如何插入UV坐标？

Question

我正在尝试将纹理应用于.md2模型。我使用了Gouraud阴影对其进行着色（带有底部/顶部平坦三角形的标准算法），并且必须对纹理坐标U和V使用类似的代码。但是我不太了解如何对它们进行插值。从我尝试过的内容来看，我的代码似乎只沿边缘插值，而不是沿边缘插值。我错过了什么？谢谢。

void Rasteriser::TfillBottomFlatTriangle(Vertex vertex1, Vertex vertex2, Vertex vertex3, COLORREF c1, COLORREF c2, COLORREF c3, HDC hdc)
{
    float slope1 = (vertex2.GetX() - vertex1.GetX()) / (vertex2.GetY() - vertex1.GetY());
    float slope2 = (vertex3.GetX() - vertex1.GetX()) / (vertex3.GetY() - vertex1.GetY());

    //U and V
    float slope1U = (vertex2.GetU() - vertex1.GetU()) / (vertex2.GetY() - vertex1.GetY());
    float slope2U = (vertex3.GetU() - vertex1.GetU()) / (vertex3.GetY() - vertex1.GetY());

    float slope1V = (vertex2.GetV() - vertex1.GetV()) / (vertex2.GetY() - vertex1.GetY());
    float slope2V = (vertex3.GetV() - vertex1.GetV()) / (vertex3.GetY() - vertex1.GetY());

    float x1 = vertex1.GetX();
    float x2 = vertex1.GetX() + 0.5f;

    //U and V
    float x1U = vertex1.GetU();
    float x2U = vertex1.GetU() + 0.5f;

    float x1V = vertex1.GetV();
    float x2V = vertex1.GetV() + 0.5f;


    if (slope2 < slope1)
    {
        float slopeTmp = slope1;
        slope1 = slope2;
        slope2 = slopeTmp;

        float slopeTmpU = slope1U;
        slope1U = slope2U;
        slope2U = slopeTmpU;

        float slopeTmpV = slope1V;
        slope1V = slope2V;
        slope2V = slopeTmpV;

    }

    for (float scanlineY = vertex1.GetY(); scanlineY <= vertex2.GetY(); scanlineY++)
    {
        /* loop over each pixel of horizontal line */

        for (float xPos = ceil(x1); xPos < x2; xPos++)
        {

                float t = (xPos - x1) / (x2 - x1);
                float u = (1 - t) * x1U + t * x2U;
                float v = (1 - t) * x1V + t * x2V;
                COLORREF colour = _model.GetTexture().GetTextureValue((int)u, (int)v);
                SetPixel(hdc, (int)xPos, (int)scanlineY, colour);

        }
        // get new x-coordinate of endpoints of horizontal line 
        x1 += slope1;
        x2 += slope2;
        x1U += slope1U;
        x2U += slope2U;
        x1V += slope1V;
        x2V += slope2V;
    }

}

Answer 1

问题在这里：

    //U and V
    float x1U = vertex1.GetU();
    float x2U = vertex1.GetU() + 0.5f;

    float x1V = vertex1.GetV();
    float x2V = vertex1.GetV() + 0.5f;

0.5对于uv坐标来说很多，所以这告诉我这是错误的。

我认为正确的方法是：

    //U and V
    float x1U = vertex1.GetU();
    float x2U = x1U;

    float x1V = vertex1.GetV();
    float x2V = x1V;

我认为正在发生的事情是每个三角形都包含您纹理的一半，我认为我们可以在图像中看到它。