# ============================================================================
# grass_bind.ludic — the kind's numbers into the blade programs: the per-vertex path (grass.vert),
# the cull's Params (grass_cull.comp, gg_params) and model.frag's BLADE colouring, which the
# scatter's blade layers share. Four floats a uniform, named u_gk_*.
# ============================================================================

# the vertex stage's (grass.vert; grass.mesh reads only the cell) and the fragment stage's
function grass_bind_kind(render3d_st: mut Render3dState, p: int) -> void {
  let k = grass_kind(render3d_st)
  u_f4(render3d_st, gpu_uniform(render3d_st, p, "u_gk_tall"), k.tall_min, k.tall_max, k.cell_lo, k.cell_hi)
  u_f4(render3d_st, gpu_uniform(render3d_st, p, "u_gk_grow"), k.tall_far, k.width, k.width_far, k.clump_freq)
  u_f4(render3d_st, gpu_uniform(render3d_st, p, "u_gk_clump"), k.clump_lo, k.clump_hi, k.arch, k.arch_var)
  u_f4(render3d_st, gpu_uniform(render3d_st, p, "u_gk_ground"), k.slope_lo, k.slope_hi, k.snow_in, k.snow_out)
  u_f4(render3d_st, gpu_uniform(render3d_st, p, "u_gk_ortho"), k.ortho_floor, k.ortho_gain, k.ortho_green, float(render3d_st.grass_cell))
  grass_bind_look(render3d_st, p)
}

# model.frag's BLADE path: the blades gone to seed, the far tufts, the root's occlusion, the roughness
function grass_bind_look(render3d_st: mut Render3dState, p: int) -> void {
  let k = grass_kind(render3d_st)
  u_f4(render3d_st, gpu_uniform(render3d_st, p, "u_gk_seed"), k.seed_r, k.seed_g, k.seed_b, k.seed_mix)
  u_f4(render3d_st, gpu_uniform(render3d_st, p, "u_gk_look"), k.seed_lo, k.seed_hi, k.tuft_mix, k.tuft_shade)
  u_f4(render3d_st, gpu_uniform(render3d_st, p, "u_gk_mat"), k.ao_root, k.rough, 0.0, 0.0)
}

# grass_cull.comp's Params from word 52: the same four vec4s as u_gk_tall .. u_gk_ortho, then the
# bands' outer distances into word 36 (they were GG_NEAR and GG_MID)
function grass_params_kind(render3d_st: mut Render3dState, pr: words) -> void {
  let k = grass_kind(render3d_st)
  pr[36] = float_bits(k.band_near);  pr[37] = float_bits(k.band_mid)
  pr[52] = float_bits(k.tall_min);  pr[53] = float_bits(k.tall_max);  pr[54] = float_bits(k.cell_lo);  pr[55] = float_bits(k.cell_hi)
  pr[56] = float_bits(k.tall_far);  pr[57] = float_bits(k.width);  pr[58] = float_bits(k.width_far);  pr[59] = float_bits(k.clump_freq)
  pr[60] = float_bits(k.clump_lo);  pr[61] = float_bits(k.clump_hi);  pr[62] = float_bits(k.arch);  pr[63] = float_bits(k.arch_var)
  pr[64] = float_bits(k.slope_lo);  pr[65] = float_bits(k.slope_hi);  pr[66] = float_bits(k.snow_in);  pr[67] = float_bits(k.snow_out)
  pr[68] = float_bits(k.ortho_floor);  pr[69] = float_bits(k.ortho_gain);  pr[70] = float_bits(k.ortho_green);  pr[71] = float_bits(float(render3d_st.grass_cell))
}