// 基于斜率的办法避免不了精度误差
/*
* List<FragmentIn> Rast(FragmentIn v1, FragmentIn v2, FragmentIn v3) {
* var frags = new List<FragmentIn>();
*
* var vv1 = v1;
* var vv2 = v2;
* var vv3 = v3;
*
* // 保证v1,v2,v3 y轴依次变小
* if (v1.vertex.y < v2.vertex.y) Swap(ref v1, ref v2);
* if (v1.vertex.y < v3.vertex.y) Swap(ref v1, ref v3);
* if (v2.vertex.y < v3.vertex.y) Swap(ref v2, ref v3);
*
* var p1 = v1.vertex;
* var p2 = v2.vertex;
* var p3 = v3.vertex;
*
* if (p2.y == p3.y) {
* RastTriangle(v2, v3, v1, frags);
* }
* else if (p1.y == p2.y) {
* RastTriangle(v1, v2, v3, frags);
* }
* else {
* // y = y0 + k(x-x0)
* // x = x0 + 1/k*(y-y0)
* // 注意斜率为0或无穷大的情况
* float k = (p1.y - p3.y) / (p1.x - p3.x);
* float splitx;
* float splity;
*
* if (p1.x != p3.x) {
* splitx = p3.x + (p2.y - p3.y) / k;
* splity = p2.y;
* } else {
* splitx = p3.x;
* splity = p2.y;
* }
*
* var splitv = new FragmentIn();
* splitv.pixelx = (int)splitx;
* splitv.pixely = (int)splity;
*
* LerpFragment(v1, v2, v3, splitv);
*
* RastTriangle(v2, splitv, v1, frags);
* RastTriangle(v2, splitv, v3, frags);
* }
*
* return frags;
* }
*
* // 扫描线
* // /\3
* // 1----2
* void RastTriangle(FragmentIn v1, FragmentIn v2, FragmentIn v3, List<FragmentIn> frags) {
*
* var p1 = v1.vertex;
* var p2 = v2.vertex;
* var p3 = v3.vertex;
*
*
* float curx1 = p1.x;
* float curx2 = p2.x;
* int inc = p1.y > p3.y ? -1 : 1;
*
* int scanline = (int)p1.y;
* int scanto = (int)p3.y;
* if (scanline == scanto) {
* //三角形退化
*
* curx1 = Mathf.Min(Mathf.Max(curx1, 0), width);
* curx2 = Mathf.Min(Mathf.Max(curx2, 0), width);
*
* var ix1 = (int)curx1;
* var ix2 = (int)curx2;
* if (ix1 == ix2) {
* var frag = new FragmentIn();
* frag.pixelx = ix1;
* frag.pixely = scanline;
*
* LerpFragment(v1, v2, v3, frag);
*
* frags.Add(frag);
* }
* else {
* var incx = ix1 > ix2 ? -1 : 1;
* for (int x = ix1; x != ix2; x += incx) {
* var frag = new FragmentIn();
* frag.pixelx = x;
* frag.pixely = scanline;
*
* LerpFragment(v1, v2, v3, frag);
*
* frags.Add(frag);
* }
* }
* }
* else {
* float slop1 = (p3.x - p1.x)/(p3.y - p1.y);
* float slop2 = (p3.x - p2.x)/(p3.y - p2.y);
*
* for (; scanline != scanto; scanline += inc) {
*
* curx1 = Mathf.Min(Mathf.Max(curx1, 0), width);
* curx2 = Mathf.Min(Mathf.Max(curx2, 0), width);
*
* var ix1 = (int)curx1;
* var ix2 = (int)curx2;
* if (ix1 == ix2) {
* var frag = new FragmentIn();
* frag.pixelx = ix1;
* frag.pixely = scanline;
*
* LerpFragment(v1, v2, v3, frag);
*
* frags.Add(frag);
* } else {
* var incx = ix1 > ix2 ? -1 : 1;
*
* for (int x = ix1; x != ix2; x += incx) {
*
* var frag = new FragmentIn();
* frag.pixelx = x;
* frag.pixely = scanline;
*
* LerpFragment(v1, v2, v3, frag);
*
* frags.Add(frag);
* }
* }
*
* curx1 += inc * slop1;
* curx2 += inc * slop2;
* }
* }
* }
*/
// 基于三角形面积做插值
bool LerpFragment(FragmentIn v1, FragmentIn v2, FragmentIn v3, FragmentIn ret)
{
var v0 = new Vector4(ret.pixelx, ret.pixely);
var d01 = v0 - v1.vertex;
var d21 = v2.vertex - v1.vertex;
var d31 = v3.vertex - v1.vertex;
var denom = Mathf.Abs(d21.x * d31.y - d21.y * d31.x);
if (denom < 0.000001)
{
return(false);
}
var u = Mathf.Abs(d01.x * d31.y - d01.y * d31.x) / denom; // close to v2
var v = Mathf.Abs(d01.x * d21.y - d01.y * d21.x) / denom; // close to v3
var w = 1 - u - v; // close to v1
// do lerp
ret.vertex = v2.vertex * u + v3.vertex * v + v1.vertex * w;
ret.normal = v2.normal * u + v3.normal * v + v1.normal * w;
