OpenGL

OpenGL is a cross-platform graphics API that specifies a standard software interface for 3D graphics processing hardware. OpenHarmony now supports OpenGL 4.2.

Supported Capabilities and Devices

Capabilities:

• OpenGL 3.0 is supported since API version 20.

• OpenGL 4.2 is supported since API version 22.

Devices:

OpenGL is supported on PC devices starting from API version 20. Starting from API version 22, support for OpenGL is newly added on some tablet devices. Whether a specific tablet device supports this capability can be determined through the OH_Graphics_QueryGL API.

Checking the Support for OpenGL

Starting from API version 22, you can call the OH_Graphics_QueryGL API to check whether the device supports OpenGL and whether it needs to fall back to OpenGL ES.

Device behavior differences: The OH_Graphics_QueryGL API works properly on PCs and tablets but returns null on other devices.

Specific examples are as follows:

typedef EGLBoolean(*OH_Graphics_QueryGL_FUNC)(void);
static napi_value QueryGL(napi_env env, napi_callback_info info)
{
    const char &r0 = u8"OH_Graphics_QueryGL does not exist. Use GLES";
    const char &r1 = u8"OH_Graphics_QueryGL exists; returns 0. Use GLES";
    const char &r2 = u8"OH_Graphics_QueryGL exists; returns 1. Use GL";
    napi_value result = nullptr;
    napi_status status = napi_invalid_arg;
    OH_Graphics_QueryGL_FUNC OH_Graphics_QueryGL = (OH_Graphics_QueryGL_FUNC)eglGetProcAddress("OH_Graphics_QueryGL");
    if (OH_Graphics_QueryGL) {
        if (OH_Graphics_QueryGL()) {
            status = napi_create_string_utf8(env, r2, (size_t)strlen(r2), &result);
        } else {
            status = napi_create_string_utf8(env, r1, (size_t)strlen(r1), &result);
        }
    } else {
        status = napi_create_string_utf8(env, r0, (size_t)strlen(r0), &result);
    }
    if (status != napi_ok) {
        napi_throw_error(env, nullptr, "Failed to create UTF-8 string");
    }
    return result;
}

Symbols Exported from the Standard Library

OpenGL Symbols Exported from Native APIs

OpenGL Extensions and Examples

For details about the OpenGL extensions and their usage, see OpenGL ES Extensions.

For details about how to use these extensions, see OpenGL ES Example.

Introducing OpenGL

To use OpenGL capabilities, you must add related dynamic link libraries (DLLs) and header files.

Adding Dynamic Link Libraries

Add the following libraries to CMakeLists.txt.

libace_ndk.z.so
libace_napi.z.so
libGLv4.so
libEGL.so

Including Header Files

#include <ace/xcomponent/native_interface_xcomponent.h>
#include <EGL/egl.h>
#include <EGL/eglext.h>
#include <EGL/eglplatform.h>
#include <GL/gl.h>
#include <GL/glcorearb.h>

Modifying the app.json5 Configuration File

"appEnvironments": [
 {
   "name":"NEED_OPENGL",
   "value": "1"
 }
],

References

To use the OpenGL API in your application development, familiarize yourself with the NDK development process and the XComponent usage, which are described in the following topics:

• Getting Started with the NDK

• Node-API

• XComponentNode

• XComponent