Question

我在opengl C ++中绘制了一个饼图，并且在初始化时，颜色变得很好。但是当我按下一个按钮来rand（）颜色时，饼图变得不可见。

见下我的饼图代码

void PieChart1(int x, int y, int radius)
{
    //float i;
    int triangleAmount = 100; //# of triangles used to draw circle
    int startPos = 0;
    int Pie1AnglePercentage[7];
    GLfloat twicePi = 2.0f * 3.14159;
    float TotalPie1Banana = 0;
    //TotalZoo1Banana = 0;
    //int zoo1Data[7] = { 200, 300, 250, 275, 150, 310, 380 };
    //Zoo1PieData

    GLfloat colorTable[7][3] = { { Pie12014R, Pie12014G, Pie12014B },
    { Pie12013R, Pie12013G, Pie12013B },
    { Pie12012R, Pie12012G, Pie12012B },
    { Pie12011R, Pie12011G, Pie12011B },
    { Pie12010R, Pie12010G, Pie12010B },
    { Pie12009R, Pie12009G, Pie12009B },
    { Pie12008R, Pie12008G, Pie12008B } };

    float Zoo1PieData[7] = { BananaDisplay2014,BananaDisplay2013,BananaDisplay2012,
        BananaDisplay2011,BananaDisplay2010,BananaDisplay2009,BananaDisplay2008 };


    //PIE 1 ZOO 1 SUM BANANAS TOTAL
    for(int i = 0; i < 7; ++i)
        TotalPie1Banana += Zoo1PieData[i];

    //PIE 1 PERCENTAGE FOR EACH YEAR
    for (int i = 0; i < 7; ++i)
        Pie1AnglePercentage[i] = (Zoo1PieData[i] / TotalPie1Banana) * 100;

    triangleAmount = 0;
    for (int i = 0; i < 7; ++i)
        triangleAmount += Pie1AnglePercentage[i];

    for (int i = 0; i < 7; ++i)
    {
        glBegin(GL_TRIANGLE_FAN);
        glColor3f(colorTable[i][0], colorTable[i][1], colorTable[i][2]);
        glVertex3f(x, y, 0);

        for (int j = startPos; j <= startPos + Pie1AnglePercentage[i]; ++j)
        {
            float const t = (twicePi*(float)j / (float)triangleAmount) + 3.141592;
            glVertex3f(x - sin(t) * radius, y + cos(t) * radius, 0);
        }
        startPos += Pie1AnglePercentage[i];

        glEnd();
    }

以上是我的饼图代码。

这是我的案例密钥代码

case 'c':
            Pie12014R = rand() % 255;
            Pie12014G = rand() % 255;
            Pie12014B = rand() % 255;

            Pie12013R = rand() % 255;
            Pie12013G = rand() % 255;
            Pie12013B = rand() % 255;

            Pie12012R = rand() % 255;
            Pie12012G = rand() % 255;
            Pie12012B = rand() % 255;

            Pie12011R = rand() % 255;
            Pie12011G = rand() % 255;
            Pie12011B = rand() % 255;

            Pie12010R = rand() % 255;
            Pie12010G = rand() % 255;
            Pie12010B = rand() % 255;

            Pie12009R = rand() % 255;
            Pie12009G = rand() % 255;
            Pie12009B = rand() % 255;

            Pie12008R = rand() % 255;
            Pie12008G = rand() % 255;
            Pie12008B = rand() % 255;

我不知道为什么当我按下C键时，馅饼会立即消失。

Answer 1

饼图颜色设置为glColor3f而非glColor3ub，但我的颜色值已声明为无符号字节。

Opengl饼图颜色更改遇到错误

1 个答案: