android: Add color correction shader setting

Former-commit-id: 894a0d6d6a07b16d3333739d565bba853ce13fc4

AndroidApp/app/build.gradle

@@ -51,6 +51,7 @@ dependencies {
     implementation 'com.google.android.material:material:1.1.0'
     implementation "androidx.documentfile:documentfile:1.0.1"
     implementation 'androidx.preference:preference:1.1.0'
+    implementation 'commons-io:commons-io:2.6'
     testImplementation 'junit:junit:4.12'
     androidTestImplementation 'androidx.test.ext:junit:1.1.0'
     androidTestImplementation 'androidx.test.espresso:espresso-core:3.1.1'

AndroidApp/app/src/main/AndroidManifest.xml

@@ -13,10 +13,10 @@
         android:allowBackup="true"
         android:icon="@drawable/icon"
         android:label="@string/app_name"
-        android:roundIcon="@mipmap/ic_launcher_round"
+        android:roundIcon="@drawable/icon"
         android:supportsRtl="true"
         android:theme="@style/AppTheme">
-        <activity android:name=".ui.snapshots.SnapshotPickerActivity"></activity>
+        <activity android:name=".ui.snapshots.SnapshotPickerActivity" />
         <activity
             android:name=".ui.snapshots.SnapshotListFragment"
             android:label="@string/title_activity_snapshot" />

AndroidApp/app/src/main/java/com/mrmichel/rustdroid_emu/ui/EmulatorActivity.java

@@ -377,7 +377,7 @@ public class EmulatorActivity extends AppCompatActivity implements View.OnClickL
 
         SharedPreferences sharedPreferences =
                 PreferenceManager.getDefaultSharedPreferences(this /* Activity context */);
-        Boolean skipBios = sharedPreferences.getBoolean("skip_bios", false);
+        boolean skipBios = sharedPreferences.getBoolean("skip_bios", false);
 
         if (null != savedInstanceState && (saveFilePath = savedInstanceState.getString("saveFile")) != null) {
             final EmulatorActivity thisActivity = this;
@@ -451,6 +451,10 @@ public class EmulatorActivity extends AppCompatActivity implements View.OnClickL
             case R.id.action_save_snapshot:
                 doSaveSnapshot();
                 return true;
+            case R.id.action_settings:
+                Intent intent = new Intent(this, SettingsActivity.class);
+                startActivity(intent);
+                return true;
             default:
                 return super.onOptionsItemSelected(item);
         }

AndroidApp/app/src/main/java/com/mrmichel/rustdroid_emu/ui/ScreenRenderer.java

@@ -1,13 +1,24 @@
 package com.mrmichel.rustdroid_emu.ui;
 
+import android.content.Context;
+import android.content.SharedPreferences;
 import android.graphics.Bitmap;
 import android.opengl.GLES20;
 import android.opengl.GLSurfaceView;
 import android.opengl.GLUtils;
 
+import androidx.preference.PreferenceManager;
+
+import com.mrmichel.rustdroid_emu.R;
+
+import org.apache.commons.io.IOUtils;
+
+import java.io.IOException;
+import java.io.InputStream;
 import java.nio.ByteBuffer;
 import java.nio.ByteOrder;
 import java.nio.FloatBuffer;
+import java.nio.charset.StandardCharsets;
 
 import javax.microedition.khronos.egl.EGLConfig;
 import javax.microedition.khronos.opengles.GL10;
@@ -16,12 +27,53 @@ public class ScreenRenderer implements GLSurfaceView.Renderer {
 
     private ScreenTexture texture;
     private boolean ready = false;
+    private Context context;
+
+    public ScreenRenderer(Context context) {
+        this.context = context;
+    }
+
+    public void updateTexture(int[] frameBuffer) {
+        this.texture.update(frameBuffer);
+    }
+
+    public void initTextureIfNotInitialized() {
+        if (this.texture == null) {
+            this.texture = new ScreenTexture(this.context);
+        }
+    }
+
+    @Override
+    public void onSurfaceCreated(GL10 gl, EGLConfig config) {
+        initTextureIfNotInitialized();
+        ready = true;
+    }
+
+    @Override
+    public void onSurfaceChanged(GL10 gl, int width, int height) {
+        gl.glViewport(0, 0, width, height);
+    }
+
+    @Override
+    public void onDrawFrame(GL10 gl) {
+        this.texture.render();
+    }
+
+    public boolean isReady() {
+        return ready;
+    }
+
+    public void setColorCorrection(boolean colorCorrection) {
+        this.texture.setColorCorrection(colorCorrection);
+    }
 
