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Octahedral Normal/Tangent Compression
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Implementation of Octahedral normal compression into Godot 4.0
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@The-O-King
The-O-King committed Aug 13, 2022
1 parent f2a6168 commit 78881b3
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Showing 7 changed files with 119 additions and 144 deletions.
16 changes: 16 additions & 0 deletions core/math/vector3.cpp
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Expand Up @@ -117,6 +117,22 @@ Vector3 Vector3::octahedron_decode(const Vector2 &p_oct) {
return n.normalized();
}

Vector2 Vector3::octahedron_tangent_encode(const float sign) const {
Vector2 res = this->octahedron_encode();
res.y = res.y * 0.5f + 0.5f;
res.y = sign >= 0.0f ? res.y : 1 - res.y;
return res;
}

Vector3 Vector3::octahedron_tangent_decode(const Vector2 &p_oct, float *sign) {
Vector2 oct_compressed = p_oct;
oct_compressed.y = oct_compressed.y * 2 - 1;
*sign = oct_compressed.y >= 0.0f ? 1.0f : -1.0f;
oct_compressed.y = Math::abs(oct_compressed.y);
Vector3 res = Vector3::octahedron_decode(oct_compressed);
return res;
}

Basis Vector3::outer(const Vector3 &p_with) const {
Vector3 row0(x * p_with.x, x * p_with.y, x * p_with.z);
Vector3 row1(y * p_with.x, y * p_with.y, y * p_with.z);
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2 changes: 2 additions & 0 deletions core/math/vector3.h
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Expand Up @@ -111,6 +111,8 @@ struct _NO_DISCARD_ Vector3 {

Vector2 octahedron_encode() const;
static Vector3 octahedron_decode(const Vector2 &p_oct);
Vector2 octahedron_tangent_encode(const float sign) const;
static Vector3 octahedron_tangent_decode(const Vector2 &p_oct, float *sign);

_FORCE_INLINE_ Vector3 cross(const Vector3 &p_with) const;
_FORCE_INLINE_ real_t dot(const Vector3 &p_with) const;
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149 changes: 47 additions & 102 deletions scene/resources/mesh.cpp
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Expand Up @@ -863,27 +863,6 @@ static Mesh::PrimitiveType _old_primitives[7] = {
};
#endif // DISABLE_DEPRECATED

// Convert Octahedron-mapped normalized vector back to Cartesian
// Assumes normalized format (elements of v within range [-1, 1])
Vector3 _oct_to_norm(const Vector2 v) {
Vector3 res(v.x, v.y, 1 - (Math::absf(v.x) + Math::absf(v.y)));
float t = MAX(-res.z, 0.0f);
res.x += t * -SIGN(res.x);
res.y += t * -SIGN(res.y);
return res.normalized();
}

// Convert Octahedron-mapped normalized tangent vector back to Cartesian
// out_sign provides the direction for the original cartesian tangent
// Assumes normalized format (elements of v within range [-1, 1])
Vector3 _oct_to_tangent(const Vector2 v, float *out_sign) {
Vector2 v_decompressed = v;
v_decompressed.y = Math::absf(v_decompressed.y) * 2 - 1;
Vector3 res = _oct_to_norm(v_decompressed);
*out_sign = SIGN(v[1]);
return res;
}

void _fix_array_compatibility(const Vector<uint8_t> &p_src, uint32_t p_old_format, uint32_t p_new_format, uint32_t p_elements, Vector<uint8_t> &vertex_data, Vector<uint8_t> &attribute_data, Vector<uint8_t> &skin_data) {
uint32_t dst_vertex_stride;
uint32_t dst_attribute_stride;
Expand Down Expand Up @@ -954,127 +933,93 @@ void _fix_array_compatibility(const Vector<uint8_t> &p_src, uint32_t p_old_forma
if ((p_old_format & OLD_ARRAY_COMPRESS_NORMAL) && (p_old_format & OLD_ARRAY_FORMAT_TANGENT) && (p_old_format & OLD_ARRAY_COMPRESS_TANGENT)) {
for (uint32_t i = 0; i < p_elements; i++) {
const int8_t *src = (const int8_t *)&src_vertex_ptr[i * src_vertex_stride + src_offset];
uint32_t *dst = (uint32_t *)&dst_vertex_ptr[i * dst_vertex_stride + dst_offsets[Mesh::ARRAY_NORMAL]];
const Vector2 src_vec(src[0] / 127.0f, src[1] / 127.0f);

