这是我第一次正确使用 OpenGL，虽然我之前使用过 C 语言
我已经编写了自己的 drawCube 函数，它接收一个坐标数组作为立方体的原点。
我希望代码能将立方体绘制成相互之间的关系，但事实并非如此。它也不会绘制另外两个单独的立方体。我已经花了几个小时来解决这个问题，但不知道为什么。是不是因为 drawCube 没有返回可用于 display() 的东西，如果是这样，它需要返回什么？
正如您可能会说的那样，这最终将成为一个魔方。完成此操作后，我对如何处理数据结构有了一半的了解，但在那之前我感到卡住了
void display() {
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); // Clear screen
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
int x, y, z = 0;
for (z = -1; z < 2; z++) {
for (y = -1; y < 2; y++) {
for (x = -1; x < 2; x++) {
float origin[3] = {x, y, z};
glPushMatrix();
glTranslatef(x, y, z);
glRotatef(45, 0.0, 1.0, 0.5);
drawCube(origin);
glPopMatrix();
}
}
}
glPushMatrix();
glTranslatef(1,1,0);
glRotatef(45, 0.1, 0.2, 0.5);
glColor3ub(255,0,255);
float origin0[3] = {-10, 10, 0};
drawCube(origin0);
glPopMatrix();
glPushMatrix();
glTranslatef(1,-1,0);
glRotatef(45, 0.1, 0.2, 0.5);
glColor3ub(255,0,0);
float origin1[3] = {10, -10, 0};
drawCube(origin1);
glPopMatrix();
// Double buffering effect
//glFlush();
glutSwapBuffers();
}
和 drawCube 功能：
void drawCube(float origin[]) {
// Rotates the cube
glLoadIdentity();
// Rotate when user changes rotate_x and rotate_y
glRotatef(rotate_x, 1.0, 0.0, 0.0);
glRotatef(rotate_y, 0.0, 1.0, 0.0);
//printf("X: %f Y: %f", rotate_x, rotate_y);
// Use glTranslate(x,y,z) to move it
//glTranslatef(0.1, 0.0, 0.0);
glScalef(0.2,0.2,0.2);
// Define the vertices counterclockwise. Not important now but will be once
// start to work with lighting, textures etc
// Red side - FRONT
glBegin(GL_POLYGON); // Start drawing front of cube
glColor3f( 1.0, 0.0, 0.0);
glVertex3f(origin[0]-0.5, origin[1]-0.5, origin[2]-0.5); // Vertex 1
glVertex3f(origin[0]-0.5, origin[1]+0.5, origin[2]-0.5); // Vertex 2
glVertex3f(origin[0]+0.5, origin[1]+0.5, origin[2]-0.5); // Vertex 3
glVertex3f(origin[0]+0.5, origin[1]-0.5, origin[2]-0.5); // Vertex 4
glEnd();
// Orange side - BACK
glBegin(GL_POLYGON);
glColor3f( 1.0, 0.5, 0.0 );
glVertex3f( origin[0]+0.5, origin[1]-0.5, origin[2]+0.5 );
glVertex3f( origin[0]+0.5, origin[1]+0.5, origin[2]+0.5 );
glVertex3f( origin[0]-0.5, origin[1]+0.5, origin[2]+0.5 );
glVertex3f( origin[0]-0.5, origin[1]-0.5, origin[2]+0.5 );
glEnd();
// White side - RIGHT
glBegin(GL_POLYGON);
glColor3f( 1.0, 1.0, 1.0 );
glVertex3f( origin[0]+0.5, origin[1]-0.5, origin[2]-0.5 );
glVertex3f( origin[0]+0.5, origin[1]+0.5, origin[2]-0.5 );
glVertex3f( origin[0]+0.5, origin[1]+0.5, origin[2]+0.5 );
glVertex3f( origin[0]+0.5, origin[1]-0.5, origin[2]+0.5 );
glEnd();
// Yellow side - LEFT
glBegin(GL_POLYGON);
glColor3f( 1.0, 1.0, 0.0 );
glVertex3f( origin[0]-0.5, origin[1]-0.5, origin[2]+0.5 );
glVertex3f( origin[0]-0.5, origin[1]+0.5, origin[2]+0.5 );
glVertex3f( origin[0]-0.5, origin[1]+0.5, origin[2]-0.5 );
glVertex3f( origin[0]-0.5, origin[1]-0.5, origin[2]-0.5 );
glEnd();
// Green side - TOP
glBegin(GL_POLYGON);
glColor3f( 0.0, 1.0, 0.0 );
glVertex3f( origin[0]+0.5, origin[1]+0.5, origin[2]+0.5 );
glVertex3f( origin[0]+0.5, origin[1]+0.5, origin[2]-0.5 );
glVertex3f( origin[0]-0.5, origin[1]+0.5, origin[2]-0.5 );
glVertex3f( origin[0]-0.5, origin[1]+0.5, origin[2]+0.5 );
glEnd();
// Blue side - BOTTOM
glBegin(GL_POLYGON);
glColor3f( 0.0, 0.0, 1.0 );
glVertex3f( origin[0]+0.5, origin[1]-0.5, origin[2]-0.5 );
glVertex3f( origin[0]+0.5, origin[1]-0.5, origin[2]+0.5 );
glVertex3f( origin[0]-0.5, origin[1]-0.5, origin[2]+0.5 );
glVertex3f( origin[0]-0.5, origin[1]-0.5, origin[2]-0.5 );
glEnd();
}