//三角形扫描
public void ScanLine_new(VertexTriangle vt, VertexTriangle orit, Scene scene)
{
Vertex A = vt.Vertices[0];
Vertex B = vt.Vertices[1];
Vertex C = vt.Vertices[2];
DrawNormalTriangle(vt, orit, scene);
}
//生成三角形数组
private List <VertexTriangle> MakeTriangle(List <Vertex> input)
{
List <VertexTriangle> temp = new List <VertexTriangle>();
for (int i = 0; i < input.Count - 2; i++)
{
VertexTriangle vt = new VertexTriangle(input[0], input[i + 1], input[i + 2]);
temp.Add(vt);
}
return(temp);
}
//消隐
private bool ShouldBackFaceCull(VertexTriangle oriVt)
{
Vector4 a = new Vector4(oriVt.Vertices[0].ScreenSpacePosition);
Vector4 b = new Vector4(oriVt.Vertices[1].ScreenSpacePosition);
Vector4 c = new Vector4(oriVt.Vertices[2].ScreenSpacePosition);
a.Z = b.Z = c.Z = 0;
Vector4 ab = b - a;
Vector4 ac = c - a;
return(Vector4.Cross(ab, ac).Z > 0);
}
private void DrawTriangle(VertexTriangle vt, VertexTriangle oriVt, Scene scene, bool isWorld)
{
if (!ShouldBackFaceCull(vt))
{
//this.scanLine.ProcessScanLine(vt, oriVt, scene);
if (scene.renderState == Scene.RenderState.WireFrame)
{
this.scanLine.ProcessScanLine(vt, oriVt, scene, isWorld);
}
else
{
this.scanLine.ScanLine_new(vt, oriVt, scene);
}
//this.scanLine.StartScanLine(vt,oriVt,scene);
//this.scanLine.StartScanTriangle(vt,oriVt,scene);
}
}
public static void GouraudColor(Scene scene, Device device, int i, Edge a1, Edge a2, VertexTriangle orivt, VertexTriangle vt, bool isworld)
{
Color4 final = new Color4();
/*
* 记过排序后的边传入连续两条边 相交的情况只有两种钝角三角形 和锐角三角形
* x 从小到大
*
* /\ /\
* / \ / \
* / \/ \_________
* x1 x3 x4
* 1. x左右分开
* 2. x相同 以斜率排序
*
*/
/* 双线性插值算法
*
*
*/
Vector4 screenA1V1 = a1.v1.ScreenSpacePosition;
Vector4 screenA1V2 = a1.v2.ScreenSpacePosition;
Vector4 screenA2V1 = a2.v1.ScreenSpacePosition;
Vector4 screenA2V2 = a2.v2.ScreenSpacePosition;
// 双线性插值系数
// 第一次插值算出交点的颜色系数
float r1 = ((float)i - screenA1V1.Y) / (float)(screenA1V2.Y - screenA1V1.Y);
float r2 = ((float)i - screenA2V1.Y) / (float)(screenA2V2.Y - screenA2V1.Y);
r1 = MathUtil.Clamp01(r1);
r2 = MathUtil.Clamp01(r2);
// 像素点深度插值
float z1 = MathUtil.Interp(screenA1V1.Z, screenA1V2.Z, r1);
float z2 = MathUtil.Interp(screenA2V1.Z, screenA2V2.Z, r2);
//float z3 = 0;
float r3 = MathUtil.Clamp01(((float)x - a1.x) / (a2.x - a1.x));
//float r3 = (float)(x - Math.Floor(a1.x)) / (a2.x - a1.x);
float z = MathUtil.Interp(z1, z2, r3);
//float z = vt.GetInterValue(z1, z2, z3);
float nDotL1 = 0, nDotL2 = 0;
switch (scene.renderState)
{
case Scene.RenderState.WireFrame: { }
break;
case Scene.RenderState.GouraduShading:
{ }
break;
case Scene.RenderState.TextureMapping:
{
orivt.CalWeight(new Vector4(x, i, 0, 0));
Vector4 uv = orivt.GetInterUV();
if (isworld)
{
//final = device.Tex2D(uv.X, uv.Y, scene.worldMap.texture);
}
else
{
if (DirectionLight.IsEnable)
{
