29 lines
967 B
Plaintext
29 lines
967 B
Plaintext
|
shader_type canvas_item;
|
||
|
|
uniform sampler2D tiles;
|
||
|
|
uniform sampler2D palette;
|
||
|
|
// uniform float tile_width = 8.0;
|
||
|
|
uniform float tilemap_width = 256.0; // Require square tilemap for now
|
||
|
|
const float index_scale = 255.0 / 16.0;
|
||
|
|
|
||
|
|
|
||
|
|
// This shader maps from tileID texels to Tiles, and then applies palette.
|
||
|
|
// tiles hardcoded to 16x16 tiles for now
|
||
|
|
// palette hardcoded to 16x16 colors for now
|
||
|
|
|
||
|
|
void fragment() {
|
||
|
|
// GLES2
|
||
|
|
float tile_idx = texture(TEXTURE, UV).a * index_scale;
|
||
|
|
vec2 tile_uv = vec2(fract(tile_idx), trunc(tile_idx) / 16.0);
|
||
|
|
vec2 sub_tile_uv = fract(UV / tilemap_width);
|
||
|
|
|
||
|
|
// TODO: add sea HScroll, waterfall VScroll tile UV modulation
|
||
|
|
// TODO: move cycling palette to a sampler2DArray or sampler3D rather than rebinding
|
||
|
|
|
||
|
|
float color_idx = texture(tiles, tile_uv + (sub_tile_uv/16.0)).a * index_scale;
|
||
|
|
float palette_uv = vec2(fract(color_idx), trunc(color_idx) / 16.0);
|
||
|
|
COLOR = texture(palette, palette_uv);
|
||
|
|
|
||
|
|
if (color_idx == 0.0)
|
||
|
|
COLOR.a = 0.0;
|
||
|
|
}
|