     /**
      * Private class to manage the screen texture rendering
      */
     private class ScreenTexture {
-        int shaderProgram;
+        int normalShaderProgram;
+        int colorCorrectionShaderProgram;
+        int currentShaderProgram;
         int positionHandle;
         int texCoordHandle;
         int samplerHandle;
@@ -32,6 +84,7 @@ public class ScreenRenderer implements GLSurfaceView.Renderer {
         private ByteBuffer indicesBuffer;
 
         private Bitmap bitmap;
+        private Context context;
 
         // square vertices
         private float[] vertices = {
@@ -55,26 +108,75 @@ public class ScreenRenderer implements GLSurfaceView.Renderer {
                 0, 2, 3
         };
 
-        private static final String VERTEX_SHADER_CODE =
+        public ScreenTexture(Context context) {
-                "attribute vec4 a_position;   \n" +
+            this.context = context;
-                        "attribute vec2 a_texCoord;   \n" +
+            this.bitmap = Bitmap.createBitmap(240, 160, Bitmap.Config.RGB_565);
-                        "varying vec2 v_texCoord;     \n" +
-                        "void main()                  \n" +
-                        "{                            \n" +
-                        "   gl_Position = a_position; \n" +
-                        "   v_texCoord = a_texCoord;  \n" +
-                        "}                            \n";
 
-        private static final String FRAGMENT_SHADER_CODE =
+            GLES20.glEnable(GLES20.GL_TEXTURE_2D);
-                "precision mediump float;                            \n" +
-                        "varying vec2 v_texCoord;                            \n" +
-                        "uniform sampler2D s_texture;                        \n" +
-                        "void main()                                         \n" +
-                        "{                                                   \n" +
-                        "  vec4 color = texture2D( s_texture, v_texCoord );  \n" +
-                        "  gl_FragColor = color;                             \n" +
-                        "}                                                   \n";
 
+            // create vertex array
+            vertexBuffer = ByteBuffer.allocateDirect(vertices.length * 4).order(ByteOrder.nativeOrder()).asFloatBuffer();
+            vertexBuffer.put(vertices);
+            vertexBuffer.position(0);
+
+            // create texture coordinate array
+            textureBuffer = ByteBuffer.allocateDirect(textureVertices.length * 4).order(ByteOrder.nativeOrder()).asFloatBuffer();
+            textureBuffer.put(textureVertices);
+            textureBuffer.position(0);
+
+            // create triangle index array
+            indicesBuffer = ByteBuffer.allocateDirect(indicies.length).order(ByteOrder.nativeOrder());
+            indicesBuffer.put(indicies);
+            indicesBuffer.position(0);
+
+            textureId = createTexture();
+
+            String vertexShader = readShaderResource(R.raw.screen_texture_vertex_shader);
+            String normalFragmentShader = readShaderResource(R.raw.screen_texture_fragment_shader);
+            String colorCorrectionFragmentShader = readShaderResource(R.raw.screen_texture_color_correction_fragment_shader);
+
+            normalShaderProgram = createShaderProgram(vertexShader, normalFragmentShader);
+            colorCorrectionShaderProgram = createShaderProgram(vertexShader, colorCorrectionFragmentShader);
+
+            SharedPreferences sharedPreferences = PreferenceManager.getDefaultSharedPreferences(this.context);
+            boolean colorCorrection = sharedPreferences.getBoolean("color_correction", false);
+            setColorCorrection(colorCorrection);
+
+            GLES20.glClearColor(1.0f, 1.0f, 1.0f, 1.0f);
+        }
+
+        private void setColorCorrection(boolean colorCorrection) {
+
+            if (colorCorrection) {
+                currentShaderProgram = colorCorrectionShaderProgram;
+            } else {
+                currentShaderProgram = normalShaderProgram;
+            }
+
+            // use the program
+            GLES20.glUseProgram(currentShaderProgram);
+
+            positionHandle = GLES20.glGetAttribLocation(currentShaderProgram, "a_position");
+
+            texCoordHandle = GLES20.glGetAttribLocation(currentShaderProgram, "a_texCoord");
+
+            samplerHandle = GLES20.glGetUniformLocation(currentShaderProgram, "s_texture");
+
+
+            // load the vertex position
+            GLES20.glVertexAttribPointer(positionHandle, 3, GLES20.GL_FLOAT, false, 0, vertexBuffer);
+            GLES20.glEnableVertexAttribArray(positionHandle);
+            // load texture coordinate
+            GLES20.glVertexAttribPointer(texCoordHandle, 2, GLES20.GL_FLOAT, false, 0, textureBuffer);
+            GLES20.glEnableVertexAttribArray(texCoordHandle);
+
+
+            GLES20.glVertexAttribPointer(positionHandle, 3, GLES20.GL_FLOAT, false, 0, vertexBuffer);
+            GLES20.glEnableVertexAttribArray(positionHandle);
+            // load texture coordinate
+            GLES20.glVertexAttribPointer(texCoordHandle, 2, GLES20.GL_FLOAT, false, 0, textureBuffer);
+            GLES20.glEnableVertexAttribArray(texCoordHandle);
+        }
 
