Reformat

.gitignore

@@ -1,6 +1,6 @@
 .cache
 compile_commands.json
-tiny
+/tiny
 *.pam
 resources/*.png
 .venv

src/constants.h

@@ -0,0 +1,7 @@
+#ifndef CONSTANTS_H
+#define CONSTANTS_H
+
+#define DEPTH_MAX 255
+#define TRIANGLE_VERTICES 3
+
+#endif // CONSTANTS_H

src/img/img.h

@@ -12,6 +12,8 @@
     TYPE *buf;                                                                 \
   } NAME
 
+#define BUF_SIZE(BUF) sizeof(*((BUF)->buf))
+
 typedef struct colour Colour;
 struct colour {
   u8 r;
@@ -24,14 +26,10 @@ BUF_TYPE(void, Buffer);
 BUF_TYPE(Colour, Image);
 BUF_TYPE(f32, Depth);
 
-#define init_buffer(ARENA, BUF)                                                \
-  _init_buffer(ARENA, (Buffer *)BUF, sizeof(*((BUF)->buf)))
-#define get_pixel(TYPE, BUF, X, Y)                                             \
-  (*((TYPE *)(_get_pixel((Buffer *)BUF, X, Y, sizeof(*((BUF)->buf))))))
-#define set_pixel(BUF, X, Y, VAL_PTR)                                          \
-  _set_pixel((Buffer *)BUF, X, Y, VAL_PTR, sizeof(*((BUF)->buf)))
-#define clear_buffer(BUF, VAL_PTR)                                             \
-  _clear_buffer((Buffer *)BUF, VAL_PTR, sizeof(*((BUF)->buf)))
+#define init_buffer(ARENA, BUF)       (_init_buffer(ARENA, (Buffer *)BUF, BUF_SIZE(BUF)))
+#define get_pixel(TYPE, BUF, X, Y)    (*((TYPE *)(_get_pixel((Buffer *)BUF, X, Y, BUF_SIZE(BUF)))))
+#define set_pixel(BUF, X, Y, VAL_PTR) (_set_pixel((Buffer *)BUF, X, Y, VAL_PTR, BUF_SIZE(BUF)))
+#define clear_buffer(BUF, VAL_PTR)    (_clear_buffer((Buffer *)BUF, VAL_PTR, BUF_SIZE(BUF)))
 
 bool _init_buffer(Arena *arena, Buffer *buffer, u64 base_size);
 u8 *_get_pixel(Buffer *buffer, u64 x, u64 y, u64 base_size);

src/main.c

@@ -1,58 +1,6 @@
-#include "img.h"
-#include "mem_arena.h"
-#include "misc_utils.h"
-#include "obj.h"
-#include "render.h"
-#include "shaders.h"
-#include <stdbool.h>
-#include <stdio.h>
-#include <string.h>
-#include <time.h>
+#include "aliases.h"
+#include "tiny.h"
 
-#define IMAGE_DIMENSION 1200
-#define RESOURCE(NAME) "resources/" NAME
-
-enum {
-  TINY_EXIT_SUCCESS,
-  TINY_EXIT_ARENA_INIT_FAILED,
-  TINY_EXIT_RENDER_INIT_FAILED,
-  TINY_EXIT_MODEL_LOAD_FAILED,
-};
-
-int main(void) {
-  Arena *arena = NULL;
-  if (!wapp_mem_arena_init(&arena, GB(10))) {
-    return TINY_EXIT_ARENA_INIT_FAILED;
-  }
-
-  Colour bg = {.r = 42, .g = 45, .b = 52, .a = 255};
-  Colour teal = {.r = 14, .g = 156, .b = 208, .a = 255};
-  Render render;
-  if (!init_render(arena, &render, IMAGE_DIMENSION, IMAGE_DIMENSION)) {
-    return TINY_EXIT_RENDER_INIT_FAILED;
-  }
-
-  Model obj = load_obj_file(arena, RESOURCE("head.obj"), RESOURCE("head.pnm"),
-                            RESOURCE("head_nm.pnm"));
-  if (IS_INVALID_MODEL(obj)) {
-    return TINY_EXIT_MODEL_LOAD_FAILED;
-  }
-
-  PhongMaterial material = {
-      .ambient = 0.3f,
-      .diffuse = 1.5f,
-      .specular = 2.0f,
-      .shininess = 1.5f,
-  };
-  obj.material = material;
-
-  load_shaders();
-
-  clear_buffer(&(render.img), &bg);
-  render_model(&obj, &render, perspective_phong, RENDER_TYPE_SHADED, teal);
-  save_image(&(render.img), "result.pam");
-
-  wapp_mem_arena_destroy(&arena);
-
-  return TINY_EXIT_SUCCESS;
+i32 main(i32 argc, char *argv[]) {
+  return tiny_main(argc, argv);
 }

src/model/obj.c

@@ -5,8 +5,7 @@
 #include "vec.h"
 #include <stdio.h>
 
-Model load_obj_file(Arena *arena, const char *filename, const char *texture,
-                    const char *normal_map) {
+Model load_obj_file(Arena *arena, const char *filename, const char *diffuse, const char *tangent) {
   if (!arena) {
     return INVALID_MODEL;
   }
@@ -22,8 +21,7 @@ Model load_obj_file(Arena *arena, const char *filename, const char *texture,
       .texture_coordinates = list_create(V2f, arena),
       .triangles           = list_create(Triangle, arena),
   };
-  if (!(model.vertices) || !(model.normals) || !(model.texture_coordinates) ||
-      !(model.triangles)) {
+  if (!(model.vertices) || !(model.normals) || !(model.texture_coordinates) || !(model.triangles)) {
     return INVALID_MODEL;
   }
 
@@ -59,8 +57,10 @@ Model load_obj_file(Arena *arena, const char *filename, const char *texture,
       coord.v = 1.0f - v;
       list_append(V2f, arena, model.texture_coordinates, coord);
     } else if (strncmp(identifier, "f", 8) == 0) {
-      sscanf(line + 2, "%lu/%lu/%lu %lu/%lu/%lu %lu/%lu/%lu", &fp0, &tx0, &vn0,
-             &fp1, &tx1, &vn1, &fp2, &tx2, &vn2);
+      sscanf(line + 2, "%lu/%lu/%lu %lu/%lu/%lu %lu/%lu/%lu",
+             &fp0, &tx0, &vn0,
+             &fp1, &tx1, &vn1,
+             &fp2, &tx2, &vn2);
       // OBJ indices start from 1
       triangle.p0  = fp0 - 1;
       triangle.p1  = fp1 - 1;
@@ -75,12 +75,12 @@ Model load_obj_file(Arena *arena, const char *filename, const char *texture,
     }
   }
 
-  if (texture) {
-    model.texture = load_p6_image(arena, texture);
+  if (diffuse) {
+    model.texture = load_p6_image(arena, diffuse);
   }
 
-  if (normal_map) {
-    model.normal = load_p6_image(arena, normal_map);
+  if (tangent) {
+    model.normal = load_p6_image(arena, tangent);
   }
 
   return model;

src/model/obj.h

@@ -2,6 +2,7 @@
 #define OBJ_H
 
 #include "aliases.h"
+#include "constants.h"
 #include "img.h"
 #include "mem_arena.h"
 #include "typed_list.h"
@@ -12,27 +13,34 @@
 
 typedef struct triangle Triangle;
 struct triangle {
+  union {
+    u64 positions[TRIANGLE_VERTICES];
+    struct {
       u64 p0;
       u64 p1;
       u64 p2;
+    };
+  };
+  union {
+    u64 normals[TRIANGLE_VERTICES];
+    struct {
       u64 n0;
       u64 n1;
       u64 n2;
+    };
+  };
+  union {
+    u64 coordinates[TRIANGLE_VERTICES];
+    struct {
       u64 tx0;
       u64 tx1;
       u64 tx2;
+    };
+  };
 };
 
 MAKE_LIST_TYPE(Triangle);
 
