1 files changed, 68 insertions, 0 deletions
diff --git a/packages/frontend/src/utility/image-compositor-functions/pixelate.glsl b/packages/frontend/src/utility/image-compositor-functions/pixelate.glsl
new file mode 100644
index 0000000000..4de3f27397
--- /dev/null
+++ b/packages/frontend/src/utility/image-compositor-functions/pixelate.glsl
@@ -0,0 +1,68 @@
+#version 300 es
+precision mediump float;
+
+/*
+ * SPDX-FileCopyrightText: syuilo and misskey-project
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+
+const float PI = 3.141592653589793;
+const float TWO_PI = 6.283185307179586;
+const float HALF_PI = 1.5707963267948966;
+
+in vec2 in_uv;
+uniform sampler2D in_texture;
+uniform vec2 in_resolution;
+uniform vec2 u_offset;
+uniform vec2 u_scale;
+uniform bool u_ellipse;
+uniform float u_angle;
+uniform int u_samples;
+uniform float u_strength;
+out vec4 out_color;
+
+// TODO: pixelateの中心を画像中心ではなく範囲の中心にする
+// TODO: 画像のアスペクト比に関わらず各画素は正方形にする
+
+void main() {
+	if (u_strength <= 0.0) {
+		out_color = texture(in_texture, in_uv);
+		return;
+	}
+
+	float angle = -(u_angle * PI);
+	vec2 centeredUv = in_uv - vec2(0.5, 0.5) - u_offset;
+	vec2 rotatedUV = vec2(
+		centeredUv.x * cos(angle) - centeredUv.y * sin(angle),
+		centeredUv.x * sin(angle) + centeredUv.y * cos(angle)
+	) + u_offset;
+
+	bool isInside = false;
+	if (u_ellipse) {
+		vec2 norm = (rotatedUV - u_offset) / u_scale;
+		isInside = dot(norm, norm) <= 1.0;
+	} else {
+		isInside = rotatedUV.x > u_offset.x - u_scale.x && rotatedUV.x < u_offset.x + u_scale.x && rotatedUV.y > u_offset.y - u_scale.y && rotatedUV.y < u_offset.y + u_scale.y;
+	}
+
+	if (!isInside) {
+		out_color = texture(in_texture, in_uv);
+		return;
+	}
+
+	float dx = u_strength / 1.0;
+	float dy = u_strength / 1.0;
+	vec2 new_uv = vec2(
+		(dx * (floor((in_uv.x - 0.5 - (dx / 2.0)) / dx) + 0.5)),
+		(dy * (floor((in_uv.y - 0.5 - (dy / 2.0)) / dy) + 0.5))
+	) + vec2(0.5 + (dx / 2.0), 0.5 + (dy / 2.0));
+
+	vec4 result = vec4(0.0);
+	float totalSamples = 0.0;
+
+	// TODO: より多くのサンプリング
+	result += texture(in_texture, new_uv);
+	totalSamples += 1.0;
+
+	out_color = totalSamples > 0.0 ? result / totalSamples : texture(in_texture, in_uv);
+}