Fully implemented lighting

Two types of light sources are currently supported: directional lights
and point lights. A scene can have only one directional light and up to
1024 point lights.

src/rendering/Device.zig

@@ -314,6 +314,11 @@ pub fn initShader(self: Self, comptime name: []const u8) !c.VkShaderModule {
     return shader_module;
 }
 
+pub fn pushConstant(self: Self, pipeline: vk.GraphicsPipeline, stage: u32, offset: u32, size: u32, data: [*c]u8, frame: usize) void {
+    _ = stage;
+    c.vkCmdPushConstants(self.command_buffers[frame], pipeline.layout, c.VK_SHADER_STAGE_FRAGMENT_BIT, offset, size, data);
+}
+
 pub fn deinitShader(self: Self, shader: c.VkShaderModule) void {
     c.vkDestroyShaderModule(self.handle, shader, null);
 }