Automatically calculate draw_texture scale from image resolution by default (closes #65)

build.zig

@@ -12,29 +12,29 @@ const Project = struct {
 	optimize: std.builtin.OptimizeMode,
 	imports: ImportList,
 
-	pub fn demos_step(self: *const Project, b: *std.Build) *std.Build.Step {
-		const Demos = struct {
-			step: std.Build.Step,
-			project: *const Project,
-
-			const Self = @This();
-
-			fn make(step: *std.Build.Step, _: std.Progress.Node) anyerror!void {
-				const demos: *const Self = @fieldParentPtr("step", step);
+	pub fn find_demos(self: Project, step: *std.Build.Step) void {
 		const absolute_path = step.owner.path("demos/").getPath(step.owner);
-				var dir = try std.fs.openDirAbsolute(absolute_path, .{.iterate = true});
+
+		var dir = std.fs.openDirAbsolute(absolute_path, .{.iterate = true}) catch |open_error| {
+			std.log.warn("failed to open demos directory at {s} with error {s}, skipping...", .{
+				absolute_path,
+				@errorName(open_error),
+			});
+
+			return;
+		};
 
 		defer {
 			dir.close();
 		}
 
-				var entries = try dir.walk(step.owner.allocator);
+		var entries = dir.walk(step.owner.allocator) catch @panic("OOM");
 
 		defer {
 			entries.deinit();
 		}
 
-				while (try entries.next()) |entry| {
+		while (entries.next() catch @panic("I/O failure")) |entry| {
 			if (entry.kind != .file or !std.mem.endsWith(u8, entry.path, ".zig")) {
 				continue;
 			}
@@ -43,46 +43,30 @@ const Project = struct {
 			var path_buffer = [_:0]u8{0} ** 255;
 
 			const demo = step.owner.addExecutable(.{
-						.name = try std.fmt.bufPrint(&path_buffer, "{s}.out", .{std.fs.path.stem(entry.basename)}),
+				.name = std.fmt.bufPrint(&path_buffer, "{s}.out", .{std.fs.path.stem(entry.basename)}) catch {
+					@panic("a demo file name is too long");
+				},
+
 				.root_source_file = step.owner.path(source_path),
-						.target = demos.project.target,
-						.optimize = demos.project.optimize,
+				.target = self.target,
+				.optimize = self.optimize,
 			});
 
-					for (demos.project.imports.items) |import| {
+			for (self.imports.items) |import| {
 				demo.root_module.addImport(import.name, import.module);
 			}
 
-					step.owner.installArtifact(demo);
+			step.dependOn(&step.owner.addInstallArtifact(demo, .{
+				.dest_dir = .{
+					.override = .{.custom = "../demos"},
+				},
+			}).step);
+		}
 	}
 
-				step.state = .success;
-			}
-		};
-
-		const demos = b.allocator.create(Demos) catch {
-			@panic("OOM");
-		};
-
-		demos.* = .{
-			.step = std.Build.Step.init(.{
-				.id = .custom,
-				.name = "demos",
-				.makeFn = Demos.make,
-				.owner = b,
-			}),
-
-			.project = self,
-		};
-
-		return &demos.step;
-	}
-
-	pub fn find_tests(self: Project, b: *std.Build) !void {
-		const tests = b.step("tests", "Build and run tests");
-
+	pub fn find_tests(self: Project, step: *std.Build.Step) void {
 		for (self.imports.items) |import| {
-			tests.dependOn(&b.addRunArtifact(b.addTest(.{
+			step.dependOn(&step.owner.addRunArtifact(step.owner.addTest(.{
 				.root_source_file = import.module.root_source_file.?,
 				.target = self.target,
 				.optimize = self.optimize,
@@ -177,11 +161,7 @@ const Project = struct {
 };
 
 pub fn build(b: *std.Build) !void {
-	const project = b.allocator.create(Project) catch {
-		@panic("OOM");
-	};
-
-	project.* = .{
+	var project = Project{
 		.imports = ImportList.init(b.allocator),
 		.target = b.standardTargetOptions(.{}),
 		.optimize = b.standardOptimizeOption(.{}),
@@ -274,7 +254,6 @@ pub fn build(b: *std.Build) !void {
 
 	gfx_module.link_libc = true;
 
