gl-renderer: implement 3 x 1D LUT color pre-curve

This makes weston_color_transform object be able to express
three-channel one-dimensional look-up table transformations. They are
useful for applying EOTF and EOTF^-1 mapping, or, gamma curves. They
will also be useful in optimizing a following 3D LUT tap distribution
once support for 3D LUT is added.

The code added here translates from the lut_3x1d fill_in() interface to
a GL texture to be used with SHADER_COLOR_CURVE_LUT_3x1D for
weston_surfaces.

It demonstrates how renderer data is attached to weston_color_transform
and cached.

GL_OES_texture_float_linear is required to be able to use bilinear
texture filtering with 32-bit floating-point textures, used for the LUT.

As the size of the LUT depends on what implements it, lut_3x1d fill_in()
interface is a callback to the color management component to ask for an
arbitrary size. For GL-renderer this is not important as it can easily
realize any LUT size, but when DRM-backend wants to offload the EOTF^-1
mapping to KMS (GAMMA_LUT), the LUT size comes from KMS.

Nothing actually implements lut_3x1d fill_in() yet, that will come in a
later patch.

Signed-off-by: Pekka Paalanen <pekka.paalanen@collabora.com>
dev
Pekka Paalanen 4 years ago committed by Pekka Paalanen
parent 9a6a4e7032
commit 92f2367e58
  1. 23
      libweston/color.h
  2. 5
      libweston/renderer-gl/gl-renderer-internal.h
  3. 7
      libweston/renderer-gl/gl-renderer.c
  4. 217
      libweston/renderer-gl/gl-shader-config-color-transformation.c
  5. 1
      libweston/renderer-gl/meson.build

@ -40,7 +40,28 @@ enum weston_color_curve_type {
/** LUT_3x1D parameters */
struct weston_color_curve_lut_3x1d {
/* To be defined */
/**
* Approximate a color curve with three 1D LUTs
*
* A 1D LUT is a mapping from [0.0, 1.0] to arbitrary values. The first
* element in the LUT corresponds to input value 0.0, and the last
* element corresponds to input value 1.0. The step from one element
* to the next in input space is 1.0 / (len - 1). When input value is
* between two elements, linear interpolation should be used.
*
* This function fills in the given array with the LUT values.
*
* \param xform This color transformation object.
* \param len The number of elements in each 1D LUT.
* \param values Array of 3 x len elements. First R channel
* LUT, immediately followed by G channel LUT, and then B channel LUT.
*/
void
(*fill_in)(struct weston_color_transform *xform,
float *values, unsigned len);
/** Optimal 1D LUT length for storage vs. precision */
unsigned optimal_len;
};
/**

@ -83,6 +83,7 @@ static_assert(sizeof(struct gl_shader_requirements) ==
"struct gl_shader_requirements must not contain implicit padding");
struct gl_shader;
struct weston_color_transform;
#define GL_SHADER_INPUT_TEX_MAX 3
struct gl_shader_config {
@ -234,4 +235,8 @@ gl_renderer_use_program(struct gl_renderer *gr,
struct weston_log_scope *
gl_shader_scope_create(struct gl_renderer *gr);
bool
gl_shader_config_set_color_transform(struct gl_shader_config *sconf,
struct weston_color_transform *xform);
#endif /* GL_RENDERER_INTERNAL_H */

@ -987,7 +987,6 @@ gl_shader_config_init_for_paint_node(struct gl_shader_config *sconf,
if (!pnode->surf_xform_valid)
return false;
assert(pnode->surf_xform.transform == NULL);
*sconf = (struct gl_shader_config) {
.projection = go->output_matrix,
@ -997,6 +996,11 @@ gl_shader_config_init_for_paint_node(struct gl_shader_config *sconf,
gl_shader_config_set_input_textures(sconf, gs);
if (!gl_shader_config_set_color_transform(sconf, pnode->surf_xform.transform)) {
weston_log("GL-renderer: failed to generate a color transformation.\n");
return false;
}
return true;
}
@ -3831,6 +3835,7 @@ gl_renderer_setup(struct weston_compositor *ec, EGLSurface egl_surface)
gr->has_egl_image_external = true;
if (gr->gl_version >= gr_gl_version(3, 0) &&
weston_check_egl_extension(extensions, "GL_OES_texture_float_linear") &&
weston_check_egl_extension(extensions, "GL_EXT_color_buffer_half_float")) {
gr->gl_supports_color_transforms = true;
}