float nDotLA1V1 = DirectionLight.ComputeNDotL(a1.v1.nowPos, a1.v1.nowNormal);
float nDotLA1V2 = DirectionLight.ComputeNDotL(a1.v2.nowPos, a1.v2.nowNormal);
float nDotLA2V1 = DirectionLight.ComputeNDotL(a2.v1.nowPos, a2.v1.nowNormal);
float nDotLA2V2 = DirectionLight.ComputeNDotL(a2.v2.nowPos, a2.v2.nowNormal);
nDotL1 = MathUtil.Interp(nDotLA1V1, nDotLA1V2, r1);
nDotL2 = MathUtil.Interp(nDotLA2V1, nDotLA2V2, r2);
float nDotL = MathUtil.Interp(nDotL1, nDotL2, r3);
//Console.WriteLine(nDotL1+" "+ nDotL2+" " + nDotL);
final = device.Tex2D(uv.X, uv.Y, scene.mesh.texture);
final = final * DirectionLight.GetFinalLightColor(nDotL);
}
else
{
final = device.Tex2D(uv.X, uv.Y, scene.mesh.texture);
}
}
}
break;
}
device.DrawPoint(new Vector4(x, i, z, 0), final);
}
/* gouraud 着色
*
* Ia = (ya - y2)*I1/(y1-y2) + (y1-ya)*I2/(y1 -y2)
*
*/
public static void GouraudColor(Scene scene, Device device, float x, float y, float z, VertexTriangle vt, VertexTriangle orivt)
{
Color4 final = new Color4();
Vertex A = vt.Vertices[0];
Vertex B = vt.Vertices[1];
Vertex C = vt.Vertices[2];
float nDotLA1V1 = DirectionLight.ComputeNDotL(A.nowPos, A.nowNormal);
A.lightColor = A.Color * DirectionLight.GetFinalLightColor(nDotLA1V1);
float nDotLA1V2 = DirectionLight.ComputeNDotL(B.nowPos, B.nowNormal);
B.lightColor = B.Color * DirectionLight.GetFinalLightColor(nDotLA1V2);
float nDotLA2V1 = DirectionLight.ComputeNDotL(C.nowPos, C.nowNormal);
C.lightColor = C.Color * DirectionLight.GetFinalLightColor(nDotLA2V1);
float ay = A.ScreenSpacePosition.Y;
float by = B.ScreenSpacePosition.Y;
float cy = C.ScreenSpacePosition.Y;
float ax = A.ScreenSpacePosition.X;
float bx = B.ScreenSpacePosition.X;
float cx = C.ScreenSpacePosition.X;
bool isIn = vt.CalculateWeight(new Vector4(x, y, 0, 0));
if (isIn)
{
final = vt.GetInterColor();
device.DrawPoint(new Vector4(x, y, z, 0), final);
}
else
{
}
}
public void renderTriangle(Vertex vertexA, Vertex vertexB, Vertex vertexC, Matrix4x4 matrixMVP, bool isWorld)
{
List <Vertex> pIn = new List <Vertex>();
vertexA.ClipSpacePosition = this.ClipSpace(vertexA.nowPos, matrixMVP);
vertexB.ClipSpacePosition = this.ClipSpace(vertexB.nowPos, matrixMVP);
vertexC.ClipSpacePosition = this.ClipSpace(vertexC.nowPos, matrixMVP);
vertexA.ScreenSpacePosition = this.ViewPort(vertexA.ClipSpacePosition);
vertexB.ScreenSpacePosition = this.ViewPort(vertexB.ClipSpacePosition);
vertexC.ScreenSpacePosition = this.ViewPort(vertexC.ClipSpacePosition);
pIn.Add(vertexA);
pIn.Add(vertexB);
pIn.Add(vertexC);
for (int i = 0; i < 6; i++)
{
if (pIn.Count == 0)
{
break;
}
clip = new HodgmanClip(this);
clip.HodgmanPolygonClip((HodgmanClip.Boundary)i, clipMin, clipMax, pIn.ToArray());
pIn = clip.GetOutputList();
}
List <VertexTriangle> vtList = this.MakeTriangle(pIn);
VertexTriangle oriVt = new VertexTriangle(vertexA, vertexB, vertexC);
