顶点缓冲区VBO和索引缓冲区IBO的结合使用

来源：互联网发布：寻侠肉身突破数据编辑：程序博客网时间：2024/05/22 08:25

virtual void onInit(){//清空窗口为黑色glClearColor(0,0,0,1);//设置视口的位置和大小--尝试改变视口的位置和大小glViewport(0,0,(GLint)_winWidth,(GLint)_winHeight);//创建VBO-顶点缓冲区glGenBuffers(1, &_vertexId);//若创建多个，第二个参数应该是数组//绑定并指定buffer类型为VBOglBindBuffer(GL_ARRAY_BUFFER,_vertexId);float   x = 100;float   y = 100;float   w = 100;float   h = 100;CELL::float2  pos[] ={CELL::float2(x, y),CELL::float2(x + w, y),CELL::float2(x + w, y + h),CELL::float2(y, y + h),};//将内存中的顶点数据传送进显存glBufferData(GL_ARRAY_BUFFER,sizeof(pos),pos,GL_STATIC_DRAW);//切换状态glBindBuffer(GL_ARRAY_BUFFER, 0);//创建索引缓冲区glGenBuffers(1, &_indexId);glBindBuffer(GL_ELEMENT_ARRAY_BUFFER,_indexId);//指定顶点索引unsigned short     arIndex[] ={0, 1, 2, 3, 0};//数据传递到显卡glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(arIndex), arIndex, GL_STATIC_DRAW);//切换状态glBindBuffer(GL_ELEMENT_ARRAY_BUFFER,0);}

渲染

virtual void render(){//清除深度缓冲和颜色缓冲glClear(GL_DEPTH_BUFFER_BIT | GL_COLOR_BUFFER_BIT);//指定视口大小glViewport(0,0,_winWidth,_winHeight);//创建一个投影矩阵CELL::matrix4 screenProj = CELL::ortho<float>(0, float(_winWidth), float(_winHeight), 0, -100.0f, 100);glBindBuffer(GL_ARRAY_BUFFER,_vertexId);_shader.begin();//启用顶点相关属性{glUniformMatrix4fv(_shader._MVP,1,false,screenProj.data());glUniform4f(_shader._color,1,0,0,1);glVertexAttribPointer(_shader._position, 2, GL_FLOAT, false, sizeof(CELL::float2), 0);unsigned short     arIndex[] ={0, 1, 2, 3, 0};glDrawElements(GL_LINE_STRIP,5,GL_UNSIGNED_SHORT,arIndex);}_shader.end();//关闭顶点相关属性glBindBuffer(GL_ARRAY_BUFFER,0);eglSwapBuffers(_display,_surface);}

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