-typedef struct phong_material PhongMaterial;
-struct phong_material {
-  f32 specular;
-  f32 diffuse;
-  f32 ambient;
-  f32 shininess;
-};
-
 typedef struct point_light PointLight;
 struct point_light {
   V3f diffuse_intensity;
@@ -42,16 +50,14 @@ struct point_light {
 
 typedef struct model Model;
 struct model {
-  LIST_TYPE(V3f) * vertices;
-  LIST_TYPE(V3f) * normals;
-  LIST_TYPE(V2f) * texture_coordinates;
-  LIST_TYPE(Triangle) * triangles;
+  LIST_TYPE(V3f)      *vertices;
+  LIST_TYPE(V3f)      *normals;
+  LIST_TYPE(V2f)      *texture_coordinates;
+  LIST_TYPE(Triangle) *triangles;
   Image               *texture;
   Image               *normal;
-  PhongMaterial material;
 };
 
-Model load_obj_file(Arena *arena, const char *filename, const char *texture,
-                    const char *normal_map);
+Model load_obj_file(Arena *arena, const char *filename, const char *diffuse, const char *tangent);
 
 #endif // OBJ_H

src/model/render.c

@@ -1,11 +1,15 @@
 #include "render.h"
 #include "aliases.h"
+#include "constants.h"
+#include "img.h"
 #include "shader.h"
+#include "typed_list.h"
 #include "utils.h"
 #include "vec.h"
+#include <stdint.h>
 #include <math.h>
 
-#define TRIANGLE_VERTICES 3
+Render g_render_passes[COUNT_RENDER_PASS] = {0};
 
 typedef struct triangle_bbox TriangleBBox;
 struct triangle_bbox {
@@ -15,18 +19,13 @@ struct triangle_bbox {
   u64 y1;
 };
 
-internal void render_triangle(const Triangle *triangle, const Model *model,
-                              ShaderID shader, Render *render,
-                              RenderType render_type, Colour colour);
-internal void fill_triangle(Render *render, ShaderID shader,
-                            V3f vertices[TRIANGLE_VERTICES],
-                            V3f normals[TRIANGLE_VERTICES],
-                            V2f coordinates[TRIANGLE_VERTICES], Colour colour,
-                            const Model *model, RenderType type);
-internal TriangleBBox get_triangle_bbox(const Image *img,
-                                        V3f vertices[TRIANGLE_VERTICES]);
-internal V3f get_barycentric_coords(V3f a, V3f b, V3f c, V3f p);
-internal V3f get_viewport_vertex(const V3f *vertex, const Image *img);
+internal void         render_triangle(const Triangle *triangle, const Model *model, ShaderID shader,
+                                      Render *render, RenderType render_type, Colour colour);
+internal void         fill_triangle(Render *render, ShaderID shader, VertexData vertices[TRIANGLE_VERTICES],
+                                    Colour colour, const Model *model, RenderType type);
+internal TriangleBBox get_triangle_bbox(const Image *img, V2f vertices[TRIANGLE_VERTICES]);
+internal V3f          get_barycentric_coords(V2f a, V2f b, V2f c, V2f p);
+internal V2f          get_viewport_vertex(const V3f *vertex, const Image *img);
 
 bool init_render(Arena *arena, Render *render, u64 width, u64 height) {
   render->img = (Image){.width = width, .height = height};
@@ -45,8 +44,7 @@ bool init_render(Arena *arena, Render *render, u64 width, u64 height) {
   return true;
 }
 
-void render_model(const Model *model, Render *render, ShaderID shader,
-                  RenderType render_type, Colour colour) {
+void render_model(const Model *model, Render *render, ShaderID shader, RenderType render_type, Colour colour) {
   Triangle triangle;
   for (u64 i = 0; i < model->triangles->count; ++i) {
     triangle = list_get(model->triangles, i);
@@ -54,136 +52,92 @@ void render_model(const Model *model, Render *render, ShaderID shader,
   }
 }
 
-internal void render_triangle(const Triangle *triangle, const Model *model,
-                              ShaderID shader, Render *render,
-                              RenderType render_type, Colour colour) {
+internal void render_triangle(const Triangle *triangle, const Model *model, ShaderID shader,
+                              Render *render, RenderType render_type, Colour colour) {
   Image *img = &(render->img);
-  V3f vertices[TRIANGLE_VERTICES] = {
-      list_get(model->vertices, triangle->p0),
-      list_get(model->vertices, triangle->p1),
-      list_get(model->vertices, triangle->p2),
-  };
-  V3f normals[TRIANGLE_VERTICES] = {
-      list_get(model->normals, triangle->n0),
-      list_get(model->normals, triangle->n1),
-      list_get(model->normals, triangle->n2),
-  };
-  V2f coordinates[TRIANGLE_VERTICES] = {
-      list_get(model->texture_coordinates, triangle->tx0),
-      list_get(model->texture_coordinates, triangle->tx1),
-      list_get(model->texture_coordinates, triangle->tx2),
-  };
-
+  VertexData vertices[TRIANGLE_VERTICES];
   for (u64 i = 0; i < TRIANGLE_VERTICES; ++i) {
-    vertices[i] = run_vertex_shader(shader, &vertices[i]);
+    vertices[i].position = list_get(model->vertices, triangle->positions[i]);
+    vertices[i].normal   = list_get(model->normals, triangle->normals[i]);
+    vertices[i].uv       = list_get(model->texture_coordinates, triangle->coordinates[i]);
+
+    vertices[i]          = run_vertex_shader(shader, &vertices[i], i, model);
   }
 
   if (render_type == RENDER_TYPE_WIREFRAME) {
-    V3f v0, v1;
-    u64 x0, y0, x1, y1;
-    for (u64 i = 0; i < TRIANGLE_VERTICES; ++i) {
-      v0 = vertices[i];
-      v1 = vertices[(i + 1) % TRIANGLE_VERTICES];
-
-      draw_line(img, (u64)v0.x, (u64)v0.y, (u64)v1.x, (u64)v1.y, colour);
-    }
-  } else if (render_type == RENDER_TYPE_FILLED ||
-             render_type == RENDER_TYPE_SHADED) {
-    fill_triangle(render, shader, vertices, normals, coordinates, colour, model,
-                  render_type);
+    // V3f v0, v1;
+    // u64 x0, y0, x1, y1;
+    // for (u64 i = 0; i < TRIANGLE_VERTICES; ++i) {
+    //   v0 = vertices[i];
+    //   v1 = vertices[(i + 1) % TRIANGLE_VERTICES];
+    //
+    //   draw_line(img, (u64)v0.x, (u64)v0.y, (u64)v1.x, (u64)v1.y, colour);
+    // }
+  } else if (render_type == RENDER_TYPE_FILLED || render_type == RENDER_TYPE_SHADED) {
+    fill_triangle(render, shader, vertices, colour, model, render_type);
   }
 }
 
-internal void fill_triangle(Render *render, ShaderID shader,
-                            V3f vertices[TRIANGLE_VERTICES],
-                            V3f normals[TRIANGLE_VERTICES],
-                            V2f coordinates[TRIANGLE_VERTICES], Colour colour,
-                            const Model *model, RenderType type) {
+internal void fill_triangle(Render *render, ShaderID shader, VertexData vertices[TRIANGLE_VERTICES],
+                            Colour colour, const Model *model, RenderType type) {
   Image   *img   = &(render->img);
   Depth   *depth = &(render->depth);
 
-  V3f vp_verts[TRIANGLE_VERTICES] = {0};
+  V2f vp_verts[TRIANGLE_VERTICES] = {0};
   for (u64 i = 0; i < TRIANGLE_VERTICES; ++i) {
-    vp_verts[i] = get_viewport_vertex(&vertices[i], img);
+    vp_verts[i] = get_viewport_vertex(&vertices[i].position, img);
   }
 
   TriangleBBox bbox = get_triangle_bbox(img, vp_verts);
 
