render: make wlr_render_pass_add_texture() take a general color_transform

Mirrors the previous changes to wlr_renderer_begin_buffer_pass(), moving
color-management decisions to wlr_scene

include/render/vulkan.h

@@ -374,7 +374,6 @@ struct wlr_vk_vert_pcr_data {
 struct wlr_vk_frag_texture_pcr_data {
 	float matrix[4][4]; // only a 3x3 subset is used
 	float alpha;
-	float luminance_multiplier;
 };
 
 struct wlr_vk_frag_output_pcr_data {

include/wlr/render/pass.h

@@ -101,16 +101,12 @@ struct wlr_render_texture_options {
 	enum wlr_scale_filter_mode filter_mode;
 	/* Blend mode */
 	enum wlr_render_blend_mode blend_mode;
-	/* Transfer function the source texture is encoded with */
+	/* Applied to convert from source texture to blend space */
-	enum wlr_color_transfer_function transfer_function;
+	struct wlr_color_transform *color_transform;
-	/* Primaries describing the color volume of the source texture */
-	const struct wlr_color_primaries *primaries;
 	/* Color encoding of the source texture for YCbCr conversion to RGB */
 	enum wlr_color_encoding color_encoding;
 	/* Color range of the source texture */
 	enum wlr_color_range color_range;
-	/* Default: 1.0 */
-	const float *luminance_multiplier;
 
 	/* Wait for a timeline synchronization point before texturing.
 	 *

include/wlr/types/wlr_output.h

@@ -53,7 +53,8 @@ struct wlr_output_cursor {
 
 	struct {
 		struct wl_listener renderer_destroy;
-		struct wlr_color_transform *color_transform;
+		struct wlr_color_transform *color_transform_linearize;
+		struct wlr_color_transform *color_transform_encode;
 	} WLR_PRIVATE;
 };
 

render/vulkan/pass.c

@@ -134,7 +134,7 @@ static bool render_pass_wait_render_buffer(struct wlr_vk_render_pass *pass,
 	return true;
 }
 
-static bool unwrap_color_transform(struct wlr_color_transform *transform,
+static bool unwrap_output_color_transform(struct wlr_color_transform *transform,
 		float matrix[static 9], enum wlr_color_transfer_function *tf) {
 	if (transform == NULL) {
 		wlr_matrix_identity(matrix);
@@ -175,6 +175,47 @@ static bool unwrap_color_transform(struct wlr_color_transform *transform,
 	return false;
 }
 
+static bool unwrap_texture_color_transform(struct wlr_color_transform *transform,
+		float matrix[static 9], enum wlr_color_transfer_function *tf) {
+	if (transform == NULL) {
+		wlr_matrix_identity(matrix);
+		*tf = WLR_COLOR_TRANSFER_FUNCTION_GAMMA22;
+		return true;
+	}
+	struct wlr_color_transform_eotf *eotf;
+	struct wlr_color_transform_matrix *as_matrix;
+	struct wlr_color_transform_pipeline *pipeline;
+	switch (transform->type) {
+	case COLOR_TRANSFORM_EOTF:
+		eotf = wlr_color_transform_eotf_from_base(transform);
+		wlr_matrix_identity(matrix);
+		*tf = eotf->tf;
+		return true;
+	case COLOR_TRANSFORM_MATRIX:
+		as_matrix = wl_container_of(transform, as_matrix, base);
+		memcpy(matrix, as_matrix->matrix, sizeof(float[9]));
+		*tf = WLR_COLOR_TRANSFER_FUNCTION_EXT_LINEAR;
+		return true;
+	case COLOR_TRANSFORM_PIPELINE:
+		pipeline = wl_container_of(transform, pipeline, base);
+		if (pipeline->len != 2
+				|| pipeline->transforms[0]->type != COLOR_TRANSFORM_EOTF
+				|| pipeline->transforms[1]->type != COLOR_TRANSFORM_MATRIX) {
+			return false;
+		}
+		eotf = wlr_color_transform_eotf_from_base(pipeline->transforms[0]);
+		*tf = eotf->tf;
+		as_matrix = wl_container_of(pipeline->transforms[1], as_matrix, base);
+		memcpy(matrix, as_matrix->matrix, sizeof(float[9]));
+		return true;
+	case COLOR_TRANSFORM_INVERSE_EOTF:
+	case COLOR_TRANSFORM_LCMS2:
+	case COLOR_TRANSFORM_LUT_3X1D:
+		return false;
+	}
+	return false;
+}
+
 static bool render_pass_submit(struct wlr_render_pass *wlr_pass) {
 	struct wlr_vk_render_pass *pass = get_render_pass(wlr_pass);
 	struct wlr_vk_renderer *renderer = pass->renderer;
@@ -789,9 +830,12 @@ static void render_pass_add_texture(struct wlr_render_pass *wlr_pass,
 	};
 	encode_proj_matrix(matrix, vert_pcr_data.mat4);
 
