Reformat

.gitignore

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

src/main.c

@@ -1,113 +1,6 @@
-#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>
+#include "aliases.h"
+#include "tiny.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 main(int 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 render;
-  if (!init_render(arena, &render, 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(&(render.img), &bg);
-
-  // render_model(&obj, &render, depth, RENDER_TYPE_SHADED, main_colour);
-  render_model(&obj, &render, perspective_diffuse, RENDER_TYPE_SHADED, main_colour);
-  save_image(&(render.img), "result.pam");
-
-  return TINY_EXIT_SUCCESS;
-}
-
-internal bool file_exists(const Str8 *path) {
-  struct stat st;
-  return stat(path->str, &st) == 0;
+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 *diffuse,
-                    const char *tangent) {
+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 *diffuse,
       .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;
   }
 

src/model/obj.h

@@ -50,15 +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;
-  Image *texture;
-  Image *normal;
+  LIST_TYPE(V3f)      *vertices;
+  LIST_TYPE(V3f)      *normals;
+  LIST_TYPE(V2f)      *texture_coordinates;
+  LIST_TYPE(Triangle) *triangles;
+  Image               *texture;
+  Image               *normal;
 };
 
-Model load_obj_file(Arena *arena, const char *filename, const char *diffuse,
-                    const char *tangent);
+Model load_obj_file(Arena *arena, const char *filename, const char *diffuse, const char *tangent);
 
 #endif // OBJ_H

src/model/render.c

@@ -6,8 +6,11 @@
 #include "typed_list.h"
 #include "utils.h"
 #include "vec.h"
+#include <stdint.h>
 #include <math.h>
 
+Render g_render_passes[COUNT_RENDER_PASS] = {0};
+
 typedef struct triangle_bbox TriangleBBox;
 struct triangle_bbox {
   u64 x0;
@@ -16,16 +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,
-                            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);
+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};
@@ -44,8 +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);
@@ -53,9 +52,8 @@ 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);
   VertexData vertices[TRIANGLE_VERTICES];
   for (u64 i = 0; i < TRIANGLE_VERTICES; ++i) {
@@ -80,12 +78,10 @@ internal void render_triangle(const Triangle *triangle, const Model *model,
   }
 }
 
-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);
+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);
 
   V2f vp_verts[TRIANGLE_VERTICES] = {0};
   for (u64 i = 0; i < TRIANGLE_VERTICES; ++i) {
@@ -94,10 +90,12 @@ internal void fill_triangle(Render *render, ShaderID shader,
 
   TriangleBBox bbox = get_triangle_bbox(img, vp_verts);
 
-  V2f point;
-  V3f coords;
-  f32 z;
-  f32 zbuf;
+  V2f            point;
+  V3f            coords;
+  f32            z;
+  f32            zbuf;
+  V4f            shader_colour;
+  Colour         output_colour;
   FragmentResult result;
 
   f32 intensity = 1.0f;
@@ -110,29 +108,36 @@ internal void fill_triangle(Render *render, ShaderID shader,
         continue;
       }
 
-      z     = 0.0f;
+      z    = 0.0f;
       z    += vertices[0].position.z * coords.x +
-           vertices[1].position.z * coords.y +
-           vertices[2].position.z * coords.z;
+              vertices[1].position.z * coords.y +
+              vertices[2].position.z * coords.z;
       zbuf = get_pixel(f32, &(render->depth), x, y);
 
       if (z <= zbuf) {
         continue;
       }
 
-      result = run_fragment_shader(shader, &coords, &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,
-                                        V2f 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));

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

@@ -1,11 +1,12 @@
 #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) {
+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);
@@ -15,17 +16,15 @@ VertexData general_shader_vertex(void *shader, const VertexData *vert, u8 index,
   shdr->vertices[index].position = project_vec4(vh);
   shdr->vertices[index].uv       = vert->uv;
 
-  M4x4f inv_transpose          = mat4x4_inv(mat4x4_transpose(shdr->proj_mv));
   V4f hnorm                    = V3_to_V4(vert->normal);
-  hnorm                        = mat4x4_mul_vec4(inv_transpose, hnorm);
+  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 Colour *colour,
+FragmentResult diffuse_shader_fragment(void *shader, const V3f *barycentric, const V4f *colour,
                                        const Model *model) {
   Shader *shdr = (Shader *)shader;
 
