From 616c2a5903c9da722f4c06607da2705e7bc6a282 Mon Sep 17 00:00:00 2001
From: 3gg <3gg@shellblade.net>
Date: Wed, 21 Jun 2023 08:53:09 -0700
Subject: Make camera optional in the renderer and move start/end frame calls
 outside so that it can be used along the imm renderer.

---
 gfx/src/renderer/renderer.c | 26 ++++++++++++++++----------
 gltfview/src/game.c         |  7 ++++++-
 2 files changed, 22 insertions(+), 11 deletions(-)

diff --git a/gfx/src/renderer/renderer.c b/gfx/src/renderer/renderer.c
index bddde90..ac6a45f 100644
--- a/gfx/src/renderer/renderer.c
+++ b/gfx/src/renderer/renderer.c
@@ -264,7 +264,10 @@ static void draw_recursively(
       gfx_set_mat4_uniform(shader, "CameraRotation", state->camera_rotation);
       gfx_set_float_uniform(shader, "Fovy", state->fovy);
       gfx_set_float_uniform(shader, "Aspect", state->aspect);
-      gfx_set_vec3_uniform(shader, "CameraPosition", state->camera->spatial.p);
+      if (state->camera) {
+        gfx_set_vec3_uniform(
+            shader, "CameraPosition", state->camera->spatial.p);
+      }
       if (state->num_joints > 0) {
         gfx_set_mat4_array_uniform(
             shader, "JointMatrices", state->joint_matrices, state->num_joints);
@@ -309,7 +312,6 @@ void gfx_render_scene(Renderer* renderer, const RenderSceneParams* params) {
   assert(renderer);
   assert(params);
   assert(params->scene);
-  assert(params->camera);
 
   ShaderProgram* const shader = load_shader(renderer, params->mode);
 
@@ -318,11 +320,17 @@ void gfx_render_scene(Renderer* renderer, const RenderSceneParams* params) {
 
   RenderBackend* render_backend = renderer->render_backend;
 
-  const mat4 projection = camera ? camera->camera.projection : mat4_id();
-  const mat4 camera_rotation =
-      mat4_rotation(spatial3_transform(&camera->camera.spatial));
-  const mat4 view_matrix =
-      camera ? spatial3_inverse_transform(&camera->camera.spatial) : mat4_id();
+  mat4 projection, camera_rotation, view_matrix;
+  if (camera) {
+    projection = camera->camera.projection;
+    camera_rotation =
+        mat4_rotation(spatial3_transform(&camera->camera.spatial));
+    view_matrix = spatial3_inverse_transform(&camera->camera.spatial);
+  } else {
+    projection      = mat4_id();
+    camera_rotation = mat4_id();
+    view_matrix     = mat4_id();
+  }
 
   int width, height;
   gfx_get_viewport(render_backend, &width, &height);
@@ -341,8 +349,6 @@ void gfx_render_scene(Renderer* renderer, const RenderSceneParams* params) {
       // Assuming a perspective matrix.
       .fovy   = atan(1.0 / (mat4_at(projection, 1, 1))) * 2,
       .aspect = aspect};
-
-  gfx_start_frame(render_backend);
+  
   draw_recursively(&state, mat4_id(), scene->root);
-  gfx_end_frame(render_backend);
 }
diff --git a/gltfview/src/game.c b/gltfview/src/game.c
index d618447..5ca9ad4 100644
--- a/gltfview/src/game.c
+++ b/gltfview/src/game.c
@@ -130,7 +130,10 @@ void game_update(Game* game, double t, double dt) {
 }
 
 void game_render(const Game* game) {
-  Renderer* renderer = gfx_get_renderer(game->gfx);
+  RenderBackend* render_backend = gfx_get_render_backend(game->gfx);
+  Renderer*      renderer       = gfx_get_renderer(game->gfx);
+
+  gfx_start_frame(render_backend);
 
   gfx_render_scene(
       renderer,
@@ -142,6 +145,8 @@ void game_render(const Game* game) {
     void* plugin_state = get_plugin_state(game->plugin);
     plugin_call(game->plugin, plugin_render, "render", plugin_state, game);
   }
+
+  gfx_end_frame(render_backend);
 }
 
 void game_set_viewport(Game* game, int width, int height) {
-- 
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