add toggleable crop mode

1 files changed, 45 insertions, 19 deletions

diff --git a/src/output.zig b/src/output.zig
index 87dc311..d15c0d4 100644
--- a/src/output.zig
+++ b/src/output.zig
@@ -37,10 +37,19 @@ pub const WindowOutput = struct {
             nearest = c.GL_NEAREST,
             linear = c.GL_LINEAR,
         };
+        const CropMode = enum(u32) {
+            contain,
+            cover,
+            center,
+            natural,
+
+            pub const last: CropMode = .natural;
+        };
 
         width: i32,
         height: i32,
         filter: FilterMode,
+        crop: CropMode,
 
         monitor: []const u8,
         fullscreen: bool,
@@ -49,6 +58,7 @@ pub const WindowOutput = struct {
             .width = 800,
             .height = 600,
             .filter = .linear,
+            .crop = .contain,
             .monitor = "",
             .fullscreen = false,
         };
@@ -80,6 +90,8 @@ pub const WindowOutput = struct {
                 ) orelse {
                     std.debug.panic("unable to create output window\n", .{});
                 },
+
+                .crop = config.crop,
             };
 
             c.glfwSetWindowUserPointer(self.window, @as(*anyopaque, @ptrCast(self)));
@@ -96,6 +108,7 @@ pub const WindowOutput = struct {
     output: Output,
     window: *c.GLFWwindow,
     constants: *gl.Constants,
+    crop: Config.CropMode,
 
     resized: bool = false,
 
@@ -112,26 +125,30 @@ pub const WindowOutput = struct {
         c.glfwWindowHint(c.GLFW_DECORATED, c.GLFW_FALSE);
 
         if (self.resized) {
-            var width: c_int = undefined;
-            var height: c_int = undefined;
-            var scaled_width: c_int = undefined;
-            var scaled_height: c_int = undefined;
-
-            c.glfwGetFramebufferSize(self.window, &width, &height);
-            const window_aspect = @as(f32, @floatFromInt(width)) / @as(f32, @floatFromInt(height));
-            if (window_aspect >= self.constants.aspect) {
-                scaled_height = height;
-                scaled_width = @as(c_int, @intFromFloat(@as(f32, @floatFromInt(height)) * self.constants.aspect));
-            } else {
-                scaled_width = width;
-                scaled_height = @as(c_int, @intFromFloat(@as(f32, @floatFromInt(width)) / self.constants.aspect));
-            }
+            var wwidth: c_int = undefined;
+            var wheight: c_int = undefined;
+            c.glfwGetFramebufferSize(self.window, &wwidth, &wheight);
+            const window_width: f32 = @floatFromInt(wwidth);
+            const window_height: f32 = @floatFromInt(wheight);
+
+            const width: f32 = @floatFromInt(self.constants.config.width);
+            const height: f32 = @floatFromInt(self.constants.config.height);
+
+            const width_scale = window_width / width;
+            const height_scale = window_height / height;
+
+            const scale: f32 = switch (self.crop) {
+                .contain => @min(width_scale, height_scale),
+                .cover => @max(width_scale, height_scale),
+                .center => 1.0,
+                .natural => 1.0 / @ceil(1.0 / @min(width_scale, height_scale)),
+            };
 
             c.glViewport(
-                @divFloor(width - scaled_width, 2),
-                @divFloor(height - scaled_height, 2),
-                scaled_width,
-                scaled_height,
+                @intFromFloat((window_width - width * scale) / 2.0),
+                @intFromFloat((window_height - height * scale) / 2.0),
+                @intFromFloat(width * scale),
+                @intFromFloat(height * scale),
             );
         }
 
@@ -163,7 +180,6 @@ pub const WindowOutput = struct {
         const userptr = c.glfwGetWindowUserPointer(win).?;
         const self = @as(*WindowOutput, @ptrCast(@alignCast(userptr)));
 
-        _ = self;
         _ = scancode;
         _ = mods;
 
@@ -171,6 +187,16 @@ pub const WindowOutput = struct {
             //        c.GLFW_KEY_F => // toggle fullscreen
             //        c.GLFW_KEY_LEFT => // cycle through monitors
             //        c.GLFW_KEY_RIGHT => // cycle through monitors
+            c.GLFW_KEY_C => {
+                self.resized = true;
+                self.crop = switch (self.crop) {
+                    .contain => .cover,
+                    .cover => .center,
+                    .center => .natural,
+                    .natural => .contain,
+                };
+                std.debug.print("crop mode: {}\n", .{self.crop});
+            },
             else => {},
         }
     }