Android rayshader sample.

samples/android_sample/jni/graphics.cc

+#include "jni/graphics.h"
+#include <GLES2/gl2.h>
+#include <GLES2/gl2ext.h>
+
+Graphics::Graphics(android_app* application, Timer* timer)
+    : application_(application),
+      timer_(timer),
+      width_(0),
+      height_(0),
+      display_(EGL_NO_DISPLAY),
+      surface_(EGL_NO_SURFACE),
+      context_(EGL_NO_CONTEXT) {
+}
+
+const int32_t& Graphics::height() {
+  return height_;
+}
+
+const int32_t& Graphics::width() {
+  return width_;
+}
+
+int32_t Graphics::Start() {
+  EGLint format, numConfigs, errorResult;
+  EGLConfig config;
+  const EGLint attributes[] = {
+      EGL_RENDERABLE_TYPE, EGL_OPENGL_ES2_BIT,
+      EGL_NONE
+  };
+  static const EGLint ctx_attribs[] = {
+    EGL_CONTEXT_CLIENT_VERSION, 2,
+    EGL_NONE
+  };
+
+  display_ = eglGetDisplay(EGL_DEFAULT_DISPLAY);
+  if (display_ != EGL_NO_DISPLAY) {
+    Log::Print("eglInitialize");
+    if (eglInitialize(display_, NULL, NULL)) {
+      Log::Print("eglChooseConfig");
+      if (eglChooseConfig(display_, attributes, &config, 1, &numConfigs) &&
+          numConfigs > 0) {
+        Log::Print("eglGetConfigAttrib");
+        if (eglGetConfigAttrib(display_, config,
+                               EGL_NATIVE_VISUAL_ID, &format)) {
+          ANativeWindow_setBuffersGeometry(application_->window, 0, 0, format);
+          surface_ = eglCreateWindowSurface(display_, config,
+                              (EGLNativeWindowType)application_->window, NULL);
+          if (surface_ != EGL_NO_SURFACE) {
+            Log::Print("eglCreateContext");
+            context_ = eglCreateContext(display_, config, EGL_NO_CONTEXT,
+                                        ctx_attribs);
+            if (context_ != EGL_NO_CONTEXT) {
+              if (eglMakeCurrent(display_, surface_, surface_, context_) &&
+                  eglQuerySurface(display_, surface_, EGL_WIDTH, &width_) &&
+                  width_ > 0 &&
+                  eglQuerySurface(display_, surface_, EGL_HEIGHT, &height_) &&
+                  height_ > 0) {
+                glViewport(0, 0, width_, height_);
+                return 0;
+              }
+            }
+          }
+        }
+      }
+    }
+  }
+  Log::PrintErr("Error starting graphics");
+  Stop();
+  return -1;
+}
+
+void Graphics::Stop() {
+  Log::Print("Stopping graphics");
+  if (display_ != EGL_NO_DISPLAY) {
+    eglMakeCurrent(display_, EGL_NO_SURFACE, EGL_NO_SURFACE, EGL_NO_CONTEXT);
+    if (context_ != EGL_NO_CONTEXT) {
+      eglDestroyContext(display_, context_);
+      context_ = EGL_NO_CONTEXT;
+    }
+    if (surface_ != EGL_NO_SURFACE) {
+      eglDestroySurface(display_, surface_);
+      surface_ = EGL_NO_SURFACE;
+    }
+    eglTerminate(display_);
+    display_ = EGL_NO_DISPLAY;
+  }
+}
+
+int32_t Graphics::Update() {
+  return 0;
+}
+