if (scene.renderState == Scene.RenderState.WireFrame)
{
// 画线框, 需要vertex的normal,pos,color
//DrawLine(vertexA, vertexB, pixelA, pixelB, scene);
//DrawLine(vertexB, vertexC, pixelB, pixelC, scene);
for (int i = 0; i < vtList.Count; i++)
{
if (!ShouldBackFaceCull(vtList[i]))
{
int length = vtList[i].Vertices.Length;
Vertex start = vtList[i].Vertices[length - 1];
for (int j = 0; j < length; j++)
{
Vector4 viewPortA = this.ViewPort(start.ClipSpacePosition);
Vector4 viewPortB = this.ViewPort(vtList[i].Vertices[j].ClipSpacePosition);
// DrawLine(start, vtList[i].Vertices[j], viewPortA, viewPortB, scene);
DrawDDALine(start, vtList[i].Vertices[j]);
start = vtList[i].Vertices[j];
}
}
}
}
else
{
// 填充三角形 bv gf
for (int i = 0; i < vtList.Count; i++)
{
//Console.WriteLine(vtList.Count);
DrawTriangle(vtList[i], oriVt, scene, isWorld);
//DrawTriangle(vtList[i]);
}
}
}
public void DrawTopTriangle(Vertex v1, Vertex v2, Vertex v3, Scene scene, VertexTriangle vt, VertexTriangle oriVt)
{
Vector4 p1 = v1.ScreenSpacePosition;
Vector4 p2 = v2.ScreenSpacePosition;
Vector4 p3 = v3.ScreenSpacePosition;
Color4 color1 = v1.Color;
Color4 color2 = v2.Color;
Color4 color3 = v3.Color;
float ax = p1.X;
float bx = p2.X;
float cx = p3.X;
float ay = p1.Y;
float by = p2.Y;
float cy = p3.Y;
float az = p1.Z;
float bz = p2.Z;
float cz = p3.Z;
Vector4 normal1 = v1.nowNormal;
Vector4 normal2 = v2.nowNormal;
Vector4 normal3 = v3.nowNormal;
oriVt.PreCalWeight();
if (bx == cx)
{
for (int y = (int)ay; y <= (int)cy; y++)
{
float y1 = (float)(y - ay) / (float)(cy - ay);
float y2 = (float)(y - by) / (float)(cy - by);
y1 = MathUtil.Clamp01(y1);
y2 = MathUtil.Clamp01(y2);
int x0 = (int)MathUtil.Interp(ax, cx, y1);
int x1 = (int)bx;
float z1 = MathUtil.Interp(az, cz, y1);
float z2 = bz;
Color4 c1 = new Color4();
Color4 c2 = new Color4();
if (scene.renderState == Scene.RenderState.GouraduShading)
{
c1 = MathUtil.ColorInterp(color1, color3, y1);
c2 = MathUtil.ColorInterp(color2, color3, y2);
}
Vector4 n1 = new Vector4(0, 0, 0, 0);
Vector4 n2 = new Vector4(0, 0, 0, 0);
if (DirectionLight.IsEnable)
{
n1 = MathUtil.Vector4Interp(normal1, normal3, y1);
n2 = MathUtil.Vector4Interp(normal2, normal3, y2);
}
for (int x = x0; x <= x1; x++)
{
float r3 = (float)(x - x0) / (float)(x1 - x0);
r3 = MathUtil.Clamp01(r3);
float z = MathUtil.Interp(z1, z2, r3);
Vector4 pos = new Vector4(x, y, z, 0);
switch (scene.renderState)
{
case Scene.RenderState.WireFrame:
{ }
break;
case Scene.RenderState.GouraduShading:
{
oriVt.CalWeight(pos);
Color4 c3 = MathUtil.ColorInterp(c1, c2, r3);
if (DirectionLight.IsEnable)
{
Vector4 n3 = MathUtil.Vector4Interp(n1, n2, r3);
n3 = oriVt.GetNormal();
final = DirectionLight.GetFinalLightColor(n3, c3);
}
else
{
final = c3;
}
}
break;
case Scene.RenderState.TextureMapping:
