#5448: Add (currently failing) test case loading an 8-Bit Greyscale P…

…NG with alpha channel

test/ImageLoading.cpp

@@ -1,6 +1,7 @@
 #include "RadiantTest.h"
 
 #include "iimage.h"
+#include "RGBAImage.h"
 
 namespace test
 {
@@ -25,4 +26,35 @@ TEST_F(ImageLoadingTest, LoadPng16Bit)
     EXPECT_EQ(img->getHeight(), 32);
 }
 
+TEST_F(ImageLoadingTest, LoadPngGreyscaleWithAlpha)
+{
+    // This is a 8-Bit Greyscale PNG with Alpha channel, so pixel depth is 16 bits
+    auto filePath = _context.getTestProjectPath() + "textures/pngs/transparent_greyscale.png";
+    auto img = GlobalImageLoader().imageFromFile(filePath);
+
+    EXPECT_EQ(img->getWidth(), 32);
+    EXPECT_EQ(img->getHeight(), 32);
+    EXPECT_FALSE(img->isPrecompressed());
+
+    // If the image loader interprets the file correctly, we should have an RGBA
+    // image with the colour values being the same for R, G and B.
+    // If the image loader didn't convert grey to RGB, the grey value is 
+    // smeared across the whole RGB channels and they are not uniform
+
+    EXPECT_TRUE(std::dynamic_pointer_cast<RGBAImage>(img));
+    auto pixels = reinterpret_cast<RGBAPixel*>(img->getPixels());
+
+    auto numPixels = img->getWidth() * img->getHeight();
+    for (auto i = 0; i < numPixels; ++i)
+    {
+        EXPECT_EQ(pixels[i].blue, pixels[i].green) << "Expected Green == Blue";
+        EXPECT_EQ(pixels[i].red, pixels[i].green) << "Expected Red == Blue";
+
+        if (pixels[i].blue != pixels[i].green || pixels[i].red != pixels[i].green)
+        {
+            break;
+        }
+    }
+}
+
 }

test/resources/tdm/materials/pngs.mtr

@@ -7,3 +7,20 @@ textures/pngs/twentyone_16bit
 {
     diffusemap textures/pngs/twentyone_16bit
 }
+
+textures/pngs/transparent_greyscale
+{	
+	DECAL_MACRO
+	noShadows
+	nonsolid
+	noimpact
+	translucent
+
+	qer_editorimage textures/pngs/transparent_greyscale
+	description "256 x 256"
+
+	{       
+		blend 	gl_src_alpha, gl_one_minus_src_alpha
+		map		textures/pngs/transparent_greyscale
+	}
+}