-  V3f vert0 = vp_verts[0];
-  V3f vert1 = vp_verts[1];
-  V3f vert2 = vp_verts[2];
-  V3f point;
-
+  V2f            point;
   V3f            coords;
   f32            z;
   f32            zbuf;
-  f32 px, py, pz;
-  V3f position;
-  f32 nx, ny, nz;
-  V3f normal;
-  f32 tx_u, tx_v;
-  u64 tx_x, tx_y;
-  V2f tex_coords;
-  FragmentData data = {0};
+  V4f            shader_colour;
+  Colour         output_colour;
   FragmentResult result;
 
   f32 intensity = 1.0f;
 
   for (u64 y = bbox.y0; y <= bbox.y1; ++y) {
     for (u64 x = bbox.x0; x <= bbox.x1; ++x) {
-      point = (V3f){x, y, 1.0f};
-      coords = get_barycentric_coords(vert0, vert1, vert2, point);
+      point = (V2f){x, y};
+      coords = get_barycentric_coords(vp_verts[0], vp_verts[1], vp_verts[2], point);
       if (coords.x < 0.0f || coords.y < 0.0f || coords.z < 0.0f) {
         continue;
       }
 
       z    = 0.0f;
-      z += vert0.z * coords.x + vert1.z * coords.y + vert2.z * coords.z;
+      z    += vertices[0].position.z * coords.x +
+              vertices[1].position.z * coords.y +
+              vertices[2].position.z * coords.z;
       zbuf = get_pixel(f32, &(render->depth), x, y);
 
       if (z <= zbuf) {
         continue;
       }
 
-      px = vp_verts[0].x * coords.x + vp_verts[1].x * coords.y +
-           vp_verts[2].x * coords.z;
-      py = vp_verts[0].y * coords.x + vp_verts[1].y * coords.y +
-           vp_verts[2].y * coords.z;
-      pz = vp_verts[0].z * coords.x + vp_verts[1].z * coords.y +
-           vp_verts[2].z * coords.z;
-      position = (V3f){px, py, pz};
-      normalise_v3(position);
-      data.position = position;
-
-      nx = normals[0].x * coords.x + normals[1].x * coords.y +
-           normals[2].x * coords.z;
-      ny = normals[0].y * coords.x + normals[1].y * coords.y +
-           normals[2].y * coords.z;
-      nz = normals[0].z * coords.x + normals[1].z * coords.y +
-           normals[2].z * coords.z;
-      normal = (V3f){nx, ny, nz};
-      data.normal = normal;
-
-      tx_u = coordinates[0].u * coords.x + coordinates[1].u * coords.y +
-             coordinates[2].u * coords.z;
-      tx_v = coordinates[0].v * coords.x + coordinates[1].v * coords.y +
-             coordinates[2].v * coords.z;
-      tex_coords = (V2f){tx_u, tx_v};
-      data.tex_coords = tex_coords;
-
-      result = run_fragment_shader(shader, &data, &colour, model);
+      shader_colour = (V4f){.r = colour.r, .g = colour.g, .b = colour.b, .a = colour.a};
+      result        = run_fragment_shader(shader, &coords, &shader_colour, model);
       if (DISCARD_FRAGMENT(result)) {
         continue;
       }
 
+      output_colour = (Colour){
+          .r = clamp(result.colour.r, 0, UINT8_MAX),
+          .g = clamp(result.colour.g, 0, UINT8_MAX),
+          .b = clamp(result.colour.b, 0, UINT8_MAX),
+          .a = clamp(result.colour.a, 0, UINT8_MAX),
+      };
+
       set_pixel(depth, x, y, &z);
-      set_pixel(img, x, y, &result.colour);
+      set_pixel(img, x, y, &output_colour);
     }
   }
 }
 
-internal TriangleBBox get_triangle_bbox(const Image *img,
-                                        V3f vertices[TRIANGLE_VERTICES]) {
+internal TriangleBBox get_triangle_bbox(const Image *img, V2f vertices[TRIANGLE_VERTICES]) {
   f32 x0 = min(vertices[0].x, min(vertices[1].x, vertices[2].x));
   f32 x1 = max(vertices[0].x, max(vertices[1].x, vertices[2].x));
   f32 y0 = min(vertices[0].y, min(vertices[1].y, vertices[2].y));
@@ -197,7 +151,7 @@ internal TriangleBBox get_triangle_bbox(const Image *img,
   };
 }
 
-internal V3f get_barycentric_coords(V3f a, V3f b, V3f c, V3f p) {
+internal V3f get_barycentric_coords(V2f a, V2f b, V2f c, V2f p) {
   V3f x_vec = V3(V3f, f32, c.x, b.x, a.x, a.x, a.x, p.x);
   V3f y_vec = V3(V3f, f32, c.y, b.y, a.y, a.y, a.y, p.y);
 
@@ -209,13 +163,10 @@ internal V3f get_barycentric_coords(V3f a, V3f b, V3f c, V3f p) {
   return (V3f){1.0f - (u.x + u.y) / u.z, u.y / u.z, u.x / u.z};
 }
 
-internal V3f get_viewport_vertex(const V3f *vertex, const Image *img) {
-  V4f vh = {.x = vertex->x, .y = 0.0f - vertex->y, .z = vertex->z, .w = 1.0f};
-  vh = mat4x4_mul_vec4(viewport(vh.x, vh.y, img->width, img->height), vh);
-
-  V3f output = project_vec4(vh);
+internal V2f get_viewport_vertex(const V3f *vertex, const Image *img) {
+  V3f output = *vertex;
   output.x = clamp(output.x, 0.0f, img->width);
   output.y = clamp(output.y, 0.0f, img->height);
 
-  return output;
+  return (V2f){output.x, output.y};
 }

src/model/render.h

@@ -5,14 +5,13 @@
 #include "mem_arena.h"
 #include "obj.h"
 #include "shader.h"
-#include <stdbool.h>
 
 typedef enum {
   RENDER_TYPE_WIREFRAME,
   RENDER_TYPE_FILLED,
   RENDER_TYPE_SHADED,
 
-  COUNT_RENDER_TYPES,
+  COUNT_RENDER_TYPE,
 } RenderType;
 
 typedef enum {
@@ -28,8 +27,16 @@ struct render {
   Depth depth;
 };
 
+enum render_pass {
+  RENDER_PASS_SHADOW,
+  RENDER_PASS_MAIN,
+
+  COUNT_RENDER_PASS,
+};
+
+extern Render g_render_passes[COUNT_RENDER_PASS];
+
 bool init_render(Arena *arena, Render *render, u64 width, u64 height);
-void render_model(const Model *model, Render *render, ShaderID shader,
-                  RenderType render_type, Colour colour);
+void render_model(const Model *model, Render *render, ShaderID shader, RenderType render_type, Colour colour);
 