{
oriVt.CalWeight(pos);
Vector4 n3 = MathUtil.Vector4Interp(n1, n2, r3);
Vector4 uv = oriVt.GetInterUV();
if (DirectionLight.IsEnable)
{
Color4 c = device.Tex2D(uv.X, uv.Y, scene.mesh.texture);
n3 = oriVt.GetNormal();
final = DirectionLight.GetFinalLightColor(n3, c);
}
else
{
final = device.Tex2D(uv.X, uv.Y, scene.mesh.texture);
}
}
break;
}
device.DrawPoint(pos, final);
}
}
}
else if (ax == cx)
{
for (int y = (int)ay; y <= (int)cy; y++)
{
float y1 = (float)(y - ay) / (float)(cy - ay);
float y2 = (float)(y - by) / (float)(cy - by);
y1 = MathUtil.Clamp01(y1);
y2 = MathUtil.Clamp01(y2);
int x0 = (int)ax;
int x1 = (int)MathUtil.Interp(bx, cx, y2);
float z1 = MathUtil.Interp(az, cz, y1);
float z2 = MathUtil.Interp(bz, cz, y2);
Color4 c1 = new Color4();
Color4 c2 = new Color4();
if (scene.renderState == Scene.RenderState.GouraduShading)
{
c1 = MathUtil.ColorInterp(color1, color3, y1);
c2 = MathUtil.ColorInterp(color2, color3, y2);
}
Vector4 n1 = new Vector4(0, 0, 0, 0);
Vector4 n2 = new Vector4(0, 0, 0, 0);
if (DirectionLight.IsEnable)
{
n1 = MathUtil.Vector4Interp(normal1, normal3, y1);
n2 = MathUtil.Vector4Interp(normal2, normal3, y2);
}
for (int x = x0; x < x1; x++)
{
float r3 = (float)(x - x0) / (float)(x1 - x0);
r3 = MathUtil.Clamp01(r3);
float z = MathUtil.Interp(z1, z2, r3);
Vector4 pos = new Vector4(x, y, z, 0);
switch (scene.renderState)
{
case Scene.RenderState.WireFrame:
{ }
break;
case Scene.RenderState.GouraduShading:
{
oriVt.CalWeight(pos);
Color4 c3 = MathUtil.ColorInterp(c1, c2, r3);
if (DirectionLight.IsEnable)
{
Vector4 n3 = MathUtil.Vector4Interp(n1, n2, r3);
n3 = oriVt.GetNormal();
final = DirectionLight.GetFinalLightColor(n3, c3);
}
else
{
final = c3;
}
}
break;
case Scene.RenderState.TextureMapping:
{
oriVt.CalWeight(pos);
Vector4 n3 = MathUtil.Vector4Interp(n1, n2, r3);
Vector4 uv = oriVt.GetInterUV();
if (DirectionLight.IsEnable)
{
Color4 c = device.Tex2D(uv.X, uv.Y, scene.mesh.texture);
n3 = oriVt.GetNormal();
final = DirectionLight.GetFinalLightColor(n3, c);
}
else
{
final = device.Tex2D(uv.X, uv.Y, scene.mesh.texture);
}
}
break;
}
device.DrawPoint(pos, final);
}
}
}
else
{
for (int y = (int)ay; y <= cy; y++)
{
float y1 = (float)(y - ay) / (float)(cy - ay);
y1 = MathUtil.Clamp01(y1);
float y2 = (y - by) / (cy - by);
y2 = MathUtil.Clamp01(y2);
float x0 = (int)MathUtil.Interp(ax, cx, y1);
float x1 = (int)MathUtil.Interp(bx, cx, y2);
float z1 = MathUtil.Interp(az, cz, y1);
float z2 = MathUtil.Interp(bz, cz, y2);
Color4 c1 = new Color4();
Color4 c2 = new Color4();
if (scene.renderState == Scene.RenderState.GouraduShading)
{
c1 = MathUtil.ColorInterp(color1, color3, y1);
c2 = MathUtil.ColorInterp(color2, color3, y2);
}
Vector4 n1 = new Vector4(0, 0, 0, 0);
Vector4 n2 = new Vector4(0, 0, 0, 0);
if (DirectionLight.IsEnable)
