From 341826e9a2b89713fc47ffbc914d18e23c7d9287 Mon Sep 17 00:00:00 2001
From: HampusM <hampus@hampusmat.com>
Date: Thu, 12 Oct 2023 21:29:36 +0200
Subject: feat(engine): add vertex coloring

---
 engine/src/renderer/vertex_array.rs | 51 +++++++++++++++++++++++++++++++++++++
 1 file changed, 51 insertions(+)

(limited to 'engine/src/renderer/vertex_array.rs')

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
-- 
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