render: introduce Gamma 2.2 color transform

backend/drm/atomic.c

@@ -186,6 +186,8 @@ static uint8_t convert_cta861_eotf(enum wlr_color_transfer_function tf) {
 		return 2;
 	case WLR_COLOR_TRANSFER_FUNCTION_EXT_LINEAR:
 		abort(); // unsupported
+	case WLR_COLOR_TRANSFER_FUNCTION_GAMMA22:
+		abort(); // unsupported
 	}
 	abort(); // unreachable
 }

include/render/vulkan.h

@@ -153,6 +153,7 @@ enum wlr_vk_texture_transform {
 	WLR_VK_TEXTURE_TRANSFORM_IDENTITY = 0,
 	WLR_VK_TEXTURE_TRANSFORM_SRGB = 1,
 	WLR_VK_TEXTURE_TRANSFORM_ST2084_PQ = 2,
+	WLR_VK_TEXTURE_TRANSFORM_GAMMA22 = 3,
 };
 
 enum wlr_vk_shader_source {
@@ -167,6 +168,7 @@ enum wlr_vk_output_transform {
 	WLR_VK_OUTPUT_TRANSFORM_INVERSE_SRGB = 1,
 	WLR_VK_OUTPUT_TRANSFORM_INVERSE_ST2084_PQ = 2,
 	WLR_VK_OUTPUT_TRANSFORM_LUT3D = 3,
+	WLR_VK_OUTPUT_TRANSFORM_INVERSE_GAMMA22 = 4,
 };
 
 struct wlr_vk_pipeline_key {
@@ -199,6 +201,7 @@ struct wlr_vk_render_format_setup {
 	VkPipeline output_pipe_srgb;
 	VkPipeline output_pipe_pq;
 	VkPipeline output_pipe_lut3d;
+	VkPipeline output_pipe_gamma22;
 
 	struct wlr_vk_renderer *renderer;
 	struct wl_list pipelines; // struct wlr_vk_pipeline.link

include/wlr/render/color.h

@@ -28,6 +28,7 @@ enum wlr_color_transfer_function {
 	WLR_COLOR_TRANSFER_FUNCTION_SRGB = 1 << 0,
 	WLR_COLOR_TRANSFER_FUNCTION_ST2084_PQ = 1 << 1,
 	WLR_COLOR_TRANSFER_FUNCTION_EXT_LINEAR = 1 << 2,
+	WLR_COLOR_TRANSFER_FUNCTION_GAMMA22 = 1 << 3,
 };
 
 /**

render/vulkan/pass.c

@@ -246,6 +246,9 @@ static bool render_pass_submit(struct wlr_render_pass *wlr_pass) {
 			case WLR_COLOR_TRANSFER_FUNCTION_ST2084_PQ:
 				pipeline = render_buffer->two_pass.render_setup->output_pipe_pq;
 				break;
+			case WLR_COLOR_TRANSFER_FUNCTION_GAMMA22:
+				pipeline = render_buffer->two_pass.render_setup->output_pipe_gamma22;
+				break;
 			}
 
 			struct wlr_color_luminances srgb_lum, dst_lum;
@@ -796,6 +799,9 @@ static void render_pass_add_texture(struct wlr_render_pass *wlr_pass,
 	case WLR_COLOR_TRANSFER_FUNCTION_ST2084_PQ:
 		tex_transform = WLR_VK_TEXTURE_TRANSFORM_ST2084_PQ;
 		break;
+	case WLR_COLOR_TRANSFER_FUNCTION_GAMMA22:
+		tex_transform = WLR_VK_TEXTURE_TRANSFORM_GAMMA22;
+		break;
 	}
 
 	struct wlr_vk_pipeline *pipe = setup_get_or_create_pipeline(
@@ -840,7 +846,8 @@ static void render_pass_add_texture(struct wlr_render_pass *wlr_pass,
 	}
 
 	float luminance_multiplier = 1;
-	if (tf != WLR_COLOR_TRANSFER_FUNCTION_SRGB) {
+	if (tf != WLR_COLOR_TRANSFER_FUNCTION_SRGB
+			&& tf != WLR_COLOR_TRANSFER_FUNCTION_GAMMA22) {
 		struct wlr_color_luminances src_lum, srgb_lum;
 		wlr_color_transfer_function_get_default_luminance(tf, &src_lum);
 		wlr_color_transfer_function_get_default_luminance(

render/vulkan/renderer.c

@@ -175,6 +175,7 @@ static void destroy_render_format_setup(struct wlr_vk_renderer *renderer,
 	vkDestroyPipeline(dev, setup->output_pipe_srgb, NULL);
 	vkDestroyPipeline(dev, setup->output_pipe_pq, NULL);
 	vkDestroyPipeline(dev, setup->output_pipe_lut3d, NULL);
+	vkDestroyPipeline(dev, setup->output_pipe_gamma22, NULL);
 
