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obs-filters: 3D LUT tetrahedral interpolation 

As requested by Adobe CUBE spec.
master
jpark37 2020-03-23 18:15:41 -07:00
parent ff2b07c032
commit 34d70c6832
2 changed files with 109 additions and 32 deletions
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56
plugins/obs-filters/color-grade-filter.c
View File

@ -274,6 +274,7 @@ static void color_grade_filter_update(void *data, obs_data_t *settings)
&filter->domain_max, &filter->clut_dim);
} else {
gs_image_file_init(&filter->image, path);
filter->cube_width = LUT_WIDTH;
filter->clut_dim = CLUT_3D;
}
}
@ -285,48 +286,48 @@ static void color_grade_filter_update(void *data, obs_data_t *settings)
filter->target = make_clut_texture_png(
filter->image.format, filter->image.cx,
filter->image.cy, filter->image.texture_data);
const float clut_scale =
(float)(LUT_WIDTH - 1) / (float)LUT_WIDTH;
const float clut_scale = (float)(LUT_WIDTH - 1);
vec3_set(&filter->clut_scale, clut_scale, clut_scale,
clut_scale);
const float clut_offset = 0.5f / (float)LUT_WIDTH;
vec3_set(&filter->clut_offset, clut_offset, clut_offset,
clut_offset);
vec3_set(&filter->clut_offset, 0.f, 0.f, 0.f);
} else if (filter->cube_data) {
const uint32_t width = filter->cube_width;
if (filter->clut_dim == CLUT_1D) {
filter->target = gs_texture_create(
width, 1, GS_RGBA16F, 1,
(uint8_t **)&filter->cube_data, 0);
(const uint8_t **)&filter->cube_data,
0);
} else {
filter->target = gs_voltexture_create(
width, width, width, GS_RGBA16F, 1,
(uint8_t **)&filter->cube_data, 0);
(const uint8_t **)&filter->cube_data,
0);
}
struct vec3 domain_scale;
vec3_sub(&domain_scale, &filter->domain_max,
&filter->domain_min);
const float clut_scale0 =
(width - 1) / (width * domain_scale.x);
const float clut_scale1 =
(width - 1) / (width * domain_scale.y);
const float clut_scale2 =
(width - 1) / (width * domain_scale.z);
vec3_set(&filter->clut_scale, clut_scale0, clut_scale1,
clut_scale2);
const float clut_offset0 =
0.5f / width -
filter->domain_min.x * clut_scale0;
const float clut_offset1 =
0.5f / width -
filter->domain_min.y * clut_scale1;
const float clut_offset2 =
0.5f / width -
filter->domain_min.z * clut_scale2;
vec3_set(&filter->clut_offset, clut_offset0,
clut_offset1, clut_offset2);
const float width_minus_one = (float)(width - 1);
vec3_set(&filter->clut_scale, width_minus_one,
width_minus_one, width_minus_one);
vec3_div(&filter->clut_scale, &filter->clut_scale,
&domain_scale);
vec3_neg(&filter->clut_offset, &filter->domain_min);
vec3_mul(&filter->clut_offset, &filter->clut_offset,
&filter->clut_scale);
/* 1D shader wants normalized UVW */
if (filter->clut_dim == CLUT_1D) {
vec3_divf(&filter->clut_scale,
&filter->clut_scale, (float)width);
vec3_addf(&filter->clut_offset,
&filter->clut_offset, 0.5f);
vec3_divf(&filter->clut_offset,
&filter->clut_offset, (float)width);
}
}
}
@ -448,6 +449,9 @@ static void color_grade_filter_render(void *data, gs_effect_t *effect)
param = gs_effect_get_param_by_name(filter->effect, "domain_max");
gs_effect_set_vec3(param, &filter->domain_max);
param = gs_effect_get_param_by_name(filter->effect, "cube_width_i");
gs_effect_set_float(param, 1.0f / filter->cube_width);
obs_source_process_filter_tech_end(filter->context, filter->effect, 0,
0, tech_name);
}

