21 files changed, 234 insertions, 271 deletions

diff --git a/CMakeLists.txt b/CMakeLists.txt
index de5f0dd..cda7b1b 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -50,9 +50,6 @@ add_library(gfx SHARED
   src/core/shader.c
   src/core/texture.c
   src/llr/llr.c
-  src/llr/light.c
-  src/llr/material.c
-  src/llr/mesh.c
   src/memory.c
   src/renderer/imm_renderer.c
   src/renderer/renderer.c
diff --git a/README.md b/README.md
index 491761d..3a30ee4 100644
--- a/README.md
+++ b/README.md
@@ -23,7 +23,7 @@ The `Gfx` object represents the graphics subsystem and is at the center of the
 library's high-level API. The `Gfx` object exposes a render backend (`GfxCore`)
 and a `Renderer`, and allows the caller to create `Scene`s.
 
-### Render Backend
+### Render Backend ("Core")
 
 The render backend (`GfxCore`) is a thin abstraction layer over low-level
 graphics APIs like OpenGL or Vulkan. It holds GPU resources such as geometry,
@@ -43,7 +43,17 @@ manage resource lifetime.
 
 ### Low-level Renderer
 
-`ImmRenderer` is a low-level, immediate mode renderer.
+The low-level renderer (`LLR`) provides a low-level, immediate-mode interface
+on top of the render backend. It understands higher-level concepts to make
+rendering more convenient (object, mesh, material, light, camera, etc), but is
+still relatively low-level and does not understand any particular scene data
+structure.
+
+### Immediate-mode Renderer
+
+The immediate-mode renderer (`Imm`) provides an API to define and render
+geometry procedurally and on the spot. It should be reserved for debug or
+not-performance-intensive rendering.
 
 ### Scene
 
diff --git a/include/gfx/llr/light.h b/include/gfx/llr/light.h
deleted file mode 100644
index 132e344..0000000
--- a/include/gfx/llr/light.h
+++ /dev/null
@@ -1,30 +0,0 @@
-#pragma once
-
-typedef struct Texture Texture;
-
-typedef struct Light Light;
-
-/// Light type.
-typedef enum LightType { EnvironmentLightType } LightType;
-
-/// Describes an environment light.
-typedef struct EnvironmentLightDesc {
-  const Texture* environment_map;
-} EnvironmentLightDesc;
-
-/// Describes a light.
-typedef struct LightDesc {
-  LightType type;
-  union {
-    EnvironmentLightDesc environment;
-  } light;
-} LightDesc;
-
-/// Create a light.
-Light* gfx_make_light(const LightDesc*);
-
-/// Destroy the light.
-///
-/// The light is conveniently removed from the scene graph and its parent scene
-/// node is destroyed.
-void gfx_destroy_light(Light**);
diff --git a/include/gfx/llr/llr.h b/include/gfx/llr/llr.h
index f84b3fb..6d78a50 100644
--- a/include/gfx/llr/llr.h
+++ b/include/gfx/llr/llr.h
@@ -1,5 +1,8 @@
 #pragma once
 
+#include <gfx/core.h>
+#include <gfx/sizes.h>
+
 #include <math/camera.h>
 #include <math/mat4.h>
 #include <math/vec3.h>
@@ -11,10 +14,75 @@ typedef struct Material      Material;
 typedef struct Mesh          Mesh;
 typedef struct ShaderProgram ShaderProgram;
 typedef struct Skeleton      Skeleton;
+typedef struct Texture       Texture;
 
 typedef struct LLR LLR;
 
