1 files changed, 72 insertions, 0 deletions
diff --git a/shaders/prebuilt/ui.vert.glsl b/shaders/prebuilt/ui.vert.glsl
new file mode 100644
index 00000000..08627dc0
--- /dev/null
+++ b/shaders/prebuilt/ui.vert.glsl
@@ -0,0 +1,72 @@
+#version 450
+
+// Terminal cell renderer. The CPU uploads one instance per visible cell; this
+// shader expands each instance into a two-triangle quad with gl_VertexIndex.
+// The fragment shader mixes fg/bg by the atlas's alpha (a glyph mask in the R
+// channel), so background fills and glyph foregrounds draw in a single pass.
+
+layout(location = 0) in vec4 a_rect; // x0, y0, x1, y1
+layout(location = 1) in vec4 a_uv_rect; // u0, v0, u1, v1
+layout(location = 2) in vec3 a_fg;
+layout(location = 3) in vec3 a_bg;
+// Final and presented panel rectangles in NDC. The CPU still uploads logical
+// final cells; this shader is the only place transition geometry is applied.
+layout(location = 4) in vec4 a_panel_rect;
+layout(location = 5) in vec4 a_present_rect;
+// effect id, eased-progress float bits, pane serial, local row/column packed
+// into one uint. The high effect bit marks the frozen-old cell layer; integer
+// transport preserves the exact cross-backend hash.
+layout(location = 6) in uvec4 a_effect;
+
+layout(location = 0) out vec2 v_uv;
+layout(location = 1) out vec3 v_fg;
+layout(location = 2) out vec3 v_bg;
+layout(location = 3) out vec2 v_cell_uv;
+layout(location = 4) flat out uvec4 v_effect;
+
+void main() {
+    vec2 pos;
+    vec2 uv;
+    int corner = gl_VertexIndex % 6;
+    if (corner == 0) {
+        pos = vec2(a_rect.x, a_rect.y);
+        uv = vec2(a_uv_rect.x, a_uv_rect.y);
+        v_cell_uv = vec2(0.0, 0.0);
+    } else if (corner == 1) {
+        pos = vec2(a_rect.z, a_rect.y);
+        uv = vec2(a_uv_rect.z, a_uv_rect.y);
+        v_cell_uv = vec2(1.0, 0.0);
+    } else if (corner == 2) {
+        pos = vec2(a_rect.z, a_rect.w);
+        uv = vec2(a_uv_rect.z, a_uv_rect.w);
+        v_cell_uv = vec2(1.0, 1.0);
+    } else if (corner == 3) {
+        pos = vec2(a_rect.x, a_rect.y);
+        uv = vec2(a_uv_rect.x, a_uv_rect.y);
+        v_cell_uv = vec2(0.0, 0.0);
+    } else if (corner == 4) {
+        pos = vec2(a_rect.z, a_rect.w);
+        uv = vec2(a_uv_rect.z, a_uv_rect.w);
+        v_cell_uv = vec2(1.0, 1.0);
+    } else {
+        pos = vec2(a_rect.x, a_rect.w);
+        uv = vec2(a_uv_rect.x, a_uv_rect.w);
+        v_cell_uv = vec2(0.0, 1.0);
+    }
+
+    uint effect = a_effect.x & 0x7fffffffu;
+    if (effect == 1u || effect == 2u || effect == 5u) {
+        // NDC y points up, so a top-left/bottom-right box has a NEGATIVE y
+        // delta. Preserve that sign or every local y is mirrored/outside.
+        vec2 panel_size = a_panel_rect.zw - a_panel_rect.xy;
+        panel_size.x = abs(panel_size.x) < 0.000001 ? 0.000001 : panel_size.x;
+        panel_size.y = abs(panel_size.y) < 0.000001 ? -0.000001 : panel_size.y;
+        vec2 within = (pos - a_panel_rect.xy) / panel_size;
+        pos = mix(a_present_rect.xy, a_present_rect.zw, within);
+    }
+    v_uv = uv;
+    v_fg = a_fg;
+    v_bg = a_bg;
+    v_effect = a_effect;
+    gl_Position = vec4(pos, 0.0, 1.0);
+}