Add SimpleFilter (#552)

* Add SimpleFilter, tests for all filter package

* Add docs

cameraview/src/androidTest/java/com/otaliastudios/cameraview/BaseEglTest.java

@@ -0,0 +1,56 @@
+package com.otaliastudios.cameraview;
+
+
+import android.graphics.Canvas;
+
+import androidx.test.ext.junit.runners.AndroidJUnit4;
+import androidx.test.filters.SmallTest;
+
+import com.otaliastudios.cameraview.internal.egl.EglBaseSurface;
+import com.otaliastudios.cameraview.internal.egl.EglCore;
+import com.otaliastudios.cameraview.internal.egl.EglViewport;
+import com.otaliastudios.cameraview.overlay.Overlay;
+import com.otaliastudios.cameraview.overlay.OverlayDrawer;
+import com.otaliastudios.cameraview.size.Size;
+
+import org.hamcrest.BaseMatcher;
+import org.hamcrest.Description;
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+
+import static org.junit.Assert.assertThat;
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.ArgumentMatchers.eq;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.spy;
+import static org.mockito.Mockito.times;
+import static org.mockito.Mockito.verify;
+
+
+@SuppressWarnings("WeakerAccess")
+public abstract class BaseEglTest extends BaseTest {
+
+    protected final static int WIDTH = 100;
+    protected final static int HEIGHT = 100;
+
+    protected EglCore eglCore;
+    protected EglBaseSurface eglSurface;
+
+    @Before
+    public void setUp() {
+        eglCore = new EglCore(null, EglCore.FLAG_RECORDABLE);
+        eglSurface = new EglBaseSurface(eglCore);
+        eglSurface.createOffscreenSurface(WIDTH, HEIGHT);
+        eglSurface.makeCurrent();
+    }
+
+    @After
+    public void tearDown() {
+        eglSurface.releaseEglSurface();
+        eglSurface = null;
+        eglCore.release();
+        eglCore = null;
+    }
+}

cameraview/src/androidTest/java/com/otaliastudios/cameraview/filter/BaseFilterTest.java

