当1除以2或4时,为什么浮点数返回0？

Question

这是我用来飞过我的精灵表的方法.在对象类中,我跟踪信息并进行所有循环,这基本上只需要分配纹理映射坐标.只是它似乎没有工作.但我记录了我翻转行/列的方式,它正确循环.但就纹理而言,我什么都看不到.一点都不 我错过了什么吗？

    public void SetToAnimatedTexture(int NumFramesWide, int NumFramesTall, int CurrentRow, int CurrentColumn) {
    /***************************************************************************************** 
     * This Assembles our Vertices in the correct spots by disassembling
     * our custom rectangles corners, and adds animation. Call this after creating the meshRect
     * *****************************************************************************************/

    float frameWidth = 1/NumFramesWide;
    float frameHeight = 1/NumFramesTall;

    float u1 = frameWidth*CurrentColumn;
    float u2 = (frameWidth*CurrentColumn) + frameWidth;
    float u3 = (frameWidth*CurrentColumn) + frameWidth;
    float u4  = frameWidth*CurrentColumn;

    float v1 = (frameHeight*CurrentRow) + frameHeight;
    float v2 = (frameHeight*CurrentRow) + frameHeight;
    float v3 = frameHeight*CurrentRow;
    float v4 = frameHeight*CurrentRow;

    ByteBuffer byteBuffer = ByteBuffer.allocateDirect(4 * VERTEX_SIZE);
    byteBuffer.order(ByteOrder.nativeOrder());
    vertices = byteBuffer.asFloatBuffer();

    float x1 = (float) rect.BottomLeftCorner.x;
    float x2 = (float) rect.BottomRightCorner.x;
    float x3 = (float) rect.TopRightCorner.x;
    float x4 = (float) rect.TopLeftCorner.x;

    float y1 = (float) rect.BottomLeftCorner.y;
    float y2 = (float) rect.BottomRightCorner.y;
    float y3 = (float) rect.TopRightCorner.y;
    float y4 = (float) rect.TopLeftCorner.y;

    vertices.put(new float[] { x1, y1, 1, 1, 1, 1, u1, v1,
                                x2, y2, 1, 1, 1, 1, u2, v2,
                                x3, y3, 1, 1, 1, 1, u3, v3,
                                x4, y4, 1, 1, 1, 1, u4, v4 });
                            //  x   y   r  g  b  A   u|s  v|t
                            //  x,y are coordinates
                            //  rgba = color red green blue alpha
                            //  u|s v|t = UV or ST texture coordinates
    vertices.flip();

    byteBuffer = ByteBuffer.allocateDirect(6 * 2);
    byteBuffer.order(ByteOrder.nativeOrder());
    indices = byteBuffer.asShortBuffer();
    indices.put(new short[] { 0, 1, 2,
                                2, 3, 0 });
    indices.flip();

}

这是我为自己设定的框架的一部分.

好的,通过做一些日志记录找出问题.这就是问题

    float frameWidth = 1/NumFramesWide;
    float frameHeight = 1/NumFramesTall;

它说这两个值都返回0

    1/2=0 , 1/4=0

我检查了所有变量的值,这就是问题所在.

Answer 1

它首先进行整数除法然后进行赋值.由于1和NumFrames*整数都是整数,因此最终为0.

您可以通过将代码更改为来解决此问题

float frameWidth = 1.f/NumFramesWide;
float frameHeight = 1.f/NumFramesTall;