 #endif // RENDER_H

src/shader/main_shader.c

@@ -0,0 +1,135 @@
+#include "main_shader.h"
+#include "img.h"
+#include "obj.h"
+#include "render.h"
+#include "shader.h"
+#include "utils.h"
+#include "vec.h"
+
+VertexData general_shader_vertex(void *shader, const VertexData *vert, u8 index, const Model *model) {
+  Shader *shdr = (Shader *)shader;
+
+  V4f vh = V3_to_V4(vert->position);
+  vh.y   = 0.0 - vh.y;
+  vh     = mat4x4_mul_vec4(shdr->final, vh);
+
+  shdr->vertices[index].position = project_vec4(vh);
+  shdr->vertices[index].uv       = vert->uv;
+
+  V4f hnorm                    = V3_to_V4(vert->normal);
+  hnorm                        = mat4x4_mul_vec4(shdr->proj_mv_inv_t, hnorm);
+  shdr->vertices[index].normal = project_vec4(hnorm);
+  normalise_v3(shdr->vertices[index].normal);
+
+  return shdr->vertices[index];
+}
+
+FragmentResult diffuse_shader_fragment(void *shader, const V3f *barycentric, const V4f *colour,
+                                       const Model *model) {
+  Shader *shdr = (Shader *)shader;
+
+  M3x3f pos_mat    = {.rows = {shdr->vertices[0].position, shdr->vertices[1].position, shdr->vertices[2].position}};
+  pos_mat          = mat3x3_transpose(pos_mat);
+  M3x3f normal_mat = {.rows = {shdr->vertices[0].normal, shdr->vertices[1].normal, shdr->vertices[2].normal}};
+  normal_mat       = mat3x3_transpose(normal_mat);
+  M3x2f uvs        = {shdr->vertices[0].uv, shdr->vertices[1].uv, shdr->vertices[2].uv};
+  M2x3f uv_mat     = mat3x2_transpose(uvs);
+
+  V3f position = mat3x3_mul_vec3(pos_mat, (*barycentric));
+  V3f normal   = mat3x3_mul_vec3(normal_mat, (*barycentric));
+  V2f uv       = mat2x3_mul_vec3(uv_mat, (*barycentric));
+
+  V4f shadow_position_h = V3_to_V4(position);
+  shadow_position_h     = mat4x4_mul_vec4(shdr->shadow_matrix, shadow_position_h);
+  V3f shadow_position   = project_vec4(shadow_position_h);
+
+  // Calculate shadow
+  const Render *shadow_pass = &(g_render_passes[RENDER_PASS_SHADOW]);
+  f32 shadow_z              = get_pixel(f32, &(shadow_pass->depth), shadow_position.x, shadow_position.y);
+  f32 shadow                = 0.3f + 0.7f * (shadow_z < shadow_position.z + 10.0f);
+
+#pragma region darboux_frame_tangent_normals
+  /**
+   * Based on the following section of the tinyrenderer tutorial
+   * https://github.com/ssloy/tinyrenderer/wiki/Lesson-6bis:-tangent-space-normal-mapping#starting-point-phong-shading
+   */
+
+  if (model->normal) {
+    u64 nm_x = uv.u * model->normal->width;
+    u64 nm_y = uv.v * model->normal->height;
+
+    Colour pixel   = get_pixel(Colour, model->normal, nm_x, nm_y);
+    V3f    tangent = (V3f){
+        .x = pixel.r / 255.f * 2.f - 1.f,
+        .y = pixel.g / 255.f * 2.f - 1.f,
+        .z = pixel.b / 255.f * 2.f - 1.f,
+    };
+
+    V3f p0p1 = sub_v3(shdr->vertices[1].position, shdr->vertices[0].position);
+    V3f p0p2 = sub_v3(shdr->vertices[2].position, shdr->vertices[0].position);
+
+    M3x3f A     = {.rows = {p0p1, p0p2, normal}};
+    M3x3f A_inv = mat3x3_inv(A);
+
+    V2f uv0 = shdr->vertices[0].uv;
+    V2f uv1 = shdr->vertices[1].uv;
+    V2f uv2 = shdr->vertices[2].uv;
+
+    V3f u_vec = {uv1.u - uv0.u, uv2.u - uv0.u, 0};
+    V3f v_vec = {uv1.v - uv0.v, uv2.v - uv0.v, 0};
+
+    V3f i = mat3x3_mul_vec3(A_inv, u_vec);
+    normalise_v3(i);
+    V3f j = mat3x3_mul_vec3(A_inv, v_vec);
+    normalise_v3(j);
+
+    M3x3f B = {.rows = {i, j, normal}};
+    B = mat3x3_transpose(B);
+
+    normal = mat3x3_mul_vec3(B, tangent);
+    normalise_v3(normal);
+  }
+#pragma endregion darboux_frame_tangent_normals
+
+  V4f output;
+  if (model->texture) {
+    u64    tx_x = uv.u * model->texture->width;
+    u64    tx_y = uv.v * model->texture->height;
+    Colour tx   = get_pixel(Colour, model->texture, tx_x, tx_y);
+    output      = (V4f){.r = tx.r, .g = tx.g, .b = tx.b, .a = tx.a};
+  } else {
+    output = *colour;
+  }
+
+  f32 intensity = max(0.001f, dot_v3(normal, shdr->light_dir));
+  f32 r         = clamp(intensity + shdr->ambient.r, 0.0f, 1.0f);
+  f32 g         = clamp(intensity + shdr->ambient.g, 0.0f, 1.0f);
+  f32 b         = clamp(intensity + shdr->ambient.b, 0.0f, 1.0f);
+
+  output.r *= r * shadow;
+  output.g *= g * shadow;
+  output.b *= b * shadow;
+
+  return (FragmentResult){.colour = output};
+}
+
+FragmentResult albedo_shader_fragment(void *shader, const V3f *barycentric, const V4f *colour,
+                                      const Model *model) {
+  Shader *shdr = (Shader *)shader;
+
+  M3x2f uvs    = {shdr->vertices[0].uv, shdr->vertices[1].uv, shdr->vertices[2].uv};
+  M2x3f uv_mat = mat3x2_transpose(uvs);
+  V2f   uv     = mat2x3_mul_vec3(uv_mat, (*barycentric));
+
+  V4f output;
+  if (model->texture) {
+    u64    tx_x = uv.u * model->texture->width;
+    u64    tx_y = uv.v * model->texture->height;
+    Colour tx   = get_pixel(Colour, model->texture, tx_x, tx_y);
+    output      = (V4f){.r = tx.r, .g = tx.g, .b = tx.b, .a = tx.a};
+  } else {
+    output = *colour;
+  }
+
+  return (FragmentResult){.colour = output};
+}

src/shader/main_shader.h

@@ -0,0 +1,18 @@
+#ifndef MAIN_SHADER_H
+#define MAIN_SHADER_H
+
+#include "shader.h"
+#include "vec.h"
+
+typedef struct shader Shader;
+struct shader {
+  #include "shader_base.inc"
+  M4x4f shadow_matrix;
+};
+
+VertexData     general_shader_vertex(void *shader, const VertexData *vert, u8 index, const Model *model);
+FragmentResult diffuse_shader_fragment(void *shader, const V3f *barycentric, const V4f *colour,
+                                       const Model *model);
+FragmentResult albedo_shader_fragment(void *shader, const V3f *barycentric, const V4f *colour,
+                                      const Model *model);
+#endif // !MAIN_SHADER_H

src/shader/shader.c

@@ -1,6 +1,5 @@
 #include "shader.h"
 #include "aliases.h"
-#include "vec.h"
 
 #define MAX_SHADER_COUNT 2048
 
@@ -14,8 +13,7 @@ struct shader_repo {
 
 internal ShaderRepo g_repository = {0};
 
-ShaderID register_shader(void *shader, VertexShader *vertex,
-                         FragmentShader *fragment) {
+ShaderID register_shader(void *shader, VertexShader *vertex, FragmentShader *fragment) {
   if (g_repository.count + 1 >= MAX_SHADER_COUNT) {
     return INVALID_SHADER;
   }
@@ -28,23 +26,23 @@ ShaderID register_shader(void *shader, VertexShader *vertex,
   return (ShaderID){g_repository.count};
 }
 
-V3f run_vertex_shader(ShaderID shader, const V3f *vertex) {
-  if (IS_INVALID_SHADER(shader) || shader.id > g_repository.count || !vertex) {
-    return (V3f){0};
+VertexData run_vertex_shader(ShaderID shader, const VertexData *vert, u8 index, const Model *model) {
+  if (IS_INVALID_SHADER(shader) || shader.id > g_repository.count || !vert || !model) {
+    return (VertexData){0};
   }
 
   void *shader_obj          = g_repository.shaders[shader.id];
   VertexShader *vertex_func = g_repository.vertex_funcs[shader.id];
 
   if (!shader_obj || !vertex_func) {
-    return (V3f){0};
+    return (VertexData){0};
   }
 
-  return vertex_func(shader_obj, vertex);
+  return vertex_func(shader_obj, vert, index, model);
 }
 
-FragmentResult run_fragment_shader(ShaderID shader, const FragmentData *data,
-                                   const Colour *colour, const Model *model) {
+FragmentResult run_fragment_shader(ShaderID shader, const V3f *barycentric, const V4f *colour,
+                                   const Model *model) {
   if (IS_INVALID_SHADER(shader) || shader.id > g_repository.count || !colour) {
     return DISCARDED_FRAGMENT;
   }
@@ -56,5 +54,5 @@ FragmentResult run_fragment_shader(ShaderID shader, const FragmentData *data,
     return DISCARDED_FRAGMENT;
   }
 
-  return fragment_func(shader_obj, data, colour, model);
+  return fragment_func(shader_obj, barycentric, colour, model);
 }

src/shader/shader.h

@@ -2,7 +2,6 @@
 #define SHADER_H
 
 #include "aliases.h"
-#include "img.h"
 #include "obj.h"
 #include "vec.h"
 
@@ -11,17 +10,17 @@ struct shader_id {
   u64 id;
 };
 
-typedef struct fragment_result FragmentResult;
-struct fragment_result {
-  Colour colour;
-  bool discard;
-};
-
-typedef struct fragment_data FragmentData;
-struct fragment_data {
+typedef struct vertex_data VertexData;
+struct vertex_data {
   V3f position;
   V3f normal;
-  V2f tex_coords;
+  V2f uv;
+};
+
+typedef struct fragment_result FragmentResult;
+struct fragment_result {
+  V4f  colour;
+  bool discard;
 };
 
 #define INVALID_SHADER           ((ShaderID){0})
@@ -29,15 +28,12 @@ struct fragment_data {
 #define DISCARDED_FRAGMENT       ((FragmentResult){.discard = true})
 #define DISCARD_FRAGMENT(RESULT) (RESULT.discard)
 