const Vector3 res = _oct_to_norm(src_vec) * Vector3(0.5, 0.5, 0.5) + Vector3(0.5, 0.5, 0.5);
*dst = 0;
*dst |= CLAMP(int(res.x * 1023.0f), 0, 1023);
*dst |= CLAMP(int(res.y * 1023.0f), 0, 1023) << 10;
*dst |= CLAMP(int(res.z * 1023.0f), 0, 1023) << 20;
int16_t *dst = (int16_t *)&dst_vertex_ptr[i * dst_vertex_stride + dst_offsets[Mesh::ARRAY_NORMAL]];

dst[0] = (int16_t)CLAMP(src[0] / 127.0f * 32767, -32768, 32767);
dst[1] = (int16_t)CLAMP(src[1] / 127.0f * 32767, -32768, 32767);
}
src_offset += sizeof(int8_t) * 2;
src_offset += sizeof(int16_t) * 2;
} else {
for (uint32_t i = 0; i < p_elements; i++) {
const int16_t *src = (const int16_t *)&src_vertex_ptr[i * src_vertex_stride + src_offset];
uint32_t *dst = (uint32_t *)&dst_vertex_ptr[i * dst_vertex_stride + dst_offsets[Mesh::ARRAY_NORMAL]];
const Vector2 src_vec(src[0] / 32767.0f, src[1] / 32767.0f);

const Vector3 res = _oct_to_norm(src_vec) * Vector3(0.5, 0.5, 0.5) + Vector3(0.5, 0.5, 0.5);
*dst = 0;
*dst |= CLAMP(int(res.x * 1023.0f), 0, 1023);
*dst |= CLAMP(int(res.y * 1023.0f), 0, 1023) << 10;
*dst |= CLAMP(int(res.z * 1023.0f), 0, 1023) << 20;
int16_t *dst = (int16_t *)&dst_vertex_ptr[i * dst_vertex_stride + dst_offsets[Mesh::ARRAY_NORMAL]];

dst[0] = src[0];
dst[1] = src[1];
}
src_offset += sizeof(int16_t) * 2;
}
} else { // No Octahedral compression
if (p_old_format & OLD_ARRAY_COMPRESS_NORMAL) {
const float multiplier = 1.f / 127.f * 1023.0f;

for (uint32_t i = 0; i < p_elements; i++) {
const int8_t *src = (const int8_t *)&src_vertex_ptr[i * src_vertex_stride + src_offset];
uint32_t *dst = (uint32_t *)&dst_vertex_ptr[i * dst_vertex_stride + dst_offsets[Mesh::ARRAY_NORMAL]];
const Vector3 original_normal(src[0], src[1], src[2]);
Vector2 res = original_normal.octahedron_encode();

*dst = 0;
*dst |= CLAMP(int(src[0] * multiplier), 0, 1023);
*dst |= CLAMP(int(src[1] * multiplier), 0, 1023) << 10;
*dst |= CLAMP(int(src[2] * multiplier), 0, 1023) << 20;
uint16_t *dst = (uint16_t *)&dst_vertex_ptr[i * dst_vertex_stride + dst_offsets[Mesh::ARRAY_NORMAL]];
dst[0] = (uint16_t)CLAMP(res.x * 65535, 0, 65535);
dst[1] = (uint16_t)CLAMP(res.y * 65535, 0, 65535);
}
src_offset += sizeof(uint32_t);
src_offset += sizeof(uint16_t) * 2;
} else {
for (uint32_t i = 0; i < p_elements; i++) {
const float *src = (const float *)&src_vertex_ptr[i * src_vertex_stride + src_offset];
uint32_t *dst = (uint32_t *)&dst_vertex_ptr[i * dst_vertex_stride + dst_offsets[Mesh::ARRAY_NORMAL]];
const Vector3 original_normal(src[0], src[1], src[2]);
Vector2 res = original_normal.octahedron_encode();

