Merge pull request godotengine#85252 from QbieShay/qbe/fix-radial-inwards-velocity

Fix radial inwards velocity clamping incorrectly (regression from godotengine#83488)

Author: akien-mga

scene/resources/particle_process_material.cpp

@@ -762,8 +762,11 @@ void ParticleProcessMaterial::_update_shader() {
 
 	code += "}\n";
 
-	code += "vec3 process_radial_displacement(DynamicsParameters param, float lifetime, inout uint alt_seed, mat4 transform, mat4 emission_transform){\n";
+	code += "vec3 process_radial_displacement(DynamicsParameters param, float lifetime, inout uint alt_seed, mat4 transform, mat4 emission_transform, float delta){\n";
 	code += "	vec3 radial_displacement = vec3(0.0);\n";
+	code += "	if (delta < 0.001){\n";
+	code += "		return radial_displacement;\n";
+	code += "	}\n";
 	code += "	float radial_displacement_multiplier = 1.0;\n";
 	if (tex_parameters[PARAM_RADIAL_VELOCITY].is_valid()) {
 		code += "   radial_displacement_multiplier = texture(radial_velocity_curve, vec2(lifetime)).r;\n";
@@ -774,7 +777,7 @@ void ParticleProcessMaterial::_update_shader() {
 	code += "	}else{radial_displacement = get_random_direction_from_spread(alt_seed, 360.0)* param.radial_velocity;} \n";
 	code += "	if (radial_displacement_multiplier * param.radial_velocity < 0.0){\n // Prevent inwards velocity to flicker once the point is reached.";
 	code += "		if (length(radial_displacement) > 0.01){\n";
-	code += "		radial_displacement = normalize(radial_displacement) * min(abs((radial_displacement_multiplier * param.radial_velocity)), length(transform[3].xyz - global_pivot));\n";
+	code += "		radial_displacement = normalize(radial_displacement) * min(abs((radial_displacement_multiplier * param.radial_velocity)), length(transform[3].xyz - global_pivot) / delta);\n";
 	code += "		}\n";
 	code += "	\n";
 	code += "	return radial_displacement;\n";
@@ -923,7 +926,7 @@ void ParticleProcessMaterial::_update_shader() {
 	}
 	code += "	// calculate all velocity\n";
 	code += "	\n";
-	code += "	controlled_displacement += process_radial_displacement(dynamic_params, lifetime_percent, alt_seed, TRANSFORM, EMISSION_TRANSFORM);\n";
+	code += "	controlled_displacement += process_radial_displacement(dynamic_params, lifetime_percent, alt_seed, TRANSFORM, EMISSION_TRANSFORM, DELTA);\n";
 	code += "	\n";
 	if (tex_parameters[PARAM_DIRECTIONAL_VELOCITY].is_valid()) {
 		code += "	controlled_displacement += process_directional_displacement(dynamic_params, lifetime_percent, TRANSFORM, EMISSION_TRANSFORM);\n";