-typedef V3f(VertexShader)(void *shader, const V3f *vertex);
-typedef FragmentResult(FragmentShader)(void *shader, const FragmentData *data,
-                                       const Colour *colour,
+typedef VertexData(VertexShader)(void *shader, const VertexData *vert, u8 index, const Model *model);
+typedef FragmentResult(FragmentShader)(void *shader, const V3f *barycentric, const V4f *colour,
                                        const Model *model);
 
-ShaderID register_shader(void *shader, VertexShader *vertex,
-                         FragmentShader *fragment);
-V3f run_vertex_shader(ShaderID shader, const V3f *vertex);
-FragmentResult run_fragment_shader(ShaderID shader, const FragmentData *data,
-                                   const Colour *colour, const Model *model);
+ShaderID register_shader(void *shader, VertexShader *vertex, FragmentShader *fragment);
+VertexData run_vertex_shader(ShaderID shader, const VertexData *vert, u8 index, const Model *model);
+FragmentResult run_fragment_shader(ShaderID shader, const V3f *barycentric, const V4f *colour, const Model *model);
 
 #endif // SHADER_H

src/shader/shader_base.inc

@@ -0,0 +1,8 @@
+V3f light_dir;
+V3f ambient;
+M4x4f proj_mv;
+M4x4f proj_mv_inv_t;
+M4x4f viewport;
+M4x4f final;
+M4x4f final_inv;
+VertexData vertices[TRIANGLE_VERTICES];

src/shader/shaders.c

@@ -1,200 +1,86 @@
+#include "shaders.h"
 #include "aliases.h"
-#include "img.h"
-#include "obj.h"
+#include "shadow_shader.h"
+#include "main_shader.h"
 #include "render.h"
 #include "shader.h"
-#include "utils.h"
 #include "vec.h"
-#include <math.h>
 
-typedef struct shader Shader;
-struct shader {
-  M4x4f model_view;
-  M4x4f projection;
-};
-
-ShaderID perspective_phong = {0};
+ShaderID depth                = {0};
+ShaderID perspective_diffuse  = {0};
 ShaderID perspective_albedo   = {0};
-ShaderID orthographic_phong = {0};
+ShaderID orthographic_diffuse = {0};
 ShaderID orthographic_albedo  = {0};
 
+internal ShadowShader depth_shader = {0};
 internal Shader       perspective  = {0};
 internal Shader       orthographic = {0};
 
-internal V3f g_ambient_light = {0.6f, 0.45f, 0.55f};
-internal PointLight g_directional_light = {
-    .diffuse_intensity = {0.9f, 1.0f, 1.0f},
-    .specular_intensity = {1.0f, 0.8f, 2.0f},
-    .position = {1.05f, 0.9f, 1.2f},
-};
-internal V3f g_eye = {0.2f, 0.1f, 0.75f};
+internal V3f g_ambient_light = {0.1f, 0.1f, 0.1f};
+internal V3f g_eye           = {0.2f, -0.1f, 0.5f};
 internal V3f g_target        = {0};
 internal V3f g_up            = {0.0f, 1.0f, 0.0f};
-internal M4x4f g_cam_matrix = mat4x4_identity;
+internal V3f g_light_dir     = {1.0f, -1.0f, 1.0f};
 
-internal V3f general_shader_vertex(void *shader, const V3f *vertex);
-internal FragmentResult phong_shader_fragment(void *shader,
-                                              const FragmentData *data,
-                                              const Colour *colour,
-                                              const Model *model);
-internal FragmentResult albedo_shader_fragment(void *shader,
-                                               const FragmentData *data,
-                                               const Colour *colour,
-                                               const Model *model);
 internal M4x4f get_projection_matrix(ProjectionType projection_type);
-internal f32 get_intensity(const V3f *normal);
 
-void load_shaders(void) {
+void load_shaders(M4x4f vp) {
+  // Set up depth shader matrices
+  M4x4f depth_model_view = lookat(g_light_dir, g_target, g_up);
+  M4x4f depth_projection = projection(0.0f);
+
+  // Set up depth shader
+  depth_shader.proj_mv       = mat4x4_mul(depth_projection, depth_model_view);
+  depth_shader.proj_mv_inv_t = mat4x4_inv(mat4x4_transpose(depth_shader.proj_mv));
+  depth_shader.viewport      = vp;
+  depth_shader.final         = mat4x4_mul(depth_shader.viewport, depth_shader.proj_mv);
+  depth_shader.light_dir     = mat3x3_mul_vec3(depth_shader.proj_mv, g_light_dir);
+  normalise_v3(depth_shader.light_dir);
+
+  // Set up main shader matrices
   M4x4f model_view              = lookat(g_eye, g_target, g_up);
-  M4x4f orthographic_projection =
-      get_projection_matrix(PROJECTION_TYPE_ORTHOGRAPHIC);
-  M4x4f perspective_projection =
-      get_projection_matrix(PROJECTION_TYPE_PERSPECTIVE);
+  M4x4f orthographic_projection = get_projection_matrix(PROJECTION_TYPE_ORTHOGRAPHIC);
+  M4x4f perspective_projection  = get_projection_matrix(PROJECTION_TYPE_PERSPECTIVE);
 
-  perspective.model_view = orthographic.model_view = model_view;
-  perspective.projection = perspective_projection;
-  orthographic.projection = orthographic_projection;
+  // Set up perspective shader
+  perspective.proj_mv       = mat4x4_mul(perspective_projection, model_view);
+  perspective.proj_mv_inv_t = mat4x4_inv(mat4x4_transpose(perspective.proj_mv));
+  perspective.viewport      = vp;
+  perspective.final         = mat4x4_mul(perspective.viewport, perspective.proj_mv);
+  perspective.final_inv     = mat4x4_inv(perspective.final);
+  perspective.ambient       = g_ambient_light;
+  perspective.light_dir     = mat3x3_mul_vec3(perspective.proj_mv, g_light_dir);
+  normalise_v3(perspective.light_dir);
+  perspective.shadow_matrix = mat4x4_mul(depth_shader.final, perspective.final_inv);
 
-  perspective_phong = register_shader(&perspective, general_shader_vertex,
-                                      phong_shader_fragment);
-  perspective_albedo = register_shader(&perspective, general_shader_vertex,
-                                       albedo_shader_fragment);
-  orthographic_phong = register_shader(&orthographic, general_shader_vertex,
-                                       phong_shader_fragment);
-  orthographic_albedo = register_shader(&orthographic, general_shader_vertex,
-                                        albedo_shader_fragment);
-}
+  // Set up orthographic shader
+  orthographic.proj_mv       = mat4x4_mul(orthographic_projection, model_view);
+  orthographic.proj_mv_inv_t = mat4x4_inv(mat4x4_transpose(orthographic.proj_mv));
+  orthographic.viewport      = vp;
+  orthographic.final         = mat4x4_mul(orthographic.viewport, orthographic.proj_mv);
+  orthographic.final_inv     = mat4x4_inv(perspective.final);
+  orthographic.shadow_matrix = mat4x4_mul(depth_shader.final, orthographic.final_inv);
+  orthographic.light_dir     = mat3x3_mul_vec3(orthographic.proj_mv, g_light_dir);
+  normalise_v3(orthographic.light_dir);
+  orthographic.ambient       = g_ambient_light;
 