ret.worldPos = v2.worldPos * u + v3.worldPos * v + v1.worldPos * w;
ret.uv = v2.uv * u + v3.uv * v + v1.uv * w;
ret.color = v2.color * u + v3.color * v + v1.color * w;
return(true);
}
void DoNDCCoord(FragmentIn frag)
{
var projectv = frag.vertex;
// 转换到NDC空间，再到viewport空间
projectv.x = (projectv.x / projectv.w / 2 + 0.5f) * width;
projectv.y = (projectv.y / projectv.w / 2 + 0.5f) * height;
projectv.z = (projectv.z / projectv.w + 0.5f);
frag.vertex = projectv;
frag.pixelx = (int)projectv.x;
frag.pixely = (int)projectv.y;
}
public Color Frag(FragmentIn v)
{
var color = ShaderGlobal.Ambient;
Vector3 dir; // 光线的反方向
float intensity; //光线强度
Vector3 viewdir = (ShaderGlobal.CameraPos - v.worldPos).normalized;
foreach (var light in ShaderGlobal.lights)
{
switch (light.type)
{
// 这一部分计算要预处理下
case LightType.Directional:
dir = -light.transform.forward;
intensity = light.intensity;
break;
case LightType.Point:
dir = light.transform.position - v.worldPos;
// 正常的intensity公式是 1/(a+b*dis+c*dis^2)
intensity = Mathf.Clamp01(light.intensity * (1 - dir.magnitude / light.range));
dir.Normalize();
break;
case LightType.Spot:
dir = light.transform.position - v.worldPos;
float rho = Mathf.Max(0, Vector3.Dot(dir.normalized, -light.transform.forward));
intensity = Mathf.Clamp01((Mathf.Cos(light.spotAngle * Mathf.Deg2Rad) - rho) * light.intensity * (1 - dir.magnitude / light.range));
dir.Normalize();
break;
default:
dir = -light.transform.forward;
intensity = light.intensity;
break;
}
float diff = Mathf.Max(0, Vector3.Dot(v.normal, dir));
Vector3 h = (dir + viewdir).normalized;
float nh = Vector3.Dot(h, v.normal);
float spec = Mathf.Pow(nh, ShaderGlobal.Specular);
color += (ShaderGlobal.Albedo * light.color * diff + ShaderGlobal.SpecularColor * light.color * spec) * intensity;
}
return(color);
//return new Color(v.uv.x, v.uv.y, 0);
//return new Color(v.normal.x, v.normal.y, v.normal.z, 1);
}
public FragmentIn Vert(VertexIn v)
{
var vert = new FragmentIn();
vert.worldPos = ShaderGlobal.l2wMat.MultiplyPoint3x4(v.pos);
vert.normal = ShaderGlobal.l2wInvTMat.MultiplyVector(v.normal).normalized;
vert.uv = v.uv;
vert.color = v.color;
Vector4 pos = v.pos;
pos.w = 1;
vert.vertex = ShaderGlobal.MVPMat * pos;
return(vert);
}
public List <FragmentIn> Rast(FragmentIn v1, FragmentIn v2, FragmentIn v3)
{
var p1 = v1.vertex;
var p2 = v2.vertex;
var p3 = v3.vertex;
int xMin = (int)Mathf.Min(p1.x, p2.x, p3.x);
int xMax = (int)Mathf.Max(p1.x, p2.x, p3.x);
int yMin = (int)Mathf.Min(p1.y, p2.y, p3.y);
int yMax = (int)Mathf.Max(p1.y, p2.y, p3.y);
var fragList = new List <FragmentIn>((xMax - xMin) * (yMax - yMin));
for (int m = xMin; m < xMax + 1; m++)
{
for (int n = yMin; n < yMax + 1; n++)
{
if (m < 0 || m > width - 1 || n < 0 || n > height - 1)
{
continue;
}
if (!isLeftPoint(p1, p2, m + 0.5f, n + 0.5f))
{
continue;
}
if (!isLeftPoint(p2, p3, m + 0.5f, n + 0.5f))
{
continue;
}
if (!isLeftPoint(p3, p1, m + 0.5f, n + 0.5f))
{
continue;
}
var frag = new FragmentIn();
frag.pixelx = m;
frag.pixely = n;
LerpFragment(v1, v2, v3, frag);
fragList.Add(frag);
}
}
return(fragList);
}
Vector4 FS(FragmentIn input)
{
float r = Sample(Tex, TexSampler, input.TexCoord).X;
return(new Vector4(r, r, r, r));
}
Vector4 FS(FragmentIn input)
{
return(Sample(Tex, TexSampler, input.TexCoord));
//float r = Sample(Tex, TexSampler, input.TexCoord).X;
//return new Vector4(r, r, r, r);
}
Vector4 FS(FragmentIn input)
{
return(Sample(Tex, TexSampler, input.TexCoord));
}
