Suppress "dead_code" warning in math3d.rs

TODO: "Vertex buffers: Staging buffer"
https://vulkan-tutorial.com/Vertex_buffers/Staging_buffer

shaders/shader.vert

@@ -1,20 +1,11 @@
 #version 450
 
+layout(location = 0) in vec2 inPosition;
+layout(location = 1) in vec3 inColor;
+
 layout(location = 0) out vec3 fragColor;
 
-vec2 positions[3] = vec2[](
-    vec2( 0.0, -0.5),
-    vec2( 0.5,  0.5),
-    vec2(-0.5,  0.5)
-);
-
-vec3 colors[3] = vec3[](
-    vec3(1.0, 0.0, 0.0),
-    vec3(0.0, 1.0, 0.0),
-    vec3(0.0, 0.0, 1.0)
-);
-
 void main() {
-    gl_Position = vec4(positions[gl_VertexIndex], 0.0, 1.0);
+    gl_Position = vec4(inPosition, 0.0, 1.0);
-    fragColor = colors[gl_VertexIndex];
+    fragColor = inColor;
 }

src/main.rs

@@ -1,8 +1,11 @@
 mod ffi;
+mod math3d;
 
 use std::collections::HashSet;
 use std::ffi::{c_void, CStr, CString};
 
+use math3d::Vertex;
+
 const WINDOW_WIDTH: i32 = 800;
 const WINDOW_HEIGHT: i32 = 600;
 
@@ -22,6 +25,21 @@ const DYNAMIC_STATES: [ffi::VkDynamicState; 2] = [
 const DEVICE_EXTENSIONS: [*const i8; 1] =
     [ffi::VK_KHR_SWAPCHAIN_EXTENSION_NAME as *const u8 as *const i8];
 
+const VERTICES: [math3d::Vertex; 3] = [
+    math3d::Vertex {
+        pos: [0.0, -0.5],
+        color: [1.0, 0.0, 0.0],
+    },
+    math3d::Vertex {
+        pos: [0.5, 0.5],
+        color: [0.0, 1.0, 0.0],
+    },
+    math3d::Vertex {
+        pos: [-0.5, 0.5],
+        color: [0.0, 0.0, 1.0],
+    },
+];
+
 fn check_validation_layer_support() -> bool {
     let mut layer_count: u32 = 0;
     unsafe {
@@ -188,6 +206,8 @@ struct VulkanApp {
     render_finished_semaphore: ffi::VkSemaphore,
     in_flight_fence: ffi::VkFence,
     framebuffer_resized: bool,
+    vertex_buffer: ffi::VkBuffer,
+    vertex_buffer_memory: ffi::VkDeviceMemory,
 }
 
 impl VulkanApp {
@@ -216,6 +236,8 @@ impl VulkanApp {
             render_finished_semaphore: std::ptr::null_mut(),
             in_flight_fence: std::ptr::null_mut(),
             framebuffer_resized: false,
+            vertex_buffer: std::ptr::null_mut(),
+            vertex_buffer_memory: std::ptr::null_mut(),
         }
     }
 
@@ -259,6 +281,7 @@ impl VulkanApp {
             .expect("Should be able to set up graphics pipeline");
         self.create_framebuffers().unwrap();
         self.create_command_pool().unwrap();
+        self.create_vertex_buffer().unwrap();
         self.create_command_buffer().unwrap();
         self.create_sync_objects().unwrap();
     }
@@ -926,7 +949,19 @@ impl VulkanApp {
         let shader_stages: [ffi::VkPipelineShaderStageCreateInfo; 2] =
             [vert_shader_stage_info, frag_shader_stage_info];
 
-        let vertex_input_info = Self::create_vertex_input_state_info_struct();
+        let mut vertex_input_info: ffi::VkPipelineVertexInputStateCreateInfo =
+            unsafe { std::mem::zeroed() };
+        vertex_input_info.sType =
+            ffi::VkStructureType_VK_STRUCTURE_TYPE_PIPELINE_VERTEX_INPUT_STATE_CREATE_INFO;
+
+        let bind_desc = Vertex::get_binding_description();
+        let attr_descs = Vertex::get_attribute_descriptions();
+
+        vertex_input_info.vertexBindingDescriptionCount = 1;
+        vertex_input_info.vertexAttributeDescriptionCount = attr_descs.len() as u32;
+
+        vertex_input_info.pVertexBindingDescriptions = std::ptr::addr_of!(bind_desc);
+        vertex_input_info.pVertexAttributeDescriptions = attr_descs.as_ptr();
 
         let mut input_assembly: ffi::VkPipelineInputAssemblyStateCreateInfo =
             unsafe { std::mem::zeroed() };
@@ -1074,19 +1109,6 @@ impl VulkanApp {
         dynamic_state
     }
 