-	b.step("demos", "Build demos").dependOn(project.demos_step(b));
-
-	try project.find_tests(b);
+	project.find_demos(b.step("demos", "Build demos"));
+	project.find_tests(b.step("tests", "Build and run tests"));
 }

demos/effects.zig

@@ -50,15 +50,14 @@ fn render(commands: gfx.Commands, effects: ona.Write(Effects), app: ona.Read(ona
 	const display_width: f32 = @floatFromInt(display.state.width);
 	const display_height: f32 = @floatFromInt(display.state.height);
 
-	const display_transform = gfx.Transform2D{
-		.origin = .{display_width / 2, display_height / 2},
-		.xbasis = .{display_width, 0},
-		.ybasis = .{0, display_height},
-	};
+	const display_transform = gfx.transform_2d(.{
+		.translation = .{display_width / 2, display_height / 2},
+	});
 
 	try commands.draw_texture(.{
 		.texture = .default,
 		.transform = display_transform,
+		.resolution = .{display.state.width, display.state.height},
 	});
 
 	try commands.set_effect(.{
@@ -72,7 +71,6 @@ fn render(commands: gfx.Commands, effects: ona.Write(Effects), app: ona.Read(ona
 	});
 
 	try commands.set_target(.{
-		.texture = null,
 		.clear_color = null,
 		.clear_depth = null,
 		.clear_stencil = null,

demos/inputs.zig

@@ -48,7 +48,7 @@ fn update(visuals: ona.Write(Visuals), events: ona.Receive(hid.Event), display:
 	const random = visuals.state.random.random();
 	const width: f32 = @floatFromInt(display.state.width);
 	const height: f32 = @floatFromInt(display.state.height);
-	const icon_scale = .{64, 64};
+	const icon_scale = .{8, 8};
 
 	for (events.messages()) |event| {
 		switch (event) {
@@ -56,7 +56,7 @@ fn update(visuals: ona.Write(Visuals), events: ona.Receive(hid.Event), display:
 				try visuals.state.spawned_keyboards.push_grow(.{
 					.lifetime_seconds = 2.5 + (5 * random.float(f32)),
 
-					.transform = gfx.Transform2D.from_simplified(.{
+					.transform = gfx.transform_2d(.{
 						.translation = .{width * random.float(f32), height},
 						.rotation = std.math.pi * random.float(f32),
 						.scale = icon_scale,
@@ -68,7 +68,7 @@ fn update(visuals: ona.Write(Visuals), events: ona.Receive(hid.Event), display:
 				try visuals.state.spawned_mouses.push_grow(.{
 					.lifetime_seconds = 2.5 + (5 * random.float(f32)),
 
-					.transform = gfx.Transform2D.from_simplified(.{
+					.transform = gfx.transform_2d(.{
 						.translation = visuals.state.mouse_position,
 						.rotation = std.math.pi * random.float(f32),
 						.scale = icon_scale,

src/gfx/gfx.zig

@@ -178,6 +178,7 @@ pub const Commands = struct {
 	pub const DrawTextureCommand = struct {
 		texture: Texture,
 		transform: Transform2D,
+		resolution: ?@Vector(2, u16) = null,
 	};
 
 	pub const SetEffectCommand = struct {
@@ -357,13 +358,34 @@ pub const Transform2D = extern struct {
 
 	pub const Vector = @Vector(2, f32);
 
