Question

当您以RTS游戏或Windows桌面的方式单击和拖动时，我正在尝试绘制一个选择框。目前，当我运行此代码时，它会在中心创建一个带有透明菱形的绿色框。

我正在尝试创建一个带有实心1px边框和内部略透明的框。

public class SelectionBox : MonoBehaviour {

    public Color borderColor = new Color(0f, 1f, 0f, 1f);
    public Color innerColor = new Color(0f, 1f, 0f, 0.2f);

    bool mouseDown = false;
    Vector2 screenStartSelect, screenEndSelect;
    Texture2D texture2d;

    void Start(){
        texture2d = new Texture2D(3, 3, TextureFormat.ARGB32, false);
        // Top Row
        texture2d.SetPixel(0, 0, borderColor);
        texture2d.SetPixel(1, 0, borderColor);
        texture2d.SetPixel(2, 0, borderColor);

        // Middle Row
        texture2d.SetPixel(0, 1, borderColor);
        texture2d.SetPixel(1, 1, innerColor);
        texture2d.SetPixel(2, 1, borderColor);

        // Bottom Row
        texture2d.SetPixel(0, 2, borderColor);
        texture2d.SetPixel(1, 2, borderColor);
        texture2d.SetPixel(2, 2, borderColor);

        texture2d.Apply();
    }

    // Update is called once per frame
    void Update () {
        // Mouse button clicked
        if(Input.GetMouseButtonDown(0) && !mouseDown){
            mouseDown = true;
            screenStartSelect = Input.mousePosition;
        }

        if(mouseDown){
            screenEndSelect = Input.mousePosition;
        }

        // Mouse button released
        if(Input.GetMouseButtonUp(0) && mouseDown){
            mouseDown = false;
        }
    }

    void OnGUI() {
        if (mouseDown) {
            GUI.DrawTexture(
                new Rect(
                    screenStartSelect.x,
                    Screen.height - screenStartSelect.y,
                    screenEndSelect.x - screenStartSelect.x,
                    -1 * ((Screen.height - screenStartSelect.y) - (Screen.height - screenEndSelect.y))
                ),
                texture2d
            );
        }
    }
}

结果如下：

Answer 1

我已经提出了一个有效的解决方案，但不确定这是多么优化：

void OnGUI() {
    if (mouseDown) {
        var width = (int)(screenEndSelect.x - screenStartSelect.x);
        var height = (int)(-1 * ((Screen.height - screenStartSelect.y) - (Screen.height - screenEndSelect.y)));
        if((width > 2 || width < -1) && (height > 2 || height < -2)){
            texture2d = new Texture2D(Mathf.Abs(width), Mathf.Abs(height), TextureFormat.ARGB32, false);

            var fillColorArray = texture2d.GetPixels();
            var size = fillColorArray.Length;
            var absWidth = Mathf.Abs(width);

            for(var i = 0; i < fillColorArray.Length; ++i){
                fillColorArray[i] = innerColor;
                if(i < absWidth){
                    fillColorArray[i] = borderColor;
                }
                if(i > size - absWidth){
                    fillColorArray[i] = borderColor;
                }
                if((i % absWidth) == 1){
                    fillColorArray[i] = borderColor;
                }
                if((i % absWidth) == absWidth - 1){
                    fillColorArray[i] = borderColor;
                }
            }

            texture2d.SetPixels(fillColorArray);
            texture2d.Apply();

            GUI.DrawTexture(
                new Rect(
                    screenStartSelect.x,
                    Screen.height - screenStartSelect.y,
                    width,
                    height
                ),
                texture2d
            );
        }
    }
}

我删除了Start()方法，现在我在OnGUI()中创建纹理

创建具有边框和alpha中心的纹理

1 个答案: