Add 2D shapes

1 files changed, 65 insertions, 0 deletions

diff --git a/shaders/shape.frag.slang b/shaders/shape.frag.slang
new file mode 100644
index 0000000..b75625b
--- /dev/null
+++ b/shaders/shape.frag.slang
@@ -0,0 +1,65 @@
+/*
+ * Tuxánci 2 - A first person shooter
+ * Copyright (C) 2025-2026  Connor Thomson
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+struct ShapeFragmentUniforms {
+    float4 bounds;
+    float4 points[3];
+    float4 viewport;
+    float4 color;
+    float4 params;
+};
+
+[[vk::binding(0, 3)]]
+ConstantBuffer<ShapeFragmentUniforms> uniforms : register(b0, space3);
+
+struct FSOutput {
+    float4 color : SV_Target0;
+};
+
+FSOutput main(float2 uv : TEXCOORD0) {
+    uint shape_type          = (uint)uniforms.params.x;
+    float distance_from_edge = 0.0;
+    float coverage           = 1.0;
+
+    if (shape_type == 1) {
+        distance_from_edge = min(
+            min(uv.x * uniforms.bounds.z, (1.0 - uv.x) * uniforms.bounds.z),
+            min(uv.y * uniforms.bounds.w, (1.0 - uv.y) * uniforms.bounds.w)
+        );
+        float edge_width = max(fwidth(distance_from_edge), 0.5);
+        coverage = 1.0 - smoothstep(uniforms.params.y - edge_width, uniforms.params.y + edge_width, distance_from_edge);
+    } else if (shape_type >= 3 && shape_type <= 4) {
+        float2 center_offset = (uv - 0.5) * uniforms.bounds.zw;
+        float radius = min(uniforms.bounds.z, uniforms.bounds.w) * 0.5;
+        float distance_from_center = length(center_offset);
+        float edge_width = max(fwidth(distance_from_center), 0.5);
+        if (shape_type == 3 && distance_from_center > radius) {
+            coverage = 1.0 - smoothstep(radius - edge_width, radius + edge_width, distance_from_center);
+        }
+        if (shape_type == 4) {
+            float outer_coverage = 1.0 - smoothstep(radius - edge_width, radius + edge_width, distance_from_center);
+            float inner_coverage = smoothstep(radius - uniforms.params.y - edge_width, radius - uniforms.params.y + edge_width, distance_from_center);
+            coverage             = outer_coverage * inner_coverage;
+        }
+    }
+
+    FSOutput output;
+    output.color = uniforms.color;
+    output.color.a *= coverage;
+    return output;
+}