedChannels used_channels;

if (!c && !a) {
used_channels = USED_CHANNELS_L;
} else if (!c && a) {
used_channels = USED_CHANNELS_LA;
} else if (r && !g && !b && !a) {
used_channels = USED_CHANNELS_R;
} else if (r && g && !b && !a) {
used_channels = USED_CHANNELS_RG;
} else if (r && g && b && !a) {
used_channels = USED_CHANNELS_RGB;
if (!c) {
// Uniform RGB (grayscale).
if (a) {
used_channels = USED_CHANNELS_LA;
} else {
used_channels = USED_CHANNELS_L;
}
} else {
used_channels = USED_CHANNELS_RGBA;
// Colored image.
if (a) {
used_channels = USED_CHANNELS_RGBA;
} else if (b) {
used_channels = USED_CHANNELS_RGB;
} else if (g) {
used_channels = USED_CHANNELS_RG;
} else {
used_channels = USED_CHANNELS_R;
}
}

if (p_source == COMPRESS_SOURCE_SRGB && (used_channels == USED_CHANNELS_R || used_channels == USED_CHANNELS_RG)) {
Expand Down
127 changes: 120 additions & 7 deletions editor/import/resource_importer_texture.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -448,8 +448,10 @@ Dictionary ResourceImporterTexture::_load_editor_meta(const String &p_path) cons
}

void ResourceImporterTexture::_remap_channels(Ref<Image> &r_image, ChannelRemap p_options[4]) {
bool attempted_hdr_inverted = false;
ERR_FAIL_COND(r_image->is_compressed());

// Currently HDR inverted remapping is not allowed.
bool attempted_hdr_inverted = false;
if (r_image->get_format() >= Image::FORMAT_RF && r_image->get_format() <= Image::FORMAT_RGBE9995) {
// Formats which can hold HDR data cannot be inverted the same way as unsigned normalized ones (1.0 - channel).
for (int i = 0; i < 4; i++) {
Expand Down Expand Up @@ -480,11 +482,127 @@ void ResourceImporterTexture::_remap_channels(Ref<Image> &r_image, ChannelRemap
WARN_PRINT("Attempted to use an inverted channel remap on an HDR image. The remap has been changed to its uninverted equivalent.");
}

if (p_options[0] == REMAP_R && p_options[1] == REMAP_G && p_options[2] == REMAP_B && p_options[3] == REMAP_A) {
// Optimization: Set the remap from 'unused' to either 0 or 1 to avoid repeated checks in the conversion loop.
for (int i = 0; i < 4; i++) {
if (p_options[i] == REMAP_UNUSED) {
p_options[i] = i == 3 ? REMAP_1 : REMAP_0;
}
}

// Expand the image's channel count in the event that the current set of channels doesn't allow for the desired remap.
const Image::Format original_format = r_image->get_format();
const uint32_t channel_mask = Image::get_format_component_mask(original_format);

// Whether a channel is supported by the format itself.
const bool has_channel_r = channel_mask & 0x1;
const bool has_channel_g = channel_mask & 0x2;
const bool has_channel_b = channel_mask & 0x4;
const bool has_channel_a = channel_mask & 0x8;

// Whether a certain channel needs to be remapped.
const bool remap_r = p_options[0] != REMAP_R ? !(!has_channel_r && p_options[0] == REMAP_0) : false;
const bool remap_g = p_options[1] != REMAP_G ? !(!has_channel_g && p_options[1] == REMAP_0) : false;
const bool remap_b = p_options[2] != REMAP_B ? !(!has_channel_b && p_options[2] == REMAP_0) : false;
const bool remap_a = p_options[3] != REMAP_A ? !(!has_channel_a && p_options[3] == REMAP_1) : false;

if (!(remap_r || remap_g || remap_b || remap_a)) {
// Default color map, do nothing.
return;
}