-internal V3f general_shader_vertex(void *shader, const V3f *vertex) {
-  Shader *shader_ptr = (Shader *)shader;
-
-  V4f vh = {.x = vertex->x, .y = vertex->y, .z = vertex->z, .w = 1.0f};
-  vh = mat4x4_mul_vec4(shader_ptr->projection,
-                       mat4x4_mul_vec4(shader_ptr->model_view, vh));
-
-  return project_vec4(vh);
-}
-
-internal FragmentResult phong_shader_fragment(void *shader,
-                                              const FragmentData *data,
-                                              const Colour *colour,
-                                              const Model *model) {
-  Shader *shader_ptr = (Shader *)shader;
-
-  V4f hnorm;
-  V3f norm;
-  if (model->normal) {
-    u64 nm_x = data->tex_coords.u * model->normal->width;
-    u64 nm_y = data->tex_coords.v * model->normal->height;
-
-    Colour pixel = get_pixel(Colour, model->normal, nm_x, nm_y);
-    hnorm = (V4f){
-        .x = pixel.r,
-        .y = pixel.g,
-        .z = pixel.b,
-        .w = 1.0f,
-    };
-  } else {
-    hnorm = V3_to_V4(data->normal);
-  }
-
-  M4x4f matrix = mat4x4_mul(shader_ptr->projection, shader_ptr->model_view);
-  M4x4f transposed = mat4x4_transpose(matrix);
-  M4x4f inv_transpose = mat4x4_inv(transposed);
-
-  hnorm = mat4x4_mul_vec4(inv_transpose, hnorm);
-  norm = project_vec4(hnorm);
-  normalise_v3(norm);
-
-  Colour output;
-  if (model->texture) {
-    u64 tx_x = data->tex_coords.u * model->texture->width;
-    u64 tx_y = data->tex_coords.v * model->texture->height;
-    output = get_pixel(Colour, model->texture, tx_x, tx_y);
-  } else {
-    output = *colour;
-  }
-
-  V3f local_colour = {.r = output.r, .g = output.g, .b = output.b};
-  local_colour = num_div_v3(local_colour, 255.0f);
-
-  // Ambient term
-  V3f intensity = num_mul_v3(g_ambient_light, model->material.ambient);
-
-  V4f hdir = V3_to_V4(g_directional_light.position);
-  hdir = mat4x4_mul_vec4(matrix, hdir);
-  V3f light_pos = project_vec4(hdir);
-  normalise_v3(light_pos);
-  V3f light_dir = sub_v3(light_pos, data->position);
-
-  // Diffuse term
-  f32 l_dot_n = dot_v3(norm, light_dir);
-  if (l_dot_n <= 0.0f) {
-    goto RETURN_OUTPUT_COLOUR;
-  }
-
-  V3f diffuse = num_mul_v3(g_directional_light.diffuse_intensity,
-                           model->material.diffuse * l_dot_n);
-  intensity = add_v3(intensity, diffuse);
-
-  // Specular term
-  V3f _2_l_dot_n_norm = num_mul_v3(norm, 2.0f * l_dot_n);
-  V3f reflected = sub_v3(_2_l_dot_n_norm, light_dir);
-  normalise_v3(reflected);
-  V3f v = sub_v3(g_eye, data->position);
-  normalise_v3(v);
-  f32 r_dot_v = dot_v3(reflected, v);
-  if (r_dot_v <= 0.0f) {
-    goto RETURN_OUTPUT_COLOUR;
-  }
-
-  V3f specular = num_mul_v3(g_directional_light.specular_intensity,
-                            model->material.specular *
-                                powf(r_dot_v, model->material.shininess));
-  intensity = add_v3(intensity, specular);
-
-RETURN_OUTPUT_COLOUR:
-  intensity.r = clamp(intensity.r, 0.0f, 1.0f);
-  intensity.g = clamp(intensity.g, 0.0f, 1.0f);
-  intensity.b = clamp(intensity.b, 0.0f, 1.0f);
-
-  local_colour = mul_v3(local_colour, intensity);
-
-  output.r = 255.0f * local_colour.r;
-  output.g = 255.0f * local_colour.g;
-  output.b = 255.0f * local_colour.b;
-
-  return (FragmentResult){.colour = output};
-}
-
-internal FragmentResult albedo_shader_fragment(void *shader,
-                                               const FragmentData *data,
-                                               const Colour *colour,
-                                               const Model *model) {
-  return (FragmentResult){.colour = *colour};
+  // Register shaders
+  depth                = register_shader(&depth_shader, shadow_shader_vertex,  shadow_shader_fragment);
+  perspective_diffuse  = register_shader(&perspective,  general_shader_vertex, diffuse_shader_fragment);
+  perspective_albedo   = register_shader(&perspective,  general_shader_vertex, albedo_shader_fragment);
+  orthographic_diffuse = register_shader(&orthographic, general_shader_vertex, diffuse_shader_fragment);
+  orthographic_albedo  = register_shader(&orthographic, general_shader_vertex, albedo_shader_fragment);
 }
 
 internal M4x4f get_projection_matrix(ProjectionType projection_type) {
   if (projection_type == PROJECTION_TYPE_PERSPECTIVE) {
-    // Calculate projection matrix
-    V3f cam = V3(V3f, f32, g_target.x, g_target.y, g_target.z, g_eye.x, g_eye.y,
-                 g_eye.z);
+    V3f cam = V3(V3f, f32, g_target.x, g_target.y, g_target.z, g_eye.x, g_eye.y, g_eye.z);
     normalise_v3(cam);
+
     f32 coeff = -1.0f / magnitude_v3(cam) * 0.5f;
+
     return projection(coeff);
   }
 
   return mat4x4_identity;
 }
-
-internal f32 get_intensity(const V3f *normal) {
-  V3f light = g_directional_light.position;
-  normalise_v3(light);
-
-  f32 intensity = dot_v3((*normal), light);
-  if (intensity < 0.0f) {
-    intensity = 0.001f;
-  }
-
-  return intensity;
-}

src/shader/shaders.h

@@ -3,11 +3,12 @@
 
 #include "shader.h"
 
-extern ShaderID perspective_phong;
+extern ShaderID depth;
+extern ShaderID perspective_diffuse;
 extern ShaderID perspective_albedo;
-extern ShaderID orthographic_phong;
+extern ShaderID orthographic_diffuse;
 extern ShaderID orthographic_albedo;
 
-void load_shaders(void);
+void load_shaders(M4x4f vp);
 
 #endif // SHADERS_H

src/shader/shadow_shader.c

@@ -0,0 +1,30 @@
+#include "shadow_shader.h"
+#include "constants.h"
+#include "shader.h"
+#include "utils.h"
+
+VertexData shadow_shader_vertex(void *shader, const VertexData *vert, u8 index, const Model *model) {
+  ShadowShader *shdr = (ShadowShader *)shader;
+
+  V4f vh = V3_to_V4(vert->position);
+  vh.y   = 0.0 - vh.y;
+  vh     = mat4x4_mul_vec4(shdr->final, vh);
+
+  shdr->vertices[index].position = project_vec4(vh);
+
+  return shdr->vertices[index];
+}
+
+FragmentResult shadow_shader_fragment(void *shader, const V3f *barycentric, const V4f *colour,
+                                     const Model *model) {
+  ShadowShader *shdr = (ShadowShader *)shader;
+
+  M3x3f pos_mat = {.rows = {shdr->vertices[0].position, shdr->vertices[1].position, shdr->vertices[2].position}};
+  pos_mat       = mat3x3_transpose(pos_mat);
+  V3f position  = mat3x3_mul_vec3(pos_mat, (*barycentric));
+
+  f32 channel = clamp(position.z + DEPTH_MAX, 0.0f, DEPTH_MAX);
+  V4f output = {.r = channel, .g = channel, .b = channel, .a = 255};
+
+  return (FragmentResult){.colour = output};
+}

src/shader/shadow_shader.h

@@ -0,0 +1,17 @@
+#ifndef SHADOW_SHADER_H
+#define SHADOW_SHADER_H
+
+#include "constants.h"
+#include "shader.h"
+#include "vec.h"
+
+typedef struct shadow_shader ShadowShader;
+struct shadow_shader {
+  #include "shader_base.inc"
+};
+
+VertexData     shadow_shader_vertex(void *shader, const VertexData *vert, u8 index, const Model *model);
+FragmentResult shadow_shader_fragment(void *shader, const V3f *barycentric, const V4f *colour,
+                                      const Model *model);
+
+#endif // !SHADOW_SHADER_H

