同时旋转多个立方体的问题

Question

我正在画一个由三个立方体组成的金字塔(两面对侧，另一边在顶部)，然后我试着在X，Y或Z轴上旋转这个金字塔，并把它上下缩放。

问题是这三个立方体没有正确地缩放(不同的尺寸)，同时旋转也会产生非常奇怪的结果。

我使用glm vec3数组为我的立方体定义了一个数组：

const glm::vec3 cube[] = {
    glm::vec3(-1.0f,-1.0f,-1.0f),
    glm::vec3( -1.0f,-1.0f, 1.0f),
    glm::vec3(-1.0f, 1.0f, 1.0f),
    glm::vec3(1.0f, 1.0f,-1.0f), 
    glm::vec3(-1.0f,-1.0f,-1.0f),
    glm::vec3(-1.0f, 1.0f,-1.0f),
    glm::vec3(1.0f,-1.0f, 1.0f),
    glm::vec3(-1.0f,-1.0f,-1.0f),
    glm::vec3(1.0f,-1.0f,-1.0f),
    glm::vec3(1.0f, 1.0f,-1.0f),
    glm::vec3(1.0f,-1.0f,-1.0f),
    glm::vec3(-1.0f,-1.0f,-1.0f),
    glm::vec3(-1.0f,-1.0f,-1.0f),
    glm::vec3(-1.0f, 1.0f, 1.0f),
    glm::vec3(-1.0f, 1.0f,-1.0f),
    glm::vec3(1.0f,-1.0f, 1.0f),
    glm::vec3(-1.0f,-1.0f, 1.0f),
    glm::vec3(-1.0f,-1.0f,-1.0f),
    glm::vec3(-1.0f, 1.0f, 1.0f),
    glm::vec3(-1.0f,-1.0f, 1.0f),
    glm::vec3(1.0f,-1.0f, 1.0f),
    glm::vec3(1.0f, 1.0f, 1.0f),
    glm::vec3(1.0f,-1.0f,-1.0f),
    glm::vec3(1.0f, 1.0f,-1.0f),
    glm::vec3(1.0f,-1.0f,-1.0f),
    glm::vec3(1.0f, 1.0f, 1.0f),
    glm::vec3(1.0f,-1.0f, 1.0f),
    glm::vec3(1.0f, 1.0f, 1.0f),
    glm::vec3(1.0f, 1.0f,-1.0f),
    glm::vec3(-1.0f, 1.0f,-1.0f),
    glm::vec3(1.0f, 1.0f, 1.0f),
    glm::vec3(-1.0f, 1.0f,-1.0f),
    glm::vec3(-1.0f, 1.0f, 1.0f),
    glm::vec3(1.0f, 1.0f, 1.0f),
    glm::vec3(-1.0f, 1.0f, 1.0f),
    glm::vec3(1.0f,-1.0f, 1.0f)
};

我生成并链接缓冲区和必要的东西，使OpenGL工作，然后我画金字塔，这是由三个立方体。我几乎可以肯定，这是代码中所有错误的部分：

glm::mat4 P = glm::perspective(glm::radians(60.0f + zoom), float(width()) / height(), 0.01f, 1000.0f);

glm::mat4 V = glm::mat4(1);
V = glm::translate(V, glm::vec3(-3 + moveX, -1 + moveY, -6 + moveZ));


V = glm::rotate(V, glm::radians(rotateCamradX), glm::vec3(1.0, 0.0, 0.0));
V = glm::rotate(V, glm::radians(rotateCamradY), glm::vec3(0.0, 1.0, 0.0));
V = glm::rotate(V, glm::radians(rotateCamradZ), glm::vec3(0.0, 0.0, 1.0));


glm::mat4 M = glm::mat4(1);  
M = glm::translate(M, glm::vec3(-1, 0, 0));

M = glm::rotate(M, glm::radians(rotateradX), glm::vec3(1.0, 0.0, 0.0));
M = glm::rotate(M, glm::radians(rotateradY), glm::vec3(0.0, 1.0, 0.0));
M = glm::rotate(M, glm::radians(rotateradZ), glm::vec3(0.0, 0.0, 1.0));

M = glm::scale(M, glm::vec3(scaleVar, scaleVar, scaleVar));

glm::mat4 M1 = glm::mat4(1);
M1 = glm::translate(M, glm::vec3(2, 0, 0));

M1 = glm::rotate(M1, glm::radians(rotateradX), glm::vec3(1.0, 0.0, 0.0));
M1 = glm::rotate(M1, glm::radians(rotateradY), glm::vec3(0.0, 1.0, 0.0));
M1 = glm::rotate(M1, glm::radians(rotateradZ), glm::vec3(0.0, 0.0, 1.0));

M1 = glm::scale(M1, glm::vec3(scaleVar, scaleVar, scaleVar));


glm::mat4 M2 = glm::mat4(1);
M2 = glm::translate(M, glm::vec3(1, 2, 0));

M2 = glm::rotate(M2, glm::radians(rotateradX), glm::vec3(1.0, 0.0, 0.0));
M2 = glm::rotate(M2, glm::radians(rotateradY), glm::vec3(0.0, 1.0, 0.0));
M2 = glm::rotate(M2, glm::radians(rotateradZ), glm::vec3(0.0, 0.0, 1.0));

M2 = glm::scale(M2, glm::vec3(scaleVar, scaleVar, scaleVar));

glm::mat4 PVM = P * V * M;
glm::mat4 PVM1 = P * V * M1;
glm::mat4 PVM2 = P * V * M2;

gl->glUniformMatrix4fv(id_shader_program_PVM_uniform, 1, GL_FALSE, glm::value_ptr(PVM));
gl->glUniform3f(id_shader_program_Color_uniform, 0.3f ,0.1f, 0.2f);
gl->glDrawArrays(GL_TRIANGLES, 0, 3*12);
gl->glUniformMatrix4fv(id_shader_program_PVM_uniform, 1, GL_FALSE, glm::value_ptr(PVM1));
gl->glUniform3f(id_shader_program_Color_uniform, 0.8f ,0.2f, 0.7f);
gl->glDrawArrays(GL_TRIANGLES, 0, 3*12);
gl->glUniformMatrix4fv(id_shader_program_PVM_uniform, 1, GL_FALSE, glm::value_ptr(PVM2));
gl->glUniform3f(id_shader_program_Color_uniform, 0.1f ,0.2f, 0.1f);
gl->glDrawArrays(GL_TRIANGLES, 0, 3*12);

摄像机运动采用V矩阵中的变量，而M、M1和M2则是缩放变量和旋转变量。所有变量都是浮动类型，我在UI应用程序中使用按钮进行更改。

Answer 1

尝试翻转您的转换顺序。代替平移，旋转，缩放，缩放，旋转，平移。

顺便提一下，使用glm::lookAt计算V矩阵通常更容易，然后使用多个步骤。