diff options
Diffstat (limited to 'source/blender/gpu/shaders/compositor/library/gpu_shader_compositor_hue_correct.glsl')
-rw-r--r-- | source/blender/gpu/shaders/compositor/library/gpu_shader_compositor_hue_correct.glsl | 39 |
1 files changed, 39 insertions, 0 deletions
diff --git a/source/blender/gpu/shaders/compositor/library/gpu_shader_compositor_hue_correct.glsl b/source/blender/gpu/shaders/compositor/library/gpu_shader_compositor_hue_correct.glsl new file mode 100644 index 00000000000..99eb125cdf2 --- /dev/null +++ b/source/blender/gpu/shaders/compositor/library/gpu_shader_compositor_hue_correct.glsl @@ -0,0 +1,39 @@ +#pragma BLENDER_REQUIRE(gpu_shader_common_color_utils.glsl) + +/* Curve maps are stored in sampler objects that are evaluated in the [0, 1] range, so normalize + * parameters accordingly. */ +#define NORMALIZE_PARAMETER(parameter, minimum, range) ((parameter - minimum) * range) + +void node_composite_hue_correct(float factor, + vec4 color, + sampler1DArray curve_map, + const float layer, + vec3 minimums, + vec3 range_dividers, + out vec4 result) +{ + vec4 hsv; + rgb_to_hsv(color, hsv); + + /* First, adjust the hue channel on its own, since corrections in the saturation and value + * channels depends on the new value of the hue, not its original value. A curve map value of 0.5 + * means no change in hue, so adjust the value to get an identity at 0.5. Since the identity of + * addition is 0, we subtract 0.5 (0.5 - 0.5 = 0). */ + const float hue_parameter = NORMALIZE_PARAMETER(hsv.x, minimums.x, range_dividers.x); + hsv.x += texture(curve_map, vec2(hue_parameter, layer)).x - 0.5; + + /* Second, adjust the saturation and value based on the new value of the hue. A curve map value + * of 0.5 means no change in hue, so adjust the value to get an identity at 0.5. Since the + * identity of duplication is 1, we multiply by 2 (0.5 * 2 = 1). */ + vec2 parameters = NORMALIZE_PARAMETER(hsv.x, minimums.yz, range_dividers.yz); + hsv.y *= texture(curve_map, vec2(parameters.x, layer)).y * 2.0; + hsv.z *= texture(curve_map, vec2(parameters.y, layer)).z * 2.0; + + /* Sanitize the new hue and saturation values. */ + hsv.x = fract(hsv.x); + hsv.y = clamp(hsv.y, 0.0, 1.0); + + hsv_to_rgb(hsv, result); + + result = mix(color, result, factor); +} |