draw_volume.cc

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/* SPDX-FileCopyrightText: 2022 Blender Authors
 *
 * SPDX-License-Identifier: GPL-2.0-or-later */

 
#include "DRW_gpu_wrapper.hh"
#include "DRW_render.hh"
 
#include "DNA_fluid_types.h"
#include "DNA_volume_types.h"
 
#include "BLI_string.h"
 
#include "BKE_global.hh"
#include "BKE_mesh.hh"
#include "BKE_modifier.hh"
#include "BKE_volume.hh"
#include "BKE_volume_render.hh"
 
#include "GPU_material.hh"
 
#include "draw_cache.hh"
#include "draw_common_c.hh"
#include "draw_context_private.hh"
 
#include "draw_common.hh"
 
namespace blender::draw {
 
using VolumeInfosBuf = blender::draw::UniformBuffer<VolumeInfos>;
 
struct VolumeUniformBufPool {
  Vector<VolumeInfosBuf *> ubos;
  uint used = 0;
 
  ~VolumeUniformBufPool()
  {
    for (VolumeInfosBuf *ubo : ubos) {
      delete ubo;
    }
  }
 
  void reset()
  {
    used = 0;
  }
 
  VolumeInfosBuf *alloc()
  {
    if (used >= ubos.size()) {
      VolumeInfosBuf *buf = new VolumeInfosBuf();
      ubos.append(buf);
    }
    return ubos[used++];
  }
};
 
struct VolumeModule {
  VolumeUniformBufPool ubo_pool;
 
  draw::Texture dummy_zero;
  draw::Texture dummy_one;
 
  VolumeModule()
  {
    const float zero[4] = {0.0f, 0.0f, 0.0f, 0.0f};
    const float one[4] = {1.0f, 1.0f, 1.0f, 1.0f};
    const eGPUTextureUsage usage = GPU_TEXTURE_USAGE_SHADER_READ;
    dummy_zero.ensure_3d(GPU_RGBA32F, int3(1), usage, zero);
    dummy_one.ensure_3d(GPU_RGBA32F, int3(1), usage, one);
    GPU_texture_extend_mode(dummy_zero, GPU_SAMPLER_EXTEND_MODE_REPEAT);
    GPU_texture_extend_mode(dummy_one, GPU_SAMPLER_EXTEND_MODE_REPEAT);
  }
 
  GPUTexture *grid_default_texture(eGPUDefaultValue default_value)
  {
    switch (default_value) {
      case GPU_DEFAULT_0:
        return dummy_zero;
      case GPU_DEFAULT_1:
        return dummy_one;
    }
    return dummy_zero;
  }
};
 
void DRW_volume_init(DRWData *drw_data)
{
  if (drw_data == nullptr) {
    drw_data = drw_get().data;
  }
  if (drw_data->volume_module == nullptr) {
    drw_data->volume_module = MEM_new<VolumeModule>("VolumeModule");
  }
  drw_data->volume_module->ubo_pool.reset();
}
 
void DRW_volume_module_free(draw::VolumeModule *module)
{
  MEM_delete(module);
}
 
/* -------------------------------------------------------------------- */
 
template<typename PassType>
PassType *volume_world_grids_init(PassType &ps, ListBaseWrapper<GPUMaterialAttribute> &attrs)
{
  VolumeModule &module = *drw_get().data->volume_module;
 
  PassType *sub = &ps.sub("World Volume");
  for (const GPUMaterialAttribute *attr : attrs) {
    sub->bind_texture(attr->input_name, module.grid_default_texture(attr->default_value));
  }
 
  return sub;
}
 
template<typename PassType>
PassType *volume_object_grids_init(PassType &ps,
                                   Object *ob,
                                   ListBaseWrapper<GPUMaterialAttribute> &attrs)
{
  Volume &volume = DRW_object_get_data_for_drawing<Volume>(*ob);
  BKE_volume_load(&volume, G.main);
 
  /* Render nothing if there is no attribute. */
  if (BKE_volume_num_grids(&volume) == 0) {
    return nullptr;
  }
 
  VolumeModule &module = *drw_get().data->volume_module;
  VolumeInfosBuf &volume_infos = *module.ubo_pool.alloc();
 
  volume_infos.density_scale = BKE_volume_density_scale(&volume, ob->object_to_world().ptr());
  volume_infos.color_mul = float4(1.0f);
  volume_infos.temperature_mul = 1.0f;
  volume_infos.temperature_bias = 0.0f;
 
  PassType *sub = &ps.sub("Volume Object SubPass");
 
  /* Bind volume grid textures. */
  int grid_id = 0;
  for (const GPUMaterialAttribute *attr : attrs) {
    const bke::VolumeGridData *volume_grid = BKE_volume_grid_find(&volume, attr->name);
    const DRWVolumeGrid *drw_grid = (volume_grid) ?
                                        DRW_volume_batch_cache_get_grid(&volume, volume_grid) :
                                        nullptr;
    /* Handle 3 cases here:
     * - Grid exists and texture was loaded -> use texture.
     * - Grid exists but has zero size or failed to load -> use zero.
     * - Grid does not exist -> use default value. */
    const GPUTexture *grid_tex = (drw_grid)    ? drw_grid->texture :
                                 (volume_grid) ? module.dummy_zero :
                                                 module.grid_default_texture(attr->default_value);
    /* TODO(@pragma37): bind_texture const support ? */
    sub->bind_texture(attr->input_name, (GPUTexture *)grid_tex);
 
    volume_infos.grids_xform[grid_id++] = drw_grid ? float4x4(drw_grid->object_to_texture) :
                                                     float4x4::identity();
  }
 
  volume_infos.push_update();
 
  sub->bind_ubo("drw_volume", volume_infos);
 
  return sub;
}
 
template<typename PassType>
PassType *drw_volume_object_mesh_init(PassType &ps,
                                      Scene *scene,
                                      Object *ob,
                                      ListBaseWrapper<GPUMaterialAttribute> &attrs)
{
  VolumeModule &module = *drw_get().data->volume_module;
  VolumeInfosBuf &volume_infos = *module.ubo_pool.alloc();
 