// Whether a certain channel set is needed, either from the source or the remap.
const bool needs_rg = remap_g || has_channel_g;
const bool needs_rgb = remap_b || has_channel_b;
const bool needs_rgba = remap_a || has_channel_a;

bool could_not_expand = false;
switch (original_format) {
case Image::FORMAT_R8:
case Image::FORMAT_RG8:
case Image::FORMAT_RGB8: {
// Convert to either RGBA8, RGB8 or RG8.
if (needs_rgba) {
r_image->convert(Image::FORMAT_RGBA8);
} else if (needs_rgb) {
r_image->convert(Image::FORMAT_RGB8);
} else if (needs_rg) {
r_image->convert(Image::FORMAT_RG8);
}
} break;
case Image::FORMAT_RH:
case Image::FORMAT_RGH:
case Image::FORMAT_RGBH: {
// Convert to either RGBAH, RGBH or RGH.
if (needs_rgba) {
r_image->convert(Image::FORMAT_RGBAH);
} else if (needs_rgb) {
r_image->convert(Image::FORMAT_RGBH);
} else if (needs_rg) {
r_image->convert(Image::FORMAT_RGH);
}
} break;
case Image::FORMAT_RF:
case Image::FORMAT_RGF:
case Image::FORMAT_RGBF: {
// Convert to either RGBAF, RGBF or RGF.
if (needs_rgba) {
r_image->convert(Image::FORMAT_RGBAF);
} else if (needs_rgb) {
r_image->convert(Image::FORMAT_RGBF);
} else if (needs_rg) {
r_image->convert(Image::FORMAT_RGF);
}
} break;
case Image::FORMAT_L8: {
const bool uniform_rgb = (p_options[0] == p_options[1] && p_options[1] == p_options[2]) || !(remap_r || remap_g || remap_b);
if (uniform_rgb) {
// Uniform RGB.
if (needs_rgba) {
r_image->convert(Image::FORMAT_LA8);
}
} else {
// Non-uniform RGB.
if (needs_rgba) {
r_image->convert(Image::FORMAT_RGBA8);
} else {
r_image->convert(Image::FORMAT_RGB8);
}
could_not_expand = true;
}
} break;
case Image::FORMAT_LA8: {
const bool uniform_rgb = (p_options[0] == p_options[1] && p_options[1] == p_options[2]) || !(remap_r || remap_g || remap_b);
if (!uniform_rgb) {
// Non-uniform RGB.
r_image->convert(Image::FORMAT_RGBA8);
could_not_expand = true;
}
} break;
case Image::FORMAT_RGB565: {
if (needs_rgba) {
// RGB565 doesn't have an alpha expansion, convert to RGBA8.
r_image->convert(Image::FORMAT_RGBA8);
could_not_expand = true;
}
} break;
case Image::FORMAT_RGBE9995: {
if (needs_rgba) {
// RGB9995 doesn't have an alpha expansion, convert to RGBAH.
r_image->convert(Image::FORMAT_RGBAH);
could_not_expand = true;
}
} break;

default: {
} break;
}

if (could_not_expand) {
WARN_PRINT(vformat("Unable to expand image format %s's channels (the target format does not exist), converting to %s as a fallback.",
Image::get_format_name(original_format), Image::get_format_name(r_image->get_format())));
}

// Remap the channels.
for (int x = 0; x < r_image->get_width(); x++) {
for (int y = 0; y < r_image->get_height(); y++) {
Color src = r_image->get_pixel(x, y);
Expand Down Expand Up @@ -518,11 +636,6 @@ void ResourceImporterTexture::_remap_channels(Ref<Image> &r_image, ChannelRemap
dst[i] = 1.0f - src.a;
break;

case REMAP_UNUSED:
// For Alpha the unused value is 1, for other channels it's 0.
dst[i] = (i == 3) ? 1.0f : 0.0f;
break;

case REMAP_0:
dst[i] = 0.0f;
break;
Expand Down