armorpaint/paint/sources/make_node_preview.c

node_shader_context_t *make_node_preview_run(material_t *data, material_context_t *matcon, ui_node_t *node, ui_node_canvas_t *group,
                                             ui_node_t_array_t *parents) {
	char              *context_id = "mesh";
	shader_context_t      *props      = GC_ALLOC_INIT(shader_context_t, {.name            = context_id,
	                                                                     .depth_write     = false,
	                                                                     .compare_mode    = "always",
	                                                                     .cull_mode       = "clockwise",
	                                                                     .vertex_elements = any_array_create_from_raw(
                                                                   (any[]){
                                                                       GC_ALLOC_INIT(vertex_element_t, {.name = "pos", .data = "short4norm"}),
                                                                       GC_ALLOC_INIT(vertex_element_t, {.name = "nor", .data = "short2norm"}),
                                                                       GC_ALLOC_INIT(vertex_element_t, {.name = "tex", .data = "short2norm"}),
                                                                       GC_ALLOC_INIT(vertex_element_t, {.name = "col", .data = "short4norm"}),
                                                                   },
                                                                   4),
	                                                                     .color_attachments = any_array_create_from_raw(
                                                                   (any[]){
                                                                       "RGBA32",
                                                                   },
                                                                   1)});
	node_shader_context_t *con_mesh   = node_shader_context_create(data, props);

	con_mesh->allow_vcols             = true;

	node_shader_t *kong               = node_shader_context_make_kong(con_mesh);

	node_shader_write_attrib_vert(kong, "output.pos = float4(input.pos.xy * 3.0, 0.0, 1.0);");
	node_shader_write_attrib_vert(kong, "var madd: float2 = float2(0.5, 0.5);");
	node_shader_add_out(kong, "tex_coord: float2");
	node_shader_write_attrib_vert(kong, "output.tex_coord = output.pos.xy * madd + madd;");
	node_shader_write_attrib_vert(kong, "output.tex_coord.y = 1.0 - output.tex_coord.y;");
	node_shader_write_attrib_frag(kong, "var tex_coord: float2 = input.tex_coord;");

	parser_material_init();
	gc_unroot(parser_material_canvases);
	parser_material_canvases = any_array_create_from_raw(
	    (any[]){
	        context_raw->material->canvas,
	    },
	    1);
	gc_root(parser_material_canvases);
	gc_unroot(parser_material_nodes);
	parser_material_nodes = context_raw->material->canvas->nodes;
	gc_root(parser_material_nodes);
	gc_unroot(parser_material_links);
	parser_material_links = context_raw->material->canvas->links;
	gc_root(parser_material_links);
	if (group != NULL) {
		parser_material_push_group(group);
		gc_unroot(parser_material_parents);
		parser_material_parents = parents;
		gc_root(parser_material_parents);
	}
	ui_node_link_t_array_t *links          = parser_material_links;
	i32                     socket_preview = i32_imap_get(context_raw->node_preview_socket_map, node->id);
	ui_node_link_t         *link           = GC_ALLOC_INIT(
        ui_node_link_t,
        {.id = ui_next_link_id(links), .from_id = node->id, .from_socket = socket_preview == -1 ? 0 : socket_preview, .to_id = -1, .to_socket = -1});
	any_array_push(links, link);

	gc_unroot(parser_material_con);
	parser_material_con = con_mesh;
	gc_root(parser_material_con);
	gc_unroot(parser_material_kong);
	parser_material_kong = kong;
	gc_root(parser_material_kong);
	gc_unroot(parser_material_matcon);
	parser_material_matcon = matcon;
	gc_root(parser_material_matcon);

	parser_material_transform_color_space = false;
	char *res                         = parser_material_write_result(link);
	parser_material_transform_color_space = true;
	char *st                          = node->outputs->buffer[link->from_socket]->type;
	if (!string_equals(st, "RGB") && !string_equals(st, "RGBA") && !string_equals(st, "VECTOR")) {
		res = string_copy(parser_material_to_vec3(res));
	}
	array_remove(links, link);

	kong->frag_out = "float4";
	node_shader_write_frag(kong, string_join(string_join("var basecol: float3 = ", res), ";"));
	node_shader_write_frag(kong, "output = float4(basecol.rgb, 1.0);");

	parser_material_finalize(con_mesh);

	con_mesh->data->shader_from_source = true;
	gpu_create_shaders_from_kong(node_shader_get(kong), ADDRESS(con_mesh->data->vertex_shader), ADDRESS(con_mesh->data->fragment_shader),
	                             ADDRESS(con_mesh->data->_->vertex_shader_size), ADDRESS(con_mesh->data->_->fragment_shader_size));
	return con_mesh;
}