Image.gl_touch - routine to prevent the image to be cleared by blender cache garbage collection system

* if the image is not loaded (bindcode == 0) load the image

This needs to be called often. If the image is 'cleaned' by Blender, it will not help to load it after.
[ gl_load returns the errors: GL_STACK_OVERFLOW(1283) or GL_STACK_UNDERFLOW (1284) ]

Thanks Campbell for the suggestion on how to handle this (BKE_image_tag_time)

1 files changed, 24 insertions, 0 deletions

diff --git a/source/blender/makesrna/intern/rna_image_api.c b/source/blender/makesrna/intern/rna_image_api.c
index 3d937fc561d..cf19002f44e 100644
--- a/source/blender/makesrna/intern/rna_image_api.c
+++ b/source/blender/makesrna/intern/rna_image_api.c
@@ -224,6 +224,19 @@ static int rna_Image_gl_load(Image *image, ReportList *reports, int filter, int
 	return error;
 }
 
+static int rna_Image_gl_touch(Image *image, ReportList *reports, int filter, int mag)
+{
+	unsigned int *bind = &image->bindcode;
+	int error = GL_NO_ERROR;
+
+	BKE_image_tag_time(image);
+
+	if (*bind == 0)
+		error = rna_Image_gl_load(image, reports, GL_LINEAR_MIPMAP_NEAREST, GL_LINEAR);
+
+	return error;
+}
+
 static void rna_Image_gl_free(Image *image)
 {
 	GPU_free_image(image);
@@ -274,6 +287,17 @@ void RNA_api_image(StructRNA *srna)
 	parm = RNA_def_int(func, "height", 0, 1, 10000, "", "Height", 1, 10000);
 	RNA_def_property_flag(parm, PROP_REQUIRED);
 
+	func = RNA_def_function(srna, "gl_touch", "rna_Image_gl_touch");
+	RNA_def_function_ui_description(func, "Delay the image from being cleaned from the cache due inactivity");
+	RNA_def_function_flag(func, FUNC_USE_REPORTS);
+	RNA_def_int(func, "filter", GL_LINEAR_MIPMAP_NEAREST, -INT_MAX, INT_MAX, "Filter",
+	            "The texture minifying function to use if the image wan't loaded", -INT_MAX, INT_MAX);
+	RNA_def_int(func, "mag", GL_LINEAR, -INT_MAX, INT_MAX, "Magnification",
+	            "The texture magnification function to use if the image wan't loaded", -INT_MAX, INT_MAX);
+	/* return value */
+	parm = RNA_def_int(func, "error", 0, -INT_MAX, INT_MAX, "Error", "OpenGL error value", -INT_MAX, INT_MAX);
+	RNA_def_function_return(func, parm);
+
 	func = RNA_def_function(srna, "gl_load", "rna_Image_gl_load");
 	RNA_def_function_ui_description(func, "Load the image into OpenGL graphics memory");
 	RNA_def_function_flag(func, FUNC_USE_REPORTS);