creator gfx 各个类的源码解读（4） WebGL2CmdObject

gfx 各个类的源码解读（4） WebGL2CmdObject
WebGL2CmdObject 在 webgl2-commands.ts
WebGL2CmdObject是命令执行的基础类
有五个子类
  WebGL2CmdBeginRenderPass
  WebGL2CmdBindStates
  WebGL2CmdDraw
  WebGL2CmdUpdateBuffer
  WebGL2CmdCopyBufferToTexture

WebGL2CmdPackage类
  对于批量命令的封装，命令的集合
成员变量:

    public cmds: CachedArray<WebGL2Cmd> = new CachedArray(1);
    public beginRenderPassCmds: CachedArray<WebGL2CmdBeginRenderPass> = new CachedArray(1);
    public bindStatesCmds: CachedArray<WebGL2CmdBindStates> = new CachedArray(1);
    public drawCmds: CachedArray<WebGL2CmdDraw> = new CachedArray(1);
    public updateBufferCmds: CachedArray<WebGL2CmdUpdateBuffer> = new CachedArray(1);
    public copyBufferToTextureCmds: CachedArray<WebGL2CmdCopyBufferToTexture> = new CachedArray(1);

WebGL2CmdFuncExecuteCmds函数(device: WebGL2Device, cmdPackage: WebGL2CmdPackage)
根据WebGL2CmdPackage里的命令集合执行命令
代码片段:

  for (let i = 0; i < cmdPackage.cmds.length; ++i) {
        const cmd = cmdPackage.cmds.array[i];
        const cmdId = cmdIds[cmd]++;
        switch (cmd) {
        case WebGL2Cmd.BEGIN_RENDER_PASS: {
            const cmd0 = cmdPackage.beginRenderPassCmds.array[cmdId];
            WebGL2CmdFuncBeginRenderPass(device, cmd0.gpuRenderPass, cmd0.gpuFramebuffer, cmd0.renderArea,
                cmd0.clearColors, cmd0.clearDepth, cmd0.clearStencil);
            break;
        }

  //........