OpenGL - 错误地创建多个 VBO
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【中文标题】OpenGL - 错误地创建多个 VBO【英文标题】：OpenGL - Creating multiple VBOs incorrectly 【发布时间】：2012-08-18 00:27:37 【问题描述】：我遇到的问题是，一旦我为关卡中的主要几何图形创建了 VBO，当我为对象创建第二个 VBO 时，对象 VBO 不起作用。我假设我有一些不正确的缓冲区绑定，但我一辈子都找不到它。我先创建关卡 VBO，然后再创建对象 VBO，当我禁用关卡 VBO 的创建时，对象 VBO 会正确创建。
这是我的代码。
在 level.h 中：
// Zone VBO
GLuint zoneVBO;
GLuint zoneVAO;
GLuint zoneIBO;
// Object VBO
GLuint objVBO;
GLuint objVAO;
GLuint objIBO;
创建区域（几何）VBO - 就像一个注释，创建在两个 VBO 中都能正常工作，所以数据移动不是问题，我认为这是一个绑定错误：
void WLD::createZoneVBO()
// Get the size for our VBO
int numVert = 0;
int numPoly = 0;
int VBOsize = 0;
int IBOsize = 0;
// Get the count of vertices and polygons
for(int i = 0; i < zoneFragMap[0x36]; i++)
numVert += zmeshes[i].numVert;
numPoly += zmeshes[i].numPoly;
VBOsize += zmeshes[i].numVert * sizeof(Vertex);
IBOsize += zmeshes[i].numPoly * 3 * sizeof(GLuint);
// Create the IBO and VBO data
GLuint* iboData = new GLuint[zonePolyProcessed * 3];
Vertex* vboData = new Vertex[zoneVertProcessed];
int iboPos = 0;
int vboPos = 0;
// Create the VBO and IBO
for(int i = 0; i < zoneFragMap[0x36]; i++)
// Copy the data to the IBO
memcpy(&iboData[iboPos], zmeshes[i].indices, zmeshes[i].numPoly * 3 * sizeof(GLuint));//sizeof(*zmeshes[i].indices));
// Advance the position
iboPos += zmeshes[i].numPoly * 3;
// Copy the data to the VBO
memcpy(&vboData[vboPos], zmeshes[i].vertices, zmeshes[i].numVert * sizeof(Vertex));//sizeof(*zmeshes[i].vertices));
// Advance the position
vboPos += zmeshes[i].numVert;
//Create VBO for the triangle
glGenBuffers(1, &zoneVBO);
glBindBuffer(GL_ARRAY_BUFFER, zoneVBO);
glBufferData(GL_ARRAY_BUFFER, zoneVertProcessed * sizeof(Vertex), vboData, GL_STATIC_DRAW);
glBindBuffer(GL_ARRAY_BUFFER, 0);
//Create the IBO for the triangle
//16 bit indices
//We could have actually made one big IBO for both the quad and triangle.
glGenBuffers(1, &zoneIBO);
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, zoneIBO);
glBufferData(GL_ELEMENT_ARRAY_BUFFER, zonePolyProcessed * 3 * sizeof(GLuint), iboData, GL_STATIC_DRAW);
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, 0);
// Create the VAO
glGenVertexArraysAPPLE(1, &zoneVAO);
glBindVertexArrayAPPLE(zoneVAO);
glBindBuffer(GL_ARRAY_BUFFER, zoneVAO);
glEnableVertexAttribArray(0);
glEnableVertexAttribArray(1);
glEnableVertexAttribArray(2);
glEnableVertexAttribArray(3);
glVertexAttribPointer(opaque["position"], 3, GL_FLOAT, GL_FALSE, sizeof(Vertex), BUFFER_OFFSET(0));
glVertexAttribPointer(opaque["normal"], 3, GL_FLOAT, GL_FALSE, sizeof(Vertex), BUFFER_OFFSET(sizeof(float) * 3));
glVertexAttribPointer(opaque["texcoord"], 2, GL_FLOAT, GL_FALSE, sizeof(Vertex), BUFFER_OFFSET(sizeof(float) * 6));
glVertexAttribPointer(opaque["color"], 4, GL_FLOAT, GL_FALSE, sizeof(Vertex), BUFFER_OFFSET(sizeof(float) * 8));
glBindBuffer(GL_ARRAY_BUFFER, 0);
glBindVertexArrayAPPLE(0);
delete[] iboData;
delete[] vboData;
还有对象——同样，对象几何体已完美加载，但前提是区域几何体尚未加载：
void WLD::createObjectVBO()
// Get the size for our VBO
int numVert = 0;
int numPoly = 0;
int VBOsize = 0;
int IBOsize = 0;
// Get the count of vertices and polygons
for(int i = 0; i < objFragMap[0x36]; i++)
numVert += objMeshes[i].numVert;
numPoly += objMeshes[i].numPoly;
VBOsize += objMeshes[i].numVert * sizeof(Vertex);
IBOsize += objMeshes[i].numPoly * 3 * sizeof(GLuint);
// Create the IBO and VBO data
GLuint* iboData = new GLuint[objPolyProcessed * 3];
Vertex* vboData = new Vertex[objVertProcessed];
int iboPos = 0;
int vboPos = 0;
// Create the VBO and IBO
for(int i = 0; i < objFragMap[0x36]; i++)
// Copy the data to the IBO
memcpy(&iboData[iboPos], objMeshes[i].indices, objMeshes[i].numPoly * 3 * sizeof(GLuint));//sizeof(*zmeshes[i].indices));
// Advance the position
iboPos += objMeshes[i].numPoly * 3;
// Copy the data to the VBO
memcpy(&vboData[vboPos], objMeshes[i].vertices, objMeshes[i].numVert * sizeof(Vertex));//sizeof(*zmeshes[i].vertices));
// Advance the position
vboPos += objMeshes[i].numVert;
//Create VBO for the triangle
glGenBuffers(1, &objVBO);
glBindBuffer(GL_ARRAY_BUFFER, objVBO);
glBufferData(GL_ARRAY_BUFFER, objVertProcessed * sizeof(Vertex), vboData, GL_STATIC_DRAW);
glBindBuffer(GL_ARRAY_BUFFER, 0);
//Create the IBO for the triangle
//16 bit indices
//We could have actually made one big IBO for both the quad and triangle.
