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Increase precision and max value of bone matrix floats

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- I just made up a technique that is probably 30% efficient, this is
  something to revisit in the future
main
Cameron Murphy Reikes 1 year ago
parent f8fcd426a1
commit 4137372292
3 changed files with 59 additions and 47 deletions
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29
armature.glsl
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@ -24,17 +24,6 @@ float decode_normalized_float32(vec4 v)
return sign * (v.z*255.0 + v.y);
}
// in textures, color elements are delivered as unsigend normalize floats
// in [0, 1]. This makes them into [-1, 1] as the bone matrices require
// such values to be correct
vec4 make_signed_again(vec4 v) {
v.x = 2.0 * v.x - 1.0;
v.y = 2.0 * v.y - 1.0;
v.z = 2.0 * v.z - 1.0;
v.w = 2.0 * v.w - 1.0;
return v;
}
void main() {
vec4 total_position = vec4(0.0f);
@ -46,17 +35,15 @@ void main() {
float y_coord = (0.5 + index)/bones_tex_size.y;
vec4 col0 = texture(bones_tex, vec2((0.5 + 0)/bones_tex_size.x, y_coord));
vec4 col1 = texture(bones_tex, vec2((0.5 + 1)/bones_tex_size.x, y_coord));
vec4 col2 = texture(bones_tex, vec2((0.5 + 2)/bones_tex_size.x, y_coord));
vec4 col3 = texture(bones_tex, vec2((0.5 + 3)/bones_tex_size.x, y_coord));
mat4 bone_mat;
col0 = make_signed_again(col0);
col1 = make_signed_again(col1);
col2 = make_signed_again(col2);
col3 = make_signed_again(col3);
mat4 bone_mat = mat4(col0, col1, col2, col3);
for(int row = 0; row < 4; row++)
{
for(int col = 0; col < 4; col++)
{
bone_mat[col][row] = decode_normalized_float32(texture(bones_tex, vec2((0.5 + col*4 + row)/bones_tex_size.x, y_coord)));
}
}
vec4 local_position = bone_mat * vec4(pos_in, 1.0f);
total_position += local_position * weight;

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art/art.blend (Stored with Git LFS)
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69
main.c
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@ -1083,7 +1083,7 @@ Armature load_armature(MD_Arena *arena, MD_String8 binary_file, MD_String8 armat
.label = (const char*)nullterm(arena, MD_S8Fmt(arena, "%.*s-vertices", MD_S8VArg(armature_name))).str,
});
to_return.bones_texture_width = 4;
to_return.bones_texture_width = 16;
to_return.bones_texture_height = (int)to_return.bones_length;
Log("Amrature %.*s has bones texture size (%d, %d)\n", MD_S8VArg(armature_name), to_return.bones_texture_width, to_return.bones_texture_height);
@ -2726,7 +2726,9 @@ PixelData encode_normalized_float32(float to_encode)
assert(to_return_vector.z < 255.0f);
to_return_vector.z /= 255.0f;
// w is unused for now
// w is unused for now, but is 1.0f (and is the alpha channel in Vec4) so that it displays properly as a texture
to_return_vector.w = 1.0f;
PixelData to_return = {0};
@ -2739,6 +2741,21 @@ PixelData encode_normalized_float32(float to_encode)
return to_return;
}
float decode_normalized_float32(PixelData encoded)
{
Vec4 v = {0};
for(int i = 0; i < 4; i++)
{
v.Elements[i] = (float)encoded.rgba[i] / 255.0f;
}
float sign = 2.0f * v.x - 1.0f;
float to_return = sign * (v.z*255.0f + v.y);
return to_return;
}
void draw_armature(Mat4 view, Mat4 projection, Transform t, Armature *armature, float elapsed_time)
{
@ -2772,28 +2789,19 @@ void draw_armature(Mat4 view, Mat4 projection, Transform t, Armature *armature,
for(int col = 0; col < 4; col++)
{
Vec4 to_upload = final.Columns[col];
assert(-1.1f <= to_upload.x && to_upload.x <= 1.1f);
assert(-1.1f <= to_upload.y && to_upload.y <= 1.1f);
assert(-1.1f <= to_upload.z && to_upload.z <= 1.1f);
assert(-1.1f <= to_upload.w && to_upload.w <= 1.1f);
// make them normalized
to_upload.x = to_upload.x/2.0f + 0.5f;
to_upload.y = to_upload.y/2.0f + 0.5f;
to_upload.z = to_upload.z/2.0f + 0.5f;
to_upload.w = to_upload.w/2.0f + 0.5f;
to_upload.x = clamp01(to_upload.x);
to_upload.y = clamp01(to_upload.y);
to_upload.z = clamp01(to_upload.z);
to_upload.w = clamp01(to_upload.w);
int bytes_per_pixel = 4;
int bytes_per_row = bytes_per_pixel * 4;
bones_tex[bytes_per_pixel*col + bytes_per_row*i + 0] = (MD_u8)(to_upload.x * 255.0);
bones_tex[bytes_per_pixel*col + bytes_per_row*i + 1] = (MD_u8)(to_upload.y * 255.0);
bones_tex[bytes_per_pixel*col + bytes_per_row*i + 2] = (MD_u8)(to_upload.z * 255.0);
bones_tex[bytes_per_pixel*col + bytes_per_row*i + 3] = (MD_u8)(to_upload.w * 255.0);
int bytes_per_column_of_mat = bytes_per_pixel * 4;
int bytes_per_row = bytes_per_pixel * armature->bones_texture_width;
for(int elem = 0; elem < 4; elem++)
{
float after_decoding = decode_normalized_float32(encode_normalized_float32(to_upload.Elements[elem]));
assert(fabsf(after_decoding - to_upload.Elements[elem]) < 0.01f);
}
memcpy(&bones_tex[bytes_per_column_of_mat*col + bytes_per_row*i + bytes_per_pixel*0], encode_normalized_float32(to_upload.Elements[0]).rgba, bytes_per_pixel);
memcpy(&bones_tex[bytes_per_column_of_mat*col + bytes_per_row*i + bytes_per_pixel*1], encode_normalized_float32(to_upload.Elements[1]).rgba, bytes_per_pixel);
memcpy(&bones_tex[bytes_per_column_of_mat*col + bytes_per_row*i + bytes_per_pixel*2], encode_normalized_float32(to_upload.Elements[2]).rgba, bytes_per_pixel);
memcpy(&bones_tex[bytes_per_column_of_mat*col + bytes_per_row*i + bytes_per_pixel*3], encode_normalized_float32(to_upload.Elements[3]).rgba, bytes_per_pixel);
}
}
sg_update_image(armature->bones_texture, &(sg_image_data){
@ -2991,6 +2999,22 @@ void do_serialization_tests()
MD_ReleaseScratch(scratch);
}
void do_float_encoding_tests()
{
float to_test[] = {
7.5f,
-2.12f,
100.2f,
-5.35f,
};
ARR_ITER(float, to_test)
{
PixelData encoded = encode_normalized_float32(*it);
float decoded = decode_normalized_float32(encoded);
assert(fabsf(decoded - *it) < 0.01f);
}
}
#endif
Armature armature = {0};
@ -3064,6 +3088,7 @@ void init(void)
do_metadesk_tests();
do_parsing_tests();
do_serialization_tests();
do_float_encoding_tests();
#endif
#ifdef WEB

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