#version 450

layout(set = 0, binding = 0) uniform sampler2D tex;

layout(location = 0) in vec2 uv;
layout(location = 0) out vec4 out_color;

layout(push_constant) uniform UBO {
	layout(offset = 80) float alpha;
} data;

void main() {
	out_color = textureLod(tex, uv, 0);

	// We expect this shader to output pre-alpha-multiplied color values.
	// alpha < 0.0 means that this shader should ignore the texture's alpha
	// value.
	if (data.alpha < 0.0) {
		out_color.a = -data.alpha;
		out_color.rgb *= -data.alpha;
	} else {
		out_color *= data.alpha;
	}
}