[android] update custom layer example with invalidation example

platform/android/src/example_custom_layer.cpp

@@ -1,14 +1,17 @@
 #include <jni.h>
 #include <GLES2/gl2.h>
 
+#include <mbgl/platform/log.hpp>
+
 #include <mbgl/style/layers/custom_layer.hpp>
 
 static const GLchar * vertexShaderSource = "attribute vec2 a_pos; void main() { gl_Position = vec4(a_pos, 0, 1); }";
-static const GLchar * fragmentShaderSource = "void main() { gl_FragColor = vec4(0, 1, 0, 1); }";
+static const GLchar * fragmentShaderSource = "uniform vec4 fill_color; void main() { gl_FragColor = fill_color; }";
 
 class ExampleCustomLayer {
 public:
     ~ExampleCustomLayer() {
+        mbgl::Log::Info(mbgl::Event::General, "~ExampleCustomLayer");
         if (program) {
             glDeleteBuffers(1, &buffer);
             glDetachShader(program, vertexShader);
@@ -20,6 +23,7 @@ public:
     }
 
     void initialize() {
+        mbgl::Log::Info(mbgl::Event::General, "Initialize");
         program = glCreateProgram();
         vertexShader = glCreateShader(GL_VERTEX_SHADER);
         fragmentShader = glCreateShader(GL_FRAGMENT_SHADER);
@@ -32,6 +36,7 @@ public:
         glAttachShader(program, fragmentShader);
         glLinkProgram(program);
         a_pos = glGetAttribLocation(program, "a_pos");
+        fill_color = glGetUniformLocation(program, "fill_color");
 
         GLfloat background[] = { -1,-1, 1,-1, -1,1, 1,1 };
         glGenBuffers(1, &buffer);
@@ -40,12 +45,15 @@ public:
     }
 
     void render() {
+        mbgl::Log::Info(mbgl::Event::General, "Render");
         glUseProgram(program);
         glBindBuffer(GL_ARRAY_BUFFER, buffer);
         glEnableVertexAttribArray(a_pos);
         glVertexAttribPointer(a_pos, 2, GL_FLOAT, GL_FALSE, 0, NULL);
         glDisable(GL_STENCIL_TEST);
         glDisable(GL_DEPTH_TEST);
+        glUniform4fv(fill_color, 1, color);
+
         glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
     }
 
@@ -54,35 +62,54 @@ public:
     GLuint fragmentShader = 0;
     GLuint buffer = 0;
     GLuint a_pos = 0;
+    GLuint fill_color = 0;
+
+    static GLfloat color[];
 };
 
+GLfloat ExampleCustomLayer::color[] = { 0.0f, 1.0f, 0.0f, 1.0f };
+
 jlong JNICALL nativeCreateContext(JNIEnv*, jobject) {
-    return reinterpret_cast<jlong>(new ExampleCustomLayer());
+     mbgl::Log::Info(mbgl::Event::General, "nativeCreateContext");
+     return reinterpret_cast<jlong>(new ExampleCustomLayer());
+}
+
+void JNICALL nativeSetColor(JNIEnv*, jobject, jfloat red, jfloat green, jfloat blue, jfloat alpha) {
+    mbgl::Log::Info(mbgl::Event::General, "nativeSetColor: %.2f, %.2f, %.2f, %.2f", red, green, blue, alpha);
+    ExampleCustomLayer::color[0] = red;
+    ExampleCustomLayer::color[1] = green;
+    ExampleCustomLayer::color[2] = blue;
+    ExampleCustomLayer::color[3] = alpha;
 }
 
 void nativeInitialize(void *context) {
+    mbgl::Log::Info(mbgl::Event::General, "nativeInitialize");
     reinterpret_cast<ExampleCustomLayer*>(context)->initialize();
 }
 
 void nativeRender(void *context, const mbgl::style::CustomLayerRenderParameters& /*parameters*/) {
+    mbgl::Log::Info(mbgl::Event::General, "nativeRender");
     reinterpret_cast<ExampleCustomLayer*>(context)->render();
 }
 
 void nativeDenitialize(void *context) {
+    mbgl::Log::Info(mbgl::Event::General, "nativeDeinitialize");
     delete reinterpret_cast<ExampleCustomLayer*>(context);
 }
 
 extern "C" JNIEXPORT jint JNICALL JNI_OnLoad(JavaVM *vm, void *) {
+    mbgl::Log::Info(mbgl::Event::General, "OnLoad");
     JNIEnv *env = nullptr;
     vm->GetEnv(reinterpret_cast<void **>(&env), JNI_VERSION_1_6);
 
     jclass customLayerClass = env->FindClass("com/mapbox/mapboxsdk/testapp/model/customlayer/ExampleCustomLayer");
 
     JNINativeMethod methods[] = {
-        {"createContext", "()J", reinterpret_cast<void *>(&nativeCreateContext)}
+        {"createContext", "()J", reinterpret_cast<void *>(&nativeCreateContext)},
+        {"setColor", "(FFFF)V", reinterpret_cast<void *>(&nativeSetColor)}
     };
 
-    if (env->RegisterNatives(customLayerClass, methods, 1) < 0) {
+    if (env->RegisterNatives(customLayerClass, methods, 2) < 0) {
         env->ExceptionDescribe();
         return JNI_ERR;
     }