src/str/str.c

@@ -0,0 +1,97 @@
+#include "str.h"
+#include "aliases.h"
+#include "mem_arena.h"
+#include <stddef.h>
+#include <string.h>
+
+#define CAPACITY_SCALAR 4
+
+Str8 str8(Arena *arena, char *str) {
+  if (!str) {
+    return (Str8){0};
+  }
+
+  u64 length = strlen(str);
+  Str8 output = {
+      .str      = str,
+      .length   = length,
+      .capacity = length,
+  };
+
+  if (arena) {
+    output.capacity *= CAPACITY_SCALAR;
+
+    output.str = wapp_mem_arena_alloc(arena, output.capacity);
+    if (!output.str) {
+      return (Str8){0};
+    }
+
+    strncpy(output.str, str, output.length);
+  }
+
+  return output;
+}
+
+Str8 str8_copy(Arena *arena, const Str8 *str) {
+  if (!arena) {
+    return str8_lit(str->str);
+  }
+
+  char *tmp = wapp_mem_arena_alloc(arena, str->capacity);
+  if (!tmp) {
+    return str8_lit(str->str);
+  }
+
+  strncpy(tmp, str->str, str->length);
+
+  return (Str8){
+      .str      = tmp,
+      .length   = str->length,
+      .capacity = str->capacity,
+  };
+}
+
+i32 str8_concat(Arena *arena, Str8 *dst, char *src) {
+  if (!src || !dst) {
+    return STR_OP_FAILED;
+  }
+
+  u64 src_length = strlen(src);
+  if (src_length + dst->length > dst->capacity) {
+    if (!arena) {
+      return STR_OP_FAILED;
+    }
+
+    u64 capacity = dst->capacity * CAPACITY_SCALAR + src_length;
+    char *str = wapp_mem_arena_alloc(arena, capacity);
+    if (!str) {
+      return STR_OP_FAILED;
+    }
+
+    strncpy(str, dst->str, dst->length);
+    strncpy(str + dst->length, src, src_length);
+
+    dst->str      = str;
+    dst->length   = dst->length + src_length;
+    dst->capacity = capacity;
+
+    return STR_OP_SUCEEDED;
+  }
+
+  strncpy(dst->str + dst->length, src, src_length);
+  return STR_OP_SUCEEDED;
+}
+
+Str8 str8_substr(Arena *arena, const Str8 *str, u64 start, u64 count) {
+  if (start > str->length || start + count > str->length) {
+    return (Str8){0};
+  }
+
+  Str8 tmp = {
+      .str      = str->str + start,
+      .length   = count,
+      .capacity = count,
+  };
+
+  return str8_copy(arena, &tmp);
+}

src/str/str.h

@@ -0,0 +1,26 @@
+#ifndef STR_H
+#define STR_H
+
+#include "aliases.h"
+#include "mem_arena.h"
+
+enum {
+  STR_OP_SUCEEDED,
+  STR_OP_FAILED,
+};
+
+typedef struct str8 Str8;
+struct str8 {
+  char *str;
+  u64  length;
+  u64  capacity;
+};
+
+#define str8_lit(STR) (str8(NULL, STR))
+
+Str8 str8(Arena *arena, char *str);
+Str8 str8_copy(Arena *arena, const Str8 *str);
+i32  str8_concat(Arena *arena, Str8 *dst, char *src);
+Str8 str8_substr(Arena *arena, const Str8 *str, u64 start, u64 count);
+
+#endif // !STR_H

src/tiny/tiny.c

@@ -0,0 +1,116 @@
+#include "img.h"
+#include "mem_arena.h"
+#include "misc_utils.h"
+#include "obj.h"
+#include "render.h"
+#include "shaders.h"
+#include "str.h"
+#include "vec.h"
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/stat.h>
+#include <time.h>
+
+#define IMAGE_DIMENSION 1200
+
+enum {
+  TINY_EXIT_SUCCESS,
+  TINY_EXIT_MISSING_ARGS,
+  TINY_EXIT_OBJ_NOT_EXIST,
+  TINY_EXIT_ARENA_INIT_FAILED,
+  TINY_EXIT_RENDER_INIT_FAILED,
+  TINY_EXIT_MODEL_LOAD_FAILED,
+};
+
+typedef struct tiny_args TinyArgs;
+struct tiny_args {
+  Str8 obj;
+  Str8 diffuse;
+  Str8 tangent;
+};
+
+internal TinyArgs parse_args(Arena *arena, int argc, char *argv[]);
+internal i32      tinyrenderer(Arena *arena, TinyArgs args);
+internal bool     file_exists(const Str8 *path);
+
+i32 tiny_main(i32 argc, char *argv[]) {
+  Arena *arena = NULL;
+  if (!wapp_mem_arena_init(&arena, GB(10))) {
+    return TINY_EXIT_ARENA_INIT_FAILED;
+  }
+
+  TinyArgs args   = parse_args(arena, argc, argv);
+  i32      output = tinyrenderer(arena, args);
+
+  wapp_mem_arena_destroy(&arena);
+
+  return output;
+}
+
+internal TinyArgs parse_args(Arena *arena, int argc, char *argv[]) {
+  if (argc < 2) {
+    exit(TINY_EXIT_MISSING_ARGS);
+  }
+
+  TinyArgs args = {
+      .obj = str8_lit(argv[1]),
+  };
+
+  if (!file_exists(&args.obj)) {
+    exit(TINY_EXIT_OBJ_NOT_EXIST);
+  }
+
+  u64 substr_end = args.obj.length - 4;
+
+  args.diffuse = str8_substr(arena, &args.obj, 0, substr_end);
+  str8_concat(arena, &args.diffuse, "_diffuse.pnm");
+  if (!file_exists(&args.diffuse)) {
+    args.diffuse = (Str8){0};
+  }
+
+  args.tangent = str8_substr(arena, &args.obj, 0, substr_end);
+  str8_concat(arena, &args.tangent, "_tangent.pnm");
+  if (!file_exists(&args.tangent)) {
+    args.tangent = (Str8){0};
+  }
+
+  return args;
+}
+
+internal i32 tinyrenderer(Arena *arena, TinyArgs args) {
+  Colour bg          = {.r = 42, .g = 45,  .b = 52,  .a = 255};
+  Colour main_colour = {.r = 14, .g = 156, .b = 208, .a = 255};
+
+  Render *shadowbuffer = &(g_render_passes[RENDER_PASS_SHADOW]);
+  Render *framebuffer  = &(g_render_passes[RENDER_PASS_MAIN]);
+  if (!init_render(arena, shadowbuffer, IMAGE_DIMENSION, IMAGE_DIMENSION) ||
+      !init_render(arena, framebuffer,  IMAGE_DIMENSION, IMAGE_DIMENSION)) {
+    return TINY_EXIT_RENDER_INIT_FAILED;
+  }
+
+  const char *diffuse = args.diffuse.length > 0 ? args.diffuse.str : NULL;
+  const char *tangent = args.tangent.length > 0 ? args.tangent.str : NULL;
+
+  Model obj = load_obj_file(arena, args.obj.str, diffuse, tangent);
+  if (IS_INVALID_MODEL(obj)) {
+    return TINY_EXIT_MODEL_LOAD_FAILED;
+  }
+
+  load_shaders(viewport(0, 0, IMAGE_DIMENSION, IMAGE_DIMENSION));
+
+  clear_buffer(&(framebuffer->img), &bg);
+
+  render_model(&obj, shadowbuffer, depth,               RENDER_TYPE_SHADED, main_colour);
+  render_model(&obj, framebuffer,  perspective_diffuse, RENDER_TYPE_SHADED, main_colour);
+
+  save_image(&(framebuffer->img), "result.pam");
+
+  return TINY_EXIT_SUCCESS;
+}
+
+internal bool file_exists(const Str8 *path) {
+  struct stat st;
+  return stat(path->str, &st) == 0;
+}

src/tiny/tiny.h

@@ -0,0 +1,8 @@
+#ifndef TINY_H
+#define TINY_H
+
+#include "aliases.h"
+
+i32 tiny_main(i32 argc, char *argv[]);
+
+#endif // !TINY_H

src/vec/vec.c

@@ -1,6 +1,5 @@
 #include "vec.h"
-
-#define DEPTH_MAX 255
+#include "constants.h"
 
 M4x4f lookat(V3f eye, V3f target, V3f up) {
   V3f z = V3(V3f, f32, target.x, target.y, target.z, eye.x, eye.y, eye.z);
@@ -30,14 +29,12 @@ M4x4f lookat(V3f eye, V3f target, V3f up) {
 }
 
 M4x4f projection(f32 coeff) {
-  // clang-format off
   return (M4x4f){
     .row0 = {1.0f, 0.0f,  0.0f, 0.0f},
     .row1 = {0.0f, 1.0f,  0.0f, 0.0f},
     .row2 = {0.0f, 0.0f,  1.0f, 0.0f},
     .row3 = {0.0f, 0.0f, coeff, 1.0f},
   };
-  // clang-format on
 }
 
 M4x4f viewport(f32 x, f32 y, u64 w, u64 h) {
@@ -56,6 +53,42 @@ M4x4f viewport(f32 x, f32 y, u64 w, u64 h) {
   return output;
 }
 
