Eevee: Transparency: Add Alpha Blend mode.

source/blender/draw/engines/eevee/eevee_materials.c

@@ -876,6 +876,9 @@ static void material_transparent(
 		case MA_BM_MULTIPLY:
 			cur_state |= DRW_STATE_MULTIPLY;
 			break;
+		case MA_BM_BLEND:
+			cur_state |= DRW_STATE_BLEND;
+			break;
 		default:
 			BLI_assert(0);
 			break;
@@ -940,9 +943,13 @@ void EEVEE_materials_cache_populate(EEVEE_Data *vedata, EEVEE_SceneLayerData *sl
 					break;
 				case MA_BM_ADD:
 				case MA_BM_MULTIPLY:
+				case MA_BM_BLEND:
 					material_transparent(ma, sldata, vedata, do_cull, use_flat_nor,
 					        &gpumat_array[i], &shgrp_array[i]);
 					break;
+				default:
+					BLI_assert(0);
+					break;
 			}
 		}
 

source/blender/makesdna/DNA_material_types.h

@@ -502,6 +502,7 @@ enum {
 	MA_BM_MULTIPLY,
 	MA_BM_CLIP,
 	MA_BM_HASHED,
+	MA_BM_BLEND,
 };
 
 #endif

source/blender/makesrna/intern/rna_material.c

@@ -1811,6 +1811,7 @@ void RNA_def_material(BlenderRNA *brna)
 		{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)"},
+		{MA_BM_BLEND, "BLEND", 0, "Alpha Blend", "Render polygon transparent, depending on alpha channel of the texture"},
 		{0, NULL, 0, NULL, NULL}
 	};