GPU_vertex_format.hh

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/* SPDX-FileCopyrightText: 2016 by Mike Erwin. All rights reserved.
 *
 * SPDX-License-Identifier: GPL-2.0-or-later */
 
#pragma once
 
#include "BLI_assert.h"
#include "BLI_compiler_compat.h"
#include "BLI_math_geom.h"
#include "GPU_common.hh"
 
struct GPUShader;
 
#define GPU_VERT_ATTR_MAX_LEN 16
#define GPU_VERT_ATTR_MAX_NAMES 6
#define GPU_VERT_ATTR_NAMES_BUF_LEN 256
#define GPU_VERT_FORMAT_MAX_NAMES 63 /* More than enough, actual max is ~30. */
/* Computed as GPU_VERT_ATTR_NAMES_BUF_LEN / 30 (actual max format name). */
#define GPU_MAX_SAFE_ATTR_NAME 12
 
enum GPUVertCompType {
  GPU_COMP_I8 = 0,
  GPU_COMP_U8,
  GPU_COMP_I16,
  GPU_COMP_U16,
  GPU_COMP_I32,
  GPU_COMP_U32,
 
  GPU_COMP_F32,
 
  GPU_COMP_I10,
  /* Warning! adjust GPUVertAttr if changing. */
 
  GPU_COMP_MAX
};
 
enum GPUVertFetchMode {
  GPU_FETCH_FLOAT = 0,
  GPU_FETCH_INT,
  GPU_FETCH_INT_TO_FLOAT_UNIT, /* 127 (ubyte) -> 0.5 (and so on for other int types) */
  GPU_FETCH_INT_TO_FLOAT,      /* 127 (any int type) -> 127.0 */
  /* Warning! adjust GPUVertAttr if changing. */
};
 
struct GPUVertAttr {
  /* GPUVertFetchMode */
  uint fetch_mode : 2;
  /* GPUVertCompType */
  uint comp_type : 3;
  /* 1 to 4 or 8 or 12 or 16 */
  uint comp_len : 5;
  /* size in bytes, 1 to 64 */
  uint size : 7;
  /* from beginning of vertex, in bytes */
  uint offset : 11;
  /* up to GPU_VERT_ATTR_MAX_NAMES */
  uint name_len : 3;
  uchar names[GPU_VERT_ATTR_MAX_NAMES];
};
 
BLI_STATIC_ASSERT(GPU_VERT_ATTR_NAMES_BUF_LEN <= 256,
                  "We use uchar as index inside the name buffer "
                  "so GPU_VERT_ATTR_NAMES_BUF_LEN needs to be "
                  "smaller than GPUVertFormat->name_offset and "
                  "GPUVertAttr->names maximum value");
 
struct GPUVertFormat {
  uint attr_len : 5;
  uint name_len : 6;
  uint stride : 11;
  uint packed : 1;
  uint name_offset : 8;
  uint deinterleaved : 1;
 
  GPUVertAttr attrs[GPU_VERT_ATTR_MAX_LEN];
  char names[GPU_VERT_ATTR_NAMES_BUF_LEN];
};
 
void GPU_vertformat_clear(GPUVertFormat *);
void GPU_vertformat_copy(GPUVertFormat *dest, const GPUVertFormat &src);
void GPU_vertformat_from_shader(GPUVertFormat *format, const GPUShader *shader);
 
uint GPU_vertformat_attr_add(
    GPUVertFormat *, const char *name, GPUVertCompType, uint comp_len, GPUVertFetchMode);
void GPU_vertformat_alias_add(GPUVertFormat *, const char *alias);
 
void GPU_vertformat_multiload_enable(GPUVertFormat *format, int load_count);
 
void GPU_vertformat_deinterleave(GPUVertFormat *format);
 
int GPU_vertformat_attr_id_get(const GPUVertFormat *, const char *name);
 
BLI_INLINE const char *GPU_vertformat_attr_name_get(const GPUVertFormat *format,
                                                    const GPUVertAttr *attr,
                                                    uint n_idx)
{
  return format->names + attr->names[n_idx];
}
 
void GPU_vertformat_attr_rename(GPUVertFormat *format, int attr, const char *new_name);
 
void GPU_vertformat_safe_attr_name(const char *attr_name, char *r_safe_name, uint max_len);
 
/* format conversion */
 
struct GPUPackedNormal {
  int x : 10;
  int y : 10;
  int z : 10;
  int w : 2; /* 0 by default, can manually set to { -2, -1, 0, 1 } */
};
 
struct GPUNormal {
  union {
    GPUPackedNormal low;
    short high[4];
  };
};
 
/* OpenGL ES packs in a different order as desktop GL but component conversion is the same.
 * Of the code here, only GPUPackedNormal needs to change. */
 
#define SIGNED_INT_10_MAX 511
#define SIGNED_INT_10_MIN -512
 
BLI_INLINE int clampi(int x, int min_allowed, int max_allowed)
{
#if TRUST_NO_ONE
  assert(min_allowed <= max_allowed);
#endif
  if (x < min_allowed) {
    return min_allowed;
  }
  else if (x > max_allowed) {
    return max_allowed;
  }
  else {
    return x;
  }
}
 
BLI_INLINE int gpu_convert_normalized_f32_to_i10(float x)
{
  int qx = x * 511.0f;
  return clampi(qx, SIGNED_INT_10_MIN, SIGNED_INT_10_MAX);
}
 
BLI_INLINE int gpu_convert_i16_to_i10(short x)
{
  /* 16-bit signed --> 10-bit signed */
  /* TODO: round? */
  return x >> 6;
}
 
BLI_INLINE GPUPackedNormal GPU_normal_convert_i10_v3(const float data[3])
{
  GPUPackedNormal n = {
      gpu_convert_normalized_f32_to_i10(data[0]),
      gpu_convert_normalized_f32_to_i10(data[1]),
      gpu_convert_normalized_f32_to_i10(data[2]),
  };
  return n;
}
 
BLI_INLINE GPUPackedNormal GPU_normal_convert_i10_s3(const short data[3])
{
  GPUPackedNormal n = {
      gpu_convert_i16_to_i10(data[0]),
      gpu_convert_i16_to_i10(data[1]),
      gpu_convert_i16_to_i10(data[2]),
  };
  return n;
}
 
BLI_INLINE void GPU_normal_convert_v3(GPUNormal *gpu_normal,
                                      const float data[3],
                                      const bool do_hq_normals)
{
  if (do_hq_normals) {
    normal_float_to_short_v3(gpu_normal->high, data);
  }
  else {
    gpu_normal->low = GPU_normal_convert_i10_v3(data);
  }
}