Eevee: Add support for Alpha clip and Hashed Alpha transparency.

Hashed Alpha transparency offers a noisy output but has the benefit of being correctly ordered. Noise can be attenuated with Multisampling / AntiAliasing.

1 files changed, 21 insertions, 1 deletions

diff --git a/source/blender/makesrna/intern/rna_material.c b/source/blender/makesrna/intern/rna_material.c
index e60832d86e6..a3c1ae7378e 100644
--- a/source/blender/makesrna/intern/rna_material.c
+++ b/source/blender/makesrna/intern/rna_material.c
@@ -1805,6 +1805,15 @@ void RNA_def_material(BlenderRNA *brna)
 		{0, NULL, 0, NULL, NULL}
 	};
 
+	static EnumPropertyItem prop_eevee_blend_items[] = {
+		{MA_BM_SOLID, "OPAQUE", 0, "Opaque", "Render surface without transparency"},
+		// {MA_BM_ADD, "ADD", 0, "Additive", "Render surface and blend the result with additive blending"},
+		// {MA_BM_MULTIPLY, "MULTIPLY", 0, "Multiply", "Render surface and blend the result with multiplicative blending"},
+		{MA_BM_CLIP, "CLIP", 0, "Alpha Clip", "Use the alpha threshold to clip the visibility (binary visibility)"},
+		{MA_BM_HASHED, "HASHED", 0, "Alpha Hashed", "Use noise to dither the binary visibility (works well with multi-samples)"},
+		{0, NULL, 0, NULL, NULL}
+	};
+
 	srna = RNA_def_struct(brna, "Material", "ID");
 	RNA_def_struct_ui_text(srna, "Material",
 	                       "Material data-block to define the appearance of geometric objects for rendering");
@@ -1827,7 +1836,18 @@ void RNA_def_material(BlenderRNA *brna)
 	RNA_def_property_enum_items(prop, transparency_items);
 	RNA_def_property_ui_text(prop, "Transparency Method", "Method to use for rendering transparency");
 	RNA_def_property_update(prop, 0, "rna_Material_update");
-	
+
+	/* Blending (only Eevee for now) */
+	prop = RNA_def_property(srna, "blend_method", PROP_ENUM, PROP_NONE);
+	RNA_def_property_enum_items(prop, prop_eevee_blend_items);
+	RNA_def_property_ui_text(prop, "Blend Mode", "Blend Mode for Transparent Faces");
+	RNA_def_property_update(prop, 0, "rna_Material_draw_update");
+
+	prop = RNA_def_property(srna, "alpha_threshold", PROP_FLOAT, PROP_FACTOR);
+	RNA_def_property_range(prop, 0, 1);
+	RNA_def_property_ui_text(prop, "Clip Threshold", "A pixel is rendered only if its alpha value is above this threshold");
+	RNA_def_property_update(prop, 0, "rna_Material_update");
+
 	/* For Preview Render */
 	prop = RNA_def_property(srna, "preview_render_type", PROP_ENUM, PROP_NONE);
 	RNA_def_property_enum_sdna(prop, NULL, "pr_type");