-    fn create_vertex_input_state_info_struct() -> ffi::VkPipelineVertexInputStateCreateInfo {
-        let mut vertex_input_info: ffi::VkPipelineVertexInputStateCreateInfo =
-            unsafe { std::mem::zeroed() };
-        vertex_input_info.sType =
-            ffi::VkStructureType_VK_STRUCTURE_TYPE_PIPELINE_VERTEX_INPUT_STATE_CREATE_INFO;
-        vertex_input_info.vertexBindingDescriptionCount = 0;
-        vertex_input_info.pVertexBindingDescriptions = std::ptr::null();
-        vertex_input_info.vertexAttributeDescriptionCount = 0;
-        vertex_input_info.pVertexBindingDescriptions = std::ptr::null();
-
-        vertex_input_info
-    }
-
     fn create_viewport(&self) -> ffi::VkViewport {
         let mut viewport: ffi::VkViewport = unsafe { std::mem::zeroed() };
         viewport.x = 0.0;
@@ -1377,6 +1399,17 @@ impl VulkanApp {
             );
         }
 
+        let offsets: [ffi::VkDeviceSize; 1] = [0];
+        unsafe {
+            ffi::vkCmdBindVertexBuffers(
+                command_buffer,
+                0,
+                1,
+                std::ptr::addr_of!(self.vertex_buffer),
+                offsets.as_ptr(),
+            );
+        }
+
         let viewport = self.create_viewport();
 
         unsafe {
@@ -1387,7 +1420,7 @@ impl VulkanApp {
 
         unsafe {
             ffi::vkCmdSetScissor(command_buffer, 0, 1, std::ptr::addr_of!(scissor));
-            ffi::vkCmdDraw(command_buffer, 3, 1, 0, 0);
+            ffi::vkCmdDraw(command_buffer, VERTICES.len() as u32, 1, 0, 0);
             ffi::vkCmdEndRenderPass(command_buffer);
 
