opengles yuv420 单纹理

在使用OpenGL ES渲染YUV420格式视频时，可以使用单个纹理来处理。下面是一些步骤：

1. 创建一个纹理对象：

GLuint textureId;
glGenTextures(1, &textureId);
glBindTexture(GL_TEXTURE_2D, textureId);

2. 设置纹理参数：

glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);

3. 绑定YUV数据到纹理：

glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, width, height, 0, GL_RGB, GL_UNSIGNED_BYTE, NULL);

4. 将YUV数据分别绑定到纹理的不同通道：

glActiveTexture(GL_TEXTURE0);
glBindTexture(GL_TEXTURE_2D, textureId);
glTexImage2D(GL_TEXTURE_2D, 0, GL_LUMINANCE, width, height, 0, GL_LUMINANCE, GL_UNSIGNED_BYTE, y_data);

glActiveTexture(GL_TEXTURE1);
glBindTexture(GL_TEXTURE_2D, textureId);
glTexImage2D(GL_TEXTURE_2D, 0, GL_LUMINANCE, width/2, height/2, 0, GL_LUMINANCE, GL_UNSIGNED_BYTE, u_data);

glActiveTexture(GL_TEXTURE2);
glBindTexture(GL_TEXTURE_2D, textureId);
glTexImage2D(GL_TEXTURE_2D, 0, GL_LUMINANCE, width/2, height/2, 0, GL_LUMINANCE, GL_UNSIGNED_BYTE, v_data);

5. 使用着色器将纹理渲染到屏幕上：

glUseProgram(program);
glUniform1i(glGetUniformLocation(program, "y_texture"), 0);
glUniform1i(glGetUniformLocation(program, "u_texture"), 1);
glUniform1i(glGetUniformLocation(program, "v_texture"), 2);

// 绘制图形

这样就可以使用单个纹理来处理YUV420格式视频了。