@@ -0,0 +1,177 @@
+package com.otaliastudios.cameraview.filter;
+
+
+import android.opengl.GLES20;
+
+import androidx.annotation.NonNull;
+import androidx.test.ext.junit.runners.AndroidJUnit4;
+import androidx.test.filters.SmallTest;
+
+import com.otaliastudios.cameraview.BaseEglTest;
+import com.otaliastudios.cameraview.BaseTest;
+import com.otaliastudios.cameraview.internal.GlUtils;
+import com.otaliastudios.cameraview.internal.egl.EglViewport;
+
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+
+import java.util.HashSet;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNotNull;
+import static org.junit.Assert.assertTrue;
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.ArgumentMatchers.anyInt;
+import static org.mockito.Mockito.never;
+import static org.mockito.Mockito.spy;
+import static org.mockito.Mockito.times;
+import static org.mockito.Mockito.verify;
+
+
+@RunWith(AndroidJUnit4.class)
+@SmallTest
+public class BaseFilterTest extends BaseEglTest {
+
+    public static class TestFilter extends BaseFilter implements TwoParameterFilter {
+
+        private float param1;
+        private float param2;
+
+        @NonNull
+        @Override
+        public String getFragmentShader() {
+            return createDefaultFragmentShader();
+        }
+
+        @Override
+        public void setParameter1(float value) {
+            param1 = value;
+        }
+
+        @Override
+        public void setParameter2(float value) {
+            param2 = value;
+        }
+
+        @Override
+        public float getParameter1() {
+            return param1;
+        }
+
+        @Override
+        public float getParameter2() {
+            return param2;
+        }
+    }
+
+    private TestFilter filter;
+
+    @Test
+    public void testCreateDefaultFragmentShader() {
+        filter = new TestFilter();
+        filter.fragmentTextureCoordinateName = "XXX";
+        String defaultFragmentShader = filter.createDefaultFragmentShader();
+        assertNotNull(defaultFragmentShader);
+        assertTrue(defaultFragmentShader.contains(filter.fragmentTextureCoordinateName));
+    }
+
+    @Test
+    public void testCreateDefaultVertexShader() {
+        filter = new TestFilter();
+        filter.vertexModelViewProjectionMatrixName = "AAA";
+        filter.vertexPositionName = "BBB";
+        filter.vertexTextureCoordinateName = "CCC";
+        filter.vertexTransformMatrixName = "DDD";
+        filter.fragmentTextureCoordinateName = "EEE";
+        String defaultVertexShader = filter.createDefaultVertexShader();
+        assertNotNull(defaultVertexShader);
+        assertTrue(defaultVertexShader.contains(filter.vertexModelViewProjectionMatrixName));
+        assertTrue(defaultVertexShader.contains(filter.vertexPositionName));
+        assertTrue(defaultVertexShader.contains(filter.vertexTextureCoordinateName));
+        assertTrue(defaultVertexShader.contains(filter.vertexTransformMatrixName));
+        assertTrue(defaultVertexShader.contains(filter.fragmentTextureCoordinateName));
+    }
+
+    @Test
+    public void testOnProgramCreate() {
+        filter = new TestFilter();
+        int handle = GlUtils.createProgram(filter.getVertexShader(), filter.getFragmentShader());
+        filter.onCreate(handle);
+        assertTrue(filter.programHandle >= 0);
+        filter.onDestroy();
+        assertTrue(filter.programHandle < 0);
+        GLES20.glDeleteProgram(handle);
+    }
+
+    @Test
+    public void testDraw_whenInvalid() {
+        filter = spy(new TestFilter());
+        float[] matrix = new float[16];
+        filter.draw(matrix);
+        verify(filter, never()).onPreDraw(matrix);
+        verify(filter, never()).onDraw();
+        verify(filter, never()).onPostDraw();
+    }
+
+    @Test
+    public void testDraw() {
+        // Use an EglViewport which cares about GL setup.
+        filter = spy(new TestFilter());
+        EglViewport viewport = new EglViewport(filter);
+        int texture = viewport.createTexture();
+
+        float[] matrix = new float[16];
+        viewport.drawFrame(texture, matrix);
+        verify(filter, times(1)).onPreDraw(matrix);
+        verify(filter, times(1)).onDraw();
+        verify(filter, times(1)).onPostDraw();
+
+        viewport.release();
+    }
+
+    @Test(expected = RuntimeException.class)
+    public void testOnCopy_invalid() {
+        // Anonymous inner classes do not have a public constructor.
+        Filter filter = new BaseFilter() {
+            @NonNull
+            @Override
+            public String getFragmentShader() {
+                return "whatever";
+            }
+        };
+        filter.copy();
+    }
+
+    @Test
+    public void testOnCopy() {
+        filter = new TestFilter();
+        BaseFilter other = filter.copy();
+        assertTrue(other instanceof TestFilter);
+    }
+
+    @Test
+    public void testCopy_withSize() {
+        filter = new TestFilter();
+        filter.setSize(WIDTH, HEIGHT);
+        BaseFilter other = filter.copy();
+        assertEquals(WIDTH, other.size.getWidth());
+        assertEquals(HEIGHT, other.size.getHeight());
+    }
+
+    @Test
+    public void testCopy_withParameter1() {
+        filter = new TestFilter();
+        filter.setParameter1(0.5F);
+        TestFilter other = (TestFilter) filter.copy();
+        assertEquals(filter.getParameter1(), other.getParameter1(), 0.001F);
+    }
+
+    @Test
+    public void testCopy_withParameter2() {
+        filter = new TestFilter();
+        filter.setParameter2(0.5F);
+        TestFilter other = (TestFilter) filter.copy();
+        assertEquals(filter.getParameter2(), other.getParameter2(), 0.001F);
+    }
+}

cameraview/src/androidTest/java/com/otaliastudios/cameraview/filter/FiltersTest.java

@@ -0,0 +1,30 @@
+package com.otaliastudios.cameraview.filter;
+
+
+import androidx.test.ext.junit.runners.AndroidJUnit4;
+import androidx.test.filters.SmallTest;
+
+import com.otaliastudios.cameraview.BaseTest;
+
+import org.junit.Test;
+import org.junit.runner.RunWith;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNotNull;
+import static org.junit.Assert.assertTrue;
+
+
+@RunWith(AndroidJUnit4.class)
+@SmallTest
+public class FiltersTest extends BaseTest {
+
+    @Test
+    public void testNewInstance() {
+        // At least tests that all our default filters have a no-args constructor.
+        Filters[] filtersArray = Filters.values();
+        for (Filters filters : filtersArray) {
+            Filter filter = filters.newInstance();
+            assertNotNull(filter);
+        }
+    }
+}

cameraview/src/androidTest/java/com/otaliastudios/cameraview/filter/NoFilterTest.java

