add faster color lut filter (some posterization)

Author: jtomson

epf/src/main/java/com/daasuu/epf/filter/GlFastLookUpTableFilter.java

@@ -0,0 +1,80 @@
+package com.daasuu.epf.filter;
+
+import android.content.res.Resources;
+import android.graphics.Bitmap;
+import android.graphics.BitmapFactory;
+import android.opengl.GLES20;
+
+import com.daasuu.epf.EglUtil;
+
+/**
+ * This will posterize the resulting video a bit since it does not interpolate between 2 LUT values
+ */
+public class GlFastLookUpTableFilter extends GlFilter {
+
+    private final static String FRAGMENT_SHADER =
+            "precision lowp float;" +
+                    "uniform sampler2D lutTexture; \n" +
+                    "uniform sampler2D sTexture; \n" +
+                    "varying vec2 vTextureCoord; \n" +
+                    "void main() {\n" +
+                    "   vec4 pixel = texture2D(sTexture, vTextureCoord);\n" +
+                    "   float width = 16.;\n" +
+                    "   float sliceSize = 1.0 / width;\n" +
+                    "   float slicePixelSize = sliceSize / width;\n" +
+                    "   float sliceInnerSize = slicePixelSize * (width - 1.0);\n" +
+                    "   float zSlice0 = min(floor(pixel.b * width), width - 1.0);\n" +
+                    "   float xOffset = slicePixelSize * 0.5 + pixel.r * sliceInnerSize;\n" +
+                    "   float s0 = xOffset + (zSlice0 * sliceSize);\n" +
+                    "   gl_FragColor = texture2D(lutTexture, vec2(s0, pixel.g));\n" +
+                    "}";
+
+    public GlFastLookUpTableFilter(Bitmap bitmap) {
+        super(DEFAULT_VERTEX_SHADER, FRAGMENT_SHADER);
+        this.lutTexture = bitmap;
+        hTex = EglUtil.NO_TEXTURE;
+    }
+
+
+    public GlFastLookUpTableFilter(Resources resources, int fxID) {
+        super(DEFAULT_VERTEX_SHADER, FRAGMENT_SHADER);
+        this.lutTexture = BitmapFactory.decodeResource(resources, fxID);
+        hTex = EglUtil.NO_TEXTURE;
+    }
+
+    private int hTex;
+
+    private Bitmap lutTexture;
+
+    @Override
+    public void onDraw() {
+        int offsetDepthMapTextureUniform = getHandle("lutTexture");
+        GLES20.glActiveTexture(GLES20.GL_TEXTURE3);
+        GLES20.glBindTexture(GLES20.GL_TEXTURE_2D, hTex);
+        GLES20.glUniform1i(offsetDepthMapTextureUniform, 3);
+    }
+
+    @Override
+    public void setup() {
+        super.setup();
+        loadTexture();
+    }
+
+    private void loadTexture() {
+        if (hTex == EglUtil.NO_TEXTURE) {
+            hTex = EglUtil.loadTexture(lutTexture, EglUtil.NO_TEXTURE, false);
+        }
+    }
+
+    public void releaseLutBitmap() {
+        if (lutTexture != null && !lutTexture.isRecycled()) {
+            lutTexture.recycle();
+            lutTexture = null;
+        }
+    }
+
+    public void reset() {
+        hTex = EglUtil.NO_TEXTURE;
+        hTex = EglUtil.loadTexture(lutTexture, EglUtil.NO_TEXTURE, false);
+    }
+}