*dst = 0;
*dst |= CLAMP(int(src[0] * 1023.0), 0, 1023);
*dst |= CLAMP(int(src[1] * 1023.0), 0, 1023) << 10;
*dst |= CLAMP(int(src[2] * 1023.0), 0, 1023) << 20;
uint16_t *dst = (uint16_t *)&dst_vertex_ptr[i * dst_vertex_stride + dst_offsets[Mesh::ARRAY_NORMAL]];
dst[0] = (uint16_t)CLAMP(res.x * 65535, 0, 65535);
dst[1] = (uint16_t)CLAMP(res.y * 65535, 0, 65535);
}
src_offset += sizeof(float) * 3;
src_offset += sizeof(uint16_t) * 2;
}
}

} break;
case OLD_ARRAY_TANGENT: {
if (p_old_format & OLD_ARRAY_FLAG_USE_OCTAHEDRAL_COMPRESSION) {
if (p_old_format & OLD_ARRAY_COMPRESS_TANGENT) { // int8
if (p_old_format & OLD_ARRAY_COMPRESS_TANGENT) { // int8 SNORM -> uint16 UNORM
for (uint32_t i = 0; i < p_elements; i++) {
const int8_t *src = (const int8_t *)&src_vertex_ptr[i * src_vertex_stride + src_offset];
uint32_t *dst = (uint32_t *)&dst_vertex_ptr[i * dst_vertex_stride + dst_offsets[Mesh::ARRAY_TANGENT]];
const Vector2 src_vec(src[0] / 127.0f, src[1] / 127.0f);
float out_sign;
const Vector3 res = _oct_to_tangent(src_vec, &out_sign) * Vector3(0.5, 0.5, 0.5) + Vector3(0.5, 0.5, 0.5);

*dst = 0;
*dst |= CLAMP(int(res.x * 1023.0), 0, 1023);
*dst |= CLAMP(int(res.y * 1023.0), 0, 1023) << 10;
*dst |= CLAMP(int(res.z * 1023.0), 0, 1023) << 20;
if (out_sign > 0) {
*dst |= 3 << 30;
}
uint16_t *dst = (uint16_t *)&dst_vertex_ptr[i * dst_vertex_stride + dst_offsets[Mesh::ARRAY_TANGENT]];

dst[0] = (uint16_t)CLAMP((src[0] / 127.0f * .5f + .5f) * 65535, 0, 65535);
dst[1] = (uint16_t)CLAMP((src[1] / 127.0f * .5f + .5f) * 65535, 0, 65535);
}
src_offset += sizeof(int8_t) * 2;
} else { // int16
src_offset += sizeof(uint16_t) * 2;
} else { // int16 SNORM -> uint16 UNORM
for (uint32_t i = 0; i < p_elements; i++) {
const int16_t *src = (const int16_t *)&src_vertex_ptr[i * src_vertex_stride + src_offset];
uint32_t *dst = (uint32_t *)&dst_vertex_ptr[i * dst_vertex_stride + dst_offsets[Mesh::ARRAY_TANGENT]];
const Vector2 src_vec(src[0] / 32767.0f, src[1] / 32767.0f);
float out_sign;
Vector3 res = _oct_to_tangent(src_vec, &out_sign) * Vector3(0.5, 0.5, 0.5) + Vector3(0.5, 0.5, 0.5);

*dst = 0;
*dst |= CLAMP(int(res.x * 1023.0), 0, 1023);
*dst |= CLAMP(int(res.y * 1023.0), 0, 1023) << 10;
*dst |= CLAMP(int(res.z * 1023.0), 0, 1023) << 20;
if (out_sign > 0) {
*dst |= 3 << 30;
}
uint16_t *dst = (uint16_t *)&dst_vertex_ptr[i * dst_vertex_stride + dst_offsets[Mesh::ARRAY_TANGENT]];

dst[0] = (uint16_t)CLAMP((src[0] / 32767.0f * .5f + .5f) * 65535, 0, 65535);
dst[1] = (uint16_t)CLAMP((src[1] / 32767.0f * .5f + .5f) * 65535, 0, 65535);
}
src_offset += sizeof(int16_t) * 2;
src_offset += sizeof(uint16_t) * 2;
}
} else { // No Octahedral compression
if (p_old_format & OLD_ARRAY_COMPRESS_TANGENT) {
const float multiplier = 1.f / 127.f * 1023.0f;

for (uint32_t i = 0; i < p_elements; i++) {
const int8_t *src = (const int8_t *)&src_vertex_ptr[i * src_vertex_stride + src_offset];
uint32_t *dst = (uint32_t *)&dst_vertex_ptr[i * dst_vertex_stride + dst_offsets[Mesh::ARRAY_TANGENT]];