@ -0,0 +1,217 @@
/*
* Copyright 2021 Collabora, Ltd.
*
* Permission is hereby granted, free of charge, to any person obtaining
* a copy of this software and associated documentation files (the
* "Software"), to deal in the Software without restriction, including
* without limitation the rights to use, copy, modify, merge, publish,
* distribute, sublicense, and/or sell copies of the Software, and to
* permit persons to whom the Software is furnished to do so, subject to
* the following conditions:
*
* The above copyright notice and this permission notice (including the
* next paragraph) shall be included in all copies or substantial
* portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
* BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
* ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*/
#include "config.h"
#include <GLES3/gl3.h>
#include <GLES2/gl2ext.h>
#include <assert.h>
#include <libweston/libweston.h>
#include "color.h"
#include "gl-renderer.h"
#include "gl-renderer-internal.h"
#include "shared/weston-egl-ext.h"
struct gl_renderer_color_curve {
enum gl_shader_color_curve type;
GLuint tex;
float scale;
float offset;
};
struct gl_renderer_color_transform {
struct weston_color_transform *owner;
struct wl_listener destroy_listener;
struct gl_renderer_color_curve pre_curve;
};
static void
gl_renderer_color_curve_fini(struct gl_renderer_color_curve *gl_curve)
{
if (gl_curve->tex)
glDeleteTextures(1, &gl_curve->tex);
}
static void
gl_renderer_color_transform_destroy(struct gl_renderer_color_transform *gl_xform)
{
gl_renderer_color_curve_fini(&gl_xform->pre_curve);
wl_list_remove(&gl_xform->destroy_listener.link);
free(gl_xform);
}
static void
color_transform_destroy_handler(struct wl_listener *l, void *data)
{
struct gl_renderer_color_transform *gl_xform;
gl_xform = wl_container_of(l, gl_xform, destroy_listener);
assert(gl_xform->owner == data);
gl_renderer_color_transform_destroy(gl_xform);
}
static struct gl_renderer_color_transform *
gl_renderer_color_transform_create(struct weston_color_transform *xform)
{
struct gl_renderer_color_transform *gl_xform;
gl_xform = zalloc(sizeof *gl_xform);
if (!gl_xform)
return NULL;
gl_xform->owner = xform;
gl_xform->destroy_listener.notify = color_transform_destroy_handler;
wl_signal_add(&xform->destroy_signal, &gl_xform->destroy_listener);
return gl_xform;
}
static struct gl_renderer_color_transform *
gl_renderer_color_transform_get(struct weston_color_transform *xform)
{
struct wl_listener *l;
l = wl_signal_get(&xform->destroy_signal,
color_transform_destroy_handler);
if (!l)
return NULL;
return container_of(l, struct gl_renderer_color_transform,
destroy_listener);
}
static bool
gl_color_curve_lut_3x1d(struct gl_renderer_color_curve *gl_curve,
const struct weston_color_curve *curve,
struct weston_color_transform *xform)
{
const unsigned lut_len = curve->u.lut_3x1d.optimal_len;
const unsigned nr_rows = 4;
GLuint tex;
float *lut;
/*
* Four rows, see fragment.glsl sample_color_pre_curve_lut_2d().
* The fourth row is unused in fragment.glsl color_pre_curve().
*/
lut = calloc(lut_len * nr_rows, sizeof *lut);
if (!lut)
return false;
curve->u.lut_3x1d.fill_in(xform, lut, lut_len);
glActiveTexture(GL_TEXTURE0);
glGenTextures(1, &tex);
glBindTexture(GL_TEXTURE_2D, tex);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
glPixelStorei(GL_UNPACK_ALIGNMENT, sizeof (float));
glPixelStorei(GL_UNPACK_ROW_LENGTH_EXT, 0);
glPixelStorei(GL_UNPACK_SKIP_PIXELS_EXT, 0);
glPixelStorei(GL_UNPACK_SKIP_ROWS_EXT, 0);
glTexImage2D(GL_TEXTURE_2D, 0, GL_R32F, lut_len, nr_rows, 0,
GL_RED_EXT, GL_FLOAT, lut);
glBindTexture(GL_TEXTURE_2D, 0);
free(lut);
gl_curve->type = SHADER_COLOR_CURVE_LUT_3x1D;
gl_curve->tex = tex;
gl_curve->scale = (float)(lut_len - 1) / lut_len;
gl_curve->offset = 0.5f / lut_len;
return true;
}
static const struct gl_renderer_color_transform *
gl_renderer_color_transform_from(struct weston_color_transform *xform)
{
static const struct gl_renderer_color_transform no_op_gl_xform = {
.pre_curve.type = SHADER_COLOR_CURVE_IDENTITY,
.pre_curve.tex = 0,
.pre_curve.scale = 0.0f,
.pre_curve.offset = 0.0f,
};
struct gl_renderer_color_transform *gl_xform;
bool ok = false;
/* Identity transformation */
if (!xform)
return &no_op_gl_xform;
/* Cached transformation */
gl_xform = gl_renderer_color_transform_get(xform);
if (gl_xform)
return gl_xform;
/* New transformation */
gl_xform = gl_renderer_color_transform_create(xform);
if (!gl_xform)
return NULL;
switch (xform->pre_curve.type) {
case WESTON_COLOR_CURVE_TYPE_IDENTITY:
gl_xform->pre_curve = no_op_gl_xform.pre_curve;
ok = true;
break;
case WESTON_COLOR_CURVE_TYPE_LUT_3x1D:
ok = gl_color_curve_lut_3x1d(&gl_xform->pre_curve,
&xform->pre_curve, xform);
break;
}
if (!ok) {
gl_renderer_color_transform_destroy(gl_xform);
return NULL;
}
return gl_xform;
}
bool
gl_shader_config_set_color_transform(struct gl_shader_config *sconf,
struct weston_color_transform *xform)
{
const struct gl_renderer_color_transform *gl_xform;
gl_xform = gl_renderer_color_transform_from(xform);
if (!gl_xform)
return false;
sconf->req.color_pre_curve = gl_xform->pre_curve.type;
sconf->color_pre_curve_lut_tex = gl_xform->pre_curve.tex;
sconf->color_pre_curve_lut_scale_offset[0] = gl_xform->pre_curve.scale;
sconf->color_pre_curve_lut_scale_offset[1] = gl_xform->pre_curve.offset;
return true;
}

@ -23,6 +23,7 @@ srcs_renderer_gl = [
fragment_glsl,
'gl-renderer.c',
'gl-shaders.c',
'gl-shader-config-color-transformation.c',
linux_dmabuf_unstable_v1_protocol_c,
linux_dmabuf_unstable_v1_server_protocol_h,
vertex_glsl,

Loading…
Cancel
Save