 	struct wlr_vk_pipeline *pipeline, *tmp_pipeline;
 	wl_list_for_each_safe(pipeline, tmp_pipeline, &setup->pipelines, link) {
@@ -2345,6 +2346,11 @@ static struct wlr_vk_render_format_setup *find_or_create_render_setup(
 				&setup->output_pipe_pq, WLR_VK_OUTPUT_TRANSFORM_INVERSE_ST2084_PQ)) {
 			goto error;
 		}
+		if (!init_blend_to_output_pipeline(
+				renderer, setup->render_pass, renderer->output_pipe_layout,
+				&setup->output_pipe_gamma22, WLR_VK_OUTPUT_TRANSFORM_INVERSE_GAMMA22)) {
+			goto error;
+		}
 	} else {
 		assert(format->vk_srgb);
 		VkAttachmentDescription attachment = {

render/vulkan/shaders/output.frag

@@ -22,6 +22,7 @@ layout (constant_id = 0) const int OUTPUT_TRANSFORM = 0;
 #define OUTPUT_TRANSFORM_INVERSE_SRGB 1
 #define OUTPUT_TRANSFORM_INVERSE_ST2084_PQ 2
 #define OUTPUT_TRANSFORM_LUT_3D 3
+#define OUTPUT_TRANSFORM_INVERSE_GAMMA22 4
 
 float linear_channel_to_srgb(float x) {
 	return max(min(x * 12.92, 0.04045), 1.055 * pow(x, 1. / 2.4) - 0.055);
@@ -71,6 +72,8 @@ void main() {
 	} else if (OUTPUT_TRANSFORM == OUTPUT_TRANSFORM_INVERSE_SRGB) {
 		// Produce sRGB encoded values
 		rgb = linear_color_to_srgb(rgb);
+	} else if (OUTPUT_TRANSFORM == OUTPUT_TRANSFORM_INVERSE_GAMMA22) {
+		rgb = pow(rgb, vec3(1. / 2.2));
 	}
 
 	// Back to pre-multiplied alpha

render/vulkan/shaders/texture.frag

@@ -18,6 +18,7 @@ layout (constant_id = 0) const int TEXTURE_TRANSFORM = 0;
 #define TEXTURE_TRANSFORM_IDENTITY 0
 #define TEXTURE_TRANSFORM_SRGB 1
 #define TEXTURE_TRANSFORM_ST2084_PQ 2
+#define TEXTURE_TRANSFORM_GAMMA22 3
 
 float srgb_channel_to_linear(float x) {
 	return mix(x / 12.92,
@@ -60,6 +61,8 @@ void main() {
 		rgb = srgb_color_to_linear(rgb);
 	} else if (TEXTURE_TRANSFORM == TEXTURE_TRANSFORM_ST2084_PQ) {
 		rgb = pq_color_to_linear(rgb);
+	} else if (TEXTURE_TRANSFORM == TEXTURE_TRANSFORM_GAMMA22) {
+		rgb = pow(rgb, vec3(2.2));
 	}
 
 	rgb *= data.luminance_multiplier;

types/scene/surface.c

@@ -42,6 +42,7 @@ static bool get_tf_preference(enum wlr_color_transfer_function tf) {
 	case WLR_COLOR_TRANSFER_FUNCTION_ST2084_PQ:
 		return 1;
 	case WLR_COLOR_TRANSFER_FUNCTION_EXT_LINEAR:
+	case WLR_COLOR_TRANSFER_FUNCTION_GAMMA22:
 		return -1;
 	}
 	abort(); // unreachable

types/wlr_color_management_v1.c

@@ -993,6 +993,8 @@ wlr_color_manager_v1_transfer_function_to_wlr(enum wp_color_manager_v1_transfer_
 		return WLR_COLOR_TRANSFER_FUNCTION_ST2084_PQ;
 	case WP_COLOR_MANAGER_V1_TRANSFER_FUNCTION_EXT_LINEAR:
 		return WLR_COLOR_TRANSFER_FUNCTION_EXT_LINEAR;
+	case WP_COLOR_MANAGER_V1_TRANSFER_FUNCTION_GAMMA22:
+		return WLR_COLOR_TRANSFER_FUNCTION_GAMMA22;
 	default:
 		abort();
 	}
@@ -1007,6 +1009,8 @@ wlr_color_manager_v1_transfer_function_from_wlr(enum wlr_color_transfer_function
 		return WP_COLOR_MANAGER_V1_TRANSFER_FUNCTION_ST2084_PQ;
 	case WLR_COLOR_TRANSFER_FUNCTION_EXT_LINEAR:
 		return WP_COLOR_MANAGER_V1_TRANSFER_FUNCTION_EXT_LINEAR;
+	case WLR_COLOR_TRANSFER_FUNCTION_GAMMA22:
+		return WP_COLOR_MANAGER_V1_TRANSFER_FUNCTION_GAMMA22;
 	}
 	abort();
 }