/*
 * Copyright 2011-2013 Blender Foundation
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

/* Constant Globals */

#ifndef __KERNEL_GLOBALS_H__
#define __KERNEL_GLOBALS_H__

#include "kernel/kernel_profiling.h"

#ifdef __KERNEL_CPU__
#  include "util/util_vector.h"
#  include "util/util_map.h"
#endif

#ifdef __KERNEL_OPENCL__
#  include "util/util_atomic.h"
#endif

CCL_NAMESPACE_BEGIN

/* On the CPU, we pass along the struct KernelGlobals to nearly everywhere in
 * the kernel, to access constant data. These are all stored as "textures", but
 * these are really just standard arrays. We can't use actually globals because
 * multiple renders may be running inside the same process. */

#ifdef __KERNEL_CPU__

#  ifdef __OSL__
struct OSLGlobals;
struct OSLThreadData;
struct OSLShadingSystem;
#  endif

typedef unordered_map<float, float> CoverageMap;

struct Intersection;
struct VolumeStep;

typedef struct KernelGlobals {
#  define KERNEL_TEX(type, name) texture<type> name;
#  include "kernel/kernel_textures.h"

  KernelData __data;

#  ifdef __OSL__
  /* On the CPU, we also have the OSL globals here. Most data structures are shared
   * with SVM, the difference is in the shaders and object/mesh attributes. */
  OSLGlobals *osl;
  OSLShadingSystem *osl_ss;
  OSLThreadData *osl_tdata;
#  endif

  /* **** Run-time data ****  */

  /* Heap-allocated storage for transparent shadows intersections. */
  Intersection *transparent_shadow_intersections;

  /* Storage for decoupled volume steps. */
  VolumeStep *decoupled_volume_steps[2];
  int decoupled_volume_steps_index;

  /* A buffer for storing per-pixel coverage for Cryptomatte. */
  CoverageMap *coverage_object;
  CoverageMap *coverage_material;
  CoverageMap *coverage_asset;

  /* split kernel */
  SplitData split_data;
  SplitParams split_param_data;

  int2 global_size;
  int2 global_id;

  ProfilingState profiler;
} KernelGlobals;

#endif /* __KERNEL_CPU__ */

/* For CUDA, constant memory textures must be globals, so we can't put them
 * into a struct. As a result we don't actually use this struct and use actual
 * globals and simply pass along a NULL pointer everywhere, which we hope gets
 * optimized out. */

#ifdef __KERNEL_CUDA__

__constant__ KernelData __data;
typedef struct KernelGlobals {
  /* NOTE: Keep the size in sync with SHADOW_STACK_MAX_HITS. */
  Intersection hits_stack[64];
} KernelGlobals;

#  define KERNEL_TEX(type, name) const __constant__ __device__ type *name;
#  include "kernel/kernel_textures.h"

#endif /* __KERNEL_CUDA__ */

/* OpenCL */

#ifdef __KERNEL_OPENCL__

#  define KERNEL_TEX(type, name) typedef type name##_t;
#  include "kernel/kernel_textures.h"

typedef ccl_addr_space struct KernelGlobals {
  ccl_constant KernelData *data;
  ccl_global char *buffers[8];

#  define KERNEL_TEX(type, name) TextureInfo name;
#  include "kernel/kernel_textures.h"

#  ifdef __SPLIT_KERNEL__
  SplitData split_data;
  SplitParams split_param_data;
#  endif
} KernelGlobals;

#  define KERNEL_BUFFER_PARAMS \
    ccl_global char *buffer0, ccl_global char *buffer1, ccl_global char *buffer2, \
        ccl_global char *buffer3, ccl_global char *buffer4, ccl_global char *buffer5, \
        ccl_global char *buffer6, ccl_global char *buffer7

#  define KERNEL_BUFFER_ARGS buffer0, buffer1, buffer2, buffer3, buffer4, buffer5, buffer6, buffer7

ccl_device_inline void kernel_set_buffer_pointers(KernelGlobals *kg, KERNEL_BUFFER_PARAMS)
{
#  ifdef __SPLIT_KERNEL__
  if (ccl_local_id(0) + ccl_local_id(1) == 0)
#  endif
  {
    kg->buffers[0] = buffer0;
    kg->buffers[1] = buffer1;
    kg->buffers[2] = buffer2;
    kg->buffers[3] = buffer3;
    kg->buffers[4] = buffer4;
    kg->buffers[5] = buffer5;
    kg->buffers[6] = buffer6;
    kg->buffers[7] = buffer7;
  }

#  ifdef __SPLIT_KERNEL__
  ccl_barrier(CCL_LOCAL_MEM_FENCE);
#  endif
}

ccl_device_inline void kernel_set_buffer_info(KernelGlobals *kg)
{
#  ifdef __SPLIT_KERNEL__
  if (ccl_local_id(0) + ccl_local_id(1) == 0)
#  endif
  {
    ccl_global TextureInfo *info = (ccl_global TextureInfo *)kg->buffers[0];

#  define KERNEL_TEX(type, name) kg->name = *(info++);
#  include "kernel/kernel_textures.h"
  }

#  ifdef __SPLIT_KERNEL__
  ccl_barrier(CCL_LOCAL_MEM_FENCE);
#  endif
}

#endif /* __KERNEL_OPENCL__ */

/* Interpolated lookup table access */

ccl_device float lookup_table_read(KernelGlobals *kg, float x, int offset, int size)
{
  x = saturate(x) * (size - 1);

  int index = min(float_to_int(x), size - 1);
  int nindex = min(index + 1, size - 1);
  float t = x - index;

  float data0 = kernel_tex_fetch(__lookup_table, index + offset);
  if (t == 0.0f)
    return data0;

  float data1 = kernel_tex_fetch(__lookup_table, nindex + offset);
  return (1.0f - t) * data0 + t * data1;
}

ccl_device float lookup_table_read_2D(
    KernelGlobals *kg, float x, float y, int offset, int xsize, int ysize)
{
  y = saturate(y) * (ysize - 1);

  int index = min(float_to_int(y), ysize - 1);
  int nindex = min(index + 1, ysize - 1);
  float t = y - index;

  float data0 = lookup_table_read(kg, x, offset + xsize * index, xsize);
  if (t == 0.0f)
    return data0;

  float data1 = lookup_table_read(kg, x, offset + xsize * nindex, xsize);
  return (1.0f - t) * data0 + t * data1;
}

CCL_NAMESPACE_END

#endif /* __KERNEL_GLOBALS_H__ */