@@ -40,6 +39,15 @@ FragmentResult diffuse_shader_fragment(void *shader, const V3f *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
@@ -50,8 +58,8 @@ FragmentResult diffuse_shader_fragment(void *shader, const V3f *barycentric,
     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){
+    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,
@@ -60,7 +68,7 @@ FragmentResult diffuse_shader_fragment(void *shader, const V3f *barycentric,
     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     = {.rows = {p0p1, p0p2, normal}};
     M3x3f A_inv = mat3x3_inv(A);
 
     V2f uv0 = shdr->vertices[0].uv;
@@ -83,11 +91,12 @@ FragmentResult diffuse_shader_fragment(void *shader, const V3f *barycentric,
   }
 #pragma endregion darboux_frame_tangent_normals
 
-  Colour output;
+  V4f output;
   if (model->texture) {
-    u64 tx_x = uv.u * model->texture->width;
-    u64 tx_y = uv.v * model->texture->height;
-    output   = get_pixel(Colour, model->texture, tx_x, tx_y);
+    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;
   }
@@ -97,30 +106,27 @@ FragmentResult diffuse_shader_fragment(void *shader, const V3f *barycentric,
   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;
-  output.g *= g;
-  output.b *= b;
+  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 Colour *colour,
+FragmentResult albedo_shader_fragment(void *shader, const V3f *barycentric, const V4f *colour,
                                       const Model *model) {
   Shader *shdr = (Shader *)shader;
 
-  // clang-format off
-  M3x2f uvs = {shdr->vertices[0].uv, shdr->vertices[1].uv, shdr->vertices[2].uv};
+  M3x2f uvs    = {shdr->vertices[0].uv, shdr->vertices[1].uv, shdr->vertices[2].uv};
   M2x3f uv_mat = mat3x2_transpose(uvs);
-  // clang-format on
+  V2f   uv     = mat2x3_mul_vec3(uv_mat, (*barycentric));
 
-  V2f uv = mat2x3_mul_vec3(uv_mat, (*barycentric));
-
-  Colour output;
+  V4f output;
   if (model->texture) {
-    u64 tx_x = uv.u * model->texture->width;
-    u64 tx_y = uv.v * model->texture->height;
-    output   = get_pixel(Colour, model->texture, tx_x, tx_y);
+    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;
   }

src/shader/main_shader.h

@@ -6,14 +6,13 @@
 
 typedef struct shader Shader;
 struct shader {
-#include "shader_base.inc"
+  #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 Colour *colour,
+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 Colour *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

@@ -5,36 +5,33 @@
 
 typedef struct shader_repo ShaderRepo;
 struct shader_repo {
-  void *shaders[MAX_SHADER_COUNT];
-  VertexShader *vertex_funcs[MAX_SHADER_COUNT];
+  void           *shaders[MAX_SHADER_COUNT];
+  VertexShader   *vertex_funcs[MAX_SHADER_COUNT];
   FragmentShader *fragment_funcs[MAX_SHADER_COUNT];
-  u64 count;
+  u64            count;
 };
 
 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;
   }
 
   ++(g_repository.count);
-  g_repository.shaders[g_repository.count] = shader;
-  g_repository.vertex_funcs[g_repository.count] = vertex;
+  g_repository.shaders[g_repository.count]        = shader;
+  g_repository.vertex_funcs[g_repository.count]   = vertex;
   g_repository.fragment_funcs[g_repository.count] = fragment;
 
   return (ShaderID){g_repository.count};
 }
 
-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) {
+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];
+  void *shader_obj          = g_repository.shaders[shader.id];
   VertexShader *vertex_func = g_repository.vertex_funcs[shader.id];
 
   if (!shader_obj || !vertex_func) {
@@ -44,13 +41,13 @@ VertexData run_vertex_shader(ShaderID shader, const VertexData *vert, u8 index,
   return vertex_func(shader_obj, vert, index, model);
 }
 
-FragmentResult run_fragment_shader(ShaderID shader, const V3f *barycentric,
-                                   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;
   }
 
-  void *shader_obj = g_repository.shaders[shader.id];
+  void *shader_obj              = g_repository.shaders[shader.id];
   FragmentShader *fragment_func = g_repository.fragment_funcs[shader.id];
 
   if (!shader_obj || !fragment_func) {

src/shader/shader.h

@@ -2,7 +2,6 @@
 #define SHADER_H
 
 #include "aliases.h"
-#include "img.h"
 #include "obj.h"
 #include "vec.h"
 
@@ -20,26 +19,21 @@ struct vertex_data {
 
 typedef struct fragment_result FragmentResult;
 struct fragment_result {
-  Colour colour;
+  V4f  colour;
   bool discard;
 };
 
