From 6b8af9cf83851c075c6c9514b1deaa931c2b19a4 Mon Sep 17 00:00:00 2001
From: Thomas Guillermo Albers Raviola <thomas@thomaslabs.org>
Date: Fri, 16 Jan 2026 23:02:32 +0100
Subject: Initial commit

---
 09-september/tomcat/renderer/mesh.c | 146 ++++++++++++++++++++++++++++++++++++
 1 file changed, 146 insertions(+)
 create mode 100644 09-september/tomcat/renderer/mesh.c

(limited to '09-september/tomcat/renderer/mesh.c')

diff --git a/09-september/tomcat/renderer/mesh.c b/09-september/tomcat/renderer/mesh.c
new file mode 100644
index 0000000..7ef27dc
--- /dev/null
+++ b/09-september/tomcat/renderer/mesh.c
@@ -0,0 +1,146 @@
+#include <stdlib.h>
+#include <stddef.h>
+#include <string.h>
+
+#include "mesh.h"
+#include "renderer.h"
+
+#define NUM_ARRAY_ELEMENTS(a) sizeof(a) / sizeof(*a)
+
+Mesh *mesh_new(vertex_t* vertices, GLsizeiptr vertexBuffersize,
+               GLushort* indices, GLsizeiptr indexBuffersize)
+{
+    Mesh *mesh;
+    mesh = malloc( sizeof(Mesh) );
+    memset(mesh, 0, sizeof(Mesh) );
+
+    render.meshes[render.num_meshes] = mesh;
+    render.num_meshes += 1;
+
+    mesh->num_indices = ( indexBuffersize / sizeof(GLushort) );
+
+    glGenVertexArrays(1, &mesh->vao);
+    glGenBuffers(1, &mesh->vbo);
+    glGenBuffers(1, &mesh->ebo);
+
+    glBindVertexArray(mesh->vao);
+
+    glBindBuffer(GL_ARRAY_BUFFER, mesh->vbo);
+    glBufferData(GL_ARRAY_BUFFER, vertexBuffersize, vertices, GL_STATIC_DRAW);
+
+    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, mesh->ebo);
+    glBufferData(GL_ELEMENT_ARRAY_BUFFER, indexBuffersize, indices, GL_STATIC_DRAW);
+
+    glEnableVertexAttribArray(0);
+    glEnableVertexAttribArray(1);
+    glEnableVertexAttribArray(2);
+    glEnableVertexAttribArray(3);
+
+    glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, sizeof(vertex_t), (const void*)offsetof(vertex_t, position) );
+    glVertexAttribPointer(1, 2, GL_FLOAT, GL_FALSE, sizeof(vertex_t), (const void*)offsetof(vertex_t, texCoord) );
+    glVertexAttribPointer(2, 3, GL_FLOAT, GL_FALSE, sizeof(vertex_t), (const void*)offsetof(vertex_t, normal) );
+    glVertexAttribPointer(3, 3, GL_FLOAT, GL_FALSE, sizeof(vertex_t), (const void*)offsetof(vertex_t, tangent) );
+
+    glBindVertexArray(0);
+    return mesh;
+}
+
+Mesh *mesh_make_skybox(float size)
+{
+    Mesh *mesh;
+    mesh = malloc( sizeof(Mesh) );
+    memset(mesh, 0, sizeof(Mesh) );
+
+    render.meshes[render.num_meshes] = mesh;
+    render.num_meshes += 1;
+
+    Vec3 positions[] =
+    {
+        {-size,  size, -size}, {-size, -size, -size}, {+size, -size, -size},
+        {+size, -size, -size}, {+size, +size, -size}, {-size, +size, -size},
+
+	    {-size, -size, +size}, {-size, -size, -size}, {-size, +size, -size},
+	    {-size, +size, -size}, {-size, +size, +size}, {-size, -size, +size},
+
+        {+size, -size, -size}, {+size, -size, +size}, {+size, +size, +size},
+	    {+size, +size, +size}, {+size, +size, -size}, {+size, -size, -size},
+
+	    {-size, -size, +size}, {-size, +size, +size}, {+size, +size, +size},
+	    {+size, +size, +size}, {+size, -size, +size}, {-size, -size, +size},
+
+	    {-size, +size, -size}, {+size, +size, -size}, {+size, +size, +size},
+	    {+size, +size, +size}, {-size, +size, +size}, {-size, +size, -size},
+
+	    {-size, -size, -size}, {-size, -size, +size}, {+size, -size, -size},
+	    {+size, -size, -size}, {-size, -size, +size}, {+size, -size, +size}
+	};
+
+    mesh->num_indices = 0;
+    mesh->num_vertices = NUM_ARRAY_ELEMENTS(positions);
+
+    glGenVertexArrays(1, &mesh->vao);
+    glGenBuffers(1, &mesh->vbo);
+    mesh->ebo = 0;
+
+    glBindVertexArray(mesh->vao);
+
+    glBindBuffer(GL_ARRAY_BUFFER, mesh->vbo);
+    glBufferData(GL_ARRAY_BUFFER, sizeof(positions), positions, GL_STATIC_DRAW);
+
+    glEnableVertexAttribArray(0);
+
+    glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 0, 0 );
+
+    glBindVertexArray(0);
+    return mesh;
+}
+
+Mesh *mesh_make_quad()
+{
+    Mesh *mesh;
+    mesh = malloc( sizeof(Mesh) );
+    memset(mesh, 0, sizeof(Mesh) );
+
+    render.meshes[render.num_meshes] = mesh;
+    render.num_meshes += 1;
+
+    Vec3 positions[] =
+    {
+        { -0.5f, +0.5f, +0.0f}, { -0.5f, -0.5f, +0.0f},
+        { +0.5f, +0.5f, +0.0f}, { +0.5f, -0.5f, +0.0f}
+    };
+
+    mesh->num_vertices = NUM_ARRAY_ELEMENTS(positions);
+    mesh->num_indices = 0;
+
+    glGenVertexArrays(1, &mesh->vao);
+    glGenBuffers(1, &mesh->vbo);
+    mesh->ebo = 0;
+
+    glBindVertexArray(mesh->vao);
+
+    glBindBuffer(GL_ARRAY_BUFFER, mesh->vbo);
+    glBufferData(GL_ARRAY_BUFFER, sizeof(positions), positions, GL_STATIC_DRAW);
+
+    glEnableVertexAttribArray(0);
+
+    glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 0, 0 );
+
+    glBindVertexArray(0);
+    return mesh;
+}
+
+void mesh_purge(Mesh *mesh)
+{
+    if(mesh)
+    {
+        if(mesh->vbo)
+            glDeleteBuffers(1, &mesh->vbo);
+        if(mesh->ebo)
+            glDeleteBuffers(1, &mesh->ebo);
+        if(mesh->vao)
+            glDeleteVertexArrays(1, &mesh->vao);
+
+        memset(mesh, 0, sizeof(Mesh));
+    }
+}
-- 
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