-	enum wlr_color_transfer_function tf = options->transfer_function;
+	enum wlr_color_transfer_function tf;
-	if (tf == 0) {
+	float color_matrix[9];
+	if (!unwrap_texture_color_transform(options->color_transform, color_matrix, &tf))
+	{
 		tf = WLR_COLOR_TRANSFER_FUNCTION_GAMMA22;
+		wlr_matrix_identity(color_matrix);
 	}
 
 	bool srgb_image_view = false;
@@ -858,25 +902,8 @@ static void render_pass_add_texture(struct wlr_render_pass *wlr_pass,
 		return;
 	}
 
-	float color_matrix[9];
-	if (options->primaries != NULL) {
-		struct wlr_color_primaries srgb;
-		wlr_color_primaries_from_named(&srgb, WLR_COLOR_NAMED_PRIMARIES_SRGB);
-
-		wlr_color_primaries_transform_absolute_colorimetric(options->primaries,
-			&srgb, color_matrix);
-	} else {
-		wlr_matrix_identity(color_matrix);
-	}
-
-	float luminance_multiplier = 1;
-	if (options->luminance_multiplier != NULL) {
-		luminance_multiplier = *options->luminance_multiplier;
-	}
-
 	struct wlr_vk_frag_texture_pcr_data frag_pcr_data = {
 		.alpha = alpha,
-		.luminance_multiplier = luminance_multiplier,
 	};
 	encode_color_matrix(color_matrix, frag_pcr_data.matrix);
 
@@ -1147,7 +1174,7 @@ static struct wlr_vk_color_transform *vk_color_transform_create(
 		return NULL;
 	}
 
-	bool need_lut = !unwrap_color_transform(transform, vk_transform->color_matrix,
+	bool need_lut = !unwrap_output_color_transform(transform, vk_transform->color_matrix,
 		&vk_transform->inverse_eotf);
 
 	if (need_lut) {

render/vulkan/shaders/texture.frag

@@ -9,7 +9,6 @@ layout(location = 0) out vec4 out_color;
 layout(push_constant, row_major) uniform UBO {
 	layout(offset = 80) mat4 matrix;
 	float alpha;
-	float luminance_multiplier;
 } data;
 
 layout (constant_id = 0) const int TEXTURE_TRANSFORM = 0;
@@ -82,8 +81,6 @@ void main() {
 		rgb = bt1886_color_to_linear(rgb);
 	}
 
-	rgb *= data.luminance_multiplier;
-
 	rgb = mat3(data.matrix) * rgb;
 
 	// Back to pre-multiplied alpha

types/output/cursor.c

@@ -256,7 +256,7 @@ static struct wlr_buffer *render_cursor_buffer(struct wlr_output_cursor *cursor)
 		buffer->width, buffer->height);
 
 	struct wlr_buffer_pass_options options = {
-		.color_transform = cursor->color_transform,
+		.color_transform = cursor->color_transform_encode,
 	};
 	struct wlr_render_pass *pass = wlr_renderer_begin_buffer_pass(renderer, buffer, &options);
 	if (pass == NULL) {
@@ -278,6 +278,7 @@ static struct wlr_buffer *render_cursor_buffer(struct wlr_output_cursor *cursor)
 		.transform = transform,
 		.wait_timeline = cursor->wait_timeline,
 		.wait_point = cursor->wait_point,
+		.color_transform = cursor->color_transform_linearize,
 	});
 
