android - 从 GL_TEXTURE_EXTERNAL_OES 读取到 GL_TEXTURE_2D 有性能问题和故障
问题描述
我需要将数据从 GL_TEXTURE_EXTERNAL_OES 发送到简单的 GL_TEXTURE_2D (将图像从 Android 播放器渲染到 Unity 纹理),目前通过从带有附加源纹理的缓冲区中读取像素来完成。此过程在我的 OnePlus 5 手机上正常工作,但在小米 note 4、mi a2 等手机上的图像存在一些故障(如图像非常绿色),并且由于此过程每帧都有效,因此存在性能问题读取更多像素,而不是更差的性能(即使我的手机在 4k 分辨率下的 fps 也很低)。知道如何优化此过程或以其他方式进行吗?
谢谢和最好的问候!
GLuint FramebufferName;
glGenFramebuffers(1, &FramebufferName);
glBindFramebuffer(GL_FRAMEBUFFER, FramebufferName);
glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_EXTERNAL_OES, g_ExtTexturePointer, 0);
if (glCheckFramebufferStatus(GL_FRAMEBUFFER) != GL_FRAMEBUFFER_COMPLETE)
{
LOGD("%s", "Error: Could not setup frame buffer.");
}
unsigned char* data = new unsigned char[g_SourceWidth * g_SourceHeight * 4];
glReadPixels(0, 0, g_SourceWidth, g_SourceHeight, GL_RGBA, GL_UNSIGNED_BYTE, data);
glBindTexture(GL_TEXTURE_2D, g_TexturePointer);
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, g_SourceWidth, g_SourceHeight, 0, GL_RGBA, GL_UNSIGNED_BYTE, data);
glDeleteFramebuffers(1, &FramebufferName);
glBindFramebuffer(GL_FRAMEBUFFER, 0);
glBindTexture(GL_TEXTURE_2D, 0);
delete[] data;
更新。 包含此代码的函数和从 Unity 端调用它的函数
static void UNITY_INTERFACE_API OnRenderEvent(int eventID) { ... }
extern "C" UnityRenderingEvent UNITY_INTERFACE_EXPORT UNITY_INTERFACE_API UMDGetRenderEventFunc()
{
return OnRenderEvent;
}
从 Unity Update 函数调用如下:
[DllImport("RenderingPlugin")]
static extern IntPtr UMDGetRenderEventFunc();
IEnumerator UpdateVideoTexture()
{
while (true)
{
...
androidPlugin.UpdateSurfaceTexture();
GL.IssuePluginEvent(UMDGetRenderEventFunc, 1);
}
}
Android 插件在其一侧执行此操作(surfaceTexture 其纹理包含 ExoPlayer 渲染视频的外部纹理)
public void exportUpdateSurfaceTexture() {
synchronized (this) {
if (this.mIsStopped) {
return;
}
surfaceTexture.updateTexImage();
}
}
解决方案
在 C++ 方面:
当您这样做时,您正在创建和销毁每一帧的像素数据new unsigned char[g_SourceWidth * g_SourceHeight * 4];
,delete[] data
并且根据纹理大小,这很昂贵。创建一次纹理数据,然后重新使用它。
一种方法是让static
C++ 端的变量保存纹理信息,然后使用函数来初始化这些变量:
static void* pixelData = nullptr;
static int _x;
static int _y;
static int _width;
static int _height;
void initPixelData(void* buffer, int x, int y, int width, int height) {
pixelData = buffer;
_x = x;
_y = y;
_width = width;
_height = height;
}
然后你的捕获函数应该被重写以删除new unsigned char[g_SourceWidth * g_SourceHeight * 4];
但delete[] data
使用静态变量。
static void UNITY_INTERFACE_API OnRenderEvent(int eventID)
{
if (pixelData == nullptr) {
//Debug::Log("Pointer is null", Color::Red);
return;
}
GLuint FramebufferName;
glGenFramebuffers(1, &FramebufferName);
glBindFramebuffer(GL_FRAMEBUFFER, FramebufferName);
glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_EXTERNAL_OES, g_ExtTexturePointer, 0);
if (glCheckFramebufferStatus(GL_FRAMEBUFFER) != GL_FRAMEBUFFER_COMPLETE)
{
LOGD("%s", "Error: Could not setup frame buffer.");
}
glReadPixels(_x, _y, _width, _height, GL_RGBA, GL_UNSIGNED_BYTE, pixelData);
glBindTexture(GL_TEXTURE_2D, g_TexturePointer);
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, _width, _height, 0, GL_RGBA, GL_UNSIGNED_BYTE, pixelData);
glDeleteFramebuffers(1, &FramebufferName);
glBindFramebuffer(GL_FRAMEBUFFER, 0);
glBindTexture(GL_TEXTURE_2D, 0);
}
extern "C" UnityRenderingEvent UNITY_INTERFACE_EXPORT UNITY_INTERFACE_API
UMDGetRenderEventFunc()
{
return OnRenderEvent;
}
在 C# 方面:
[DllImport("RenderingPlugin", CallingConvention = CallingConvention.Cdecl)]
public static extern void initPixelData(IntPtr buffer, int x, int y, int width, int height);
[DllImport("RenderingPlugin", CallingConvention = CallingConvention.StdCall)]
private static extern IntPtr UMDGetRenderEventFunc();
创建纹理信息,将其固定并将指针发送到 C++:
int width = 500;
int height = 500;
//Where Pixel data will be saved
byte[] screenData;
//Where handle that pins the Pixel data will stay
GCHandle pinHandler;
//Used to test the color
public RawImage rawImageColor;
private Texture2D texture;
// Use this for initialization
void Awake()
{
Resolution res = Screen.currentResolution;
width = res.width;
height = res.height;
//Allocate array to be used
screenData = new byte[width * height * 4];
texture = new Texture2D(width, height, TextureFormat.RGBA32, false, false);
//Pin the Array so that it doesn't move around
pinHandler = GCHandle.Alloc(screenData, GCHandleType.Pinned);
//Register the screenshot and pass the array that will receive the pixels
IntPtr arrayPtr = pinHandler.AddrOfPinnedObject();
initPixelData(arrayPtr, 0, 0, width, height);
StartCoroutine(UpdateVideoTexture());
}
然后要更新纹理,请参见下面的示例。请注意,有两种方法可以更新纹理,如下面的代码所示。如果遇到 Method1 的问题,请注释掉texture.LoadRawTextureData
使用and的两行代码,texture.Apply
并取消注释使用ByteArrayToColor
, texture.SetPixels
andtexture.Apply
函数的 Method2 代码:
IEnumerator UpdateVideoTexture()
{
while (true)
{
//Take screenshot of the screen
GL.IssuePluginEvent(UMDGetRenderEventFunc(), 1);
//Update Texture Method1
texture.LoadRawTextureData(screenData);
texture.Apply();
//Update Texture Method2. Use this if the Method1 above crashes
/*
ByteArrayToColor();
texture.SetPixels(colors);
texture.Apply();
*/
//Test it by assigning the texture to a raw image
rawImageColor.texture = texture;
//Wait for a frame
yield return null;
}
}
Color[] colors = null;
void ByteArrayToColor()
{
if (colors == null)
{
colors = new Color[screenData.Length / 4];
}
for (int i = 0; i < screenData.Length; i += 4)
{
colors[i / 4] = new Color(screenData[i],
screenData[i + 1],
screenData[i + 2],
screenData[i + 3]);
}
}
完成后或脚本即将被销毁时取消固定数组:
void OnDisable()
{
//Unpin the array when disabled
pinHandler.Free();
}
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