VaryingData GeometryProcessing(Vector3[] vertices, Matrix4x4 mvp)
{
var result = new VaryingData();
var count = vertices.Length;
for (int i = 0; i < count; i++)
{
result.sv_position.Add(mvp * new Vector4(vertices[i].x, vertices[i].y, vertices[i].z, 1));
}
return(result);
}
FragmentData ClippingAndRasterization(VaryingData varyingData, int[] indexes)
{
var result = new FragmentData();
var count = indexes.Length;
for (int i = 0; i < count; i += 3)
{
var index0 = indexes[i];
var index1 = indexes[i + 1];
var index2 = indexes[i + 2];
var v0 = new Vector4(varyingData.sv_position[index0].x, varyingData.sv_position[index0].y, varyingData.sv_position[index0].z, 1f) / varyingData.sv_position[index0].w;
var v1 = new Vector4(varyingData.sv_position[index1].x, varyingData.sv_position[index1].y, varyingData.sv_position[index1].z, 1f) / varyingData.sv_position[index1].w;
var v2 = new Vector4(varyingData.sv_position[index2].x, varyingData.sv_position[index2].y, varyingData.sv_position[index2].z, 1f) / varyingData.sv_position[index2].w;
var area = EdgeFunction(v0, v1, v2);
var xMin = Mathf.Max(Mathf.FloorToInt((Mathf.Min(v0.x, v1.x, v2.x) * 0.5f + 0.5f) / pixelSize.x), 0);
var xMax = Mathf.Min(Mathf.CeilToInt((Mathf.Max(v0.x, v1.x, v2.x) * 0.5f + 0.5f) / pixelSize.x) + 1, width);
var yMin = Mathf.Max(Mathf.FloorToInt((Mathf.Min(v0.y, v1.y, v2.y) * 0.5f + 0.5f) / pixelSize.y), 0);
var yMax = Mathf.Min(Mathf.CeilToInt((Mathf.Max(v0.y, v1.y, v2.y) * 0.5f + 0.5f) / pixelSize.y) + 1, height);
for (int x = xMin; x < xMax; x++)
{
for (int y = yMin; y < yMax; y++)
{
var p = new Vector2(x * pixelSize.x, y * pixelSize.y) + pixelSize * 0.5f;
p = p * 2f - new Vector2(1f, 1f);
var w0 = EdgeFunction(v1, v2, p);
var w1 = EdgeFunction(v2, v0, p);
var w2 = EdgeFunction(v0, v1, p);
if (w0 < 0 || w1 < 0 || w2 < 0)
{
// triangle not contains the point
continue;
}
w0 /= area;
w1 /= area;
w2 /= area;
var interpolated_z = v0.z * w0 + v1.z * w1 + v2.z * w2;
var interpolated_w = v0.w * w0 + v1.w * w1 + v2.w * w2;
if (interpolated_z < 0f || interpolated_z > 1f)
{
// clip fragments outside the near/far planes
continue;
}
// perspective correct interpolation
// w0 = w0 * v0.w / interpolated_w;
// w1 = w1 * v1.w / interpolated_w;
// w2 = w2 * v2.w / interpolated_w;
// var varying = varying0 * w0 + varying1 * w1 + varying2 * w2;
var depth = interpolated_z;
var index = y * width + x;
result.index.Add(index);
result.sv_depth.Add(depth);
}
}
}
return(result);
}