[android] Custom layer bindings

platform/android/example_custom_layer.cpp

@@ -0,0 +1,104 @@
+#include <jni.h>
+#include <GLES2/gl2.h>
+
+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); }";
+
+class ExampleCustomLayer {
+public:
+    ~ExampleCustomLayer() {
+        if (program) {
+            glDeleteBuffers(1, &buffer);
+            glDetachShader(program, vertexShader);
+            glDetachShader(program, fragmentShader);
+            glDeleteShader(vertexShader);
+            glDeleteShader(fragmentShader);
+            glDeleteProgram(program);
+        }
+    }
+
+    void initialize() {
+        program = glCreateProgram();
+        vertexShader = glCreateShader(GL_VERTEX_SHADER);
+        fragmentShader = glCreateShader(GL_FRAGMENT_SHADER);
+
+        glShaderSource(vertexShader, 1, &vertexShaderSource, nullptr);
+        glCompileShader(vertexShader);
+        glAttachShader(program, vertexShader);
+        glShaderSource(fragmentShader, 1, &fragmentShaderSource, nullptr);
+        glCompileShader(fragmentShader);
+        glAttachShader(program, fragmentShader);
+        glLinkProgram(program);
+        a_pos = glGetAttribLocation(program, "a_pos");
+
+        GLfloat background[] = { -1,-1, 1,-1, -1,1, 1,1 };
+        glGenBuffers(1, &buffer);
+        glBindBuffer(GL_ARRAY_BUFFER, buffer);
+        glBufferData(GL_ARRAY_BUFFER, 8 * sizeof(GLfloat), background, GL_STATIC_DRAW);
+    }
+
+    void 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);
+        glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
+    }
+
+    GLuint program = 0;
+    GLuint vertexShader = 0;
+    GLuint fragmentShader = 0;
+    GLuint buffer = 0;
+    GLuint a_pos = 0;
+};
+
+jlong JNICALL nativeCreateContext(JNIEnv*, jobject) {
+    return reinterpret_cast<jlong>(new ExampleCustomLayer());
+}
+
+void nativeInitialize(void *context) {
+    reinterpret_cast<ExampleCustomLayer*>(context)->initialize();
+}
+
+void nativeRender(void *context) {
+    reinterpret_cast<ExampleCustomLayer*>(context)->render();
+}
+
+void nativeDenitialize(void *context) {
+    delete reinterpret_cast<ExampleCustomLayer*>(context);
+}
+
+extern "C" JNIEXPORT jint JNICALL JNI_OnLoad(JavaVM *vm, void *) {
+    JNIEnv *env = nullptr;
+    vm->GetEnv(reinterpret_cast<void **>(&env), JNI_VERSION_1_6);
+
+    jclass customLayerClass = env->FindClass("com/mapbox/mapboxsdk/testapp/ExampleCustomLayer");
+
+    JNINativeMethod methods[] = {
+        {"createContext", "()J", reinterpret_cast<void *>(&nativeCreateContext)}
+    };
+
+    if (env->RegisterNatives(customLayerClass, methods, 1) < 0) {
+        env->ExceptionDescribe();
+        return JNI_ERR;
+    }
+
+    env->SetStaticLongField(customLayerClass,
+        env->GetStaticFieldID(customLayerClass, "InitializeFunction", "J"),
+        reinterpret_cast<jlong>(nativeInitialize));
+
+    env->SetStaticLongField(customLayerClass,
+        env->GetStaticFieldID(customLayerClass, "RenderFunction", "J"),
+        reinterpret_cast<jlong>(nativeRender));
+
+    env->SetStaticLongField(customLayerClass,
+        env->GetStaticFieldID(customLayerClass, "DeinitializeFunction", "J"),
+        reinterpret_cast<jlong>(nativeDenitialize));
+
+    return JNI_VERSION_1_6;
+}
+
+extern "C" JNIEXPORT void JNICALL JNI_OnUnload(JavaVM *, void *) {
+}