private void ProcessScanLine(ScanLine data, Vertex va, Vertex vb, Vertex vc, Vertex vd, Color4 color)
{
Vector3 pointA = va.Coordinates;
Vector3 pointB = vb.Coordinates;
Vector3 pointC = vc.Coordinates;
Vector3 pointD = vd.Coordinates;
var gradient1 = pointA.Y != pointB.Y ? (data.CurrentY - pointA.Y) / (pointB.Y - pointA.Y) : 1;
var gradient2 = pointC.Y != pointD.Y ? (data.CurrentY - pointC.Y) / (pointD.Y - pointC.Y) : 1;
int sx = (int)Interpolate(pointA.X, pointB.X, gradient1);
int ex = (int)Interpolate(pointC.X, pointD.X, gradient2);
double z1 = Interpolate(pointA.Z, pointB.Z, gradient1);
double z2 = Interpolate(pointC.Z, pointD.Z, gradient2);
ShadingAlgorithm.InterpolateValue(data, gradient1, gradient2);
// var snl = Interpolate(data.NormalAndLightDotProductA, data.NormalAndLightDotProductB, gradient1);
// var enl = Interpolate(data.NormalAndLightDotProductC, data.NormalAndLightDotProductD, gradient2);
for (var x = sx; x < ex; x++)
{
double gradient = (x - sx) / (double)(ex - sx);
var z = Interpolate(z1, z2, gradient);
var ndotl = ShadingAlgorithm.ComputeShadingCoefficient(gradient, data);
var shaded = color * (float)ndotl;
var I = (float)PhongReflection.PhongReflectionValue;
var illuminated = new Color4(Check(shaded.Red + I), Check(shaded.Green + I), Check(shaded.Blue + I), shaded.Alpha);
DrawPoint(new Vector3(x, data.CurrentY, (float)z), illuminated);
}
}
public void InterpolateValue(ScanLine scanLineData, float gradient1, float gradient2)
{
}
public double ComputeShadingCoefficient(double gradient, ScanLine scanLine)
{
return(scanLine.FaceNormalAndLightDotProduct);
}
private void DrawTriangle(Vertex v1, Vertex v2, Vertex v3, Color4 color, Camera camera, Vector3 lightPos)
{
var data = new ScanLine {
};
data.FaceNormal = (v1.Normal + v2.Normal + v3.Normal) / 3;
var facePoint = (v1.WorldCoordinates + v2.WorldCoordinates + v3.WorldCoordinates) / 3;
data.FaceNormalAndLightDotProduct =
ComputeNormalAndLightDotProduct(facePoint, data.FaceNormal,
lightPos);
PhongReflection.ComputePhongReflection(data.FaceNormal, lightPos, facePoint, camera.Position);
Vertex[] sortedVertices = SortVertices(v1, v2, v3);
v1 = sortedVertices[0];
v2 = sortedVertices[1];
v3 = sortedVertices[2];
Vector3 p1 = v1.Coordinates;
Vector3 p2 = v2.Coordinates;
Vector3 p3 = v3.Coordinates;
double nl1 = ComputeNormalAndLightDotProduct(v1.WorldCoordinates, v1.Normal, lightPos);
double nl2 = ComputeNormalAndLightDotProduct(v2.WorldCoordinates, v2.Normal, lightPos);
double nl3 = ComputeNormalAndLightDotProduct(v3.WorldCoordinates, v3.Normal, lightPos);
var slopeP1P2 = ComputeInverseSlope(p1, p2);
var slopeP1P3 = ComputeInverseSlope(p1, p3);
if (slopeP1P2 > slopeP1P3)
{
for (var y = (int)p1.Y; y <= (int)p3.Y; y++)
{
data.CurrentY = y;
if (y < p2.Y)
{
data.NormalAndLightDotProductA = nl1;
data.NormalAndLightDotProductB = nl3;
data.NormalAndLightDotProductC = nl1;
data.NormalAndLightDotProductD = nl2;
ProcessScanLine(data, v1, v3, v1, v2, color);
}
else
{
data.NormalAndLightDotProductA = nl1;
data.NormalAndLightDotProductB = nl3;
data.NormalAndLightDotProductC = nl2;
data.NormalAndLightDotProductD = nl3;
ProcessScanLine(data, v1, v3, v2, v3, color);
}
}
}
else
{
for (var y = (int)p1.Y; y <= (int)p3.Y; y++)
{
data.CurrentY = y;
if (y < p2.Y)
{
data.NormalAndLightDotProductA = nl1;
data.NormalAndLightDotProductB = nl2;
data.NormalAndLightDotProductC = nl1;
data.NormalAndLightDotProductD = nl3;
ProcessScanLine(data, v1, v2, v1, v3, color);
}
else
{
data.NormalAndLightDotProductA = nl2;
data.NormalAndLightDotProductB = nl3;
data.NormalAndLightDotProductC = nl1;
data.NormalAndLightDotProductD = nl3;
ProcessScanLine(data, v2, v3, v1, v3, color);
}
}
}
}
public void InterpolateValue(ScanLine scanLineData, float gradient1, float gradient2)
{
startNormalLightDotProduct = Interpolate(scanLineData.NormalAndLightDotProductA, scanLineData.NormalAndLightDotProductB, gradient1);
endNormalLightDotProduct = Interpolate(scanLineData.NormalAndLightDotProductC, scanLineData.NormalAndLightDotProductD, gradient2);
}
public double ComputeShadingCoefficient(double gradient, ScanLine scanLine)
{
return(Interpolate(startNormalLightDotProduct, endNormalLightDotProduct, gradient));
}
