Hello! I need some help.
I recently came across a technique in Godot where a repeated overlay texture is applied on tilemaps using a shader (based on world position). I’m trying to achieve something similar in Defold.
Is it possible to do this using a tilemap material in Defold?
Here’s the shader I’m referencing:
shader_type canvas_item;
uniform sampler2D overlay_tex: repeat_enable, filter_nearest;
uniform float scale = 0.006944444; // calculated by 1/texture size e.g. 1/144
varying vec2 world_position;
void vertex(){
// calculate the world position for use in the fragment shader
world_position = (MODEL_MATRIX * vec4(VERTEX, 0.0, 1.0)).xy;
}
void fragment() {
// only apply overlay_tex on the fully red parts of the original tiles
float mix_amount = floor(COLOR.r);
// sample the overlay_tex using world position
vec4 overlay_color = texture(overlay_tex, world_position * scale);
// combine original color and overlay color together
COLOR = mix(COLOR, overlay_color, mix_amount);
}
Specifically, I want:
-
A repeating overlay texture across the whole tilemap (not per-tile UVs)
-
Sampling based on world position
-
Masking using tile color (like the red channel in this example)
Is this achievable in Defold’s tilemap system, or would I need a different approach?
Thanks!