+M3x3f mat3x3_inv(M3x3f matrix) {
+  M3x3f dest = {0};
+  float det;
+
+  float a = matrix.rows[0].elements[0], b = matrix.rows[0].elements[1],
+        c = matrix.rows[0].elements[2], d = matrix.rows[1].elements[0],
+        e = matrix.rows[1].elements[1], f = matrix.rows[1].elements[2],
+        g = matrix.rows[2].elements[0], h = matrix.rows[2].elements[1],
+        i = matrix.rows[2].elements[2];
+
+  dest.rows[0].elements[0] = e * i - f * h;
+  dest.rows[0].elements[1] = -(b * i - h * c);
+  dest.rows[0].elements[2] = b * f - e * c;
+  dest.rows[1].elements[0] = -(d * i - g * f);
+  dest.rows[1].elements[1] = a * i - c * g;
+  dest.rows[1].elements[2] = -(a * f - d * c);
+  dest.rows[2].elements[0] = d * h - g * e;
+  dest.rows[2].elements[1] = -(a * h - g * b);
+  dest.rows[2].elements[2] = a * e - b * d;
+
+  det = 1.0f / (a * dest.rows[0].elements[0] + b * dest.rows[1].elements[0] +
+                c * dest.rows[2].elements[0]);
+
+  dest.rows[0].elements[0] *= det;
+  dest.rows[0].elements[1] *= det;
+  dest.rows[0].elements[2] *= det;
+  dest.rows[1].elements[0] *= det;
+  dest.rows[1].elements[1] *= det;
+  dest.rows[1].elements[2] *= det;
+  dest.rows[2].elements[0] *= det;
+  dest.rows[2].elements[1] *= det;
+  dest.rows[2].elements[2] *= det;
+
+  return dest;
+}
+
 M4x4f mat4x4_inv(M4x4f matrix) {
   f32 mat[4][4] = mat4x4_to_array(matrix);
   f32 dest[4][4] = {0};

src/vec/vec.h

@@ -5,8 +5,6 @@
 #include "typed_list.h"
 #include <math.h>
 
-#define V3_ELEM_COUNT 3
-
 typedef struct i64x2 V2i;
 struct i64x2 {
   i64 x;
@@ -19,8 +17,10 @@ struct u64x2 {
   u64 y;
 };
 
-typedef struct f32x2 V2f;
-struct f32x2 {
+typedef union f32x2 V2f;
+union f32x2 {
+  f32 elements[2];
+  struct {
     union {
       f32 x;
       f32 u;
@@ -29,11 +29,12 @@ struct f32x2 {
       f32 y;
       f32 v;
     };
+  };
 };
 
 typedef union f32x3 V3f;
 union f32x3 {
-  f32 elements[V3_ELEM_COUNT];
+  f32 elements[3];
   struct {
     union {
       f32 x;
@@ -50,12 +51,27 @@ union f32x3 {
   };
 };
 
-typedef struct f32x4 V4f;
-struct f32x4 {
+typedef union f32x4 V4f;
+union f32x4 {
+  f32 elements[4];
+  struct {
+    union {
       f32 x;
+      f32 r;
+    };
+    union {
       f32 y;
+      f32 g;
+    };
+    union {
       f32 z;
+      f32 b;
+    };
+    union {
       f32 w;
+      f32 a;
+    };
+  };
 };
 
 typedef struct u64x3 V3u;
@@ -65,19 +81,44 @@ struct u64x3 {
   u64 z;
 };
 
-typedef struct f32_3x3 M3x3f;
-struct f32_3x3 {
+typedef union f32_3x2 M3x2f;
+union f32_3x2 {
+  V2f rows[3];
+  struct {
+    V2f row0;
+    V2f row1;
+    V2f row2;
+  };
+};
+
+typedef union f32_2x3 M2x3f;
+union f32_2x3 {
+  V3f rows[2];
+  struct {
+    V3f row0;
+    V3f row1;
+  };
+};
+
+typedef union f32_3x3 M3x3f;
+union f32_3x3 {
+  V3f rows[3];
+  struct {
     V3f row0;
     V3f row1;
     V3f row2;
+  };
 };
 
-typedef struct f32_4x4 M4x4f;
-struct f32_4x4 {
+typedef union f32_4x4 M4x4f;
+union f32_4x4 {
+  V4f rows[4];
+  struct {
     V4f row0;
     V4f row1;
     V4f row2;
     V4f row3;
+  };
 };
 
 MAKE_LIST_TYPE(V3f);
@@ -94,6 +135,35 @@ MAKE_LIST_TYPE(V2f);
 
 #define dot_v2(V1, V2) ((f32)V1.x * (f32)V2.x + (f32)V1.y * (f32)V2.y)
 
+#define add_v2(V1, V2)                                                         \
+  ((V2f){                                                                      \
+      .x = V1.x + V2.x,                                                        \
+      .y = V1.y + V2.y,                                                        \
+  })
+
+#define sub_v2(V1, V2)                                                         \
+  ((V2f){                                                                      \
+      .x = V1.x - V2.x,                                                        \
+      .y = V1.y - V2.y,                                                        \
+  })
+
+#define mul_v2(V1, V2)                                                         \
+  ((V2f){                                                                      \
+      .x = V1.x * V2.x,                                                        \
+      .y = V1.y * V2.y,                                                        \
+  })
+
+#define num_mul_v2(V, N) ((V2f){.x = (N) * V.x, .y = (N) * V.y})
+
+#define magnitude_v2(V) (sqrtf(dot_v2(V, V)))
+
+#define normalise_v2(V)                                                        \
+  do {                                                                         \
+    f32 magnitude = magnitude_v2(V);                                           \
+    V.x /= magnitude;                                                          \
+    V.y /= magnitude;                                                          \
+  } while (0)
+
 #define dot_v3(V1, V2)                                                         \
   ((f32)V1.x * (f32)V2.x + (f32)V1.y * (f32)V2.y + (f32)V1.z * (f32)V2.z)
 
@@ -139,6 +209,32 @@ MAKE_LIST_TYPE(V2f);
       .z = V1.x * V2.y - V1.y * V2.x,                                          \
   })
 
+#define mat3x2_transpose(MAT)                                                  \
+  ((M2x3f){                                                                    \
+      .row0 = {.x = MAT.row0.x, .y = MAT.row1.x, .z = MAT.row2.x},             \
+      .row1 = {.x = MAT.row0.y, .y = MAT.row1.y, .z = MAT.row2.y},             \
+  })
+
+#define mat2x3_mul_vec3(MAT, V)                                                \
+  ((V2f){                                                                      \
+      .elements[0] = dot_v3(MAT.rows[0], V),                                   \
+      .elements[1] = dot_v3(MAT.rows[1], V),                                   \
+  })
+
+#define mat3x3_transpose(MAT)                                                  \
+  ((M3x3f){                                                                    \
+      .row0 = {.x = MAT.row0.x, .y = MAT.row1.x, .z = MAT.row2.x},             \
+      .row1 = {.x = MAT.row0.y, .y = MAT.row1.y, .z = MAT.row2.y},             \
+      .row2 = {.x = MAT.row0.z, .y = MAT.row1.z, .z = MAT.row2.z},             \
+  })
+
+#define mat3x3_mul_vec3(MAT, V)                                                \
+  ((V3f){                                                                      \
+      .elements[0] = dot_v3(MAT.rows[0], V),                                   \
+      .elements[1] = dot_v3(MAT.rows[1], V),                                   \
+      .elements[2] = dot_v3(MAT.rows[2], V),                                   \
+  })
+
 #define mat4x4_identity                                                        \
   ((M4x4f){                                                                    \
       .row0 = {1.0f, 0.0f, 0.0f, 0.0f},                                        \
@@ -233,9 +329,12 @@ MAKE_LIST_TYPE(V2f);
 
 #define project_vec4(V) ((V3f){.x = V.x / V.w, .y = V.y / V.w, .z = V.z / V.w})
 
+#define mat_access(MAT, i, j) (MAT.rows[i].elements[j])
+
 M4x4f lookat(V3f eye, V3f target, V3f up);
 M4x4f projection(f32 coeff);
 M4x4f viewport(f32 x, f32 y, u64 w, u64 h);
+M3x3f mat3x3_inv(M3x3f matrix);
 M4x4f mat4x4_inv(M4x4f matrix);
 
 #endif // VEC_H