Add colors

1 files changed, 25 insertions, 1 deletions

diff --git a/src/wasm_ttd.zig b/src/wasm_ttd.zig
index 374986f..03d5941 100644
--- a/src/wasm_ttd.zig
+++ b/src/wasm_ttd.zig
@@ -149,8 +149,10 @@ pub fn pow(comptime T: type, base: T, exp: T) T {
 
 const Star = struct {
     dist: f32,
+    pdist: f32,
     angle: f32,
     initial_len: f32,
+    col: Color,
 };
 const max_dist = 100;
 
@@ -182,6 +184,12 @@ export fn init() void {
         s.angle = lerp(0, 2 * pi, rng.randFloat(f32));
         s.initial_len = lerp(0, height / 2, rng.randFloat(f32));
         s.dist = max_dist;
+        s.pdist = max_dist;
+        s.col = .{
+            .r = rng.randFloat(f32),
+            .g = rng.randFloat(f32),
+            .b = rng.randFloat(f32),
+        };
     }
     //const msg = "Welcome to TBD";
     //consoleLog(msg.ptr, msg.len);
@@ -337,17 +345,25 @@ export fn update(elapsed_time: f32) void {
     const width = getScreenWidth();
     const height = getScreenHeight();
     for (stars[0..sub_count]) |*s| {
+        s.pdist = s.dist;
         s.dist -= speed;
+        const plen = lerp(1000, s.initial_len, s.pdist / max_dist);
+        const psx = (@cos(s.angle) * plen) + width * 0.5;
+        const psy = (@sin(s.angle) * plen) + height * 0.5;
+
         const len = lerp(1000, s.initial_len, s.dist / max_dist);
         const sx = (@cos(s.angle) * len) + width * 0.5;
         const sy = (@sin(s.angle) * len) + height * 0.5;
         const scale = lerp(8, 0, s.dist / max_dist);
-        drawCircle(.{ sx, sy }, scale, Color.white);
+
+        drawLine(&.{ .{ psx, psy }, .{ sx, sy } }, s.col);
+        drawCircle(.{ sx, sy }, scale, s.col);
 
         if (sx < 0 or sx > 1280 or sy < 0 or sy > height) {
             s.angle = lerp(0, 2 * pi, rng.randFloat(f32));
             s.initial_len = lerp(0, 360, rng.randFloat(f32));
             s.dist = max_dist;
+            s.pdist = max_dist;
         }
     }
 }
@@ -433,6 +449,14 @@ const TriangleGroup = struct {
     }
 };
 
+fn drawLine(points: *const [2][2]f32, col: Color) void {
+    setDrawColor(col);
+    webgl.uniformMatrix3fv(mat_uniform_location, &Mat3.identity.data);
+    webgl.bufferData(.array_buffer, @ptrCast(points), 4, .dynamic_draw);
+
+    webgl.drawArrays(.lines, 0, 2);
+}
+
 fn drawTri(points: *const [3][2]f32) void {
     //webgl.useProgram(prog);
     //webgl.uniform1i(tex_uniform_location, 0);