-	pub fn from_simplified(simplified: Simplified) Transform2D {
-		const rotation_skew = simplified.rotation + simplified.skew;
+	pub fn scaled(self: Transform2D, scale: Vector) Transform2D {
+		var transform = self;
+		const scale_x, const scale_y = scale;
+
+		transform.xbasis *= @splat(scale_x);
+        transform.ybasis *= @splat(scale_y);
+
+		return transform;
+	}
+
+	pub fn transformed(self: Transform2D, other: Transform2D) Transform2D {
+		const xbasis_x, const xbasis_y = other.xbasis;
+		const ybasis_x, const ybasis_y = other.ybasis;
+		const origin_x, const origin_y = other.origin;
 
 		return .{
-			.xbasis = simplified.scale * Vector{std.math.cos(simplified.rotation), std.math.sin(simplified.rotation)},
-			.ybasis = simplified.scale * Vector{-std.math.sin(rotation_skew), std.math.cos(rotation_skew)},
-			.origin = simplified.translation,
+			.xbasis =
+				(self.xbasis * @as(Vector, @splat(xbasis_x))) +
+				(self.ybasis * @as(Vector, @splat(xbasis_y))),
+
+			.ybasis =
+				(self.xbasis * @as(Vector, @splat(ybasis_x))) +
+				(self.ybasis * @as(Vector, @splat(ybasis_y))),
+
+			.origin =
+				(self.xbasis * @as(Vector, @splat(origin_x))) +
+				(self.ybasis * @as(Vector, @splat(origin_y))) +
+				self.origin,
 		};
 	}
 
@@ -586,3 +608,21 @@ pub fn synchronize(exclusive: ona.Exclusive(&.{Assets, Display})) !void {
 		assets.frame_rendered.set();
 	}
 }
+
+pub fn transform_2d(simplified: Transform2D.Simplified) Transform2D {
+	const rotation_skew = simplified.rotation + simplified.skew;
+
+	return .{
+		.xbasis = simplified.scale * Transform2D.Vector{
+			std.math.cos(simplified.rotation),
+			std.math.sin(simplified.rotation),
+		},
+
+		.ybasis = simplified.scale * Transform2D.Vector{
+			-std.math.sin(rotation_skew),
+			std.math.cos(rotation_skew),
+		},
+
+		.origin = simplified.translation,
+	};
+}

src/gfx/rendering.zig

@@ -96,8 +96,13 @@ const Frame = struct {
 			try self.texture_batch_buffers.push_grow(instance_buffer);
 		}
 
+		const texture = resources.get_texture(command.texture).?;
+
 		_ = sokol.gfx.appendBuffer(self.texture_batch_buffers.get().?.*, sokol.gfx.asRange(&DrawTexture{
-			.transform = command.transform,
+			.transform = command.transform.scaled(@floatFromInt(command.resolution orelse .{
+				texture.width,
+				texture.height,
+			})),
 		}));
 
 		self.drawn_count += 1;

src/gfx/shaders/2d_default.vert

@@ -8,7 +8,7 @@ layout (location = 3) in vec2 instance_ybasis;
 layout (location = 4) in vec2 instance_origin;
 layout (location = 5) in vec4 instance_tint;
 layout (location = 6) in float instance_depth;
-layout (location = 7) in vec4 instance_rect;
+layout (location = 7) in vec4 instance_clip;
 
 layout (location = 0) out vec4 color;
 layout (location = 1) out vec2 uv;
@@ -20,10 +20,10 @@ layout (binding = 0) uniform View {
 void main() {
 	const vec2 world_position = instance_origin + mesh_xy.x * instance_xbasis + mesh_xy.y * instance_ybasis;
 	const vec2 projected_position = (projection_matrix * vec4(world_position, 0, 1)).xy;
-	const vec2 rect_size = instance_rect.zw - instance_rect.xy;
+	const vec2 rect_size = instance_clip.zw - instance_clip.xy;
 	const vec4 screen_position = vec4(projected_position, instance_depth, 1.0);
 
 	gl_Position = screen_position;
 	color = instance_tint;
-	uv = instance_rect.xy + (mesh_uv * rect_size);
+	uv = instance_clip.xy + (mesh_uv * rect_size);
 }