private ScanLine CalculateStepPerRow(Vertex left, Vertex right, int row)
{
ScanLine ret = new ScanLine();
double width = right.point.x - left.point.x;
ret.x = (int)(left.point.x + 0.5);
ret.y = row;
ret.width = (int)(right.point.x + 0.5) - ret.x;
ret.leftvertex = left;
if (left.point.x >= right.point.x)
{
ret.width = 0;
}
//计算步长
double rate = 1.0 / width;
ret.step.point.x = (right.point.x - left.point.x) * rate;
ret.step.point.y = (right.point.y - left.point.y) * rate;
ret.step.point.z = (right.point.z - left.point.z) * rate;
ret.step.point.t = (right.point.t - left.point.t) * rate;
ret.step.uv.u = (right.uv.u - left.uv.u) * rate;
ret.step.uv.v = (right.uv.v - left.uv.v) * rate;
ret.step.color.r = (right.color.r - left.color.r) * rate;
ret.step.color.g = (right.color.g - left.color.g) * rate;
ret.step.color.b = (right.color.b - left.color.b) * rate;
ret.step.normal.x = (right.normal.x - left.normal.x) * rate;
ret.step.normal.y = (right.normal.y - left.normal.y) * rate;
ret.step.normal.z = (right.normal.z - left.normal.z) * rate;
ret.step.WorldPos.x = (right.WorldPos.x - left.WorldPos.x) * rate;
ret.step.WorldPos.y = (right.WorldPos.y - left.WorldPos.y) * rate;
ret.step.WorldPos.z = (right.WorldPos.z - left.WorldPos.z) * rate;
return(ret);
}
private void StartRenderLine(ScanLine scanline)
{
int x = scanline.x;
int width = scanline.width;
if ((x + width) < 0)
{
return;
}
for (; width > 0; x++, width--)//逐像素计算，直到扫描完width长度的点
{
if (x >= 0 && x < BitMapWidth)
{
//深度缓存
if (scanline.leftvertex.point.t < DepthBuffer[scanline.y, x])
{
DepthBuffer[scanline.y, x] = scanline.leftvertex.point.t;
double u = scanline.leftvertex.uv.u;
double v = scanline.leftvertex.uv.v;
MyColor mycolor = ReadTexture(u, v); //根据uv读取颜色 非立方体纹理映射
//MyColor mycolor = CubeMap(scanline.leftvertex.WorldPos, this.mesh.CubeCenter);
a2v FS = new a2v(scanline.leftvertex.WorldPos,
scanline.leftvertex.normal,
this.MyCamera.eye);
mycolor = Light.LightMode_BlinnPhong(FS, mycolor, IsTexture, IsPointLighting, MyLight);
Color color = mycolor.ConvertToColor();
MyBitMap.SetPixel(x, scanline.y, color); //设置对应像素点颜色
}
}
scanline.leftvertex.NextStep(scanline.step);
if (x > BitMapWidth)
{
break;
}
}
}
private void StartRenderTrapezoid(RenderTriangle r)
{
int top, bottom;
top = (int)(r.topline + 0.5);
bottom = (int)(r.downline + 0.5);
for (int row = top; row < bottom; row++)
{
if (row >= 0 && row < this.BitMapHeight)
{
Vertex left, right;
DoubleLinedInterp(r, (double)row + 0.5f, out left, out right);
//DoubleLinedInterp(r, (double)row, out left, out right);
ScanLine s = CalculateStepPerRow(left, right, row);
StartRenderLine(s);
}
if (row >= this.BitMapHeight)
{
break;
}
}
}