*dst = 0;
*dst |= CLAMP(int(src[0] * multiplier), 0, 1023);
*dst |= CLAMP(int(src[1] * multiplier), 0, 1023) << 10;
*dst |= CLAMP(int(src[2] * multiplier), 0, 1023) << 20;
if (src[3] > 0) {
*dst |= 3 << 30;
}
const Vector3 original_tangent(src[0], src[1], src[2]);
Vector2 res = original_tangent.octahedron_tangent_encode(src[3]);

uint16_t *dst = (uint16_t *)&dst_vertex_ptr[i * dst_vertex_stride + dst_offsets[Mesh::ARRAY_NORMAL]];
dst[0] = (uint16_t)CLAMP(res.x * 65535, 0, 65535);
dst[1] = (uint16_t)CLAMP(res.y * 65535, 0, 65535);
}
src_offset += sizeof(uint32_t);
src_offset += sizeof(uint16_t) * 2;
} else {
for (uint32_t i = 0; i < p_elements; i++) {
const float *src = (const float *)&src_vertex_ptr[i * src_vertex_stride + src_offset];
uint32_t *dst = (uint32_t *)&dst_vertex_ptr[i * dst_vertex_stride + dst_offsets[Mesh::ARRAY_TANGENT]];

*dst = 0;
*dst |= CLAMP(int(src[0] * 1023.0), 0, 1023);
*dst |= CLAMP(int(src[1] * 1023.0), 0, 1023) << 10;
*dst |= CLAMP(int(src[2] * 1023.0), 0, 1023) << 20;
if (src[3] > 0) {
*dst |= 3 << 30;
}
const Vector3 original_tangent(src[0], src[1], src[2]);
Vector2 res = original_tangent.octahedron_tangent_encode(src[3]);

uint16_t *dst = (uint16_t *)&dst_vertex_ptr[i * dst_vertex_stride + dst_offsets[Mesh::ARRAY_NORMAL]];
dst[0] = (uint16_t)CLAMP(res.x * 65535, 0, 65535);
dst[1] = (uint16_t)CLAMP(res.y * 65535, 0, 65535);
}
src_offset += sizeof(float) * 4;
src_offset += sizeof(uint16_t) * 2;
}
}
} break;
Expand Down
18 changes: 13 additions & 5 deletions servers/rendering/renderer_rd/shaders/scene_forward_clustered.glsl
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Original file line number Diff line number Diff line change
Expand Up @@ -15,11 +15,11 @@ layout(location = 0) in vec3 vertex_attrib;
//only for pure render depth when normal is not used

#ifdef NORMAL_USED
layout(location = 1) in vec3 normal_attrib;
layout(location = 1) in vec2 normal_attrib;
#endif

#if defined(TANGENT_USED) || defined(NORMAL_MAP_USED) || defined(LIGHT_ANISOTROPY_USED)
layout(location = 2) in vec4 tangent_attrib;
layout(location = 2) in vec2 tangent_attrib;
#endif

#if defined(COLOR_USED)
Expand Down Expand Up @@ -58,6 +58,13 @@ layout(location = 10) in uvec4 bone_attrib;
layout(location = 11) in vec4 weight_attrib;
#endif

vec3 oct_to_vec3(vec2 e) {
vec3 v = vec3(e.xy, 1.0 - abs(e.x) - abs(e.y));
float t = max(-v.z, 0.0);
v.xy += t * -sign(v.xy);
return v;
}

/* Varyings */

layout(location = 0) out vec3 vertex_interp;
Expand Down Expand Up @@ -231,12 +238,13 @@ void vertex_shader(in uint instance_index, in bool is_multimesh, in SceneData sc

vec3 vertex = vertex_attrib;
#ifdef NORMAL_USED
vec3 normal = normal_attrib * 2.0 - 1.0;
vec3 normal = oct_to_vec3(normal_attrib * 2.0 - 1.0);
#endif

