1 files changed, 75 insertions, 2 deletions

diff --git a/src/misc.zig b/src/misc.zig
index d6063eb..6f1d893 100644
--- a/src/misc.zig
+++ b/src/misc.zig
@@ -1,4 +1,5 @@
 // Miscellaneous functions
+// Copyright (C) 2002  David Rosen
 // Copyright (C) 2021-2023  Nguyễn Gia Phong
 //
 // This file is part of Black Shades.
@@ -27,6 +28,7 @@ const endsWith = std.mem.endsWith;
 const eql = std.mem.eql;
 const free = std.c.free;
 const join = std.fs.path.joinZ;
+const len = std.mem.len;
 const maxInt = std.math.maxInt;
 const parseFloat = std.fmt.parseFloat;
 const parseInt = std.fmt.parseInt;
@@ -375,6 +377,77 @@ pub fn saveScores(base_dir: []const u8, current: Scores) !void {
     try dir.writeFile("scores.ini", data);
 }
 
+const Text = struct {
+    texture: u32,
+    base: u32,
+};
+
+export fn buildFont(text: *Text) void {
+    text.base = c.glGenLists(256);
+    c.glBindTexture(c.GL_TEXTURE_2D, text.texture);
+    var i = @as(u16, 0);
+    while (i < 256) : (i += 1) {
+        // Character coords
+        const x = @intToFloat(f32, i % 16) / 16.0;
+        const y = @intToFloat(f32, i / 16) / 16.0;
+        c.glNewList(text.base + i, c.GL_COMPILE);
+        // Use A Quad For Each Character
+        c.glBegin(c.GL_QUADS);
+        // Bottom left
+        c.glTexCoord2f(x, 1 - y - 0.0625 + 0.001);
+        c.glVertex2i(0,0);
+        // Bottom right
+        c.glTexCoord2f(x + 0.0625, 1 - y - 0.0625 + 0.001);
+        c.glVertex2i(16, 0);
+        // Top right
+        c.glTexCoord2f(x + 0.0625, 1 - y - 0.001);
+        c.glVertex2i(16, 16);
+        // Top left
+        c.glTexCoord2f(x, 1 - y - 0.001);
+        c.glVertex2i(0, 16);
+        c.glEnd();
+        // Move to the right of the character
+        c.glTranslated(10, 0, 0);
+        c.glEndList();
+    }
+}
+
+export fn glPrint(text: *const Text, x: f64, y: f64, str: [*:0]const u8,
+                  set: bool, size: f32, width: f32, height: f32) void {
+    c.glTexEnvi(c.GL_TEXTURE_ENV, c.GL_TEXTURE_ENV_MODE, c.GL_MODULATE);
+    c.glBindTexture(c.GL_TEXTURE_2D, text.texture);
+    c.glDisable(c.GL_DEPTH_TEST);
+    c.glDisable(c.GL_LIGHTING);
+    c.glEnable(c.GL_BLEND);
+    c.glBlendFunc(c.GL_SRC_ALPHA, c.GL_ONE_MINUS_SRC_ALPHA);
+    c.glMatrixMode(c.GL_PROJECTION);
+    c.glPushMatrix();
+    c.glLoadIdentity();
+    c.glOrtho(0, width, 0, height, -100, 100);
+    c.glMatrixMode(c.GL_MODELVIEW);
+    c.glPushMatrix();
+    c.glLoadIdentity();
+
+    c.glScalef(size, size, 1);
+    // Position the text (0,0 - bottom left)
+    c.glTranslated(x, y, 0);
+    // Choose the font set (0 or 1)
+    if (set)
+        c.glListBase(text.base + 128 - 32)
+    else
+        c.glListBase(text.base -% 32);
+    // Write to screen
+    c.glCallLists(@intCast(c_int, len(str)), c.GL_BYTE, str);
+
+    // Restore
+    c.glMatrixMode(c.GL_PROJECTION);
+    c.glPopMatrix();
+    c.glMatrixMode(c.GL_MODELVIEW);
+    c.glPopMatrix();
+    c.glEnable(c.GL_DEPTH_TEST);
+    c.glTexEnvi(c.GL_TEXTURE_ENV, c.GL_TEXTURE_ENV_MODE, c.GL_MODULATE);
+}
+
 /// OpenGL fog state.
 const Fog = extern struct {
     color: [4]f32,
@@ -394,7 +467,7 @@ export fn setFog(fog: *Fog, r: f32, g: f32, b: f32,
 }
 
 /// Set temporary fog effect.
-export fn tempFog(fog: *Fog, r: f32, g: f32, b: f32) void {
+export fn tempFog(fog: *const Fog, r: f32, g: f32, b: f32) void {
     const color = [4]f32{r, g, b, 1.0};
     c.glFogi(c.GL_FOG_MODE, c.GL_LINEAR);
     c.glFogfv(c.GL_FOG_COLOR, &color);
@@ -406,7 +479,7 @@ export fn tempFog(fog: *Fog, r: f32, g: f32, b: f32) void {
 }
 
 /// Reset fog effect.
-export fn resetFog(fog: *Fog) void {
+export fn resetFog(fog: *const Fog) void {
     c.glFogi(c.GL_FOG_MODE, c.GL_LINEAR);
     c.glFogfv(c.GL_FOG_COLOR, &fog.color);
     c.glFogf(c.GL_FOG_DENSITY, fog.density);