/// <summary>
/// 扫描线填充
/// </summary>
/// <param name="left">左端点，值已经经过插值</param>
/// <param name="right">右端点，值已经经过插值</param>
private void ScanlineFill(Vertex left, Vertex right, int yIndex)
{
float dx = right.point.x - left.point.x;
float step = 1;
if (dx != 0)
{
step = 1 / dx;
}
for (float x = left.point.x; x <= right.point.x; x += 0.5f)
{
int xIndex = (int)(x + 0.5f);
if (xIndex >= 0 && xIndex < this.MaximumSize.Width)
{
float lerpFactor = 0;
if (dx != 0)
{
lerpFactor = (x - left.point.x) / dx;
}
//1/z’与x’和y'是线性关系的
float onePreZ = MathUntil.Lerp(left.onePerZ, right.onePerZ, lerpFactor);
if (onePreZ >= _zBuff[yIndex, xIndex]) //使用1/z进行深度测试
{ //通过测试
float w = 1 / onePreZ;
_zBuff[yIndex, xIndex] = onePreZ;
//uv 插值，求纹理颜色
float u = MathUntil.Lerp(left.u, right.u, lerpFactor) * w * (_texture.Width - 1);
float v = MathUntil.Lerp(left.v, right.v, lerpFactor) * w * (_texture.Height - 1);
//纹理采样
SoftRenderer.RenderData.Color texColor = new RenderData.Color(1, 1, 1);
if (_textureFilterMode == TextureFilterMode.point)
{//点采样
int uIndex = (int)System.Math.Round(u, MidpointRounding.AwayFromZero);
int vIndex = (int)System.Math.Round(v, MidpointRounding.AwayFromZero);
uIndex = MathUntil.Range(uIndex, 0, _texture.Width - 1);
vIndex = MathUntil.Range(vIndex, 0, _texture.Height - 1);
//uv坐标系采用dx风格
texColor = new RenderData.Color(ReadTexture(uIndex, vIndex));//转到我们自定义的color进行计算
}
else if (_textureFilterMode == TextureFilterMode.Bilinear)
{//双线性采样
float uIndex = (float)System.Math.Floor(u);
float vIndex = (float)System.Math.Floor(v);
float du = u - uIndex;
float dv = v - vIndex;
SoftRenderer.RenderData.Color texcolor1 = new RenderData.Color(ReadTexture((int)uIndex, (int)vIndex)) * (1 - du) * (1 - dv);
SoftRenderer.RenderData.Color texcolor2 = new RenderData.Color(ReadTexture((int)uIndex + 1, (int)vIndex)) * du * (1 - dv);
SoftRenderer.RenderData.Color texcolor3 = new RenderData.Color(ReadTexture((int)uIndex, (int)vIndex + 1)) * (1 - du) * dv;
SoftRenderer.RenderData.Color texcolor4 = new RenderData.Color(ReadTexture((int)uIndex + 1, (int)vIndex + 1)) * du * dv;
texColor = texcolor1 + texcolor2 + texcolor3 + texcolor4;
}
//插值顶点颜色
SoftRenderer.RenderData.Color vertColor = MathUntil.Lerp(left.vcolor, right.vcolor, lerpFactor) * w;
//插值光照颜色
SoftRenderer.RenderData.Color lightColor = MathUntil.Lerp(left.lightingColor, right.lightingColor, lerpFactor) * w;;
if (_lightMode == LightMode.On)
{//光照模式，需要混合光照的颜色
if (RenderMode.Textured == _currentMode)
{
SoftRenderer.RenderData.Color finalColor = texColor * lightColor;
_frameBuff.SetPixel(xIndex, yIndex, finalColor.TransFormToSystemColor());
}
else if (RenderMode.VertexColor == _currentMode)
{
SoftRenderer.RenderData.Color finalColor = vertColor * lightColor;
_frameBuff.SetPixel(xIndex, yIndex, finalColor.TransFormToSystemColor());
}
}
else
{
if (RenderMode.Textured == _currentMode)
{
_frameBuff.SetPixel(xIndex, yIndex, texColor.TransFormToSystemColor());
}
else if (RenderMode.VertexColor == _currentMode)
{
_frameBuff.SetPixel(xIndex, yIndex, vertColor.TransFormToSystemColor());
}
}
}
}
}
}
