c++ - 在 opengl 中绘制具有六个不同颜色面的立方体

Question

我在 OpenGL 中绘制了一个立方体，但我希望立方体的每个面都填充一种颜色。

这就是我所做的，我不知道为什么只有2张脸被填充了颜色。

void DrawCube(GLfloat centerPosX, GLfloat centerPosY, GLfloat centerPosZ, GLfloat edgeLength)
{
    GLfloat halfSideLength = edgeLength * 0.5f;

    GLfloat vertices[] =
    {
        // front face
        centerPosX - halfSideLength, centerPosY + halfSideLength, centerPosZ + halfSideLength, // top left
        centerPosX + halfSideLength, centerPosY + halfSideLength, centerPosZ + halfSideLength, // top right
        centerPosX + halfSideLength, centerPosY - halfSideLength, centerPosZ + halfSideLength, // bottom right
        centerPosX - halfSideLength, centerPosY - halfSideLength, centerPosZ + halfSideLength, // bottom left

        // back face
        centerPosX - halfSideLength, centerPosY + halfSideLength, centerPosZ - halfSideLength, // top left
        centerPosX + halfSideLength, centerPosY + halfSideLength, centerPosZ - halfSideLength, // top right
        centerPosX + halfSideLength, centerPosY - halfSideLength, centerPosZ - halfSideLength, // bottom right
        centerPosX - halfSideLength, centerPosY - halfSideLength, centerPosZ - halfSideLength, // bottom left

        // left face
        centerPosX - halfSideLength, centerPosY + halfSideLength, centerPosZ + halfSideLength, // top left
        centerPosX - halfSideLength, centerPosY + halfSideLength, centerPosZ - halfSideLength, // top right
        centerPosX - halfSideLength, centerPosY - halfSideLength, centerPosZ - halfSideLength, // bottom right
        centerPosX - halfSideLength, centerPosY - halfSideLength, centerPosZ + halfSideLength, // bottom left

        // right face
        centerPosX - halfSideLength, centerPosY + halfSideLength, centerPosZ + halfSideLength, // top left
        centerPosX - halfSideLength, centerPosY + halfSideLength, centerPosZ - halfSideLength, // top right
        centerPosX - halfSideLength, centerPosY - halfSideLength, centerPosZ - halfSideLength, // bottom right
        centerPosX - halfSideLength, centerPosY - halfSideLength, centerPosZ + halfSideLength, // bottom left

        // top face
        centerPosX - halfSideLength, centerPosY + halfSideLength, centerPosZ + halfSideLength, // top left
        centerPosX - halfSideLength, centerPosY + halfSideLength, centerPosZ - halfSideLength, // top right
        centerPosX + halfSideLength, centerPosY + halfSideLength, centerPosZ - halfSideLength, // bottom right
        centerPosX + halfSideLength, centerPosY + halfSideLength, centerPosZ + halfSideLength, // bottom left

        // bottom face                                                                                                                                                                           // right face
        centerPosX - halfSideLength, centerPosY - halfSideLength, centerPosZ + halfSideLength, // top left
        centerPosX - halfSideLength, centerPosY - halfSideLength, centerPosZ - halfSideLength, // top right
        centerPosX + halfSideLength, centerPosY - halfSideLength, centerPosZ - halfSideLength, // bottom right
        centerPosX + halfSideLength, centerPosY - halfSideLength, centerPosZ + halfSideLength, // bottom left                                                                                                                                                                                                                                                                                                                                                                                                                                                  centerPosX + halfSideLength, centerPosY - halfSideLength, centerPosZ - halfSideLength, // bottom right                                                                                                                                                                                                                                                                                                                                                                                                                                                  centerPosX + halfSideLength, centerPosY - halfSideLength, centerPosZ + halfSideLength  // bottom left
    };

    GLfloat colour[] = {
        255, 0, 0,
        255, 0, 0,
        255, 0, 0,
        255, 0, 0,
        0, 255, 0,
        0, 255, 0,
        0, 255, 0,
        0, 255, 0,
        0, 0, 255,
        0, 0, 255,
        0, 0, 255,
        0, 0, 255,
        100,100,100,
        100,100,100,
        100,100,100,
        100,100,100,
        200,200,200,
        200,200,200,
        200,200,200,
        200,200,200,
        40,220,75,
        40,220,75,
        40,220,75,
        40,220,75,
    };

    glEnableClientState(GL_VERTEX_ARRAY);
    glEnableClientState(GL_COLOR_ARRAY);
    glVertexPointer(3, GL_FLOAT, 0, vertices);
    glColorPointer(3, GL_FLOAT, 0, colour);
    glDrawArrays(GL_QUADS, 0, 24);
    glDisableClientState(GL_VERTEX_ARRAY);
    glDisableClientState(GL_COLOR_ARRAY);
}

我的程序的输出是这样的:

如你所见，我有 1 张红脸、1 张绿脸和 4 张非彩色脸

Answer 1

虽然 Armen 是正确的，但还有其他问题。

您忘记开启深度测试。这就是为什么你可以看到红色的一面，即使从你的角度来看你不应该看到。这也是为什么您可以“透过”前墙看到后绿墙的原因。