From 828b252a6530816f7dab87a7c725edbc81324465 Mon Sep 17 00:00:00 2001
From: luboslenco <lubos.lenco@gmail.com>
Date: Wed, 20 May 2026 09:12:17 +0200
Subject: [PATCH] paint: fix mask apply

---
 paint/shaders/mask_apply.kong | 3 ++-
 paint/sources/globals.h       | 1 +
 paint/sources/pipes.c         | 2 ++
 paint/sources/slot_layer.c    | 1 +
 4 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/paint/shaders/mask_apply.kong b/paint/shaders/mask_apply.kong
index 19ff6ce6..50e4b3da 100644
--- a/paint/shaders/mask_apply.kong
+++ b/paint/shaders/mask_apply.kong
@@ -1,7 +1,7 @@
 
 #[set(everything)]
 const constants: {
-	empty: float4;
+	mask_opacity: float;
 };
 
 #[set(everything)]
@@ -33,6 +33,7 @@ fun mask_apply_vert(input: vert_in): vert_out {
 fun mask_apply_frag(input: vert_out): float4 {
 	var col0: float4 = sample_lod(tex0, sampler_linear, input.tex, 0.0);
 	var mask: float = sample_lod(texa, sampler_linear, input.tex, 0.0).r;
+	mask = lerp(1.0, mask, constants.mask_opacity);
 	return float4(col0.rgb, col0.a * mask);
 }
 
diff --git a/paint/sources/globals.h b/paint/sources/globals.h
index a5505295..b64eb837 100644
--- a/paint/sources/globals.h
+++ b/paint/sources/globals.h
@@ -60,6 +60,7 @@ i32              pipes_blending;
 i32              pipes_tex1w;
 i32              pipes_tex0_mask;
 i32              pipes_texa_mask;
+i32              pipes_opac_apply_mask;
 i32              pipes_tex0_merge_mask;
 i32              pipes_texa_merge_mask;
 i32              pipes_tex_colorid;
diff --git a/paint/sources/pipes.c b/paint/sources/pipes.c
index 298ea4d9..469aa63c 100644
--- a/paint/sources/pipes.c
+++ b/paint/sources/pipes.c
@@ -142,6 +142,8 @@ void pipes_init() {
 		gpu_pipeline_compile(pipes_apply_mask);
 		pipes_tex0_mask = 0;
 		pipes_texa_mask = 1;
+		pipes_offset           = 0;
+		pipes_opac_apply_mask  = pipes_get_constant_location("float");
 	}
 
 	{
diff --git a/paint/sources/slot_layer.c b/paint/sources/slot_layer.c
index 7290607b..0ceed669 100644
--- a/paint/sources/slot_layer.c
+++ b/paint/sources/slot_layer.c
@@ -273,6 +273,7 @@ void layers_apply_mask(slot_layer_t *l, slot_layer_t *m) {
 	gpu_set_pipeline(pipes_apply_mask);
 	gpu_set_texture(pipes_tex0_mask, layers_temp_image);
 	gpu_set_texture(pipes_texa_mask, m->texpaint);
+	gpu_set_float(pipes_opac_apply_mask, m->mask_opacity);
 	gpu_set_vertex_buffer(const_data_screen_aligned_vb);
 	gpu_set_index_buffer(const_data_screen_aligned_ib);
 	gpu_draw();