 // -----------------------------------------------------------------------------
+// Data structures.
+
+/// Light type.
+typedef enum LightType { EnvironmentLightType } LightType;
+
+/// Describes an environment light.
+typedef struct EnvironmentLightDesc {
+  const Texture* environment_map;
+} EnvironmentLightDesc;
+
+/// Describes a light.
+typedef struct LightDesc {
+  LightType type;
+  union {
+    EnvironmentLightDesc environment;
+  } light;
+} LightDesc;
+
+/// Describes a material.
+///
+/// TODO: It doesn't hold the shader program anymore...It's in the Mesh.
+/// A material holds a shader program and a set of shader-specific uniform
+/// variables. Two materials can share the same shader, but shader parameters
+/// generally give two materials a different appearance.
+typedef struct MaterialDesc {
+  ShaderUniform uniforms[GFX_MAX_UNIFORMS_PER_MATERIAL];
+  int           num_uniforms;
+} MaterialDesc;
+
+/// Describes a mesh.
+typedef struct MeshDesc {
+  const Geometry* geometry;
+  const Material* material;
+  ShaderProgram*  shader;
+} MeshDesc;
+
+/// Create a light.
+Light* gfx_make_light(const LightDesc*);
+
+/// Destroy the light.
+///
+/// The light is conveniently removed from the scene graph and its parent scene
+/// node is destroyed.
+void gfx_destroy_light(Light**);
+
+/// Create a material.
+Material* gfx_make_material(const MaterialDesc*);
+
+/// Destroy the material.
+///
+/// The caller must make sure that no Mesh points to the given Material.
+/// For a safe purge of unused resources, see scene_purge().
+void gfx_destroy_material(Material**);
+
+/// Create a mesh.
+Mesh* gfx_make_mesh(const MeshDesc*);
+
+/// Destroy the mesh.
+///
+/// The caller must make sure that no SceneObject points to the given Mesh.
+/// For a safe purge of unused resources, see scene_purge().
+void gfx_destroy_mesh(Mesh**);
+
+// -----------------------------------------------------------------------------
 // Low-level rendering.
 