             if ffi::vkEndCommandBuffer(command_buffer) != ffi::VkResult_VK_SUCCESS {
@@ -1583,12 +1616,138 @@ impl VulkanApp {
     pub fn set_resize_flag(&mut self) {
         self.framebuffer_resized = true;
     }
+
+    fn create_vertex_buffer(&mut self) -> Result<(), String> {
+        let mut buffer_info: ffi::VkBufferCreateInfo = unsafe { std::mem::zeroed() };
+
+        buffer_info.sType = ffi::VkStructureType_VK_STRUCTURE_TYPE_BUFFER_CREATE_INFO;
+        buffer_info.size = (std::mem::size_of::<math3d::Vertex>() * VERTICES.len()) as u64;
+        buffer_info.usage = ffi::VkBufferUsageFlagBits_VK_BUFFER_USAGE_VERTEX_BUFFER_BIT;
+        buffer_info.sharingMode = ffi::VkSharingMode_VK_SHARING_MODE_EXCLUSIVE;
+
+        let result = unsafe {
+            ffi::vkCreateBuffer(
+                self.device,
+                std::ptr::addr_of!(buffer_info),
+                std::ptr::null(),
+                std::ptr::addr_of_mut!(self.vertex_buffer),
+            )
+        };
+        if result != ffi::VkResult_VK_SUCCESS {
+            return Err(String::from("Failed to create vertex buffer!"));
+        }
+
+        let mut mem_reqs: ffi::VkMemoryRequirements = unsafe { std::mem::zeroed() };
+        unsafe {
+            ffi::vkGetBufferMemoryRequirements(
+                self.device,
+                self.vertex_buffer,
+                std::ptr::addr_of_mut!(mem_reqs),
+            );
+        }
+
+        let mut alloc_info: ffi::VkMemoryAllocateInfo = unsafe { std::mem::zeroed() };
+        alloc_info.sType = ffi::VkStructureType_VK_STRUCTURE_TYPE_MEMORY_ALLOCATE_INFO;
+        alloc_info.allocationSize = mem_reqs.size;
+        alloc_info.memoryTypeIndex = self.find_memory_type(
+            mem_reqs.memoryTypeBits,
+            ffi::VkMemoryPropertyFlagBits_VK_MEMORY_PROPERTY_HOST_VISIBLE_BIT
+                | ffi::VkMemoryPropertyFlagBits_VK_MEMORY_PROPERTY_HOST_COHERENT_BIT,
+        )?;
+
+        let result = unsafe {
+            ffi::vkAllocateMemory(
+                self.device,
+                std::ptr::addr_of!(alloc_info),
+                std::ptr::null(),
+                std::ptr::addr_of_mut!(self.vertex_buffer_memory),
+            )
+        };
+        if result != ffi::VkResult_VK_SUCCESS {
+            return Err(String::from("Failed to allocate vertex buffer memory!"));
+        }
+
+        unsafe {
+            ffi::vkBindBufferMemory(
+                self.device,
+                self.vertex_buffer,
+                self.vertex_buffer_memory,
+                0,
+            );
+        }
+
+        let mut data_ptr: *mut c_void = unsafe { std::mem::zeroed() };
+        unsafe {
+            ffi::vkMapMemory(
+                self.device,
+                self.vertex_buffer_memory,
+                0,
+                buffer_info.size,
+                0,
+                std::ptr::addr_of_mut!(data_ptr),
+            );
+        }
+
+        {
+            let data_ptr_vertices: &mut [math3d::Vertex; 3] =
+                unsafe { std::mem::transmute(data_ptr) };
+            *data_ptr_vertices = VERTICES;
+        }
+
+        unsafe {
+            ffi::vkUnmapMemory(self.device, self.vertex_buffer_memory);
+        }
+
+        Ok(())
+    }
+
+    fn find_memory_type(
+        &mut self,
+        type_filter: u32,
+        properties: ffi::VkMemoryPropertyFlags,
+    ) -> Result<u32, String> {
+        if self.physical_device.is_null() {
+            return Err(String::from(
+                "Cannot find memory type if physical_device is null!",
+            ));
+        }
+
+        let mut mem_props: ffi::VkPhysicalDeviceMemoryProperties = unsafe { std::mem::zeroed() };
+        unsafe {
+            ffi::vkGetPhysicalDeviceMemoryProperties(
+                self.physical_device,
+                std::ptr::addr_of_mut!(mem_props),
+            );
+        }
+
+        for idx in 0..mem_props.memoryTypeCount {
+            if (type_filter & (1 << idx)) != 0
+                && (mem_props.memoryTypes[idx as usize].propertyFlags & properties) == properties
+            {
+                return Ok(idx);
+            }
+        }
+
+        Err(String::from("Failed to find suitable memory type!"))
+    }
 }
 
 impl Drop for VulkanApp {
     fn drop(&mut self) {
         self.cleanup_swap_chain().unwrap();
 
+        if !self.vertex_buffer.is_null() {
+            unsafe {
+                ffi::vkDestroyBuffer(self.device, self.vertex_buffer, std::ptr::null());
+            }
+        }
+
+        if !self.vertex_buffer_memory.is_null() {
+            unsafe {
+                ffi::vkFreeMemory(self.device, self.vertex_buffer_memory, std::ptr::null());
+            }
+        }
+
         if !self.in_flight_fence.is_null() {
             unsafe {
                 ffi::vkDestroyFence(self.device, self.in_flight_fence, std::ptr::null());

