vtfpp: change default compression quality so dxt1-5, ati1n, ati2n are max quality by default

Author: craftablescience

include/vtfpp/ImageConversion.h

@@ -324,7 +324,10 @@ concept PixelType =
 
 namespace ImageConversion {
 
-constexpr float DEFAULT_COMPRESSED_QUALITY = 0.105f;
+// Negative means use default quality
+// BC7, BC6H: 0.1
+// Everything else: 1.0
+constexpr float DEFAULT_COMPRESSED_QUALITY = -1.f;
 
 /// Converts an image from one format to another.
 [[nodiscard]] std::vector<std::byte> convertImageDataToFormat(std::span<const std::byte> imageData, ImageFormat oldFormat, ImageFormat newFormat, uint16_t width, uint16_t height, float quality = DEFAULT_COMPRESSED_QUALITY);

src/vtfpp/ImageConversion.cpp

@@ -317,8 +317,14 @@ namespace {
 	destTexture.pData = reinterpret_cast<CMP_BYTE*>(destData.data());
 
 	CMP_CompressOptions options{};
-	options.dwSize        = sizeof(options);
-	options.fquality      = std::clamp(quality, 0.f, 1.f);
+	options.dwSize = sizeof(options);
+	if (quality >= 0.f) {
+		options.fquality  = std::min(quality, 1.f);
+	} else if (oldFormat == ImageFormat::BC7 || newFormat == ImageFormat::BC7 || oldFormat == ImageFormat::BC6H || newFormat == ImageFormat::BC6H) {
+		options.fquality = 0.1f;
+	} else {
+		options.fquality = 1.f;
+	}
 	options.bDXT1UseAlpha = oldFormat == ImageFormat::DXT1_ONE_BIT_ALPHA || newFormat == ImageFormat::DXT1_ONE_BIT_ALPHA;
 	if (options.bDXT1UseAlpha) {
 		options.nAlphaThreshold = 128;