{
n1 = MathUtil.Vector4Interp(normal1, normal3, y1);
n2 = MathUtil.Vector4Interp(normal2, normal3, y2);
}
for (float x = x0; x < x1; x++)
{
float r3 = (float)(x - x0) / (float)(x1 - x0);
r3 = MathUtil.Clamp01(r3);
float z = MathUtil.Interp(z1, z2, r3);
//Color4 c3 = MathUtil.ColorInterp(c1, c2, r3);
Vector4 pos = new Vector4(x, y, z, 0);
switch (scene.renderState)
{
case Scene.RenderState.WireFrame:
{ }
break;
case Scene.RenderState.GouraduShading:
{
Color4 c3 = MathUtil.ColorInterp(c1, c2, r3);
oriVt.CalWeight(pos);
if (DirectionLight.IsEnable)
{
Vector4 n3 = MathUtil.Vector4Interp(n1, n2, r3);
n3 = oriVt.GetNormal();
final = DirectionLight.GetFinalLightColor(n3, c3);
}
else
{
final = c3;
}
}
break;
case Scene.RenderState.TextureMapping:
{
oriVt.CalWeight(pos);
Vector4 n3 = MathUtil.Vector4Interp(n1, n2, r3);
Vector4 uv = oriVt.GetInterUV();
if (DirectionLight.IsEnable)
{
Color4 c = device.Tex2D(uv.X, uv.Y, scene.mesh.texture);
n3 = oriVt.GetNormal();
final = DirectionLight.GetFinalLightColor(n3, c);
}
else
{
final = device.Tex2D(uv.X, uv.Y, scene.mesh.texture);
}
}
break;
}
device.DrawPoint(pos, final);
}
}
}
}
/* 三角形扫描
* 搜索三角形光栅化
* __________ top
* \ /
* \ /
* \ /
* \/
* bottom
* /\
* / \
* / \
* ---------
*/
public void DrawNormalTriangle(VertexTriangle vt, VertexTriangle orit, Scene scene)
{
Vertex[] vv = GetList(vt.Vertices);
Vertex v1 = vv[0];
Vertex v2 = vv[1];
Vertex v3 = vv[2];
if (v1 == null)
{
return;
}
Vector4 p1 = v1.ScreenSpacePosition;
Vector4 p2 = v2.ScreenSpacePosition;
Vector4 p3 = v3.ScreenSpacePosition;
float ax = p1.X;
float bx = p2.X;
float cx = p3.X;
float ay = p1.Y;
float by = p2.Y;
float cy = p3.Y;
float az = p1.Z;
float bz = p2.Z;
float cz = p3.Z;
Color4 color1 = v1.Color;
Color4 color2 = v2.Color;
Color4 color3 = v3.Color;
Vector4 normal1 = v1.nowNormal;
Vector4 normal2 = v2.nowNormal;
Vector4 normal3 = v3.nowNormal;
if (ay == by)
{
DrawTopTriangle(v1, v2, v3, scene, vt, orit);
}
else if (by == cy)
{
DrawBottomTriangle(v1, v2, v3, scene, vt, orit);
}
else
{
if (ax == cx)
{
Vertex newVt = new Vertex();
float y1 = (by - ay) / (cy - ay);
y1 = MathUtil.Clamp01(y1);
float x = MathUtil.Interp(ax, cx, y1);
float z = MathUtil.Interp(az, cz, y1);
Color4 c = MathUtil.ColorInterp(color1, color3, y1);
newVt.ScreenSpacePosition = new Vector4(x, by, z, 0);
newVt.lightColor = c;
newVt.Color = c;
newVt.nowNormal = MathUtil.Vector4Interp(normal1, normal3, y1);
newVt.UV = MathUtil.Vector4Interp(v1.UV, v3.UV, y1);
if ((int)bx > (int)cx)
{
DrawBottomTriangle(v1, newVt, v2, scene, vt, orit);
DrawTopTriangle(newVt, v2, v3, scene, vt, orit);
}
else
{
DrawBottomTriangle(v1, v2, newVt, scene, vt, orit);
DrawTopTriangle(v2, newVt, v3, scene, vt, orit);
}
}
else if (ax == bx)
{
Vertex newVt = new Vertex();
float y1 = (by - ay) / (cy - ay);
