Feature: add filter of color invert

CameraFilter/src/main/java/com/frank/camerafilter/factory/BeautyFilterFactory.java

@@ -3,6 +3,7 @@ package com.frank.camerafilter.factory;
 import android.content.Context;
 
 import com.frank.camerafilter.filter.advance.BeautyBlurFilter;
+import com.frank.camerafilter.filter.advance.BeautyColorInvertFilter;
 import com.frank.camerafilter.filter.advance.BeautyHueFilter;
 import com.frank.camerafilter.filter.advance.BeautySketchFilter;
 import com.frank.camerafilter.filter.BaseFilter;
@@ -19,6 +20,8 @@ public class BeautyFilterFactory {
                 return new BeautySketchFilter(context);
             case BLUR:
                 return new BeautyBlurFilter(context);
+            case COLOR_INVERT:
+                return new BeautyColorInvertFilter(context);
             case HUE:
                 return new BeautyHueFilter(context);
             case WHITE_BALANCE:

CameraFilter/src/main/java/com/frank/camerafilter/factory/BeautyFilterType.java

@@ -3,6 +3,7 @@ package com.frank.camerafilter.factory;
 public enum BeautyFilterType {
     NONE,
     BLUR,
+    COLOR_INVERT,
     HUE,
     WHITE_BALANCE,
     SKETCH

CameraFilter/src/main/java/com/frank/camerafilter/filter/advance/BeautyColorInvertFilter.java

@@ -0,0 +1,29 @@
+package com.frank.camerafilter.filter.advance;
+
+import android.content.Context;
+import android.opengl.GLES30;
+
+import com.frank.camerafilter.R;
+import com.frank.camerafilter.filter.BaseFilter;
+import com.frank.camerafilter.util.OpenGLUtil;
+
+public class BeautyColorInvertFilter extends BaseFilter {
+
+    public BeautyColorInvertFilter(Context context) {
+        super(NORMAL_VERTEX_SHADER, OpenGLUtil.readShaderFromSource(context, R.raw.color_invert));
+    }
+
+    protected void onInit() {
+        super.onInit();
+    }
+
+    protected void onInitialized() {
+        super.onInitialized();
+    }
+
+    @Override
+    public void onInputSizeChanged(int width, int height) {
+        super.onInputSizeChanged(width, height);
+    }
+
+}

CameraFilter/src/main/res/raw/color_invert.glsl

@@ -0,0 +1,10 @@
+varying highp vec2 textureCoordinate;
+
+uniform sampler2D inputImageTexture;
+
+void main()
+{
+	lowp vec4 textureColor = texture2D(inputImageTexture, textureCoordinate);
+
+	gl_FragColor = vec4((1.0 - textureColor.rgb), 1.0);
+}

app/src/main/java/com/frank/ffmpeg/activity/CameraFilterActivity.kt

@@ -16,6 +16,7 @@ class CameraFilterActivity : BaseActivity() {
     private val filterType: Array<BeautyFilterType> = arrayOf(
         BeautyFilterType.NONE,
         BeautyFilterType.BLUR,
+        BeautyFilterType.COLOR_INVERT,
         BeautyFilterType.HUE,
         BeautyFilterType.WHITE_BALANCE,
         BeautyFilterType.SKETCH

app/src/main/java/com/frank/ffmpeg/util/FilterTypeUtil.kt

@@ -14,6 +14,7 @@ object FilterTypeUtil {
         return when (type) {
             BeautyFilterType.NONE -> R.string.camera_filter_none
             BeautyFilterType.BLUR -> R.string.camera_filter_blur
+            BeautyFilterType.COLOR_INVERT -> R.string.camera_filter_invert
             BeautyFilterType.HUE -> R.string.camera_filter_hue
             BeautyFilterType.WHITE_BALANCE -> R.string.camera_filter_balance
             BeautyFilterType.SKETCH -> R.string.camera_filter_sketch

app/src/main/res/values-en/strings.xml

@@ -117,5 +117,6 @@
     <string name="camera_filter_balance">White balance</string>
     <string name="camera_filter_sketch">Sketch</string>
     <string name="camera_filter_blur">Blur</string>
+    <string name="camera_filter_invert">Invert</string>
 
 </resources>

app/src/main/res/values/strings.xml

@@ -117,5 +117,6 @@
     <string name="camera_filter_balance">白平衡</string>
     <string name="camera_filter_sketch">素描</string>
     <string name="camera_filter_blur">模糊</string>
+    <string name="camera_filter_invert">反相</string>
 
 </resources>