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#ifndef __RAY_MARCHING_INC
#define __RAY_MARCHING_INC
#include "math.cginc"
#include "ray_marching_maps.hlsl"
#include "texture_utils.cginc"
#include "vertex.cginc"
struct RayMarchResult {
float3 objPos;
float3 objNorm;
float3 objTan;
};
float3 getObjPos(v2f i)
{
return i.objPos_orig;
}
void GetRoRd(v2f i, out float3 ro, out float3 rd) {
ro = getObjPos(i);
float3 objCamPos = mul(unity_WorldToObject, float4(_WorldSpaceCameraPos, 1));
float3 obj_space_camera_pos = mul(unity_WorldToObject, float4(_WorldSpaceCameraPos, 1.0));
rd = normalize(getObjPos(i) - obj_space_camera_pos);
}
void ray_march(inout v2f i) {
#if defined(_RAY_MARCHING)
float3 ro, rd;
GetRoRd(i, ro, rd);
#if defined(_VERTEX_DEFORMATION)
float3 rd_perp = i.normal * dot(i.normal, rd);
float3 rd_tan = rd - rd_perp;
float3 tmp = ro;
undeform_normal(tmp, rd_perp, rd_tan);
rd = normalize(rd_perp + rd_tan);
#endif
const float kMinDist = _Ray_Marching_Min_Dist;
const float kMaxDist = _Ray_Marching_Max_Dist;
const uint kMaxIter = _Ray_Marching_Max_Iter;
float d_cur;
float d_acc = 0;
for (uint ii = 0; ii < kMaxIter; ++ii) {
float3 p = ro + rd * d_acc;
d_cur = 1e9;
#if defined(_RAY_MARCHING_BALL_GRID)
float3 count = float3(_Ray_Marching_Ball_Grid_Count_X, _Ray_Marching_Ball_Grid_Count_Y, _Ray_Marching_Ball_Grid_Count_Z);
d_cur = min(d_cur, map_ball_grid(p, count));
#endif
#if defined(_RAY_MARCHING_OVERSTEP)
d_cur *= (d_cur > 0 ? _Ray_Marching_Overstepping_Factor : 1.0f);
#endif
d_acc += d_cur;
if (abs(d_cur) < kMinDist) {
break;
}
if (d_acc > kMaxDist) {
break;
}
}
if (abs(d_cur) > kMinDist) {
discard;
}
// TODO clip / hit detection
float3 lclPos = ro + rd * d_acc;
float3 lclNorm;
float3 lclTan;
#if defined(_RAY_MARCHING_BALL_GRID)
float3 count = float3(_Ray_Marching_Ball_Grid_Count_X, _Ray_Marching_Ball_Grid_Count_Y, _Ray_Marching_Ball_Grid_Count_Z);
map_ball_grid_normal(count, lclPos, lclNorm, lclTan);
#endif
i.objPos = lclPos;
i.normal = lclNorm;
i.tangent.xyz = lclTan;
#endif // _RAY_MARCHING
}
#endif // __RAY_MARCHING_INC
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