y1 = MathUtil.Clamp01(y1);
float x = MathUtil.Interp(ax, cx, y1);
float z = MathUtil.Interp(az, cz, y1);
Color4 c = MathUtil.ColorInterp(color1, color3, y1);
newVt.ScreenSpacePosition = new Vector4(x, by, z, 0);
newVt.lightColor = c;
newVt.Color = c;
newVt.nowNormal = MathUtil.Vector4Interp(normal1, normal3, y1);
newVt.UV = MathUtil.Vector4Interp(v1.UV, v3.UV, y1);
if (cx < bx)
{
DrawBottomTriangle(v1, newVt, v2, scene, vt, orit);
DrawTopTriangle(newVt, v2, v3, scene, vt, orit);
}
else
{
DrawBottomTriangle(v1, v2, newVt, scene, vt, orit);
DrawTopTriangle(v2, newVt, v3, scene, vt, orit);
}
}
else if (bx == cx)
{
Vertex newVt = new Vertex();
float y1 = (by - ay) / (cy - ay);
y1 = MathUtil.Clamp01(y1);
float x = MathUtil.Interp(ax, cx, y1);
float z = MathUtil.Interp(az, cz, y1);
Color4 c = MathUtil.ColorInterp(color1, color3, y1);
newVt.ScreenSpacePosition = new Vector4(x, by, z, 0);
newVt.lightColor = c;
newVt.Color = c;
newVt.nowNormal = MathUtil.Vector4Interp(normal1, normal3, y1);
newVt.UV = MathUtil.Vector4Interp(v1.UV, v3.UV, y1);
if (ax < bx)
{
DrawBottomTriangle(v1, newVt, v2, scene, vt, orit);
DrawTopTriangle(newVt, v2, v3, scene, vt, orit);
}
else
{
DrawBottomTriangle(v1, v2, newVt, scene, vt, orit);
DrawTopTriangle(v2, newVt, v3, scene, vt, orit);
}
}
else
{
Vertex newVt = new Vertex();
float y1 = (float)(by - ay) / (float)(cy - ay);
y1 = MathUtil.Clamp01(y1);
float x = MathUtil.Interp(ax, cx, y1);
float z = MathUtil.Interp(az, cz, y1);
Color4 c = MathUtil.ColorInterp(color1, color3, y1);
newVt.ScreenSpacePosition = new Vector4(x, by, z, 0);
newVt.lightColor = c;
newVt.Color = c;
newVt.nowNormal = MathUtil.Vector4Interp(normal1, normal3, y1);
newVt.UV = MathUtil.Vector4Interp(v1.UV, v3.UV, y1);
// 计算线条的方向
float dP1P2, dP1P3;
// http://en.wikipedia.org/wiki/Slope
// 计算斜率
if (p2.Y - p1.Y > 0)
{
dP1P2 = (p2.X - p1.X) / (p2.Y - p1.Y);
}
else
{
dP1P2 = 0;
}
if (p3.Y - p1.Y > 0)
{
dP1P3 = (p3.X - p1.X) / (p3.Y - p1.Y);
}
else
{
dP1P3 = 0;
}
if (dP1P2 > dP1P3)
{
DrawBottomTriangle(v1, newVt, v2, scene, vt, orit);
DrawTopTriangle(newVt, v2, v3, scene, vt, orit);
}
else
{
DrawBottomTriangle(v1, v2, newVt, scene, vt, orit);
DrawTopTriangle(v2, newVt, v3, scene, vt, orit);
}
}
}
}
/* 边表法填充
* 优点 扫描效率高，结构清晰
* 缺点 光栅化时三角形斜边在水平情况下差值不均匀造成颜色区块
* vt是裁剪后的三角形，
* orivt是原始三角形,目的是在纹理映射的时候计算权重
*
*/
public void ProcessScanLine(VertexTriangle vt, VertexTriangle oriVt, Scene scene, bool isworld)
{
int yMin = this.height;
int yMax = 0;
Vertex A = vt.Vertices[0];
Vertex B = vt.Vertices[1];
Vertex C = vt.Vertices[2];
/* 扫描线原理
*
* 1. 求扫描线与多边形的交点
* 2. 对所求得的交点按 x 从小到大排序
* 3. 将交点两两配对，并填充每一区段
*
*/
// ET AEL 扫描算法见 72 页 4.2.2
/* 1. 找到三角形 y 的最大值和最小值
* 并将三角形的边以顶点坐标X的值从左往右(x 从小到大)填充
* 在边表 ET[] 中对应三角形的Ymin处
*/
Vertex[] vertices = vt.Vertices;
for (int i = 0; i < vertices.Length; i++)
