vtl_mesh_view.h

/*
 * Fermat
 *
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 * modification, are permitted provided that the following conditions are met:
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 *      notice, this list of conditions and the following disclaimer.
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 *      notice, this list of conditions and the following disclaimer in the
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 *      names of its contributors may be used to endorse or promote products
 *      derived from this software without specific prior written permission.
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 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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 */

#pragma once

#include <mesh/MeshView.h>
#include <cugar/basic/vector.h>
#include <cugar/spherical/mappings.h>
#include <cugar/bvh/bvh_node.h>
#include <uv_bvh_view.h>

struct VTLMeshView
{
    FERMAT_HOST_DEVICE
    VTLMeshView() :
        n_vtls(0), vtls(NULL), uvbvh(), mesh(), textures(NULL) {}

    FERMAT_HOST_DEVICE
    VTLMeshView(const uint32 _n_vtls, const VTL* _vtls, const UVBvhView& _uvbvh, const MeshView& _mesh, const MipMapView* _textures) :
        n_vtls(_n_vtls), vtls(_vtls), uvbvh(_uvbvh), mesh(_mesh), textures(_textures) {}


    FERMAT_HOST_DEVICE
    void sample(
        const uint32            vtl_idx,
        const cugar::Vector2f   vtl_uv,
        uint32_t*               prim_id,
        cugar::Vector2f*        uv,
        VertexGeometry*         geom,
        float*                  pdf,
        Edf*                    edf) const
    {
        //const float one = cugar::binary_cast<float>(FERMAT_ALMOST_ONE_AS_INT);

        // sample one of the VTLs
        *prim_id = vtls[vtl_idx].prim_id;
        *uv      = vtls[vtl_idx].interpolate_uv( vtl_uv );
        *pdf     = 1.0f / vtls[vtl_idx].area;

        FERMAT_ASSERT(*prim_id < uint32(mesh.num_triangles));
        setup_differential_geometry(mesh, *prim_id, uv->x, uv->y, geom);

        const int material_id = mesh.material_indices[*prim_id];
        MeshMaterial material = mesh.materials[material_id];

        material.emissive = cugar::Vector4f(material.emissive) * texture_lookup(geom->texture_coords, material.emissive_map, textures, cugar::Vector4f(1.0f));

        *edf = Edf(material);
    }

    FERMAT_HOST_DEVICE
    uint32 map(const uint32_t prim_id, const cugar::Vector2f& uv, const VertexGeometry& geom, float* pdf, Edf* edf) const
    {
        if (n_vtls)
        {
            FERMAT_ASSERT(prim_id < uint32(mesh.num_triangles));
            const int material_id = mesh.material_indices[prim_id];
            MeshMaterial material = mesh.materials[material_id];

            material.emissive = cugar::Vector4f(material.emissive) * texture_lookup(geom.texture_coords, material.emissive_map, textures, cugar::Vector4f(1.0f));

            *edf = Edf(material);

            // find the VTL containing this uv
            const uint32 vtl_idx = locate( uvbvh, vtls, prim_id, uv );
            *pdf = vtl_idx != uint32(-1) ?  1.0f / vtls[vtl_idx].area : 0.0f;
            return vtl_idx;
        }
        else
        {
            *pdf = 1.0f;
            *edf = Edf();
            return uint32(-1);
        }
    }

    FERMAT_HOST_DEVICE
    uint32 vtl_count() const { return n_vtls; }

    FERMAT_HOST_DEVICE
    VTL get_vtl(const uint32 i) const { return vtls[i]; }

    uint32              n_vtls;
    const VTL*          vtls;
    UVBvhView           uvbvh;
    MeshView            mesh;
    const MipMapView*   textures;
};