gtk2/gsk/resources/glsl/repeat.glsl
Alexander Larsson bacb3affb3 gl: Add some namespacing to the preamble symbols
This adds a gsk prefix to the stuff in the preamble, as we want to
avoid it conflicting with things in the main shader. Especially once
we start allow some customization of shaders.
2020-09-29 09:51:16 +02:00

42 lines
1.0 KiB
GLSL

// VERTEX_SHADER:
void main() {
gl_Position = u_projection * u_modelview * vec4(aPosition, 0.0, 1.0);
vUv = vec2(aUv.x, aUv.y);
}
// FRAGMENT_SHADER:
uniform vec4 u_child_bounds;
uniform vec4 u_texture_rect;
float wrap(float f, float wrap_for) {
return mod(f, wrap_for);
}
/* We get the texture coordinates via vUv,
* but that might be on a texture atlas, so we need to do the
* wrapping ourselves.
*/
void main() {
/* We map the texture coordinate to [1;0], then wrap it and scale the result again */
float tw = u_texture_rect.z - u_texture_rect.x;
float th = u_texture_rect.w - u_texture_rect.y;
float mapped_x = (vUv.x - u_texture_rect.x) / tw;
float mapped_y = (vUv.y - u_texture_rect.y) / th;
float wrapped_x = wrap(u_child_bounds.x + mapped_x * u_child_bounds.z, 1.0);
float wrapped_y = wrap(u_child_bounds.y + mapped_y * u_child_bounds.w, 1.0);
vec2 tp;
tp.x = u_texture_rect.x + (wrapped_x * tw);
tp.y = u_texture_rect.y + (wrapped_y * th);
vec4 diffuse = GskTexture(u_source, tp);
gskSetOutputColor(diffuse * u_alpha);
}