Implement rendering model with texture

src/img.h

@@ -6,7 +6,7 @@
 #include <stdbool.h>
 
 #define BUF_TYPE(TYPE, NAME)                                                   \
-  typedef struct {                                                             \
+  typedef struct NAME {                                                        \
     u64 width;                                                                 \
     u64 height;                                                                \
     TYPE *buf;                                                                 \

src/main.c

@@ -31,7 +31,8 @@ int main(void) {
     return TINY_EXIT_RENDER_INIT_FAILED;
   }
 
-  Model model = load_obj_file(arena, "resources/head.obj");
+  Model model =
+      load_obj_file(arena, "resources/head_new.obj", "resources/head.pnm");
   if (IS_NULL_MODEL(model)) {
     return TINY_EXIT_MODEL_LOAD_FAILED;
   }

src/obj.c

@@ -2,6 +2,7 @@
 #include "aliases.h"
 #include "img.h"
 #include "mem_arena.h"
+#include "pam.h"
 #include "typed_list.h"
 #include "utils.h"
 #include <limits.h>
@@ -72,19 +73,20 @@ struct f32_3x3 {
 internal void render_triangle(const Triangle *triangle, const Model *model,
                               Render *render, Colour colour, RenderType type);
 internal void fill_triangle(Render *render, Vertex vertices[TRIANGLE_VERTICES],
-                            Colour colour);
+                            TexCoord coordinates[TRIANGLE_VERTICES],
+                            Colour colour, f32 intensity, Image *texture);
 internal TriangleBBox get_triangle_bbox(const Image *img,
                                         Vertex vertices[TRIANGLE_VERTICES]);
 internal V3f get_barycentric_coords(f32 d00, f32 d01, f32 d11, f32 denom,
                                     const V2i *ab, const V2i *ac,
                                     const V2i *ap);
-internal void get_image_coordinates(const Vertex *vertex, const Image *img,
+internal void get_image_coordinates(f32 norm_x, f32 norm_y, const Image *img,
                                     u64 *x, u64 *y);
 internal u64 ndc_to_image_coordinate(f32 value, u64 max);
 
 V3f g_light_dir = {0.0f, 0.0f, -1.0f};
 
-Model load_obj_file(Arena *arena, const char *filename) {
+Model load_obj_file(Arena *arena, const char *filename, const char *texture) {
   if (!arena) {
     return NULL_MODEL;
   }
@@ -96,21 +98,25 @@ Model load_obj_file(Arena *arena, const char *filename) {
 
   Model model = (Model){
       .vertices = list_create(Vertex, arena),
+      .texture_coordinates = list_create(TexCoord, arena),
       .triangles = list_create(Triangle, arena),
   };
-  if (!(model.vertices) || !(model.triangles)) {
+  if (!(model.vertices) || !(model.texture_coordinates) || !(model.triangles)) {
     return NULL_MODEL;
   }
 
   char line[8192];
   char identifier[8];
   Vertex vertex;
+  TexCoord coord;
   Triangle triangle;
   f32 vx, vy, vz;
+  f32 u, v;
   u64 fp0, fp1, fp2;
-  u64 ign_0_1, ign_0_2;
-  u64 ign_1_1, ign_1_2;
-  u64 ign_2_1, ign_2_2;
+  u64 tx0, tx1, tx2;
+  u64 ign_0_2;
+  u64 ign_1_2;
+  u64 ign_2_2;
   while (fgets(line, 8191, fp) != NULL) {
     sscanf(line, "%s", identifier);
     if (strncmp(identifier, "v", 8) == 0) {
@@ -119,17 +125,29 @@ Model load_obj_file(Arena *arena, const char *filename) {
       vertex.y = vy;
       vertex.z = vz;
       list_append(Vertex, arena, model.vertices, vertex);
+    } else if (strncmp(identifier, "vt", 8) == 0) {
+      sscanf(line + 2, "%f %f", &u, &v);
+      coord.u = u;
+      coord.v = v;
+      list_append(TexCoord, 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, &ign_0_1,
-             &ign_0_2, &fp1, &ign_1_1, &ign_1_2, &fp2, &ign_2_1, &ign_2_2);
+      sscanf(line + 2, "%lu/%lu/%lu %lu/%lu/%lu %lu/%lu/%lu", &fp0, &tx0,
+             &ign_0_2, &fp1, &tx1, &ign_1_2, &fp2, &tx2, &ign_2_2);
       // OBJ indices start from 1
       triangle.p0 = fp0 - 1;
       triangle.p1 = fp1 - 1;
       triangle.p2 = fp2 - 1;
+      triangle.tx0 = tx0 - 1;
+      triangle.tx1 = tx1 - 1;
+      triangle.tx2 = tx2 - 1;
       list_append(Triangle, arena, model.triangles, triangle);
     }
   }
 
