LibGL: Fix interpretation of BGRA byte order

This fixes byte order interpretation in several places.

Userland/Applications/3DFileViewer/main.cpp

@@ -225,7 +225,7 @@ bool GLContextWidget::load(const String& filename)
     if (texture_image) {
         // Upload texture data to the GL
         glBindTexture(GL_TEXTURE_2D, tex);
-        glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, texture_image->width(), texture_image->height(), 0, GL_RGBA, GL_UNSIGNED_BYTE, texture_image->scanline(0));
+        glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, texture_image->width(), texture_image->height(), 0, GL_BGRA, GL_UNSIGNED_BYTE, texture_image->scanline(0));
     } else {
         dbgln("3DFileViewer: Couldn't load texture for {}", filename);
     }

Userland/Libraries/LibGL/SoftwareRasterizer.cpp

@@ -35,15 +35,15 @@ static Gfx::RGBA32 to_rgba32(const FloatVector4& v)
     u8 g = clamped.y() * 255;
     u8 b = clamped.z() * 255;
     u8 a = clamped.w() * 255;
-    return a << 24 | b << 16 | g << 8 | r;
+    return a << 24 | r << 16 | g << 8 | b;
 }
 
 static FloatVector4 to_vec4(Gfx::RGBA32 rgba)
 {
     return {
-        (rgba & 0xff) / 255.0f,
-        ((rgba >> 8) & 0xff) / 255.0f,
         ((rgba >> 16) & 0xff) / 255.0f,
+        ((rgba >> 8) & 0xff) / 255.0f,
+        (rgba & 0xff) / 255.0f,
         ((rgba >> 24) & 0xff) / 255.0f
     };
 }

Userland/Libraries/LibGL/Tex/MipMap.h

@@ -34,9 +34,9 @@ public:
         u32 texel = m_pixel_data.at(y * m_width + x);
 
         return {
-            (texel & 0xff) / 255.f,
-            ((texel >> 8) & 0xff) / 255.f,
             ((texel >> 16) & 0xff) / 255.f,
+            ((texel >> 8) & 0xff) / 255.f,
+            (texel & 0xff) / 255.f,
             ((texel >> 24) & 0xff) / 255.f
         };
     }

Userland/Libraries/LibGL/Tex/Texture2D.cpp

@@ -31,81 +31,48 @@ void Texture2D::upload_texture_data(GLenum, GLint lod, GLint internal_format, GL
     auto& mip = m_mipmaps[lod];
     const u8* pixel_byte_array = reinterpret_cast<const u8*>(pixels);
 
-    // Copy pixel data to storage
-
-    // Pixels are already 32-bits wide
-    if (format == GL_RGBA || format == GL_BGRA) {
-        mip.pixel_data().resize(width * height * sizeof(u32));
-        memcpy(mip.pixel_data().data(), pixels, width * height * sizeof(u32));
-    } else {
-        mip.pixel_data().resize(width * height * 3);
-        // Copy RGB or BGR pixel data
-        for (auto i = 0; i < width * height * 3; i += 3) {
-            u32 b0 = pixel_byte_array[i];     // B or R
-            u32 b1 = pixel_byte_array[i + 1]; // G
-            u32 b2 = pixel_byte_array[i + 2]; // R or B
-
-            u32 pixel = ((0xffu << 24) | (b0 << 16) | (b1 << 8) | b2);
+    mip.pixel_data().clear();
+    if (format == GL_RGBA) {
+        for (auto i = 0; i < width * height * 4; i += 4) {
+            u32 r = pixel_byte_array[i + 0];
+            u32 g = pixel_byte_array[i + 1];
+            u32 b = pixel_byte_array[i + 2];
+            u32 a = pixel_byte_array[i + 3];
+
+            u32 pixel = ((a << 24) | (r << 16) | (g << 8) | b);
             mip.pixel_data().append(pixel);
         }
-    }
-
-    // Now we need to swizzle the texture data from `format` to `internal_format`
-    switch (format) {
-    case GL_BGR: {
-        if (internal_format == GL_RGB) {
-            swizzle(mip.pixel_data(), [](u32 pixel) -> u32 {
-                u8 r = pixel & 0xff;
-                u8 g = (pixel >> 8) & 0xff;
-                u8 b = (pixel >> 16) & 0xff;
-
-                return (0xff << 24) | (r << 16) | (g << 8) | b;
-            });
-        } else if (internal_format == GL_RGBA) {
-            swizzle(mip.pixel_data(), [](u32 pixel) -> u32 {
-                u8 r = pixel & 0xff;
-                u8 g = (pixel >> 8) & 0xff;
-                u8 b = (pixel >> 16) & 0xff;
-
-                return (r << 24) | (g << 16) | (b << 8) | 0xff;
-            });
+    } else if (format == GL_BGRA) {
+        for (auto i = 0; i < width * height * 4; i += 4) {
+            u32 b = pixel_byte_array[i + 0];
+            u32 g = pixel_byte_array[i + 1];
+            u32 r = pixel_byte_array[i + 2];
+            u32 a = pixel_byte_array[i + 3];
+
+            u32 pixel = ((a << 24) | (r << 16) | (g << 8) | b);
+            mip.pixel_data().append(pixel);
         }
-    } break;
-    case GL_BGRA: {
-        if (internal_format == GL_RGB) {
-            swizzle(mip.pixel_data(), [](u32 pixel) -> u32 {
-                u8 r = (pixel >> 8) & 0xff;
-                u8 g = (pixel >> 16) & 0xff;
-                u8 b = (pixel >> 24) & 0xff;
-
-                return (0xff << 24) | (r << 16) | (g << 8) | b;
-            });
-        } else if (internal_format == GL_RGBA) {
-            swizzle(mip.pixel_data(), [](u32 pixel) -> u32 {
-                u8 a = pixel & 0xff;
-                u8 r = (pixel >> 8) & 0xff;
-                u8 g = (pixel >> 16) & 0xff;
-                u8 b = (pixel >> 24) & 0xff;
+    } else if (format == GL_BGR) {
+        for (auto i = 0; i < width * height * 3; i += 3) {
+            u32 b = pixel_byte_array[i + 0];
+            u32 g = pixel_byte_array[i + 1];
+            u32 r = pixel_byte_array[i + 2];
+            u32 a = 255;
 
-                return (r << 24) | (g << 16) | (b << 8) | a;
-            });
+            u32 pixel = ((a << 24) | (r << 16) | (g << 8) | b);
+            mip.pixel_data().append(pixel);
         }
-    } break;
-    case GL_RGB: {
-        if (internal_format == GL_RGBA) {
-            swizzle(mip.pixel_data(), [](u32 pixel) -> u32 {
-                u8 r = pixel & 0xff;
-                u8 g = (pixel >> 8) & 0xff;
-                u8 b = (pixel >> 16) & 0xff;
+    } else if (format == GL_RGB) {
+        for (auto i = 0; i < width * height * 3; i += 3) {
+            u32 r = pixel_byte_array[i + 0];
+            u32 g = pixel_byte_array[i + 1];
+            u32 b = pixel_byte_array[i + 2];
+            u32 a = 255;
 
-                return (r << 24) | (g << 16) | (b << 8) | 0xff;
-            });
+            u32 pixel = ((a << 24) | (r << 16) | (g << 8) | b);
+            mip.pixel_data().append(pixel);
         }
-    } break;
-    case GL_RGBA:
-        break;
-    default:
-        // Let's crash for now so we can implement format by format
+    } else {
         VERIFY_NOT_REACHED();
     }