{
for (int j = i + 1; j < vertices.Length; j++)
{
Vector4 screen1 = vertices[i].ScreenSpacePosition;
Vector4 screen2 = vertices[j].ScreenSpacePosition;
if ((int)screen1.Y != (int)screen2.Y)
{
if (screen1.Y > yMax)
{
yMax = (int)screen1.Y;
}
if (screen2.Y > yMax)
{
yMax = (int)screen2.Y;
}
if (screen1.Y < yMin)
{
yMin = (int)screen1.Y;
}
if (screen2.Y < yMin)
{
yMin = (int)screen2.Y;
}
if (yMax > this.height)
{
yMax = this.height;
}
if (yMin < 0)
{
yMin = 0;
}
int x1 = (int)screen1.X;
int y1 = (int)screen1.Y;
int x2 = (int)screen2.X;
int y2 = (int)screen2.Y;
int ymin = y1 > y2 ? y2 : y1;
if (ymin < 0)
{
ymin = 0;
}
int ymax = y1 > y2 ? y1 : y2;
if (ymax > this.height)
{
ymax = this.height;
}
// 保存的边的上端点x坐标
float x = y1 > y2 ? x2 : x1;
//边的斜率的倒数
float dx = (float)(x1 - x2) * 1.0f / (float)(y1 - y2);
Edge e = new Edge();
e.yMax = ymax;
// 保存x的目的是为了插入时保证边的顺序是按照x从小到大插入
// 在AEL中表示当前扫描线与边的交点x坐标，初值(在ET中的值)为边的下端点的x坐标
e.x = x;
// 斜率是保证在插入时，如果 x相同，以斜率大小比较
e.deltaX = dx;
// 保存边的上端点
e.v1 = y1 > y2 ? vertices[j] : vertices[i];
// 保存边的下端点
e.v2 = y1 > y2 ? vertices[i] : vertices[j];
EdgeTable.InsertEdge(ref ET[ymin].nextEdge, e);
}
}
}
/* 2. 置空活动边表 AEL
* AEL 存储的是 ET表在 扫描线 y = i 有交点的三角形的边
*/
AEL = new Edge();
oriVt.PreCalWeight();
for (int i = yMin; i < yMax; i++)
{
// 将边表中在 y = i 的边 插入活动边表AEL中，并删除边表里的边
EdgeTable.SearchTable(i, ET, AEL);
if (AEL.nextEdge == null)
{
continue;
}
// 获取连续的两条边
Edge a1 = (Edge)AEL.nextEdge.Clone();
Edge a2 = (Edge)AEL.nextEdge.nextEdge.Clone();
// 从ymin开始扫描填充
/*
* 记过排序后的边传入连续两条边 相交的情况只有两种钝角三角形 和锐角三角形
* x 从小到大
*
* /\ /\
* / \ / \
* / \/ \_________
* x1 x3 x4
* 1. x左右分开
* 2. x相同 以斜率排序
*
*/
/* 双线性插值算法
* 斜边一次差值找出交点
* 水平扫描差值找出当前点
*/
Vector4 screenA1V1 = a1.v1.ScreenSpacePosition;
Vector4 screenA1V2 = a1.v2.ScreenSpacePosition;
Vector4 screenA2V1 = a2.v1.ScreenSpacePosition;
Vector4 screenA2V2 = a2.v2.ScreenSpacePosition;
// 第一次插值算出交点的颜色系数
float r1 = ((float)i - screenA1V1.Y) / (float)(screenA1V2.Y - screenA1V1.Y);
float r2 = ((float)i - screenA2V1.Y) / (float)(screenA2V2.Y - screenA2V1.Y);
r1 = MathUtil.Clamp01(r1);
r2 = MathUtil.Clamp01(r2);
// 像素点深度插值
float z1 = MathUtil.Interp(screenA1V1.Z, screenA1V2.Z, r1);
float z2 = MathUtil.Interp(screenA2V1.Z, screenA2V2.Z, r2);
float nDotLA1V1 = 0, nDotLA1V2 = 0, nDotLA2V1 = 0, nDotLA2V2 = 0, nDotL1 = 0, nDotL2 = 0;
if (DirectionLight.IsEnable)
{
nDotLA1V1 = DirectionLight.ComputeNDotL(a1.v1.nowPos, a1.v1.nowNormal);
nDotLA1V2 = DirectionLight.ComputeNDotL(a1.v2.nowPos, a1.v2.nowNormal);
nDotLA2V1 = DirectionLight.ComputeNDotL(a2.v1.nowPos, a2.v1.nowNormal);
nDotLA2V2 = DirectionLight.ComputeNDotL(a2.v2.nowPos, a2.v2.nowNormal);
// 双线性插值系数
nDotL1 = MathUtil.Interp(nDotLA1V1, nDotLA1V2, r1);
nDotL2 = MathUtil.Interp(nDotLA2V1, nDotLA2V2, r2);
}
// 横向填充
while (a1 != null && a2 != null)
{