+  if (texture) {
+    model.texture = load_p6_image(arena, texture);
+  }
+
   return model;
 }
 
@@ -174,6 +192,11 @@ internal void render_triangle(const Triangle *triangle, const Model *model,
       list_get(model->vertices, triangle->p1),
       list_get(model->vertices, triangle->p2),
   };
+  TexCoord coordinates[TRIANGLE_VERTICES] = {
+      list_get(model->texture_coordinates, triangle->tx0),
+      list_get(model->texture_coordinates, triangle->tx1),
+      list_get(model->texture_coordinates, triangle->tx2),
+  };
 
   if (type == RENDER_TYPE_WIREFRAME) {
     Vertex v0, v1;
@@ -182,8 +205,8 @@ internal void render_triangle(const Triangle *triangle, const Model *model,
       v0 = vertices[i];
       v1 = vertices[(i + 1) % TRIANGLE_VERTICES];
 
-      get_image_coordinates(&v0, img, &x0, &y0);
-      get_image_coordinates(&v1, img, &x1, &y1);
+      get_image_coordinates(v0.x, v0.y, img, &x0, &y0);
+      get_image_coordinates(v1.x, v1.y, img, &x1, &y1);
 
       draw_line(img, x0, y0, x1, y1, colour);
     }
@@ -200,28 +223,26 @@ internal void render_triangle(const Triangle *triangle, const Model *model,
       normalise_v3(normal);
 
       intensity = dot_v3(normal, g_light_dir);
-
-      colour.r *= intensity;
-      colour.g *= intensity;
-      colour.b *= intensity;
     }
 
     if (intensity > 0.0f) {
-      fill_triangle(render, vertices, colour);
+      fill_triangle(render, vertices, coordinates, colour, intensity,
+                    model->texture);
     }
   }
 }
 
 internal void fill_triangle(Render *render, Vertex vertices[TRIANGLE_VERTICES],
-                            Colour colour) {
+                            TexCoord coordinates[TRIANGLE_VERTICES],
+                            Colour colour, f32 intensity, Image *texture) {
   Image *img = &(render->img);
   Depth *depth = &(render->depth);
   TriangleBBox bbox = get_triangle_bbox(img, vertices);
 
   u64 v0x, v0y, v1x, v1y, v2x, v2y;
-  get_image_coordinates(&(vertices[0]), img, &v0x, &v0y);
-  get_image_coordinates(&(vertices[1]), img, &v1x, &v1y);
-  get_image_coordinates(&(vertices[2]), img, &v2x, &v2y);
+  get_image_coordinates(vertices[0].x, vertices[0].y, img, &v0x, &v0y);
+  get_image_coordinates(vertices[1].x, vertices[1].y, img, &v1x, &v1y);
+  get_image_coordinates(vertices[2].x, vertices[2].y, img, &v2x, &v2y);
 
   V2i ab = V2(V2i, i64, v0x, v0y, v1x, v1y);
   V2i ac = V2(V2i, i64, v0x, v0y, v2x, v2y);
@@ -233,6 +254,14 @@ internal void fill_triangle(Render *render, Vertex vertices[TRIANGLE_VERTICES],
   V3f coords;
   f32 z;
   f32 zbuf;
+  f32 tx_u, tx_v;
+  u64 tx_x, tx_y;
+
+  if (!texture) {
+    colour.r *= intensity;
+    colour.g *= intensity;
+    colour.b *= intensity;
+  }
 
   for (u64 y = bbox.y0; y < bbox.y1; ++y) {
     for (u64 x = bbox.x0; x < bbox.x1; ++x) {
@@ -248,6 +277,20 @@ internal void fill_triangle(Render *render, Vertex vertices[TRIANGLE_VERTICES],
       zbuf = get_pixel(f32, &(render->depth), x, y);
 
       if (z > zbuf) {
+        if (texture) {
+          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;
+          tx_x = tx_u * texture->width;
+          tx_y = (1.0f - tx_v) * texture->height;
+
+          colour = get_pixel(Colour, texture, tx_x, tx_y);
+          colour.r *= intensity;
+          colour.g *= intensity;
+          colour.b *= intensity;
+        }
+
         set_pixel(depth, x, y, &z);
         set_pixel(img, x, y, &colour);
       }
@@ -264,12 +307,11 @@ internal TriangleBBox get_triangle_bbox(const Image *img,
   f32 y0 = max(vertices[0].y, max(vertices[1].y, vertices[2].y));
   f32 y1 = min(vertices[0].y, min(vertices[1].y, vertices[2].y));
 
