adding base descriptor set layout

src/vulkan/lib.zig

@@ -55,6 +55,44 @@ pub const DRIVER_NAME = "Unnamed Stroll Driver";
 /// Default Vulkan version
 pub const VULKAN_VERSION = vk.makeApiVersion(0, 1, 0, 0);
 
+/// Maximum number of descriptor sets per pipeline
+pub const VULKAN_MAX_DESCRIPTOR_SETS = 32;
+
+/// From the Vulkan 1.3.274 spec:
+///
+///    VUID-VkPipelineLayoutCreateInfo-pPushConstantRanges-00292
+///
+///    "Any two elements of pPushConstantRanges must not include the same
+///    stage in stageFlags"
+///
+/// and
+///
+///    VUID-VkPushConstantRange-stageFlags-requiredbitmask
+///
+///    "stageFlags must not be 0"
+///
+/// This means that the number of push constant ranges is effectively bounded
+/// by the number of possible shader stages.  Not the number of stages that can
+/// be compiled together (a pipeline layout can be used in multiple pipelnes
+/// wth different sets of shaders) but the total number of stage bits supported
+/// by the implementation.  Currently, those are
+///
+///    - VK_SHADER_STAGE_VERTEX_BIT
+///    - VK_SHADER_STAGE_TESSELLATION_CONTROL_BIT
+///    - VK_SHADER_STAGE_TESSELLATION_EVALUATION_BIT
+///    - VK_SHADER_STAGE_GEOMETRY_BIT
+///    - VK_SHADER_STAGE_FRAGMENT_BIT
+///    - VK_SHADER_STAGE_COMPUTE_BIT
+///    - VK_SHADER_STAGE_RAYGEN_BIT_KHR
+///    - VK_SHADER_STAGE_ANY_HIT_BIT_KHR
+///    - VK_SHADER_STAGE_CLOSEST_HIT_BIT_KHR
+///    - VK_SHADER_STAGE_MISS_BIT_KHR
+///    - VK_SHADER_STAGE_INTERSECTION_BIT_KHR
+///    - VK_SHADER_STAGE_CALLABLE_BIT_KHR
+///    - VK_SHADER_STAGE_TASK_BIT_EXT
+///    - VK_SHADER_STAGE_MESH_BIT_EXT
+pub const VULKAN_MAX_PUSH_CONSTANT_RANGES = 14;
+
 pub const std_options: std.Options = .{
     .log_level = .debug,
     .logFn = logger.log,