-#define INVALID_SHADER ((ShaderID){0})
-#define IS_INVALID_SHADER(ID) (ID.id == 0)
-#define DISCARDED_FRAGMENT ((FragmentResult){.discard = true})
+#define INVALID_SHADER           ((ShaderID){0})
+#define IS_INVALID_SHADER(ID)    (ID.id == 0)
+#define DISCARDED_FRAGMENT       ((FragmentResult){.discard = true})
 #define DISCARD_FRAGMENT(RESULT) (RESULT.discard)
 
-typedef VertexData(VertexShader)(void *shader, const VertexData *vert, u8 index,
-                                 const Model *model);
-typedef FragmentResult(FragmentShader)(void *shader, const V3f *barycentric,
-                                       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);
-VertexData run_vertex_shader(ShaderID shader, const VertexData *vert, u8 index,
-                             const Model *model);
-FragmentResult run_fragment_shader(ShaderID shader, const V3f *barycentric,
-                                   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

@@ -4,4 +4,5 @@ M4x4f proj_mv;
 M4x4f proj_mv_inv_t;
 M4x4f viewport;
 M4x4f final;
+M4x4f final_inv;
 VertexData vertices[TRIANGLE_VERTICES];

src/shader/shaders.c

@@ -1,20 +1,20 @@
 #include "shaders.h"
 #include "aliases.h"
-#include "depth_shader.h"
+#include "shadow_shader.h"
 #include "main_shader.h"
 #include "render.h"
 #include "shader.h"
 #include "vec.h"
 
+ShaderID depth                = {0};
 ShaderID perspective_diffuse  = {0};
 ShaderID perspective_albedo   = {0};
 ShaderID orthographic_diffuse = {0};
 ShaderID orthographic_albedo  = {0};
-ShaderID depth                = {0};
 
-internal Shader perspective       = {0};
-internal Shader orthographic      = {0};
-internal DepthShader depth_shader = {0};
+internal ShadowShader depth_shader = {0};
+internal Shader       perspective  = {0};
+internal Shader       orthographic = {0};
 
 internal V3f g_ambient_light = {0.1f, 0.1f, 0.1f};
 internal V3f g_eye           = {0.2f, -0.1f, 0.5f};
@@ -25,6 +25,19 @@ internal V3f g_light_dir     = {1.0f, -1.0f, 1.0f};
 internal M4x4f get_projection_matrix(ProjectionType projection_type);
 
 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);
@@ -34,36 +47,29 @@ void load_shaders(M4x4f vp) {
   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.ambient       = g_ambient_light;
+  perspective.shadow_matrix = mat4x4_mul(depth_shader.final, perspective.final_inv);
 
   // 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;
 
-  // Set up depth shader
-  M4x4f depth_model_view = lookat(g_light_dir, g_target, g_up);
-  M4x4f depth_projection = projection(0.0f);
-
-  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);
-
   // Register shaders
-  perspective_diffuse  = register_shader(&perspective, general_shader_vertex, diffuse_shader_fragment);
-  perspective_albedo   = register_shader(&perspective, general_shader_vertex, albedo_shader_fragment);
+  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);
-  depth                = register_shader(&depth_shader, depth_shader_vertex, depth_shader_fragment);
 }
 
 internal M4x4f get_projection_matrix(ProjectionType projection_type) {

src/shader/shaders.h

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

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

@@ -6,9 +6,6 @@
 
 #define CAPACITY_SCALAR 4
 
-internal Arena *get_temp_arena(void);
-internal void destroy_temp_arena(Arena *arena);
-
 Str8 str8(Arena *arena, char *str) {
   if (!str) {
     return (Str8){0};

src/str/str.h

@@ -12,15 +12,15 @@ enum {
 typedef struct str8 Str8;
 struct str8 {
   char *str;
-  u64 length;
-  u64 capacity;
+  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);
+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

@@ -29,14 +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) {

src/vec/vec.h

@@ -55,10 +55,22 @@ typedef union f32x4 V4f;
 union f32x4 {
   f32 elements[4];
   struct {
-    f32 x;
-    f32 y;
-    f32 z;
-    f32 w;
+    union {
+      f32 x;
+      f32 r;
+    };
+    union {
+      f32 y;
+      f32 g;
+    };
+    union {
+      f32 z;
+      f32 b;
+    };
+    union {
+      f32 w;
+      f32 a;
+    };
   };
 };
 
@@ -123,6 +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)