         private int compileShader(int type, String code) {
             int shader = GLES20.glCreateShader(type);
@@ -123,58 +225,28 @@ public class ScreenRenderer implements GLSurfaceView.Renderer {
             return texturesIds[0];
         }
 
-        public ScreenTexture() {
+        private String readShaderResource(int resourceId) {
-            this.bitmap = Bitmap.createBitmap(240, 160, Bitmap.Config.RGB_565);
+            InputStream in = context.getResources().openRawResource(resourceId);
-
+            String code;
-            GLES20.glEnable(GLES20.GL_TEXTURE_2D);
+            try {
-
+                code = IOUtils.toString(in, StandardCharsets.UTF_8);
-            // create vertex array
+            } catch (IOException e) {
-            vertexBuffer = ByteBuffer.allocateDirect(vertices.length * 4).order(ByteOrder.nativeOrder()).asFloatBuffer();
+                code = "";
-            vertexBuffer.put(vertices);
+            }
-            vertexBuffer.position(0);
+            return code;
-
-            // create texture coordinate array
-            textureBuffer = ByteBuffer.allocateDirect(textureVertices.length * 4).order(ByteOrder.nativeOrder()).asFloatBuffer();
-            textureBuffer.put(textureVertices);
-            textureBuffer.position(0);
-
-            // create triangle index array
-            indicesBuffer = ByteBuffer.allocateDirect(indicies.length).order(ByteOrder.nativeOrder());
-            indicesBuffer.put(indicies);
-            indicesBuffer.position(0);
-
-            textureId = createTexture();
-
-            shaderProgram = createShaderProgram(VERTEX_SHADER_CODE, FRAGMENT_SHADER_CODE);
-
-            // use the program
-            GLES20.glUseProgram(shaderProgram);
-
-            positionHandle = GLES20.glGetAttribLocation(shaderProgram, "a_position");
-
-            texCoordHandle = GLES20.glGetAttribLocation(shaderProgram, "a_texCoord");
-
-            samplerHandle = GLES20.glGetUniformLocation(shaderProgram, "s_texture");
-
-
-            // load the vertex position
-            GLES20.glVertexAttribPointer(positionHandle, 3, GLES20.GL_FLOAT, false, 0, vertexBuffer);
-            GLES20.glEnableVertexAttribArray(positionHandle);
-            // load texture coordinate
-            GLES20.glVertexAttribPointer(texCoordHandle, 2, GLES20.GL_FLOAT, false, 0, textureBuffer);
-            GLES20.glEnableVertexAttribArray(texCoordHandle);
-
-
-            GLES20.glClearColor(1.0f, 1.0f, 1.0f, 1.0f);
         }
 
         protected void destroy() {
-            GLES20.glDeleteProgram(shaderProgram);
+            GLES20.glDeleteProgram(normalShaderProgram);
+            GLES20.glDeleteProgram(colorCorrectionShaderProgram);
             int[] textures = {textureId};
             GLES20.glDeleteTextures(1, textures, 0);
         }
 
         public void render() {
+            // use the shader program
+            GLES20.glUseProgram(currentShaderProgram);
+
             // clear the color buffer
             GLES20.glClear(GLES20.GL_COLOR_BUFFER_BIT);
 