#if defined(TANGENT_USED) || defined(NORMAL_MAP_USED) || defined(LIGHT_ANISOTROPY_USED)
vec3 tangent = tangent_attrib.xyz * 2.0 - 1.0;
float binormalf = tangent_attrib.a * 2.0 - 1.0;
vec2 signed_tangent_attrib = tangent_attrib * 2.0 - 1.0;
vec3 tangent = oct_to_vec3(vec2(signed_tangent_attrib.x, abs(signed_tangent_attrib.y) * 2.0 - 1.0));
float binormalf = sign(signed_tangent_attrib.y);
vec3 binormal = normalize(cross(normal, tangent) * binormalf);
#endif

Expand Down
18 changes: 13 additions & 5 deletions servers/rendering/renderer_rd/shaders/scene_forward_mobile.glsl
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Original file line number Diff line number Diff line change
Expand Up @@ -16,11 +16,11 @@ layout(location = 0) in vec3 vertex_attrib;
//only for pure render depth when normal is not used

#ifdef NORMAL_USED
layout(location = 1) in vec3 normal_attrib;
layout(location = 1) in vec2 normal_attrib;
#endif

#if defined(TANGENT_USED) || defined(NORMAL_MAP_USED) || defined(LIGHT_ANISOTROPY_USED)
layout(location = 2) in vec4 tangent_attrib;
layout(location = 2) in vec2 tangent_attrib;
#endif

#if defined(COLOR_USED)
Expand Down Expand Up @@ -59,6 +59,13 @@ layout(location = 10) in uvec4 bone_attrib;
layout(location = 11) in vec4 weight_attrib;
#endif

vec3 oct_to_vec3(vec2 e) {
vec3 v = vec3(e.xy, 1.0 - abs(e.x) - abs(e.y));
float t = max(-v.z, 0.0);
v.xy += t * -sign(v.xy);
return v;
}

/* Varyings */

layout(location = 0) highp out vec3 vertex_interp;
Expand Down Expand Up @@ -229,12 +236,13 @@ void main() {

vec3 vertex = vertex_attrib;
#ifdef NORMAL_USED
vec3 normal = normal_attrib * 2.0 - 1.0;
vec3 normal = oct_to_vec3(normal_attrib * 2.0 - 1.0);
#endif

#if defined(TANGENT_USED) || defined(NORMAL_MAP_USED) || defined(LIGHT_ANISOTROPY_USED)
vec3 tangent = tangent_attrib.xyz * 2.0 - 1.0;
float binormalf = tangent_attrib.a * 2.0 - 1.0;
vec3 signed_tangent_attrib = tangent_attrib * 2.0 - 1.0;
vec3 tangent = oct_to_vec3(vec2(signed_tangent_attrib.x, abs(signed_tangent_attrib.y) * 2.0 - 1.0));
float binormalf = sign(signed_tangent_attrib.y);
vec3 binormal = normalize(cross(normal, tangent) * binormalf);
#endif

Expand Down
9 changes: 4 additions & 5 deletions servers/rendering/renderer_rd/storage_rd/mesh_storage.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -1057,10 +1057,9 @@ void MeshStorage::_mesh_surface_generate_version_for_input_mask(Mesh::Surface::V
} break;
case RS::ARRAY_NORMAL: {
vd.offset = stride;
vd.format = RD::DATA_FORMAT_R16G16_UNORM;
stride += sizeof(uint16_t) * 2;

vd.format = RD::DATA_FORMAT_A2B10G10R10_UNORM_PACK32;

stride += sizeof(uint32_t);
if (mis) {
buffer = mis->vertex_buffer;
} else {
Expand All @@ -1069,9 +1068,9 @@ void MeshStorage::_mesh_surface_generate_version_for_input_mask(Mesh::Surface::V
} break;
case RS::ARRAY_TANGENT: {
vd.offset = stride;
vd.format = RD::DATA_FORMAT_R16G16_UNORM;
stride += sizeof(uint16_t) * 2;

vd.format = RD::DATA_FORMAT_A2B10G10R10_UNORM_PACK32;
stride += sizeof(uint32_t);
if (mis) {
buffer = mis->vertex_buffer;
} else {
Expand Down
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