public PSOutput FragShader(VSOutput v)
{
//invert uv
if (shaderContext.invertTexture)
{
//v.texcoord = new Vector2(1 - v.texcoord.X, 1 - v.texcoord.Y);
v.texcoord = new Vector2(v.texcoord.X, 1 - v.texcoord.Y);
//v.texcoord = new Vector2(1 - v.texcoord.X, v.texcoord.Y);
}
PSOutput OUT = new PSOutput();
Vector4 col = v.color;
if ((shaderContext.shadeMode == ShadeMode.Lighting ||
shaderContext.shadeMode == ShadeMode.NDotL) &&
shaderContext.light != null)
{
Vector3 normalWorld = v.normalWorld;
normalWorld = Vector3.Normalize(normalWorld);
Vector3 lightDir = shaderContext.light.lightDirForShader;
//Lambert Lighting
float NDotL = Vector3.Dot(normalWorld, lightDir);
NDotL = Utils.Clamp(NDotL, 0, 1);
if (shaderContext.shadeMode == ShadeMode.Lighting && texture != null)
{
Vector4 tex = texture.Tex2D(v.texcoord, shaderContext.textureFilterMode);
col = tex * (NDotL * shaderContext.light.lightColor + shaderContext.ambient);
}
else
{
col = new Vector4(NDotL, NDotL, NDotL, 1f);
}
}
else if (shaderContext.shadeMode == ShadeMode.Texture && texture != null)
{
col = texture.Tex2D(v.texcoord, shaderContext.textureFilterMode);
}
//col = new Vector4(v.texcoord.X, v.texcoord.Y, 0, 1 );
OUT.color = col;
return(OUT);
}
public void BarycentricRasterizeTriangle(VSOutput v0, VSOutput v1, VSOutput v2)
{
int width = context.frameSize.Width;
int height = context.frameSize.Height;
Vector2 xy0 = new Vector2(v0.posScreen.X, v0.posScreen.Y);
Vector2 xy1 = new Vector2(v1.posScreen.X, v1.posScreen.Y);
Vector2 xy2 = new Vector2(v2.posScreen.X, v2.posScreen.Y);
float z0 = v0.posScreen.Z;
float z1 = v1.posScreen.Z;
float z2 = v2.posScreen.Z;
//求包围盒
float xmin = Math.Min(Math.Min(xy0.X, xy1.X), xy2.X);
float xmax = Math.Max(Math.Max(xy0.X, xy1.X), xy2.X);
float ymin = Math.Min(Math.Min(xy0.Y, xy1.Y), xy2.Y);
float ymax = Math.Max(Math.Max(xy0.Y, xy1.Y), xy2.Y);
//像素坐标包围盒
int x0 = Utils.Clamp((int)xmin, 0, width - 1);
int y0 = Utils.Clamp((int)ymin, 0, height - 1);
int x1 = Utils.Clamp((int)xmax, 0, width - 1);
int y1 = Utils.Clamp((int)ymax, 0, height - 1);
for (int y = y0; y <= y1; ++y)
{
for (int x = x0; x <= x1; ++x)
{
//加0.5取像素的中间位置的坐标
Vector2 pixel = new Vector2(x + 0.5f, y + 0.5f);
Vector3 w = BarycentricCoordinates(pixel, xy0, xy1, xy2);
float w0 = w.X; float w1 = w.Y; float w2 = w.Z;
if (!(w0 >= 0 && w1 >= 0 && w2 >= 0))
{
//像素点不在三角形内
continue;
}
context.statics.fragmentCount += 1;
//深度测试
float depth = w0 * z0 + w1 * z1 + w2 * z2;
if (context.depthBuffer[x, y] < depth)
{
continue;
}
Color col;
if (context.drawMode == DrawMode.Depth)
{
Vector4 depthColor = new Vector4(depth, depth, depth, 1);
col = Utils.VectorToColor(depthColor);
}
else
{
//正常渲染
//插值UV等顶点属性
float fInvW = w0 * v0.position.W + w1 * v1.position.W + w2 * v2.position.W;
//由于position.W是1/W = 1/-Z_Eye
float Z_Eye = 1f / fInvW;
Vector2 uv = w0 * v0.texcoord + w1 * v1.texcoord + w2 * v2.texcoord;
uv *= Z_Eye;
Vector4 color = w0 * v0.color + w1 * v1.color + w2 * v2.color;
color *= Z_Eye;
Vector3 normalWorld = w0 * v0.normalWorld + w1 * v1.normalWorld + w2 * v2.normalWorld;
if (shader != null)
{
VSOutput fragment = new VSOutput();
//v.position =
fragment.normalWorld = normalWorld;
fragment.texcoord = uv;
fragment.color = color;
PSOutput OUT = shader.FragShader(fragment);
if (OUT.isDiscard)
{
continue;
}
col = Utils.VectorToColor(OUT.color);
}
else
{
col = Utils.VectorToColor(color);
}
}
context.depthBuffer[x, y] = depth;
DrawPixel(x, y, col);
}
}
}
