如果我缓冲的字节多于所需的字节数，那么opengl中的缓冲区数据问题只会绘制

Question

Here are the paste bins for the code main.cpp and the shaders . It uses devIL, glload and glfw. Runs on windows and linux. any png named pic.png will load.

I buffer my data in a fairly normal way. Just a simple triangle.

glGenBuffers(1, &vbo);
glBindBuffer(GL_ARRAY_BUFFER, vbo);
//vX     vY    vZ   vW       nX   nY   nZ     U    V        
float bufferDataThree[9*3] = {  
-1.0f, -1.0f, 0.0f,1.0f,    0.0f,1.0f,0.0f,  0.0f,0.0f,
1.0f, -1.0f, 0.0f,1.0f,    0.0f,1.0f,0.0f,  0.0f,1.0f,
1.0f,  1.0f, 0.0f,1.0f,    0.0f,1.0f,0.0f,  1.0f,1.0f};
//TOTAL 4 + 3 + 2 = 9;  
glBufferData(GL_ARRAY_BUFFER, (9*3)*4, bufferDataThree, GL_STATIC_DRAW); //Doesnt Work
//glBufferData(GL_ARRAY_BUFFER, (10*3)*4, bufferDataThree, GL_STATIC_DRAW); //Works

There is 9*3 = 27 floats. Therefore 108 bytes. if I buffer 108 bytes it will screw up the texture coords. If I buffer 116 bytes, (2 floats more) It renders fine.

My display method.

void display()
{
    glClearColor(1.0f, 1.0f, 1.0f, 1.0f);
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

    glUseProgram(program);

    glActiveTexture(GL_TEXTURE0);
    glBindTexture(GL_TEXTURE_2D,tbo);

    glBindBuffer(GL_ARRAY_BUFFER, vbo);
    glEnableVertexAttribArray(0);
    glVertexAttribPointer(0, 4, GL_FLOAT, GL_FALSE, (4 + 3 + 2)*sizeof(float), 0);
    glEnableVertexAttribArray(1);
    glVertexAttribPointer(1, 4, GL_FLOAT, GL_FALSE, (4 + 3 + 2)*sizeof(float),(void*) (4*sizeof(float)));
    glEnableVertexAttribArray(2);
    glVertexAttribPointer(2, 4, GL_FLOAT, GL_FALSE, (4 + 3 + 2)*sizeof(float),(void*) ((4+3)*sizeof(float)));

    glDrawArrays(GL_TRIANGLES,0,3);
    glDisableVertexAttribArray(0);
    glUseProgram(0);

    glfwSwapBuffers();
}

How can this be happening?

Answer 1

glVertexAttribPointer第二个参数是组件数，对于纹理坐标，它是2和3表示正常。