@@ -190,34 +262,4 @@ public class ScreenRenderer implements GLSurfaceView.Renderer {
             GLES20.glDrawElements(GLES20.GL_TRIANGLE_STRIP, 6, GLES20.GL_UNSIGNED_BYTE, indicesBuffer);
         }
     }
-
-    public void updateTexture(int[] frameBuffer) {
-        this.texture.update(frameBuffer);
-    }
-
-    public void initTextureIfNotInitialized() {
-        if (this.texture == null) {
-            this.texture = new ScreenTexture();
-        }
-    }
-
-    @Override
-    public void onSurfaceCreated(GL10 gl, EGLConfig config) {
-        initTextureIfNotInitialized();
-        ready = true;
-    }
-
-    @Override
-    public void onSurfaceChanged(GL10 gl, int width, int height) {
-        gl.glViewport(0, 0, width, height);
-    }
-
-    @Override
-    public void onDrawFrame(GL10 gl) {
-        this.texture.render();
-    }
-
-    public boolean isReady() {
-        return ready;
-    }
 }

AndroidApp/app/src/main/java/com/mrmichel/rustdroid_emu/ui/ScreenView.java

@@ -1,10 +1,13 @@
 package com.mrmichel.rustdroid_emu.ui;
 
 import android.content.Context;
+import android.content.SharedPreferences;
 import android.opengl.GLSurfaceView;
 import android.util.AttributeSet;
 
-public class ScreenView extends GLSurfaceView {
+import androidx.preference.PreferenceManager;
+
+public class ScreenView extends GLSurfaceView implements SharedPreferences.OnSharedPreferenceChangeListener {
     private ScreenRenderer mRenderer;
 
     public ScreenView(Context context) {
@@ -21,7 +24,11 @@ public class ScreenView extends GLSurfaceView {
         this.setEGLContextClientVersion(2);
         this.setPreserveEGLContextOnPause(true);
 
-        mRenderer = new ScreenRenderer();
+        SharedPreferences sharedPreferences =
+                PreferenceManager.getDefaultSharedPreferences(getContext());
+        sharedPreferences.registerOnSharedPreferenceChangeListener(this);
+
+        mRenderer = new ScreenRenderer(getContext());
         this.setRenderer(mRenderer);
         this.setRenderMode(RENDERMODE_WHEN_DIRTY);
     }
@@ -34,4 +41,12 @@ public class ScreenView extends GLSurfaceView {
     public ScreenRenderer getRenderer() {
         return mRenderer;
     }
+
+    @Override
+    public void onSharedPreferenceChanged(SharedPreferences sharedPreferences, String key) {
+        if (key.equals("color_correction")) {
+            boolean colorCorrection = sharedPreferences.getBoolean("color_correction", false);
+            mRenderer.setColorCorrection(colorCorrection);
+        }
+    }
 }

AndroidApp/app/src/main/java/com/mrmichel/rustdroid_emu/ui/SettingsActivity.java

@@ -2,18 +2,32 @@ package com.mrmichel.rustdroid_emu.ui;
 
 import android.os.Bundle;
 
+import androidx.appcompat.app.ActionBar;
 import androidx.appcompat.app.AppCompatActivity;
+import androidx.preference.PreferenceFragmentCompat;
 
 import com.mrmichel.rustdroid_emu.R;
 
 public class SettingsActivity extends AppCompatActivity {
+
     @Override
     protected void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         setContentView(R.layout.activity_settings);
         getSupportFragmentManager()
                 .beginTransaction()
-                .replace(R.id.settings_container, new SettingsFragment())
+                .replace(R.id.settings, new SettingsFragment())
                 .commit();
+        ActionBar actionBar = getSupportActionBar();
+        if (actionBar != null) {
+            actionBar.setDisplayHomeAsUpEnabled(true);
+        }
+    }
+
+    public static class SettingsFragment extends PreferenceFragmentCompat {
+        @Override
+        public void onCreatePreferences(Bundle savedInstanceState, String rootKey) {
+            setPreferencesFromResource(R.xml.app_preferences, rootKey);
+        }
     }
 }

