internal static void Index2EntryPointKernel(
Index2 index,
ArrayView <int> output,
Index2 extent)
{
var linearIndex = index.ComputeLinearIndex(extent);
output[linearIndex] = linearIndex;
}
static void NearFieldKernel1(
Index2 index, // Contains (sample, line) First dimension changes fastest
int target_line, // row within the 128 x 128 target patch
int target_sample, // column
int slope_idx_start,
int slope_idx_stop,
ArrayView <short> gpu_terrain,
ArrayView <float> gpu_range,
ArrayView <float> gpu_slope,
ArrayView <float> gpu_rise,
ArrayView <int> gpu_range_limit)
{
var flip = -LonFactor;
// From ILGPU source code: public int ComputeLinearIndex(Index2 dimension) => Y * dimension.X + X;
var rise_idx = index.ComputeLinearIndex(Dimension);
var rise = gpu_rise[rise_idx];
var center_line = target_line + index.Y;
var center_sample = target_sample + index.X;
var center_idx = center_line * TerrainSize + center_sample;
var center_height = 0.5f * gpu_terrain[center_idx];
GetVector3d(center_line, center_sample, center_height, out float center_x, out float center_y, out float center_z);
center_z *= flip;
for (var slope_idx = slope_idx_start; slope_idx < slope_idx_stop; slope_idx++)
{
var slope = gpu_slope[slope_idx];
// Work out the direction vector
var ray_rad = XMath.PI * 2f * slope_idx / cpu_slope_size; // 0 deg in ME frame points toward the earth
var ray_cos = XMath.Cos(ray_rad); // varies the line
var ray_sin = XMath.Sin(ray_rad); // varies the sample
// iterate over the ranges
var range_limit = gpu_range_limit[slope_idx];
for (var range_idx = 0; range_idx < range_limit; range_idx++)
{
var range = gpu_range[range_idx];
var caster_line = center_line + ray_sin * range;
var caster_sample = center_sample + ray_cos * range;
var x1 = (int)caster_sample; // Calculate the caster point by interpolating between four points from the points array
var y1 = (int)caster_line;
int x2 = x1 + 1;
int y2 = y1 + 1;
var q11_idx = y1 * TerrainSize + x1;
var q11 = gpu_terrain[q11_idx];
var q12_idx = q11_idx + TerrainSize;
var q12 = gpu_terrain[q12_idx];
// First interpolation across rows (line)
var q1_line = q11 + (caster_line - y1) * (q12 - q11);
var q21_idx = q11_idx + 1;
var q21 = gpu_terrain[q21_idx];
var q22_idx = q11_idx + TerrainSize + 1;
var q22 = gpu_terrain[q22_idx];
// Second interpolation across rows
var q2_line = q21 + (caster_line - y1) * (q22 - q21);
// Interpolate across samples and convert to meters
var caster_height = q1_line + (caster_sample - x1) * (q2_line - q1_line);
caster_height *= 0.5f;
GetVector3d(caster_line, caster_sample, caster_height, out float caster_x, out float caster_y, out float caster_z);
caster_z *= flip;
var dx = caster_x - center_x;
var dy = caster_y - center_y;
var d = XMath.Sqrt(dx * dx + dy * dy); // horizontal distance in moon radius units
var light_ray_height = caster_z - slope * d; // negative slope gets higher as light ray goes toward the center
var ray_rise_height = light_ray_height - center_z; // moon radius units
var ray_rise_meters = ray_rise_height * 1000f;
// Alternative
//var dInMeters = d * 1000f;
//var deltaHeightInMeters = (caster_z - center_z) * 1000f;
//var rise2 = deltaHeightInMeters - dInMeters * slope;
rise = XMath.Max(rise, ray_rise_meters);
}
}
gpu_rise[rise_idx] = rise;
}
public void InstanceKernel(Index2 index, ArrayView <int> output, Index2 extent)
{
var linearIndex = index.ComputeLinearIndex(extent);
output[linearIndex] = NestedFunction(linearIndex);
}
