From bce85c5c71a8f5159fc116be819a0e089fe8499c Mon Sep 17 00:00:00 2001
From: Abdelrahman <said.abdelrahman89@gmail.com>
Date: Sun, 4 Aug 2024 14:38:52 +0100
Subject: [PATCH] Prep for adding z buffer

---
 src/main.c | 14 +++++++-------
 src/obj.c  | 28 +++++++++++++++++++++-------
 src/obj.h  |  9 ++++++++-
 3 files changed, 36 insertions(+), 15 deletions(-)

diff --git a/src/main.c b/src/main.c
index b01779d..17c0f66 100644
--- a/src/main.c
+++ b/src/main.c
@@ -10,7 +10,7 @@
 enum {
   TINY_EXIT_SUCCESS,
   TINY_EXIT_ARENA_INIT_FAILED,
-  TINY_EXIT_IMAGE_INIT_FAILED,
+  TINY_EXIT_RENDER_INIT_FAILED,
   TINY_EXIT_MODEL_LOAD_FAILED,
 };
 
@@ -26,9 +26,9 @@ int main(void) {
   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};
-  Image img = {.width = 1200, .height = 1200};
-  if (!init_image(arena, &img)) {
-    return TINY_EXIT_IMAGE_INIT_FAILED;
+  Render render;
+  if (!init_render(arena, &render, 1200, 1200)) {
+    return TINY_EXIT_RENDER_INIT_FAILED;
   }
 
   Model model = load_obj_file(arena, "resources/head.obj");
@@ -36,9 +36,9 @@ int main(void) {
     return TINY_EXIT_MODEL_LOAD_FAILED;
   }
 
-  clear_image(&img, bg);
-  render_model(&model, &img, teal, RENDER_TYPE_SHADED, COLOUR_TYPE_FIXED);
-  save_image(&img, "result.pam");
+  clear_image(&(render.img), bg);
+  render_model(&model, &render, teal, RENDER_TYPE_SHADED, COLOUR_TYPE_FIXED);
+  save_image(&(render.img), "result.pam");
 
   wapp_mem_arena_destroy(&arena);
 
diff --git a/src/obj.c b/src/obj.c
index 3386b07..246d83c 100644
--- a/src/obj.c
+++ b/src/obj.c
@@ -69,8 +69,8 @@ struct f32_3x3 {
 };
 
 internal void render_triangle(const Triangle *triangle, const Model *model,
-                              Image *img, Colour colour, RenderType type);
-internal void fill_triangle(Image *img, Vertex vertices[TRIANGLE_VERTICES],
+                              Render *render, Colour colour, RenderType type);
+internal void fill_triangle(Render *render, Vertex vertices[TRIANGLE_VERTICES],
                             Colour colour);
 internal TriangleBBox get_triangle_bbox(const Image *img,
                                         Vertex vertices[TRIANGLE_VERTICES]);
@@ -132,7 +132,19 @@ Model load_obj_file(Arena *arena, const char *filename) {
   return model;
 }
 
-void render_model(const Model *model, Image *img, Colour colour,
+bool init_render(Arena *arena, Render *render, u64 width, u64 height) {
+  render->img = (Image){.width = width, .height = height};
+  render->zbuf = (Image){.width = width, .height = height};
+
+  if (!init_image(arena, &(render->img)) ||
+      !init_image(arena, &(render->zbuf))) {
+    return false;
+  }
+
+  return true;
+}
+
+void render_model(const Model *model, Render *render, Colour colour,
                   RenderType type, ColourType colour_type) {
   Triangle triangle;
 
@@ -144,12 +156,13 @@ void render_model(const Model *model, Image *img, Colour colour,
                         .b = rand() % UINT8_MAX,
                         .a = 255};
     }
-    render_triangle(&triangle, model, img, colour, type);
+    render_triangle(&triangle, model, render, colour, type);
   }
 }
 
 internal void render_triangle(const Triangle *triangle, const Model *model,
-                              Image *img, Colour colour, RenderType type) {
+                              Render *render, Colour colour, RenderType type) {
+  Image *img = &(render->img);
   Vertex vertices[TRIANGLE_VERTICES] = {
       list_get(model->vertices, triangle->p0),
       list_get(model->vertices, triangle->p1),
@@ -188,13 +201,14 @@ internal void render_triangle(const Triangle *triangle, const Model *model,
     }
 
     if (intensity > 0.0f) {
-      fill_triangle(img, vertices, colour);
+      fill_triangle(render, vertices, colour);
     }
   }
 }
 
-internal void fill_triangle(Image *img, Vertex vertices[TRIANGLE_VERTICES],
+internal void fill_triangle(Render *render, Vertex vertices[TRIANGLE_VERTICES],
                             Colour colour) {
+  Image *img = &(render->img);
   TriangleBBox bbox = get_triangle_bbox(img, vertices);
 
   u64 v0x, v0y, v1x, v1y, v2x, v2y;
diff --git a/src/obj.h b/src/obj.h
index 6c70ef4..1f07fc3 100644
--- a/src/obj.h
+++ b/src/obj.h
@@ -47,8 +47,15 @@ struct model {
   LIST_TYPE(Triangle) * triangles;
 };
 
+typedef struct render Render;
+struct render {
+  Image img;
+  Image zbuf;
+};
+
 Model load_obj_file(Arena *arena, const char *filename);
-void render_model(const Model *model, Image *img, Colour colour,
+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);
 
 #endif // OBJ_H