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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;
}
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);
}
RayMarchResult ray_march(v2f i) {
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;
deform_normal(tmp, rd_perp, rd_tan);
rd = rd_perp + rd_tan;
#endif
const float kMinDist = 1e-3;
// TODO dial this in & parameterize
const float kMaxDist = 10;
// TODO parameterize
const uint kMaxIter = 10;
float d_acc = 0;
for (uint ii = 0; ii < kMaxIter; ++ii) {
float3 p = ro + rd * d_acc;
float d_cur = map(p);
d_acc += d_cur;
if (d_cur < kMinDist) {
break;
}
if (d_acc > kMaxDist) {
break;
}
}
// TODO clip / hit detection
float3 lclPos = ro + rd * d_acc;
float3 lclNorm;
float3 lclTan;
map_normal(lclPos, lclNorm, lclTan);
RayMarchResult res;
res.objPos = lclPos;
res.objNorm = lclNorm;
res.objTan = lclTan;
return res;
}
#endif // __RAY_MARCHING_INC
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