for (int x = (int)AEL.nextEdge.x; x < (int)AEL.nextEdge.nextEdge.x; x++)
{
float r3 = MathUtil.Clamp01(((float)x - a1.x) / (a2.x - a1.x));
float z = MathUtil.Interp(z1, z2, r3);
switch (scene.renderState)
{
case Scene.RenderState.WireFrame:
{
}
break;
case Scene.RenderState.GouraduShading:
{
//Padding.x = x;
//Padding.GouraudColor(scene,device,x,i,z,vt,oriVt);
}
break;
case Scene.RenderState.TextureMapping:
{
oriVt.CalWeight(new Vector4(x, i, 0, 0));
Vector4 uv = oriVt.GetInterUV();
if (isworld)
{
final = device.Tex2D(uv.X, uv.Y, scene.worldMap.texture);
}
else
{
if (DirectionLight.IsEnable)
{
float nDotL = MathUtil.Interp(nDotL1, nDotL2, r3);
final = device.Tex2D(uv.X, uv.Y, scene.mesh.texture);
final = final * DirectionLight.GetFinalLightColor(nDotL);
}
else
{
final = device.Tex2D(uv.X, uv.Y, scene.mesh.texture);
}
}
}
break;
}
device.DrawPoint(new Vector4(x, i, z, 0), final);
}
if (a2.nextEdge != null)
{
a1 = (Edge)a2.nextEdge.Clone();
a2 = (Edge)a1.nextEdge.Clone();
}
else
{
break;
}
}
// 删除y=yMax-1的边 ， 边的特性是上开下闭， 所以 当扫描到y = yamx后，ymax以前的边和扫描线不会再有交点
// 所以要删除，避免盲目求交
// 同时算出 x 的下一个坐标 并保存在 AEL的第一个边中 p.nextEdge.x += p.nextEdge.deltaX;
EdgeTable.DeleteEdge(AEL, i);
}
}
/* 重心坐标填充
* 填充效果明显，但基于精度问题，会有漏点
* 切效率低，不建议使用
*/
public void StartScanLine(VertexTriangle vt, VertexTriangle oriVt, Scene scene)
{
float yMin = this.height;
float yMax = 0;
Vertex[] vv = GetList(vt.Vertices);
Vertex A = vv[0];
Vertex B = vv[1];
Vertex C = vv[2];
float nDotLA1V1 = DirectionLight.ComputeNDotL(A.nowPos, A.nowNormal);
A.lightColor = A.Color * DirectionLight.GetFinalLightColor(nDotLA1V1);
float nDotLA1V2 = DirectionLight.ComputeNDotL(B.nowPos, B.nowNormal);
B.lightColor = B.Color * DirectionLight.GetFinalLightColor(nDotLA1V2);
float nDotLA2V1 = DirectionLight.ComputeNDotL(C.nowPos, C.nowNormal);
C.lightColor = C.Color * DirectionLight.GetFinalLightColor(nDotLA2V1);
float ay = A.ScreenSpacePosition.Y;
float by = B.ScreenSpacePosition.Y;
float cy = C.ScreenSpacePosition.Y;
float ax = A.ScreenSpacePosition.X;
float bx = B.ScreenSpacePosition.X;
float cx = C.ScreenSpacePosition.X;
float az = A.ScreenSpacePosition.Z;
float bz = B.ScreenSpacePosition.Z;
float cz = C.ScreenSpacePosition.Z;
yMin = Math.Min(Math.Min(ay, by), Math.Min(by, cy));
yMax = Math.Max(Math.Max(ay, by), Math.Max(by, cy));
float xMin = (int)Math.Min(Math.Min(ax, bx), Math.Min(bx, cx));
float xMax = (int)Math.Max(Math.Max(ax, bx), Math.Max(bx, cx));
vt.Preproccess();
float dtx = 0;
float dty = 0;
if (yMax - yMin > xMax - xMin)
{
dtx = (xMax - xMin) / (yMax - yMin);
dty = 1;
}
else
{
dtx = 1;
dty = (yMax - yMin) / (xMax - xMin);
}
for (int y = (int)yMin; y < yMax; y++)
{
for (int x = (int)xMin; x < xMax; x++)
{
float z = vt.GetInterValue(az, bz, cz);
Padding.GouraudColor(scene, device, x, y, z, vt, oriVt);
}
}
}
