add blended triangle_2d drawing operations for IndexedBitmaps

ggdt/src/graphics/bitmap/indexed/triangles.rs

@@ -1,5 +1,6 @@
 use crate::graphics::bitmap::indexed::IndexedBitmap;
 use crate::graphics::bitmap::triangles::{edge_function, per_pixel_triangle_2d};
+use crate::graphics::blendmap::BlendMap;
 use crate::math::vector2::Vector2;
 
 #[derive(Debug, Clone, PartialEq)]
@@ -8,11 +9,22 @@ pub enum IndexedTriangle2d<'a> {
 		position: [Vector2; 3], //
 		color: u8,
 	},
+	SolidBlended {
+		position: [Vector2; 3], //
+		color: u8,
+		blendmap: &'a BlendMap,
+	},
 	SolidTextured {
 		position: [Vector2; 3], //
 		texcoord: [Vector2; 3],
 		bitmap: &'a IndexedBitmap,
 	},
+	SolidTexturedBlended {
+		position: [Vector2; 3], //
+		texcoord: [Vector2; 3],
+		bitmap: &'a IndexedBitmap,
+		blendmap: &'a BlendMap,
+	},
 }
 
 impl IndexedBitmap {
@@ -28,6 +40,18 @@ impl IndexedBitmap {
 					|dest_pixels, _w0, _w1, _w2| *dest_pixels = *color,
 				)
 			}
+			SolidBlended { position, color, blendmap } => {
+				per_pixel_triangle_2d(
+					self, //
+					position[0],
+					position[1],
+					position[2],
+					|dest_pixels, _w0, _w1, _w2| {
+						*dest_pixels =
+							if let Some(blended) = blendmap.blend(*color, *dest_pixels) { blended } else { *color };
+					},
+				)
+			}
 			SolidTextured { position, texcoord, bitmap } => {
 				let inverse_area = 1.0 / edge_function(position[0], position[1], position[2]);
 				per_pixel_triangle_2d(
@@ -42,6 +66,22 @@ impl IndexedBitmap {
 					},
 				)
 			}
+			SolidTexturedBlended { position, texcoord, bitmap, blendmap } => {
+				let inverse_area = 1.0 / edge_function(position[0], position[1], position[2]);
+				per_pixel_triangle_2d(
+					self, //
+					position[0],
+					position[1],
+					position[2],
+					|dest_pixels, w0, w1, w2| {
+						let u = (w0 * texcoord[0].x + w1 * texcoord[1].x + w2 * texcoord[2].x) * inverse_area;
+						let v = (w0 * texcoord[0].y + w1 * texcoord[1].y + w2 * texcoord[2].y) * inverse_area;
+						let texel = bitmap.sample_at(u, v);
+						*dest_pixels =
+							if let Some(blended) = blendmap.blend(texel, *dest_pixels) { blended } else { texel };
+					},
+				)
+			}
 		}
 	}