vertex paint controlled simple 3D wind sway shader

In Blender, use vertex paint to paint your object black in the areas where you want it to animate. and white for the opposite action. export as gltf, with attributes, vertex color as active (see given screenshot) … add the shader onto the mesh and wala you’re done.

Shader code

shader_type spatial;
//specular_schlick_ggx for shaded in place of unshaded
render_mode blend_mix, unshaded, cull_disabled, diffuse_burley, depth_prepass_alpha;

// Base material properties
uniform vec4 albedo : source_color;
uniform sampler2D texture_albedo : source_color, filter_linear_mipmap, repeat_enable;

uniform float roughness : hint_range(0.0, 1.0);
uniform sampler2D texture_metallic : hint_default_white, filter_linear_mipmap, repeat_enable;
uniform vec4 metallic_texture_channel;
uniform sampler2D texture_roughness : hint_roughness_r, filter_linear_mipmap, repeat_enable;

uniform float specular : hint_range(0.0, 1.0, 0.01);
uniform float metallic : hint_range(0.0, 1.0, 0.01);

// Normal mapping
uniform sampler2D texture_normal : hint_normal, filter_linear_mipmap, repeat_enable;
uniform float normal_scale : hint_range(0.0, 2.0) = 1.0;

// Wind sway parameters
uniform bool enable_wind = false;
uniform int wind_type = 0; // 0: Smooth, 1: Gusty, 2: Wave, 3: Directional

uniform float wind_strength : hint_range(0.0, 2.0) = 0.9;
uniform float wind_speed : hint_range(0.0, 5.0) = 1.0;
uniform float wind_frequency : hint_range(0.0, 10.0) = 2.0;
uniform vec2 wind_direction = vec2(1.0, 0.0);

// Distance fade settings
uniform bool enable_fade = false; // Toggle for enabling/disabling fade effect
uniform float fade_start_distance : hint_range(0.0, 200.0) = 50.0; // Distance at which fading starts
uniform float fade_length : hint_range(1.0, 50.0) = 20.0; // Distance over which fading occurs

void vertex() {
    if (enable_wind) {
        float sway_intensity = 1.0 - COLOR.r; // Control wind intensity with vertex color
        if (wind_type == 0) { // Smooth wind
            VERTEX.y += sin(VERTEX.x * wind_frequency + TIME * wind_speed) * wind_strength * sway_intensity;
        } else if (wind_type == 1) { // Gusty wind
            float turbulence = sin(TIME * wind_speed * 0.7) * cos(TIME * wind_speed * 1.3);
            VERTEX.y += sin(VERTEX.x * wind_frequency + TIME * wind_speed) * turbulence * wind_strength * sway_intensity;
        } else if (wind_type == 2) { // Wave-like wind
            VERTEX.y += sin(VERTEX.x * wind_frequency + TIME * wind_speed) * cos(VERTEX.z * wind_frequency + TIME * wind_speed) * wind_strength * sway_intensity;
        } else if (wind_type == 3) { // Directional wind
            VERTEX.xz += wind_direction * sin(TIME * wind_speed) * wind_strength * sway_intensity;
        }
    }
}

void fragment() {
    vec2 base_uv = UV;

    // Sample textures
    vec4 albedo_tex = texture(texture_albedo, base_uv);
    float metallic_tex = dot(texture(texture_metallic, base_uv), metallic_texture_channel);
    float roughness_tex = texture(texture_roughness, base_uv).r;

    // Compute base material properties
    ALBEDO = albedo.rgb * albedo_tex.rgb;
    METALLIC = metallic_tex * metallic;
    SPECULAR = specular;
    ROUGHNESS = roughness_tex * roughness;

    // Normal mapping
    vec3 normal_map = texture(texture_normal, base_uv).rgb * 2.0 - 1.0;
    normal_map.xy *= normal_scale;
    NORMAL_MAP = normal_map;

    // Compute fade effect only if enabled
    float fade = 1.0; // Default fully visible
    if (enable_fade) {
        float dist = length(VERTEX);
        fade = clamp(1.0 - (dist - fade_start_distance) / fade_length, 0.0, 1.0);
    }

    // Apply fading to alpha
    ALPHA = albedo.a * albedo_tex.a * fade;
}

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