@@ -0,0 +1,35 @@
+package com.otaliastudios.cameraview.filter;
+
+
+import androidx.annotation.NonNull;
+import androidx.test.ext.junit.runners.AndroidJUnit4;
+import androidx.test.filters.SmallTest;
+
+import com.otaliastudios.cameraview.BaseTest;
+
+import org.junit.Test;
+import org.junit.runner.RunWith;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertTrue;
+
+
+@RunWith(AndroidJUnit4.class)
+@SmallTest
+public class NoFilterTest extends BaseTest {
+
+    public static class DummyFilter extends BaseFilter {
+        @NonNull
+        @Override
+        public String getFragmentShader() {
+            return "whatever";
+        }
+    }
+
+    @Test
+    public void testGetFragmentShader() {
+        NoFilter filter = new NoFilter();
+        String defaultFragmentShader = new DummyFilter().createDefaultFragmentShader();
+        assertEquals(defaultFragmentShader, filter.getFragmentShader());
+    }
+}

cameraview/src/androidTest/java/com/otaliastudios/cameraview/filter/SimpleFilterTest.java

@@ -0,0 +1,43 @@
+package com.otaliastudios.cameraview.filter;
+
+
+import android.content.res.TypedArray;
+
+import androidx.annotation.NonNull;
+import androidx.test.ext.junit.runners.AndroidJUnit4;
+import androidx.test.filters.SmallTest;
+
+import com.otaliastudios.cameraview.BaseTest;
+import com.otaliastudios.cameraview.R;
+
+import org.junit.Test;
+import org.junit.runner.RunWith;
+
+import static junit.framework.TestCase.assertNotNull;
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertTrue;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.when;
+
+
+@RunWith(AndroidJUnit4.class)
+@SmallTest
+public class SimpleFilterTest extends BaseTest {
+
+    @Test
+    public void testGetFragmentShader() {
+        String shader = "shader";
+        SimpleFilter filter = new SimpleFilter(shader);
+        assertEquals(shader, filter.getFragmentShader());
+    }
+
+    @Test
+    public void testCopy() {
+        String shader = "shader";
+        SimpleFilter filter = new SimpleFilter(shader);
+        BaseFilter copy = filter.copy();
+        assertTrue(copy instanceof SimpleFilter);
+        SimpleFilter simpleCopy = (SimpleFilter) copy;
+        assertEquals(shader, simpleCopy.getFragmentShader());
+    }
+}

cameraview/src/androidTest/java/com/otaliastudios/cameraview/overlay/OverlayDrawerTest.java

@@ -13,6 +13,7 @@ import androidx.test.annotation.UiThreadTest;
 import androidx.test.ext.junit.runners.AndroidJUnit4;
 import androidx.test.filters.SmallTest;
 
+import com.otaliastudios.cameraview.BaseEglTest;
 import com.otaliastudios.cameraview.BaseTest;
 import com.otaliastudios.cameraview.internal.egl.EglBaseSurface;
 import com.otaliastudios.cameraview.internal.egl.EglCore;
@@ -45,29 +46,7 @@ import static org.mockito.Mockito.when;
 
 @RunWith(AndroidJUnit4.class)
 @SmallTest
-public class OverlayDrawerTest extends BaseTest {
-
-    private final static int WIDTH = 100;
-    private final static int HEIGHT = 100;
-
-    private EglCore eglCore;
-    private EglBaseSurface eglSurface;
-
-    @Before
-    public void setUp() {
-        eglCore = new EglCore(null, EglCore.FLAG_RECORDABLE);
-        eglSurface = new EglBaseSurface(eglCore);
-        eglSurface.createOffscreenSurface(WIDTH, HEIGHT);
-        eglSurface.makeCurrent();
-    }
-
-    @After
-    public void tearDown() {
-        eglSurface.releaseEglSurface();
-        eglSurface = null;
-        eglCore.release();
-        eglCore = null;
-    }
+public class OverlayDrawerTest extends BaseEglTest {
 