  ModifierData *md = nullptr;
 
  volume_infos.density_scale = 1.0f;
  volume_infos.color_mul = float4(1.0f);
  volume_infos.temperature_mul = 1.0f;
  volume_infos.temperature_bias = 0.0f;
 
  bool has_fluid_modifier = (md = BKE_modifiers_findby_type(ob, eModifierType_Fluid)) &&
                            BKE_modifier_is_enabled(scene, md, eModifierMode_Realtime) &&
                            ((FluidModifierData *)md)->domain != nullptr;
  FluidModifierData *fmd = has_fluid_modifier ? (FluidModifierData *)md : nullptr;
  FluidDomainSettings *fds = has_fluid_modifier ? fmd->domain : nullptr;
 
  PassType *sub = nullptr;
 
  if (!has_fluid_modifier || (fds->type != FLUID_DOMAIN_TYPE_GAS)) {
    /* No volume attributes or fluid domain. */
    sub = &ps.sub("Volume Mesh SubPass");
    int grid_id = 0;
    for (const GPUMaterialAttribute *attr : attrs) {
      sub->bind_texture(attr->input_name, module.grid_default_texture(attr->default_value));
      volume_infos.grids_xform[grid_id++] = float4x4::identity();
    }
  }
  else if (fds->fluid) {
    /* Smoke Simulation. */
    DRW_smoke_ensure(fmd, fds->flags & FLUID_DOMAIN_USE_NOISE);
 
    sub = &ps.sub("Volume Modifier SubPass");
 
    float3 location, scale;
    BKE_mesh_texspace_get(&DRW_object_get_data_for_drawing<Mesh>(*ob), location, scale);
    float3 orco_mul = math::safe_rcp(scale * 2.0);
    float3 orco_add = (location - scale) * -orco_mul;
    /* Replace OrcoTexCoFactors with a matrix multiplication. */
    float4x4 orco_mat = math::from_scale<float4x4>(orco_mul);
    orco_mat.location() = orco_add;
 
    int grid_id = 0;
    for (const GPUMaterialAttribute *attr : attrs) {
      if (STREQ(attr->name, "density")) {
        sub->bind_texture(attr->input_name,
                          fds->tex_density ? &fds->tex_density : &module.dummy_one);
      }
      else if (STREQ(attr->name, "color")) {
        sub->bind_texture(attr->input_name, fds->tex_color ? &fds->tex_color : &module.dummy_one);
      }
      else if (STR_ELEM(attr->name, "flame", "temperature")) {
        sub->bind_texture(attr->input_name, fds->tex_flame ? &fds->tex_flame : &module.dummy_zero);
      }
      else {
        sub->bind_texture(attr->input_name, module.grid_default_texture(attr->default_value));
      }
      volume_infos.grids_xform[grid_id++] = orco_mat;
    }
 
    bool use_constant_color = ((fds->active_fields & FLUID_DOMAIN_ACTIVE_COLORS) == 0 &&
                               (fds->active_fields & FLUID_DOMAIN_ACTIVE_COLOR_SET) != 0);
    if (use_constant_color) {
      volume_infos.color_mul = float4(UNPACK3(fds->active_color), 1.0f);
    }
 
    /* Output is such that 0..1 maps to 0..1000K. */
    volume_infos.temperature_mul = fds->flame_max_temp - fds->flame_ignition;
    volume_infos.temperature_bias = fds->flame_ignition;
  }
 
  if (sub) {
    volume_infos.push_update();
    sub->bind_ubo("drw_volume", volume_infos);
  }
 
  return sub;
}
 
template<typename PassType>
PassType *volume_sub_pass_implementation(PassType &ps,
                                         Scene *scene,
                                         Object *ob,
                                         GPUMaterial *gpu_material)
{
  ListBase attr_list = GPU_material_attributes(gpu_material);
  ListBaseWrapper<GPUMaterialAttribute> attrs(attr_list);
  if (ob == nullptr) {
    return volume_world_grids_init(ps, attrs);
  }
  if (ob->type == OB_VOLUME) {
    return volume_object_grids_init(ps, ob, attrs);
  }
  return drw_volume_object_mesh_init(ps, scene, ob, attrs);
}
 
PassMain::Sub *volume_sub_pass(PassMain::Sub &ps,
                               Scene *scene,
                               Object *ob,
                               GPUMaterial *gpu_material)
{
  return volume_sub_pass_implementation(ps, scene, ob, gpu_material);
}
 
PassSimple::Sub *volume_sub_pass(PassSimple::Sub &ps,
                                 Scene *scene,
                                 Object *ob,
                                 GPUMaterial *gpu_material)
{
  return volume_sub_pass_implementation(ps, scene, ob, gpu_material);
}

 
}  // namespace blender::draw