feat(engine): add vertex coloring

10 files changed, 190 insertions, 36 deletions

diff --git a/engine/fragment.glsl b/engine/fragment.glsl
index 0c56a32..8b209c4 100644
--- a/engine/fragment.glsl
+++ b/engine/fragment.glsl
@@ -1,7 +1,9 @@
 #version 330 core
 out vec4 FragColor;
 
+in vec3 in_frag_color;
+
 void main()
 {
-    FragColor = vec4(1.0f, 0.5f, 0.2f, 1.0f);
+	FragColor = vec4(in_frag_color, 1.0);
 }
diff --git a/engine/src/color.rs b/engine/src/color.rs
new file mode 100644
index 0000000..339b427
--- /dev/null
+++ b/engine/src/color.rs
@@ -0,0 +1,8 @@
+#[derive(Debug, Clone)]
+#[repr(C)]
+pub struct Color<Value>
+{
+    pub red: Value,
+    pub green: Value,
+    pub blue: Value,
+}
diff --git a/engine/src/lib.rs b/engine/src/lib.rs
index ebb635f..b93a0bb 100644
--- a/engine/src/lib.rs
+++ b/engine/src/lib.rs
@@ -9,8 +9,10 @@ use crate::vector::Vec2;
 mod renderer;
 mod shader;
 
+pub mod color;
 pub mod object;
 pub mod vector;
+pub mod vertex;
 
 #[derive(Debug)]
 pub struct Engine
diff --git a/engine/src/object.rs b/engine/src/object.rs
index d1ac859..6b4bf4e 100644
--- a/engine/src/object.rs
+++ b/engine/src/object.rs
@@ -1,5 +1,6 @@
 use crate::renderer::Renderable;
 use crate::shader::{Kind as ShaderKind, Program as ShaderProgram, Shader};
+use crate::vertex::Vertex;
 
 #[derive(Debug)]
 pub struct Object
@@ -13,7 +14,7 @@ impl Object
     ///
     /// # Errors
     /// Will return `Err` if shader creation fails or if shader program linking fails.
-    pub fn new(vertices: &[f32]) -> Result<Self, Error>
+    pub fn new(vertices: &[Vertex]) -> Result<Self, Error>
     {
         let vertex_shader = Shader::new(ShaderKind::Vertex);
 
diff --git a/engine/src/renderer/mod.rs b/engine/src/renderer/mod.rs
index 13091fd..bbcb5e9 100644
--- a/engine/src/renderer/mod.rs
+++ b/engine/src/renderer/mod.rs
@@ -1,13 +1,12 @@
-use std::ffi::{c_float, c_void, CString};
-use std::mem::size_of;
+use std::ffi::{c_void, CString};
 use std::process::abort;
-use std::ptr::null;
 
 use glfw::WindowSize;
 
 use crate::renderer::vertex_array::{PrimitiveKind, VertexArray};
 use crate::renderer::vertex_buffers::{BufferUsage, VertexBuffers};
 use crate::vector::Vec2;
+use crate::vertex::Vertex;
 
 mod vertex_array;
 mod vertex_buffers;
@@ -62,7 +61,7 @@ pub struct Renderable
 
 impl Renderable
 {
-    pub fn new(shader_program: crate::shader::Program, vertices: &[f32]) -> Self
+    pub fn new(shader_program: crate::shader::Program, vertices: &[Vertex]) -> Self
     {
         let vertex_arr = VertexArray::new();
 
@@ -74,8 +73,7 @@ impl Renderable
             .store(0, vertices, BufferUsage::Static)
             .unwrap();
 
-        vertex_attrib_ptr(0);
-        enable_vertex_attrib_array(0);
+        VertexArray::configure_attrs();
 
         Self {
             shader_program,
@@ -105,28 +103,3 @@ pub enum Error
     #[error("Failed to get window size")]
     GetWindowSizeFailed(#[source] glfw::Error),
 }
-
-fn vertex_attrib_ptr(index: usize)
-{
-    let stride = 3 * size_of::<c_float>();
-
-    unsafe {
-        #[allow(clippy::cast_possible_wrap, clippy::cast_possible_truncation)]
-        gl::VertexAttribPointer(
-            index as gl::types::GLuint,
-            3,
-            gl::FLOAT,
-            gl::FALSE,
-            stride as gl::types::GLsizei,
-            null(),
-        );
-    }
-}
-
-fn enable_vertex_attrib_array(index: usize)
-{
-    unsafe {
-        #[allow(clippy::cast_possible_truncation)]
-        gl::EnableVertexAttribArray(index as gl::types::GLuint);
-    }
-}
diff --git a/engine/src/renderer/vertex_array.rs b/engine/src/renderer/vertex_array.rs
index 5862c7b..b0aac81 100644
--- a/engine/src/renderer/vertex_array.rs
+++ b/engine/src/renderer/vertex_array.rs
@@ -1,3 +1,9 @@
+use std::mem::size_of;
+
+use crate::vertex::{Attribute, AttributeComponentType, Vertex};
+
+const VERTEX_STRIDE: usize = size_of::<Vertex>();
+
 #[derive(Debug)]
 pub struct VertexArray
 {
@@ -31,10 +37,55 @@ impl VertexArray
         }
     }
 
