private void SortVectorByY(ref ScanLineData a, ref ScanLineData b)
{
if (a.Pos.y > b.Pos.y)
{
var temp = a;
a = b;
b = temp;
}
}
private float CalculateSlope(ScanLineData a, ScanLineData b)
{
if (b.Pos.y > a.Pos.y)
{
return((b.Pos.x - a.Pos.x) / (b.Pos.y - a.Pos.y));
}
else
{
return(0);
}
}
private void ProcessScanLine(int y, ScanLineData a, ScanLineData b, ScanLineData c, ScanLineData d)
{
var gradient1 = (int)a.Pos.y != (int)b.Pos.y ? (y - a.Pos.y) / (b.Pos.y - a.Pos.y) : 1;
var gradient2 = (int)c.Pos.y != (int)d.Pos.y ? (y - c.Pos.y) / (d.Pos.y - c.Pos.y) : 1;
var sx = (int)Interpolate(a.Pos.x, b.Pos.x, gradient1);
var ex = (int)Interpolate(c.Pos.x, d.Pos.x, gradient2);
var z1 = Interpolate(a.Pos.z, b.Pos.z, gradient1);
var z2 = Interpolate(c.Pos.z, d.Pos.z, gradient2);
var snl = Interpolate(a.NDotL, b.NDotL, gradient1);
var enl = Interpolate(c.NDotL, d.NDotL, gradient2);
var su = Interpolate(a.Texcoord.x, b.Texcoord.x, gradient1);
var eu = Interpolate(c.Texcoord.x, d.Texcoord.x, gradient2);
var sv = Interpolate(a.Texcoord.y, b.Texcoord.y, gradient1);
var ev = Interpolate(c.Texcoord.y, d.Texcoord.y, gradient2);
for (int x = sx; x < ex; x++)
{
var gradient3 = (float)(x - sx) / (ex - sx);
var z = Interpolate(z1, z2, gradient3);
var index = y * m_screenWidth + x;
if (index >= 0 && index < m_depthBuffer.Length)
{
if (m_depthBuffer[index] > z)
{
m_depthBuffer[index] = z;
var ndotl = Interpolate(snl, enl, gradient3);
var color = m_light.LightColor * ndotl;
if (m_texture != null)
{
var u = Interpolate(su, eu, gradient3);
var v = Interpolate(sv, ev, gradient3);
color *= Map(u, v);
}
color.a = 1;
DrawPoint(x, y, color);
}
}
}
}
private void RenderBuffer(MeshData mesh)
{
var world = mesh.GetLocalToWorld();
var view = m_camera.GetViewMatrix4X4(mesh.Position, Vector3.up);
var projection = m_camera.GetProjectionMatrix4X4();
var matrix = projection * view;
m_worldPoints.Clear();
m_screePoints.Clear();
m_worldNormals.Clear();
for (int i = 0, m = mesh.Triangle.GetLength(0); i < m; i++)
{
var i0 = mesh.Triangle[i, 0];
var i1 = mesh.Triangle[i, 1];
var i2 = mesh.Triangle[i, 2];
var wP0 = GetWorldPoint(world, mesh.Vertex[i0].Pos, i0);
var wP1 = GetWorldPoint(world, mesh.Vertex[i1].Pos, i1);
var wP2 = GetWorldPoint(world, mesh.Vertex[i2].Pos, i2);
if (Mode == ShadingMode.Shaded)
{
if (!BackFaceCull(wP0, wP1, wP2))
{
var sP0 = GetScreenPoint(matrix, wP0, i0);
var sP1 = GetScreenPoint(matrix, wP1, i1);
var sP2 = GetScreenPoint(matrix, wP2, i2);
var wN0 = GetWorldNormal(world, mesh.Vertex[i0].Normal, i0);
var wN1 = GetWorldNormal(world, mesh.Vertex[i1].Normal, i1);
var wN2 = GetWorldNormal(world, mesh.Vertex[i2].Normal, i2);
var ndotl0 = ComputeNDotL(wP0, wN0);
var ndotl1 = ComputeNDotL(wP1, wN1);
var ndotl2 = ComputeNDotL(wP2, wN2);
var v0 = new ScanLineData {
Pos = sP0, NDotL = ndotl0, Texcoord = mesh.Vertex[i0].Texcoord
};
var v1 = new ScanLineData {
Pos = sP1, NDotL = ndotl1, Texcoord = mesh.Vertex[i1].Texcoord
};
var v2 = new ScanLineData {
Pos = sP2, NDotL = ndotl2, Texcoord = mesh.Vertex[i2].Texcoord
};
DrawTriangle(v0, v1, v2);
}
}
else
{
var sP0 = GetScreenPoint(matrix, wP0, i0);
var sP1 = GetScreenPoint(matrix, wP1, i1);
var sP2 = GetScreenPoint(matrix, wP2, i2);
DrawLine((int)sP0.x, (int)sP0.y, (int)sP1.x, (int)sP1.y);
DrawLine((int)sP1.x, (int)sP1.y, (int)sP2.x, (int)sP2.y);
DrawLine((int)sP2.x, (int)sP2.y, (int)sP0.x, (int)sP0.y);
}
}
mesh.Rotation += new Vector3(0, 1, 0);
}
private void DrawTriangle(ScanLineData point0, ScanLineData point1, ScanLineData point2)
{
SortVectorByY(ref point0, ref point1);
SortVectorByY(ref point1, ref point2);
SortVectorByY(ref point0, ref point1);
if ((int)point0.Pos.y == (int)point1.Pos.y)
{
if (point0.Pos.x > point1.Pos.x)
{
for (int i = (int)point0.Pos.y, max = (int)point2.Pos.y; i <= max; i++)
{
ProcessScanLine(i, point1, point2, point0, point2);
}
}
else
{
for (int i = (int)point0.Pos.y, max = (int)point2.Pos.y; i <= max; i++)
{
ProcessScanLine(i, point0, point2, point1, point2);
}
}
}
else if ((int)point2.Pos.y == (int)point1.Pos.y)
{
if (point2.Pos.x > point1.Pos.x)
{
for (int i = (int)point0.Pos.y, max = (int)point2.Pos.y; i <= max; i++)
{
ProcessScanLine(i, point0, point1, point0, point2);
}
}
else
{
for (int i = (int)point0.Pos.y, max = (int)point2.Pos.y; i <= max; i++)
{
ProcessScanLine(i, point0, point2, point0, point1);
}
}
}
else
{
var dP0P1 = CalculateSlope(point0, point1);
var dP0P2 = CalculateSlope(point0, point2);
if (dP0P1 > dP0P2)
{
for (int i = (int)point0.Pos.y, max = (int)point2.Pos.y; i <= max; i++)
{
if (i < point1.Pos.y)
{
ProcessScanLine(i, point0, point2, point0, point1);
}
else
{
ProcessScanLine(i, point0, point2, point1, point2);
}
}
}
else
{
for (int i = (int)point0.Pos.y, max = (int)point2.Pos.y; i <= max; i++)
{
if (i < point1.Pos.y)
{
ProcessScanLine(i, point0, point1, point0, point2);
}
else
{
ProcessScanLine(i, point1, point2, point0, point2);
}
}
}
}
}