85
plugins/obs-filters/data/color_grade_filter.effect
View File

@ -8,6 +8,7 @@ uniform float3 clut_scale;
uniform float3 clut_offset;
uniform float3 domain_min;
uniform float3 domain_max;
uniform float cube_width_i;
sampler_state textureSampler {
Filter = Linear;
@ -62,13 +63,85 @@ float4 LUT1D(VertDataOut v_in) : TARGET
float4 LUT3D(VertDataOut v_in) : TARGET
{
float4 textureColor = image.Sample(textureSampler, v_in.uv);
if (textureColor.r >= domain_min.r && textureColor.r <= domain_max.r &&
textureColor.g >= domain_min.g && textureColor.g <= domain_max.g &&
textureColor.b >= domain_min.b && textureColor.b <= domain_max.b)
float r = textureColor.r;
float g = textureColor.g;
float b = textureColor.b;
if (r >= domain_min.r && r <= domain_max.r &&
g >= domain_min.g && g <= domain_max.g &&
b >= domain_min.b && b <= domain_max.b)
{
float3 clut_uvw = textureColor.rgb * clut_scale + clut_offset;
float3 luttedColor = clut_3d.Sample(textureSampler, clut_uvw).rgb;
float3 clut_pos = textureColor.rgb * clut_scale + clut_offset;
float3 floor_pos = floor(clut_pos);
float3 fracRGB = clut_pos - floor_pos;
float3 uvw0 = (floor_pos + 0.5) * cube_width_i;
float3 uvw3 = (floor_pos + 1.5) * cube_width_i;
float fracL, fracM, fracS;
float3 uvw1, uvw2;
if (fracRGB.r < fracRGB.g) {
if (fracRGB.r < fracRGB.b) {
if (fracRGB.g < fracRGB.b) {
// f(R) < f(G) < f(B)
fracL = fracRGB.b;
fracM = fracRGB.g;
fracS = fracRGB.r;
uvw1 = float3(uvw0.x, uvw0.y, uvw3.z);
uvw2 = float3(uvw0.x, uvw3.y, uvw3.z);
} else {
// f(R) < f(B) <= f(G)
fracL = fracRGB.g;
fracM = fracRGB.b;
fracS = fracRGB.r;
uvw1 = float3(uvw0.x, uvw3.y, uvw0.z);
uvw2 = float3(uvw0.x, uvw3.y, uvw3.z);
}
} else {
// f(B) <= f(R) < f(G)
fracL = fracRGB.g;
fracM = fracRGB.r;
fracS = fracRGB.b;
uvw1 = float3(uvw0.x, uvw3.y, uvw0.z);
uvw2 = float3(uvw3.x, uvw3.y, uvw0.z);
}
} else if (fracRGB.r < fracRGB.b) {
// f(G) <= f(R) < f(B)
fracL = fracRGB.b;
fracM = fracRGB.r;
fracS = fracRGB.g;
uvw1 = float3(uvw0.x, uvw0.y, uvw3.z);
uvw2 = float3(uvw3.x, uvw0.y, uvw3.z);
} else if (fracRGB.g < fracRGB.b) {
// f(G) < f(B) <= f(R)
fracL = fracRGB.r;
fracM = fracRGB.b;
fracS = fracRGB.g;
uvw1 = float3(uvw3.x, uvw0.y, uvw0.z);
uvw2 = float3(uvw3.x, uvw0.y, uvw3.z);
} else {
// f(B) <= f(G) <= f(R)
fracL = fracRGB.r;
fracM = fracRGB.g;
fracS = fracRGB.b;
uvw1 = float3(uvw3.x, uvw0.y, uvw0.z);
uvw2 = float3(uvw3.x, uvw3.y, uvw0.z);
}
/* use filtering to collapse 4 taps to 2 */
/* use max to kill potential zero-divide NaN */
float coeff01 = (1.0 - fracM);
float weight01 = max((fracL - fracM) / coeff01, 0.0);
float3 uvw01 = lerp(uvw0, uvw1, weight01);
float3 sample01 = clut_3d.Sample(textureSampler, uvw01).rgb;
float coeff23 = fracM;
float weight23 = max(fracS / coeff23, 0.0);
float3 uvw23 = lerp(uvw2, uvw3, weight23);
float3 sample23 = clut_3d.Sample(textureSampler, uvw23).rgb;
float3 luttedColor = (coeff01 * sample01) + (coeff23 * sample23);
textureColor.rgb = lerp(textureColor.rgb, luttedColor, clut_amount);
}