pke: first-pass 2d overlay render pass scaffolding

1 files changed, 24 insertions, 0 deletions

diff --git a/assets/shaders/glyph.frag b/assets/shaders/glyph.frag
new file mode 100644
index 0000000..90186a3
--- /dev/null
+++ b/assets/shaders/glyph.frag
@@ -0,0 +1,24 @@
+# version 450
+
+layout(location = 0) in vec4 in_fg_color;
+layout(location = 1) in vec4 in_bg_color;
+layout(location = 2) in vec4 in_sprite_region;
+layout(location = 3) in vec2 in_uv;
+layout(location = 4) in float in_width;
+
+layout(location = 0) out vec4 out_color;
+
+layout(binding = 1) uniform sampler2D mtsdfSampler;
+
+float median(float r, float g, float b) {
+	return max(min(r, g), min(max(r, g), b));
+}
+
+void main() {
+	vec2 atlas_coord = (in_uv - in_sprite_region.xy) / in_sprite_region.zw;
+	vec4 msd = texture(mtsdfSampler, atlas_coord);
+	float sd = median(msd.r, msd.g, msd.b);
+	float screenPxDistance = in_width * (sd - 0.5);
+	float opacity = clamp(screenPxDistance + 0.5, 0.0, 1.0);
+	out_color = mix(in_bg_color, in_fg_color, opacity);
+}