Add support for randomising colours

src/main.c

@@ -5,6 +5,7 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+#include <time.h>
 
 enum {
   TINY_EXIT_SUCCESS,
@@ -20,6 +21,8 @@ int main(void) {
     return TINY_EXIT_ARENA_INIT_FAILED;
   }
 
+  srand(time(NULL));
+
   Colour bg = {.r = 42, .g = 45, .b = 52, .a = 255};
   Colour teal = {.r = 14, .g = 156, .b = 208, .a = 255};
   Colour orange = {.r = 242, .g = 100, .b = 48, .a = 255};
@@ -34,8 +37,8 @@ int main(void) {
   }
 
   clear_image(&img, bg);
-  render_model(&model, &img, teal, RENDER_TYPE_FILLED);
-  render_model(&model, &img, orange, RENDER_TYPE_WIREFRAME);
+  render_model(&model, &img, teal, RENDER_TYPE_FILLED, COLOUR_TYPE_RANDOM);
+  render_model(&model, &img, orange, RENDER_TYPE_WIREFRAME, COLOUR_TYPE_FIXED);
   save_image(&img, "result.pam");
 
   wapp_mem_arena_destroy(&arena);

src/obj.c

@@ -4,7 +4,9 @@
 #include "mem_arena.h"
 #include "typed_list.h"
 #include "utils.h"
+#include <limits.h>
 #include <stdio.h>
+#include <stdlib.h>
 
 #define TRIANGLE_VERTICES 3
 #define dot_v2(V1, V2) ((f32)V1.x * (f32)V2.x + (f32)V1.y * (f32)V2.y)
@@ -111,11 +113,17 @@ Model load_obj_file(Arena *arena, const char *filename) {
 }
 
 void render_model(const Model *model, Image *img, Colour colour,
-                  RenderType type) {
+                  RenderType type, ColourType colour_type) {
   Triangle triangle;
 
   for (u64 i = 0; i < model->triangles->count; ++i) {
     triangle = list_get(model->triangles, i);
+    if (colour_type == COLOUR_TYPE_RANDOM) {
+      colour = (Colour){.r = rand() % UINT8_MAX,
+                        .g = rand() % UINT8_MAX,
+                        .b = rand() % UINT8_MAX,
+                        .a = 255};
+    }
     render_triangle(&triangle, model, img, colour, type);
   }
 }

src/obj.h

@@ -30,6 +30,13 @@ typedef enum {
   COUNT_RENDER_TYPES,
 } RenderType;
 
+typedef enum {
+  COLOUR_TYPE_FIXED,
+  COLOUR_TYPE_RANDOM,
+
+  COUNT_COLOUR_TYPE,
+} ColourType;
+
 MAKE_LIST_TYPE(Vertex);
 MAKE_LIST_TYPE(Triangle);
 
@@ -41,6 +48,6 @@ struct model {
 
 Model load_obj_file(Arena *arena, const char *filename);
 void render_model(const Model *model, Image *img, Colour colour,
-                  RenderType type);
+                  RenderType type, ColourType colour_type);
 
 #endif // OBJ_H