MultimeshInstance2D Animation Variance

I started using the PerfBullets addon, but found that it wasn’t flexible enough for what I wanted from a projectile system so I decided to build my own. Using MultimeshInstance2D and some shader shenanigans, I was able to get thousands of animated projectiles on the screen at once with a noise texture to introduce color variance over time.

 

Here’s the shader code for that, enjoy!

Shader code
shader_type canvas_item;

// separates the texture into animation frames; derived from PerfBullets' implementation
uniform float col; //float for performance sake but never input a float here, only int
uniform float row;

uniform vec4 custom; //visiblity, offsetx, offsety (defines which frame to show)
uniform bool should_flicker_brightness; // add color variance to animation instances
uniform sampler2D noise : hint_normal; // only if should_flicker_brightness == true

varying vec2 v_local_position;
varying vec2 v_normalized_screen_position;

void vertex() {
	if (should_flicker_brightness == true) {
		v_local_position = UV;
    		vec2 v_clip_position = (SCREEN_MATRIX * MODEL_MATRIX * vec4(v_local_position, 0.0, 1.0)).xy;
    		v_normalized_screen_position = v_clip_position * 0.5 + vec2(0.5);
	}
}
void fragment() {
	vec2 uv = UV;
	
	uv = vec2(uv.x/col, uv.y/row);
	uv.y += custom.b/row; // only use ints or sadness happens
	uv.x += custom.g/col;
	vec4 pixel_color = texture(TEXTURE, uv);
	
	if (should_flicker_brightness == true){
		vec4 noise_adjust = texture(noise, vec2(v_normalized_screen_position.x, 1.0-v_normalized_screen_position.y));
		pixel_color *= (noise_adjust + 0.25 );
		
	}
	COLOR = pixel_color;
}
Tags
2d, animation, bullet, canvas, changing, multimesh, noise, projectile, variable color, variance
The shader code and all code snippets in this post are under CC0 license and can be used freely without the author's permission. Images and videos, and assets depicted in those, do not fall under this license. For more info, see our License terms.

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