 	if (!wlr_render_pass_submit(pass)) {
@@ -493,18 +494,27 @@ void wlr_output_cursor_destroy(struct wlr_output_cursor *cursor) {
 	}
 	wlr_drm_syncobj_timeline_unref(cursor->wait_timeline);
 	wl_list_remove(&cursor->link);
-	wlr_color_transform_unref(cursor->color_transform);
+	wlr_color_transform_unref(cursor->color_transform_linearize);
+	wlr_color_transform_unref(cursor->color_transform_encode);
 	free(cursor);
 }
 
 bool output_cursor_refresh_color_transform(struct wlr_output_cursor *output_cursor,
 		const struct wlr_output_image_description *img_desc) {
-	wlr_color_transform_unref(output_cursor->color_transform);
+	wlr_color_transform_unref(output_cursor->color_transform_linearize);
-	output_cursor->color_transform = NULL;
+	output_cursor->color_transform_linearize = NULL;
+	wlr_color_transform_unref(output_cursor->color_transform_encode);
+	output_cursor->color_transform_encode = NULL;
 	if (img_desc == NULL) {
 		return true;
 	}
 
+	output_cursor->color_transform_linearize = wlr_color_transform_init_eotf_to_linear(
+		WLR_COLOR_TRANSFER_FUNCTION_GAMMA22);
+	if (output_cursor->color_transform_linearize == NULL) {
+		goto err;
+	}
+
 	struct wlr_color_primaries primaries_srgb;
 	wlr_color_primaries_from_named(&primaries_srgb, WLR_COLOR_NAMED_PRIMARIES_SRGB);
 	struct wlr_color_primaries primaries;
@@ -525,13 +535,22 @@ bool output_cursor_refresh_color_transform(struct wlr_output_cursor *output_curs
 		wlr_color_transform_init_linear_to_inverse_eotf(img_desc->transfer_function),
 	};
 	if (transforms[0] == NULL || transforms[1] == NULL) {
-		wlr_color_transform_unref(transforms[0]);
+		goto err;
-		wlr_color_transform_unref(transforms[1]);
-		return false;
 	}
-	output_cursor->color_transform = wlr_color_transform_init_pipeline(transforms,
+	output_cursor->color_transform_encode = wlr_color_transform_init_pipeline(transforms,
 		sizeof(transforms) / sizeof(transforms[0]));
+	if (output_cursor->color_transform_encode == NULL) {
+		goto err;
+	}
+
 	wlr_color_transform_unref(transforms[0]);
 	wlr_color_transform_unref(transforms[1]);
-	return output_cursor->color_transform != NULL;
+	return true;
+
+err:
+	wlr_color_transform_unref(output_cursor->color_transform_linearize);
+	output_cursor->color_transform_linearize = NULL;
+	wlr_color_transform_unref(transforms[0]);
+	wlr_color_transform_unref(transforms[1]);
+	return false;
 }

types/scene/wlr_scene.c

@@ -20,6 +20,7 @@
 #include "types/wlr_scene.h"
 #include "util/array.h"
 #include "util/env.h"
+#include "util/matrix.h"
 #include "util/time.h"
 
 #include <wlr/config.h>
@@ -1411,6 +1412,63 @@ static float get_luminance_multiplier(const struct wlr_color_luminances *src_lum
 	return (dst_lum->reference / src_lum->reference) * (src_lum->max / dst_lum->max);
 }
 
