Clamp brush and layer opacity to [0,1] range

Prevent invalid opacity values from propagating through the UI and
rendering pipeline by clamping after slider input and in uniform reads.
Affected: brush output node, layer mask opacity, swatch opacity,
picked color opacity, brush opacity uniform.

Resolved merge conflict with upstream (ui-> renamed to g_ui->).

Author: ikonnow

paint/sources/nodes_brush/brush_output_node.c

@@ -56,7 +56,7 @@ void brush_output_node_parse_inputs() {
 		}
 	}
 	else {
-		g_context->brush_nodes_opacity = opac->_f32;
+		g_context->brush_nodes_opacity = math_max(0.0, math_min(1.0, opac->_f32));
 		g_context->brush_mask_image    = NULL;
 	}
 

paint/sources/ui/tab_layers.c

@@ -702,6 +702,7 @@ void tab_layers_draw_layer_context_menu_draw() {
 	ui_handle_t *layer_opac_handle = ui_nest(ui_handle(__ID__), l->id);
 	layer_opac_handle->f           = l->mask_opacity;
 	ui_slider(layer_opac_handle, tr("Opacity"), 0.0, 1.0, true, 100.0, true, UI_ALIGN_RIGHT, true);
+	layer_opac_handle->f = math_max(0.0, math_min(1.0, layer_opac_handle->f));
 	if (layer_opac_handle->changed) {
 		if (g_ui->input_started) {
 			history_layer_opacity();

paint/sources/ui/tab_swatches.c

@@ -76,6 +76,7 @@ void tab_swatches_draw_edit_menu() {
 	ui_handle_t *hopacity      = ui_handle(__ID__);
 	hopacity->f                = g_context->swatch->opacity;
 	g_context->swatch->opacity = ui_slider(hopacity, "Opacity", 0, 1, true, 100.0, true, UI_ALIGN_RIGHT, true);
+	g_context->swatch->opacity = math_max(0.0, math_min(1.0, g_context->swatch->opacity));
 
 	if (g_config->workflow == WORKFLOW_PBR) {
 		ui_handle_t *hocclusion      = ui_handle(__ID__);

paint/sources/ui/ui_header.c

@@ -273,6 +273,7 @@ void ui_header_draw_tool_properties() {
 		ui_handle_t *hopac               = ui_handle(__ID__);
 		hopac->f                         = g_context->picked_color->opacity;
 		g_context->picked_color->opacity = ui_slider(hopac, tr("Opacity"), 0.0, 1.0, true, 100.0, true, UI_ALIGN_RIGHT, true);
+		g_context->picked_color->opacity = math_max(0.0, math_min(1.0, g_context->picked_color->opacity));
 
 		ui_handle_t *h_select_mat         = ui_handle(__ID__);
 		h_select_mat->b                   = g_context->picker_select_material;
@@ -369,6 +370,7 @@ void ui_header_draw_tool_properties() {
 		ui_handle_t *brush_opacity_handle = ui_handle(__ID__);
 		brush_opacity_handle->f           = g_context->brush_opacity;
 		g_context->brush_opacity          = ui_slider(brush_opacity_handle, tr("Opacity"), 0.0, 1.0, true, 100.0, true, UI_ALIGN_RIGHT, true);
+		g_context->brush_opacity          = math_max(0.0, math_min(1.0, g_context->brush_opacity));
 		if (g_ui->is_hovered) {
 			any_map_t *vars = any_map_create();
 			any_map_set(vars, "brush_opacity", any_map_get(g_keymap, "brush_opacity"));

paint/sources/uniforms.c

@@ -60,7 +60,7 @@ f32 uniforms_ext_f32_link(object_t *object, material_data_t *mat, char *link) {
 		if (g_config->pressure_opacity && pen_down("tip") && !slot_layer_is_path(g_context->layer)) {
 			val *= pen_pressure * g_config->pressure_sensitivity;
 		}
-		return val;
+		return math_max(0.0, math_min(1.0, val));
 	}
 	else if (string_equals(link, "_brush_hardness")) {
 		bool decal_mask = context_is_decal_mask_paint();