     @Test
     public void testDraw() {

cameraview/src/main/java/com/otaliastudios/cameraview/filter/BaseFilter.java

@@ -3,6 +3,7 @@ package com.otaliastudios.cameraview.filter;
 import android.opengl.GLES20;
 
 import androidx.annotation.NonNull;
+import androidx.annotation.VisibleForTesting;
 
 import com.otaliastudios.cameraview.CameraLogger;
 import com.otaliastudios.cameraview.internal.GlUtils;
@@ -96,8 +97,8 @@ public abstract class BaseFilter implements Filter {
     private int vertexTranformMatrixLocation = -1;
     private int vertexPositionLocation = -1;
     private int vertexTextureCoordinateLocation = -1;
-    private int programHandle = -1;
-    private Size size;
+    @VisibleForTesting int programHandle = -1;
+    @VisibleForTesting Size size;
 
     @SuppressWarnings("WeakerAccess")
     protected String vertexPositionName = DEFAULT_VERTEX_POSITION_NAME;
@@ -120,7 +121,6 @@ public abstract class BaseFilter implements Filter {
                 fragmentTextureCoordinateName);
     }
 
-    @SuppressWarnings("WeakerAccess")
     @NonNull
     protected String createDefaultFragmentShader() {
         return createDefaultFragmentShader(fragmentTextureCoordinateName);
@@ -210,7 +210,9 @@ public abstract class BaseFilter implements Filter {
     @Override
     public final BaseFilter copy() {
         BaseFilter copy = onCopy();
-        copy.setSize(size.getWidth(), size.getHeight());
+        if (size != null) {
+            copy.setSize(size.getWidth(), size.getHeight());
+        }
         if (this instanceof OneParameterFilter) {
             ((OneParameterFilter) copy).setParameter1(((OneParameterFilter) this).getParameter1());
         }
@@ -220,7 +222,6 @@ public abstract class BaseFilter implements Filter {
         return copy;
     }
 
-    @SuppressWarnings("WeakerAccess")
     protected BaseFilter onCopy() {
         try {
             return getClass().newInstance();

cameraview/src/main/java/com/otaliastudios/cameraview/filter/NoFilter.java

@@ -4,7 +4,10 @@ import androidx.annotation.NonNull;
 
 import com.otaliastudios.cameraview.filter.BaseFilter;
 
-public class NoFilter extends BaseFilter {
+/**
+ * A {@link Filter} that draws frames without any modification.
+ */
+public final class NoFilter extends BaseFilter {
 
     @NonNull
     @Override

cameraview/src/main/java/com/otaliastudios/cameraview/filter/SimpleFilter.java

@@ -0,0 +1,40 @@
+package com.otaliastudios.cameraview.filter;
+
+import androidx.annotation.NonNull;
+
+/**
+ * The simplest possible filter that accepts a fragment shader in its constructor.
+ * This can be used when your fragment shader is static and has no 'runtime' parameters
+ * that influence its behavior.
+ *
+ * The given fragment shader should respect the default variable names, as listed
+ * in the {@link BaseFilter} class.
+ *
+ * NOTE: SimpleFilter is not meant to be subclassed!
+ * Subclassing it would require you to override {@link #onCopy()}, which would make
+ * this class useless. Instead, you can extend {@link BaseFilter} directly.
+ */
+public final class SimpleFilter extends BaseFilter {
+
+    private final String fragmentShader;
+
+    /**
+     * Creates a new filter with the given fragment shader.
+     * @param fragmentShader a fragment shader
+     */
+    @SuppressWarnings("WeakerAccess")
+    public SimpleFilter(@NonNull String fragmentShader) {
+        this.fragmentShader = fragmentShader;
+    }
+
+    @NonNull
+    @Override
+    public String getFragmentShader() {
+        return fragmentShader;
+    }
+
+    @Override
+    protected BaseFilter onCopy() {
+        return new SimpleFilter(fragmentShader);
+    }
+}

docs/_posts/2019-08-06-filters.md

@@ -96,6 +96,17 @@ camera.mapGesture(Gesture.SCROLL_VERTICAL, GestureAction.FILTER_CONTROL_2);
 Advanced users with OpenGL experience can create their own filters by implementing the `Filter` interface
 and passing in a fragment shader and a vertex shader that will be used for drawing.
 
+#### Simple filters
+
+For very simple filters that have a static fragment shader, you can create a working filter
+implementation by simply creating an instance of `SimpleFilter`:
+
+```java
+Filter filter = new SimpleFilter(myFragmentShader);
+```
+
+#### More complex filters
+
 We recommend:
 
 - Subclassing `BaseFilter` instead of implementing `Filter`, since that takes care of most of the work