FlipY texture flag, display world texture atlas

internal/igwrap/imagewrap.go

@@ -38,6 +38,7 @@ func ImageV(tex uint32, size itype.Vec2f, texRange itype.Rectf, texColor itype.V
 	)
 }
 
+// Per-texture flags. This is passed to the shader as-is and handled only there.
 type TextureFlag int
 
 const (
@@ -48,6 +49,7 @@ const (
 
 	TextureFlag_Linear    // Linear source data, requires gamma correction.
 	TextureFlag_ImGUIFont // This is a font texture from ImGUI, with a single red channel.
+	TextureFlag_FlipY     // The render should flip the Y axis of the texture. By default ImageXXX()s render textures with (0,0) at the bottom left, and this is for in case you want to flip them.
 
 	TextureFlag_RGB  = TextureFlag_Red | TextureFlag_Green | TextureFlag_Blue
 	TextureFlag_RGBA = TextureFlag_Red | TextureFlag_Green | TextureFlag_Blue | TextureFlag_Alpha
@@ -70,6 +72,18 @@ func SetTextureFlag(tex uint32, flags ...TextureFlag) {
 	texflags[tex] = f
 }
 
+// AddTextureFlag adds the given flags to the texture.
+func AddTextureFlag(tex uint32, flags ...TextureFlag) {
+	var f TextureFlag
+	for _, f0 := range flags {
+		f |= f0
+	}
+
+	texflagslock.Lock()
+	defer texflagslock.Unlock()
+	texflags[tex] |= f
+}
+
 // TextureFlag returns the flags of a given texture.
 func GetTextureFlag(tex uint32) TextureFlag {
 	texflagslock.RLock()