-  return (TriangleBBox){
-      .x0 = ndc_to_image_coordinate(x0, img->width),
-      .y0 = ndc_to_image_coordinate(0.0f - y0, img->height),
-      .x1 = ndc_to_image_coordinate(x1, img->width),
-      .y1 = ndc_to_image_coordinate(0.0f - y1, img->height),
-  };
+  TriangleBBox bbox = {0};
+  get_image_coordinates(x0, y0, img, &(bbox.x0), &(bbox.y0));
+  get_image_coordinates(x1, y1, img, &(bbox.x1), &(bbox.y1));
+
+  return bbox;
 }
 
 internal V3f get_barycentric_coords(f32 d00, f32 d01, f32 d11, f32 denom,
@@ -285,10 +327,10 @@ internal V3f get_barycentric_coords(f32 d00, f32 d01, f32 d11, f32 denom,
   return (V3f){v, w, u};
 }
 
-internal void get_image_coordinates(const Vertex *vertex, const Image *img,
+internal void get_image_coordinates(f32 norm_x, f32 norm_y, const Image *img,
                                     u64 *x, u64 *y) {
-  *x = ndc_to_image_coordinate(vertex->x, img->width);
-  *y = ndc_to_image_coordinate(0.0f - vertex->y, img->height);
+  *x = ndc_to_image_coordinate(norm_x, img->width);
+  *y = ndc_to_image_coordinate(0.0f - norm_y, img->height);
 }
 
 internal u64 ndc_to_image_coordinate(f32 value, u64 max) {

src/obj.h

@@ -16,11 +16,20 @@ struct vertex {
   f32 z;
 };
 
+typedef struct texcoord TexCoord;
+struct texcoord {
+  f32 u;
+  f32 v;
+};
+
 typedef struct triangle Triangle;
 struct triangle {
   u64 p0;
   u64 p1;
   u64 p2;
+  u64 tx0;
+  u64 tx1;
+  u64 tx2;
 };
 
 typedef enum {
@@ -39,12 +48,15 @@ typedef enum {
 } ColourType;
 
 MAKE_LIST_TYPE(Vertex);
+MAKE_LIST_TYPE(TexCoord);
 MAKE_LIST_TYPE(Triangle);
 
 typedef struct model Model;
 struct model {
   LIST_TYPE(Vertex) * vertices;
+  LIST_TYPE(TexCoord) * texture_coordinates;
   LIST_TYPE(Triangle) * triangles;
+  Image *texture;
 };
 
 typedef struct render Render;
@@ -53,7 +65,7 @@ struct render {
   Depth depth;
 };
 
-Model load_obj_file(Arena *arena, const char *filename);
+Model load_obj_file(Arena *arena, const char *filename, const char *texture);
 bool init_render(Arena *arena, Render *render, u64 width, u64 height);
 void render_model(const Model *model, Render *render, Colour colour,
                   RenderType type, ColourType colour_type);

src/pam.c

@@ -1,4 +1,8 @@
 #include "pam.h"
+#include "img.h"
+#include "mem_arena.h"
+#include <stddef.h>
+#include <stdint.h>
 #include <stdio.h>
 #include <string.h>
 
@@ -28,3 +32,57 @@ void write_p7_image(u64 width, u64 height, u8 *buf, const char *outfile) {
 
   fclose(fp);
 }
+
+Image *load_p6_image(Arena *arena, const char *filename) {
+  Image *output = NULL;
+
+  if (!arena || !filename) {
+    goto RETURN_VALUE;
+  }
+
+  FILE *fp = fopen(filename, "rb");
+  if (!fp) {
+    goto RETURN_VALUE;
+  }
+
+  char type[4] = {0};
+  fread(type, 3, 1, fp);
+  if (strncmp(type, "P6\n", 4) != 0) {
+    goto CLOSE_FILE;
+  }
+
+  u64 w, h;
+  fscanf(fp, "%lu %lu\n", &w, &h);
+
+  u64 max;
+  fscanf(fp, "%lu\n", &max);
+  if (max > UINT8_MAX) {
+    goto CLOSE_FILE;
+  }
+
+  output = wapp_mem_arena_alloc(arena, sizeof(Image));
+  if (!output) {
+    goto CLOSE_FILE;
+  }
+
+  output->width = w;
+  output->height = h;
+  if (!init_buffer(arena, output)) {
+    goto CLOSE_FILE;
+  }
+
+  Colour colour = {0};
+  for (u64 y = 0; y < h; ++y) {
+    for (u64 x = 0; x < w; ++x) {
+      fread(&colour, 3, 1, fp);
+      colour.a = 255;
+      set_pixel(output, x, y, &colour);
+    }
+  }
+
+CLOSE_FILE:
+  fclose(fp);
+
+RETURN_VALUE:
+  return output;
+}

src/pam.h

@@ -2,7 +2,9 @@
 #define PAM_H
 
 #include "aliases.h"
+#include "img.h"
 
 void write_p7_image(u64 width, u64 height, u8 *buf, const char *outfile);
+Image *load_p6_image(Arena *arena, const char *filename);
 
 #endif // PAM_H