我正在尝试使用 IBO 渲染两个不同的三角形。我将六个顶点存储在一个 VBO 中,并尝试通过两个独立的 IBO 访问它们。问题是第一个 IBO 渲染但第二个没有。createVertices 和 createIndices 在初始化时被调用。
void createVertices()
{
//Vertex Data
GLfloat v[] = { 0.95f, 0.75f, 0.0f, 1.0f,
0.75f, -0.75f, 0.0f, 1.0f,
0.0f, -0.75f, 0.0f, 1.0f, // END OF TRIANGLE 1
-0.75, 0.75f, 0.5f, 1.0f,
-0.75, -0.75f, 0.5f, 1.0f,
0.0f, -0.75f, 0.5f, 1.0f }; // END OF TRIANGLE 2
glGenVertexArrays(1, &VAO);
glBindVertexArray(VAO);
glGenBuffers(1, &VBO);
glBindBuffer(GL_ARRAY_BUFFER, VBO);
glBufferData(GL_ARRAY_BUFFER, sizeof(v), v, GL_STATIC_DRAW);
glEnableVertexAttribArray(0);
glBindBuffer(GL_ARRAY_BUFFER, 0);
}
//////////
void createIndices()
{
GLushort i[] = { 0,1,2};
glGenBuffers(2, IBO);
glBindBuffer(GL_ARRAY_BUFFER, VBO);
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, IBO[0]);
glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(i), i, GL_STATIC_DRAW);
size = (sizeof(i)/sizeof(GLushort)); // USED IN DRAWELEMENTS
GLushort w[] = { 3,4,5};
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, IBO[1]);
glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(w), w, GL_STATIC_DRAW);
size2 = (sizeof(i)/sizeof(GLushort)); // USED IN DRAWELEMENTS
glBindBuffer(GL_ARRAY_BUFFER, 0);
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, 0);
}
/////////
void Render()
{
glClear(GL_COLOR_BUFFER_BIT);
glUseProgram(shader.SProgram);
glBindBuffer(GL_ARRAY_BUFFER, VBO);
glVertexAttribPointer(0,4, GL_FLOAT, GL_FALSE, 0, 0);
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, IBO[0]);
glDrawElements(GL_TRIANGLES,size,GL_UNSIGNED_SHORT,(GLvoid*)IBO[0]);
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, IBO[1]);
glDrawElements(GL_TRIANGLES,size2,GL_UNSIGNED_SHORT,(GLvoid*)IBO[1]);
glUseProgram(0);
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, 0);
}