glGenBuffers(1, &objIBO);
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, objIBO);
glBufferData(GL_ELEMENT_ARRAY_BUFFER, objPolyProcessed * 3 * sizeof(GLuint), iboData, GL_STATIC_DRAW);
glBindBuffer(GL_ARRAY_BUFFER, 0);
// Create the VAO
glGenVertexArraysAPPLE(1, &objVAO);
glBindVertexArrayAPPLE(objVAO);
glBindBuffer(GL_ARRAY_BUFFER, objVAO);
glEnableVertexAttribArray(0);
glEnableVertexAttribArray(1);
glEnableVertexAttribArray(2);
glEnableVertexAttribArray(3);
glVertexAttribPointer(opaque["position"], 3, GL_FLOAT, GL_FALSE, sizeof(Vertex), BUFFER_OFFSET(0));
glVertexAttribPointer(opaque["normal"], 3, GL_FLOAT, GL_FALSE, sizeof(Vertex), BUFFER_OFFSET(sizeof(float) * 3));
glVertexAttribPointer(opaque["texcoord"], 2, GL_FLOAT, GL_FALSE, sizeof(Vertex), BUFFER_OFFSET(sizeof(float) * 6));
glVertexAttribPointer(opaque["color"], 4, GL_FLOAT, GL_FALSE, sizeof(Vertex), BUFFER_OFFSET(sizeof(float) * 8));
glBindBuffer(GL_ARRAY_BUFFER, 0);
glBindVertexArrayAPPLE(0);
渲染这两个 VBO：
opaque.Use();
glBindVertexArrayAPPLE(getVAO(2));
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, zoneIBO);
glBindBuffer(GL_ARRAY_BUFFER, zoneVBO);
glUniformMatrix4fv(opaque("camera"), 1, GL_FALSE, glm::value_ptr(cameraMat));
renderGeometry(&cameraMat, 0, curRegion);
glBindVertexArrayAPPLE(0);
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, 0);
glBindBuffer(GL_ARRAY_BUFFER, 0);
glBindVertexArrayAPPLE(objVAO);
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, objIBO);
glBindBuffer(GL_ARRAY_BUFFER, objVBO);
glUniformMatrix4fv(opaque("camera"), 1, GL_FALSE, glm::value_ptr(cameraMat));
renderObjects(&cameraMat);
glBindVertexArrayAPPLE(0);
glBindBuffer(GL_ARRAY_BUFFER, 0);
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, 0);
opaque.UnUse();
总而言之，我认为这是创建 VBO 的一个问题。我认为我做错了什么，并在应该绑定的时候保持绑定。
【问题讨论】：
尝试从渲染代码中删除 glBindBuffer。如果内存正常，您只需重新绑定顶点数组。 @iKlsR 当我这样做时，我得到一个 EXC_BAD_ACCESS 运行时错误。 【参考方案1】：// Create the VAO
glGenVertexArraysAPPLE(1, &zoneVAO);
glBindVertexArrayAPPLE(zoneVAO);
glBindBuffer(GL_ARRAY_BUFFER, zoneVAO); //<-------
glEnableVertexAttribArray(0);
在我突出显示的行中，这看起来应该是zoneVBO，而不是zoneVAO。
您应该使用 glGetError 检查错误，它可能已经发现了这个错误。
在调用 renderObjects 之前不需要绑定缓冲区。如果您将顶点指针存储在 VAO 中，则无需绑定缓冲区，因为顶点指针已经指向正确的位置。
【讨论】：
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