AndroidApp/app/src/main/java/com/mrmichel/rustdroid_emu/ui/library/RomListActivity.java

@@ -13,7 +13,6 @@ import android.view.Menu;
 import android.view.MenuInflater;
 import android.view.MenuItem;
 import android.view.View;
-import android.webkit.MimeTypeMap;
 import android.widget.AdapterView;
 import android.widget.GridView;
 

AndroidApp/app/src/main/res/layout/activity_settings.xml

@@ -1,13 +1,9 @@
-<?xml version="1.0" encoding="utf-8"?>
 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
     android:layout_width="match_parent"
-    android:layout_height="match_parent"
+    android:layout_height="match_parent">
-    android:orientation="vertical" >
 
     <FrameLayout
-        android:id="@+id/settings_container"
+        android:id="@+id/settings"
         android:layout_width="match_parent"
-        android:layout_height="match_parent">
+        android:layout_height="match_parent" />
-    </FrameLayout>
-
 </LinearLayout>

AndroidApp/app/src/main/res/raw/screen_texture_color_correction_fragment_shader.glsl

@@ -0,0 +1,21 @@
+/*
+ Port of byuu's color correction shader as described in https://byuu.net/video/color-emulation
+ */
+
+precision mediump float;
+
+varying vec2 v_texCoord;
+uniform sampler2D s_texture;
+
+void main()
+{
+    float lcdGamma = 4.0, outGamma = 2.2;
+
+    vec4 color = texture2D( s_texture, v_texCoord );
+
+    color.rgb = pow(color.rgb, vec3(lcdGamma));
+    gl_FragColor.r = pow((  0.0 * color.b +  50.0 * color.g + 255.0 * color.r) / 255.0, 1.0 / outGamma) * 255.0 / 280.0;
+    gl_FragColor.g = pow(( 30.0 * color.b + 230.0 * color.g +  10.0 * color.r) / 255.0, 1.0 / outGamma) * 255.0 / 280.0;
+    gl_FragColor.b = pow((220.0 * color.b +  10.0 * color.g +  50.0 * color.r) / 255.0, 1.0 / outGamma) * 255.0 / 280.0;
+    gl_FragColor.a = 1.0;
+}

AndroidApp/app/src/main/res/raw/screen_texture_fragment_shader.glsl

@@ -0,0 +1,8 @@
+precision mediump float;
+varying vec2 v_texCoord;
+uniform sampler2D s_texture;
+void main()
+{
+  vec4 color = texture2D( s_texture, v_texCoord );
+  gl_FragColor = color;
+}

AndroidApp/app/src/main/res/raw/screen_texture_vertex_shader.glsl

@@ -0,0 +1,8 @@
+attribute vec4 a_position;
+attribute vec2 a_texCoord;
+varying vec2 v_texCoord;
+void main()
+{
+    gl_Position = a_position;
+    v_texCoord = a_texCoord;
+}

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

@@ -16,4 +16,9 @@
     <string name="action_delete">Delete</string>
 
     <string name="title_activity_snapshot">Snapshot Manager</string>
+
+    <string name="color_correction_setting">Apply color correction shader</string>
+    <string name="color_correction_summary">
+        Makes colors look closer to the real GBA LCD screen.
+    </string>
 </resources>

AndroidApp/app/src/main/res/xml/app_preferences.xml

@@ -1,8 +1,18 @@
 <PreferenceScreen
     xmlns:app="http://schemas.android.com/apk/res-auto">
 
-    <CheckBoxPreference
+    <PreferenceCategory app:title="Emulation">
+        <SwitchPreferenceCompat
             app:key="skip_bios"
             app:title="Skip bios boot animation"/>
+    </PreferenceCategory>
+
+    <PreferenceCategory app:title="Graphics">
+        <SwitchPreferenceCompat
+            app:key="color_correction"
+            app:title="@string/color_correction_setting"
+            app:summary="@string/color_correction_summary"
+            />
+    </PreferenceCategory>
 
 </PreferenceScreen>