src/math3d.rs

@@ -0,0 +1,116 @@
+use crate::ffi;
+
+#[repr(C)]
+#[derive(Copy, Clone, PartialEq, Debug)]
+pub struct Vertex {
+    pub pos: [f32; 2],
+    pub color: [f32; 3],
+}
+
+impl Default for Vertex {
+    fn default() -> Self {
+        Self {
+            pos: [0.0, 0.0],
+            color: [0.0, 0.0, 0.0],
+        }
+    }
+}
+
+#[allow(dead_code)]
+impl Vertex {
+    pub fn new(pos: [f32; 2], color: [f32; 3]) -> Self {
+        Self { pos, color }
+    }
+
+    pub fn pos_offset() -> usize {
+        0
+    }
+
+    pub fn color_offset() -> usize {
+        let mut offset = std::mem::size_of::<[f32; 2]>();
+        let alignment = std::mem::align_of::<[f32; 3]>();
+        while offset % alignment != 0 {
+            offset += 1;
+        }
+
+        offset
+    }
+
+    pub fn get_binding_description() -> ffi::VkVertexInputBindingDescription {
+        let mut bind_desc: ffi::VkVertexInputBindingDescription = unsafe { std::mem::zeroed() };
+
+        bind_desc.binding = 0;
+        bind_desc.stride = std::mem::size_of::<Self>() as u32;
+        bind_desc.inputRate = ffi::VkVertexInputRate_VK_VERTEX_INPUT_RATE_VERTEX;
+
+        bind_desc
+    }
+
+    pub fn get_attribute_descriptions() -> [ffi::VkVertexInputAttributeDescription; 2] {
+        let mut attr_descs: [ffi::VkVertexInputAttributeDescription; 2] =
+            unsafe { std::mem::zeroed() };
+
+        attr_descs[0].binding = 0;
+        attr_descs[0].location = 0;
+        attr_descs[0].format = ffi::VkFormat_VK_FORMAT_R32G32_SFLOAT;
+        attr_descs[0].offset = Self::pos_offset() as u32;
+
+        attr_descs[1].binding = 0;
+        attr_descs[1].location = 1;
+        attr_descs[1].format = ffi::VkFormat_VK_FORMAT_R32G32B32_SFLOAT;
+        attr_descs[1].offset = Self::color_offset() as u32;
+
+        attr_descs
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn offsets() {
+        let mut vertex = Vertex {
+            pos: [1.0, 2.0],
+            color: [3.0, 4.0, 5.0],
+        };
+
+        let root_ptr: *const f32 = &vertex as *const Vertex as *const f32;
+
+        let pos_offset = Vertex::pos_offset();
+        assert!(pos_offset + 4 <= std::mem::size_of::<Vertex>());
+
+        let pos_0_ptr = unsafe { root_ptr.byte_add(pos_offset) };
+        assert_eq!(unsafe { *pos_0_ptr }, vertex.pos[0]);
+
+        assert!(pos_offset + 8 <= std::mem::size_of::<Vertex>());
+        let pos_1_ptr = unsafe { root_ptr.byte_add(pos_offset + 4) };
+        assert_eq!(unsafe { *pos_1_ptr }, vertex.pos[1]);
+
+        let color_offset = Vertex::color_offset();
+        assert!(color_offset + 4 <= std::mem::size_of::<Vertex>());
+
+        let col_0_ptr = unsafe { root_ptr.byte_add(color_offset) };
+        assert_eq!(unsafe { *col_0_ptr }, vertex.color[0]);
+
+        assert!(color_offset + 8 <= std::mem::size_of::<Vertex>());
+        let col_1_ptr = unsafe { root_ptr.byte_add(color_offset + 4) };
+        assert_eq!(unsafe { *col_1_ptr }, vertex.color[1]);
+
+        assert!(color_offset + 12 <= std::mem::size_of::<Vertex>());
+        let col_2_ptr = unsafe { root_ptr.byte_add(color_offset + 8) };
+        assert_eq!(unsafe { *col_2_ptr }, vertex.color[2]);
+
+        vertex.pos[0] = 0.123;
+        vertex.pos[1] = 0.456;
+        vertex.color[0] = 0.789;
+        vertex.color[1] = 1.234;
+        vertex.color[2] = 1.567;
+
+        assert_eq!(unsafe { *pos_0_ptr }, vertex.pos[0]);
+        assert_eq!(unsafe { *pos_1_ptr }, vertex.pos[1]);
+        assert_eq!(unsafe { *col_0_ptr }, vertex.color[0]);
+        assert_eq!(unsafe { *col_1_ptr }, vertex.color[1]);
+        assert_eq!(unsafe { *col_2_ptr }, vertex.color[2]);
+    }
+}