+static struct wlr_color_transform *scene_texture_to_blend_space(
+		struct wlr_scene_buffer *source, enum wlr_color_named_primaries dest_primaries,
+		const struct wlr_color_luminances *dest_luminance) {
+	struct wlr_color_transform *color_matrix = NULL;
+	struct wlr_color_transform *eotf = NULL;
+	struct wlr_color_transform *combined = NULL;
+
+	enum wlr_color_transfer_function source_tf = WLR_COLOR_TRANSFER_FUNCTION_GAMMA22;
+	if (source->transfer_function != 0) {
+		source_tf = source->transfer_function;
+	}
+	eotf = wlr_color_transform_init_eotf_to_linear(source_tf);
+	if (eotf == NULL) {
+		goto cleanup_transforms;
+	}
+
+	struct wlr_color_luminances source_lum;
+	wlr_color_transfer_function_get_default_luminance(source_tf, &source_lum);
+	float luminance_multiplier = get_luminance_multiplier(&source_lum, dest_luminance);
+
+	float matrix[9];
+
+	enum wlr_color_named_primaries source_primaries = WLR_COLOR_NAMED_PRIMARIES_SRGB;
+	if (source->primaries != 0) {
+		source_primaries = source->primaries;
+	}
+	if (source_primaries != dest_primaries) {
+		struct wlr_color_primaries primaries;
+		wlr_color_primaries_from_named(&primaries, source_primaries);
+		struct wlr_color_primaries primaries_blend;
+		wlr_color_primaries_from_named(&primaries_blend, dest_primaries);
+		wlr_color_primaries_transform_absolute_colorimetric(&primaries, &primaries_blend, matrix);
+	} else {
+		wlr_matrix_identity(matrix);
+	}
+
+	for (int i = 0; i < 9; ++i) {
+		matrix[i] *= luminance_multiplier;
+	}
+	color_matrix = wlr_color_transform_init_matrix(matrix);
+	if (color_matrix == NULL) {
+		goto cleanup_transforms;
+	}
+
+	struct wlr_color_transform *transforms[] = {
+		eotf,
+		color_matrix,
+	};
+	const size_t transforms_len = sizeof(transforms) / sizeof(transforms[0]);
+	color_transform_compose(&combined, transforms, transforms_len);
+
+cleanup_transforms:
+	wlr_color_transform_unref(eotf);
+	wlr_color_transform_unref(color_matrix);
+	return combined;
+}
+
 static void scene_entry_render(struct render_list_entry *entry, const struct render_data *data) {
 	struct wlr_scene_node *node = entry->node;
 
@@ -1489,17 +1547,14 @@ static void scene_entry_render(struct render_list_entry *entry, const struct ren
 			wlr_output_transform_invert(scene_buffer->transform);
 		transform = wlr_output_transform_compose(transform, data->transform);
 
-		struct wlr_color_primaries primaries = {0};
+		struct wlr_color_transform *source_to_blend = NULL;
-		if (scene_buffer->primaries != 0) {
+		if (data->output->output->renderer->features.input_color_transform) {
-			wlr_color_primaries_from_named(&primaries, scene_buffer->primaries);
+			struct wlr_color_luminances srgb_lum;
-		}
+			wlr_color_transfer_function_get_default_luminance(WLR_COLOR_TRANSFER_FUNCTION_SRGB, &srgb_lum);
 
-		struct wlr_color_luminances src_lum, srgb_lum;
+			source_to_blend = scene_texture_to_blend_space(
-		wlr_color_transfer_function_get_default_luminance(
+				scene_buffer, WLR_COLOR_NAMED_PRIMARIES_SRGB, &srgb_lum);
-			scene_buffer->transfer_function, &src_lum);
+		}
-		wlr_color_transfer_function_get_default_luminance(
-			WLR_COLOR_TRANSFER_FUNCTION_SRGB, &srgb_lum);
-		float luminance_multiplier = get_luminance_multiplier(&src_lum, &srgb_lum);
 
 		wlr_render_pass_add_texture(data->render_pass, &(struct wlr_render_texture_options) {
 			.texture = texture,
@@ -1512,15 +1567,15 @@ static void scene_entry_render(struct render_list_entry *entry, const struct ren
 			.blend_mode = !data->output->scene->calculate_visibility ||
 					!pixman_region32_empty(&opaque) ?
 				WLR_RENDER_BLEND_MODE_PREMULTIPLIED : WLR_RENDER_BLEND_MODE_NONE,
-			.transfer_function = scene_buffer->transfer_function,
+			.color_transform = source_to_blend,
-			.primaries = scene_buffer->primaries != 0 ? &primaries : NULL,
 			.color_encoding = scene_buffer->color_encoding,
 			.color_range = scene_buffer->color_range,
-			.luminance_multiplier = &luminance_multiplier,
 			.wait_timeline = scene_buffer->wait_timeline,
 			.wait_point = scene_buffer->wait_point,
 		});
 
+		wlr_color_transform_unref(source_to_blend);
+
 		struct wlr_scene_output_sample_event sample_event = {
 			.output = data->output,
 			.direct_scanout = false,