-Fix particles with size==0, closes #13931

-Fixed material previews (dont show sphere unless for spatial)

editor/plugins/editor_preview_plugins.cpp

@@ -235,6 +235,8 @@ Ref<Texture> EditorMaterialPreviewPlugin::generate(const RES &p_from) {
 	Ref<Material> material = p_from;
 	ERR_FAIL_COND_V(material.is_null(), Ref<Texture>());
 
+	if (material->get_shader_mode() == Shader::MODE_SPATIAL) {
+
 		VS::get_singleton()->mesh_surface_set_material(sphere, 0, material->get_rid());
 
 		VS::get_singleton()->viewport_set_update_mode(viewport, VS::VIEWPORT_UPDATE_ONCE); //once used for capture
@@ -258,6 +260,9 @@ Ref<Texture> EditorMaterialPreviewPlugin::generate(const RES &p_from) {
 		Ref<ImageTexture> ptex = Ref<ImageTexture>(memnew(ImageTexture));
 		ptex->create_from_image(img, 0);
 		return ptex;
+	}
+
+	return Ref<Texture>();
 }
 
 EditorMaterialPreviewPlugin::EditorMaterialPreviewPlugin() {

scene/2d/canvas_item.cpp

@@ -184,6 +184,11 @@ RID CanvasItemMaterial::get_shader_rid() const {
 	return shader_map[current_key].shader;
 }
 
+Shader::Mode CanvasItemMaterial::get_shader_mode() const {
+
+	return Shader::MODE_CANVAS_ITEM;
+}
+
 void CanvasItemMaterial::_bind_methods() {
 
 	ClassDB::bind_method(D_METHOD("set_blend_mode", "blend_mode"), &CanvasItemMaterial::set_blend_mode);

scene/2d/canvas_item.h

@@ -123,6 +123,8 @@ public:
 
 	RID get_shader_rid() const;
 
+	virtual Shader::Mode get_shader_mode() const;
+
 	CanvasItemMaterial();
 	virtual ~CanvasItemMaterial();
 };

scene/3d/particles.cpp

@@ -869,6 +869,7 @@ void ParticlesMaterial::_update_shader() {
 	}
 	//scale by scale
 	code += "	float base_scale = mix(scale*tex_scale,1.0,scale_random*scale_rand);\n";
+	code += "	if (base_scale==0.0) base_scale=0.000001;\n";
 	if (trail_size_modifier.is_valid()) {
 		code += "	if (trail_divisor > 1) { base_scale *= textureLod(trail_size_modifier,vec2(float(int(NUMBER)%trail_divisor)/float(trail_divisor-1),0.0),0.0).r; } \n";
 	}
@@ -1360,6 +1361,11 @@ void ParticlesMaterial::_validate_property(PropertyInfo &property) const {
 	}
 }
 
+Shader::Mode ParticlesMaterial::get_shader_mode() const {
+
+	return Shader::MODE_PARTICLES;
+}
+
 void ParticlesMaterial::_bind_methods() {
 
 	ClassDB::bind_method(D_METHOD("set_spread", "degrees"), &ParticlesMaterial::set_spread);

scene/3d/particles.h

@@ -390,6 +390,8 @@ public:
 
 	RID get_shader_rid() const;
 
+	virtual Shader::Mode get_shader_mode() const;
+
 	ParticlesMaterial();
 	~ParticlesMaterial();
 };

scene/resources/material.cpp

@@ -215,6 +215,13 @@ bool ShaderMaterial::_can_do_next_pass() const {
 	return shader.is_valid() && shader->get_mode() == Shader::MODE_SPATIAL;
 }
 
+Shader::Mode ShaderMaterial::get_shader_mode() const {
+	if (shader.is_valid())
+		return shader->get_mode();
+	else
+		return Shader::MODE_SPATIAL;
+}
+
 ShaderMaterial::ShaderMaterial() {
 }
 
@@ -1662,6 +1669,11 @@ RID SpatialMaterial::get_shader_rid() const {
 	return shader_map[current_key].shader;
 }
 
+Shader::Mode SpatialMaterial::get_shader_mode() const {
+
+	return Shader::MODE_SPATIAL;
+}
+
 void SpatialMaterial::_bind_methods() {
 
 	ClassDB::bind_method(D_METHOD("set_albedo", "albedo"), &SpatialMaterial::set_albedo);

scene/resources/material.h

@@ -69,6 +69,8 @@ public:
 	int get_render_priority() const;
 
 	virtual RID get_rid() const;
+
+	virtual Shader::Mode get_shader_mode() const = 0;
 	Material();
 	virtual ~Material();
 };
@@ -96,6 +98,8 @@ public:
 	void set_shader_param(const StringName &p_param, const Variant &p_value);
 	Variant get_shader_param(const StringName &p_param) const;
 
+	virtual Shader::Mode get_shader_mode() const;
+
 	ShaderMaterial();
 	~ShaderMaterial();
 };
@@ -600,6 +604,8 @@ public:
 
 	RID get_shader_rid() const;
 
+	virtual Shader::Mode get_shader_mode() const;
+
 	SpatialMaterial();
 	virtual ~SpatialMaterial();
 };