+    pub fn configure_attrs()
+    {
+        let mut offset = 0;
+
+        for attr in Vertex::attrs() {
+            Self::vertex_attrib_ptr(attr, offset);
+
+            Self::enable_vertex_attrib_array(attr.index);
+
+            offset += attr.component_size * attr.component_cnt as usize;
+        }
+    }
+
     pub fn bind(&self)
     {
         unsafe { gl::BindVertexArray(self.array) }
     }
+
+    fn vertex_attrib_ptr(vertex_attr: &Attribute, offset: usize)
+    {
+        unsafe {
+            #[allow(clippy::cast_possible_wrap, clippy::cast_possible_truncation)]
+            gl::VertexAttribPointer(
+                vertex_attr.index as gl::types::GLuint,
+                vertex_attr.component_cnt as i32,
+                Self::vertex_attr_type_to_gl(&vertex_attr.component_type),
+                gl::FALSE,
+                VERTEX_STRIDE as gl::types::GLsizei,
+                offset as *const _,
+            );
+        }
+    }
+
+    fn enable_vertex_attrib_array(index: usize)
+    {
+        unsafe {
+            #[allow(clippy::cast_possible_truncation)]
+            gl::EnableVertexAttribArray(index as gl::types::GLuint);
+        }
+    }
+
+    fn vertex_attr_type_to_gl(
+        vertex_attr_type: &AttributeComponentType,
+    ) -> gl::types::GLenum
+    {
+        match vertex_attr_type {
+            AttributeComponentType::Float => gl::FLOAT,
+        }
+    }
 }
 
 impl Drop for VertexArray
diff --git a/engine/src/renderer/vertex_buffers.rs b/engine/src/renderer/vertex_buffers.rs
index bb988d9..e7cba91 100644
--- a/engine/src/renderer/vertex_buffers.rs
+++ b/engine/src/renderer/vertex_buffers.rs
@@ -1,5 +1,7 @@
 use std::mem::size_of_val;
 
+use crate::vertex::Vertex;
+
 #[derive(Debug)]
 pub struct VertexBuffers<const CNT: usize>
 {
@@ -23,7 +25,7 @@ impl<const CNT: usize> VertexBuffers<CNT>
     pub fn store(
         &self,
         buffer_index: usize,
-        vertices: &[f32],
+        vertices: &[Vertex],
         usage: BufferUsage,
     ) -> Option<()>
     {
diff --git a/engine/src/vector.rs b/engine/src/vector.rs
index 48550fa..ada64c4 100644
--- a/engine/src/vector.rs
+++ b/engine/src/vector.rs
@@ -9,3 +9,12 @@ impl Vec2<u32>
 {
     pub const ZERO: Self = Self { x: 0, y: 0 };
 }
+
+#[derive(Debug)]
+#[repr(C)]
+pub struct Vec3<Value>
+{
+    pub x: Value,
+    pub y: Value,
+    pub z: Value,
+}
diff --git a/engine/src/vertex.rs b/engine/src/vertex.rs
new file mode 100644
index 0000000..e03eacb
--- /dev/null
+++ b/engine/src/vertex.rs
@@ -0,0 +1,101 @@
+use std::mem::size_of;
+
+use crate::color::Color;
+use crate::vector::Vec3;
+
+#[derive(Debug)]
+#[repr(C)]
+pub struct Vertex
+{
+    pos: Vec3<f32>,
+    color: Color<f32>,
+}
+
+#[derive(Debug, Default)]
+pub struct Builder
+{
+    pos: Option<Vec3<f32>>,
+    color: Option<Color<f32>>,
+}
+
+impl Builder
+{
+    #[must_use]
+    pub fn new() -> Self
+    {
+        Self {
+            pos: None,
+            color: None,
+        }
+    }
+
+    #[must_use]
+    pub fn pos(mut self, pos: Vec3<f32>) -> Self
+    {
+        self.pos = Some(pos);
+
+        self
+    }
+
+    #[must_use]
+    pub fn color(mut self, color: Color<f32>) -> Self
+    {
+        self.color = Some(color);
+
+        self
+    }
+
+    #[must_use]
+    pub fn build(self) -> Option<Vertex>
+    {
+        let pos = self.pos?;
+        let color = self.color?;
+
+        Some(Vertex { pos, color })
+    }
+}
+
+impl Vertex
+{
+    pub(crate) fn attrs() -> &'static [Attribute]
+    {
+        &[
+            Attribute {
+                index: 0,
+                component_type: AttributeComponentType::Float,
+                component_cnt: AttributeComponentCnt::Three,
+                component_size: size_of::<f32>(),
+            },
+            Attribute {
+                index: 1,
+                component_type: AttributeComponentType::Float,
+                component_cnt: AttributeComponentCnt::Three,
+                component_size: size_of::<f32>(),
+            },
+        ]
+    }
+}
+
+pub(crate) struct Attribute
+{
+    pub(crate) index: usize,
+    pub(crate) component_type: AttributeComponentType,
+    pub(crate) component_cnt: AttributeComponentCnt,
+    pub(crate) component_size: usize,
+}
+
+pub(crate) enum AttributeComponentType
+{
+    Float,
+}
+
+#[derive(Debug, Clone, Copy)]
+#[repr(u32)]
+#[allow(dead_code)]
+pub(crate) enum AttributeComponentCnt
+{
+    One = 1,
+    Two = 2,
+    Three = 3,
+    Four = 4,
+}
diff --git a/engine/vertex.glsl b/engine/vertex.glsl
index c74ea10..37d5677 100644
--- a/engine/vertex.glsl
+++ b/engine/vertex.glsl
@@ -1,7 +1,12 @@
 #version 330 core
-layout (location = 0) in vec3 aPos;
+layout (location = 0) in vec3 pos;
+layout (location = 1) in vec3 color;
+
+out vec3 in_frag_color;
 
 void main()
 {
-    gl_Position = vec4(aPos.x, aPos.y, aPos.z, 1.0);
+    gl_Position = vec4(pos.x, pos.y, pos.z, 1.0);
+
+	in_frag_color = color;
 }