 /// Set the shader to be used for subsequent draw calls.
diff --git a/include/gfx/llr/material.h b/include/gfx/llr/material.h
deleted file mode 100644
index 9ebf9b3..0000000
--- a/include/gfx/llr/material.h
+++ /dev/null
@@ -1,26 +0,0 @@
-#pragma once
-
-#include <gfx/core.h>
-#include <gfx/sizes.h>
-
-typedef struct Material Material;
-
-/// Describes a material.
-///
-/// TODO: It doesn't hold the shader program anymore...It's in the Mesh.
-/// A material holds a shader program and a set of shader-specific uniform
-/// variables. Two materials can share the same shader, but shader parameters
-/// generally give two materials a different appearance.
-typedef struct MaterialDesc {
-  ShaderUniform uniforms[GFX_MAX_UNIFORMS_PER_MATERIAL];
-  int           num_uniforms;
-} MaterialDesc;
-
-/// Create a material.
-Material* gfx_make_material(const MaterialDesc*);
-
-/// Destroy the material.
-///
-/// The caller must make sure that no Mesh points to the given Material.
-/// For a safe purge of unused resources, see scene_purge().
-void gfx_destroy_material(Material**);
diff --git a/include/gfx/llr/mesh.h b/include/gfx/llr/mesh.h
deleted file mode 100644
index 0d3b4d4..0000000
--- a/include/gfx/llr/mesh.h
+++ /dev/null
@@ -1,23 +0,0 @@
-#pragma once
-
-typedef struct Geometry      Geometry;
-typedef struct Material      Material;
-typedef struct ShaderProgram ShaderProgram;
-
-typedef struct Mesh Mesh;
-
-/// Describes a mesh.
-typedef struct MeshDesc {
-  const Geometry* geometry;
-  const Material* material;
-  ShaderProgram*  shader;
-} MeshDesc;
-
-/// Create a mesh.
-Mesh* gfx_make_mesh(const MeshDesc*);
-
-/// Destroy the mesh.
-///
-/// The caller must make sure that no SceneObject points to the given Mesh.
-/// For a safe purge of unused resources, see scene_purge().
-void gfx_destroy_mesh(Mesh**);
diff --git a/src/asset/model.c b/src/asset/model.c
index 0c57470..96d200f 100644
--- a/src/asset/model.c
+++ b/src/asset/model.c
@@ -84,8 +84,7 @@
 #include "asset/texture.h"
 #include "gfx/core.h"
 #include "gfx/gfx.h"
-#include "gfx/llr/material.h"
-#include "gfx/llr/mesh.h"
+#include "gfx/llr/llr.h"
 #include "gfx/scene/animation.h"
 #include "gfx/scene/camera.h"
 #include "gfx/scene/node.h"
diff --git a/src/llr/light.c b/src/llr/light.c
deleted file mode 100644
index 0fa1522..0000000
--- a/src/llr/light.c
+++ /dev/null
@@ -1,42 +0,0 @@
-#include "light_impl.h"
-
-#include "memory.h"
-#include "scene/node_impl.h"
-
-#include <error.h>
-
-static void make_environment_light(
-    Light* light, const EnvironmentLightDesc* desc) {
-  assert(light);
-  assert(desc);
-  light->type                        = EnvironmentLightType;
-  light->environment.environment_map = desc->environment_map;
-}
-
-Light* gfx_make_light(const LightDesc* desc) {
-  assert(desc);
-
-  Light* light = mem_alloc_light();
-
-  switch (desc->type) {
-  case EnvironmentLightType:
-    make_environment_light(light, &desc->light.environment);
-    break;
-  default:
-    log_error("Unhandled light type");
-    gfx_destroy_light(&light);
-    return 0;
-  }
-
-  return light;
-}
-
-void gfx_destroy_light(Light** light) {
-  assert(light);
-  if (*light) {
-    if ((*light)->parent.val) {
-      gfx_del_node((*light)->parent);
-    }
-    mem_free_light(light);
-  }
-}
diff --git a/src/llr/light_impl.h b/src/llr/light_impl.h
deleted file mode 100644
index 5ec8145..0000000
--- a/src/llr/light_impl.h
+++ /dev/null
@@ -1,25 +0,0 @@
-#pragma once
-
-#include <gfx/llr/light.h>
-
-#include "scene/types.h"
-
-typedef struct Texture Texture;
-
-/// An environment light.
-typedef struct EnvironmentLight {
-  const Texture* environment_map;
-  const Texture* irradiance_map;              // Renderer implementation.
-  const Texture* prefiltered_environment_map; // Renderer implementation.
-  int max_reflection_lod; // Mandatory when prefiltered_environment_map is
-                          // given.
-} EnvironmentLight;
-
-/// A scene light.
-typedef struct Light {
-  LightType type;
-  union {
-    EnvironmentLight environment;
-  };
-  node_idx parent; // Parent SceneNode.
-} Light;
diff --git a/src/llr/llr.c b/src/llr/llr.c
index 25cdf9f..a1b37be 100644
--- a/src/llr/llr.c
+++ b/src/llr/llr.c
@@ -1,14 +1,14 @@
-#include "light_impl.h"
 #include "llr_impl.h"
-#include "mesh_impl.h"
 
-#include "llr/material_impl.h"
+#include "memory.h"
 #include "scene/animation_impl.h"
+#include "scene/node_impl.h"
 
 #include <gfx/core.h>
 #include <gfx/util/ibl.h>
 
 #include <cassert.h>
+#include <error.h>
 
 static const int IRRADIANCE_MAP_WIDTH               = 1024;
 static const int IRRADIANCE_MAP_HEIGHT              = 1024;
@@ -17,6 +17,117 @@ static const int PREFILTERED_ENVIRONMENT_MAP_HEIGHT = 128;
 static const int BRDF_INTEGRATION_MAP_WIDTH         = 512;
 static const int BRDF_INTEGRATION_MAP_HEIGHT        = 512;
 
+static void make_environment_light(
+    Light* light, const EnvironmentLightDesc* desc) {
+  assert(light);
+  assert(desc);
+  light->type                        = EnvironmentLightType;
+  light->environment.environment_map = desc->environment_map;
+}
+
+Light* gfx_make_light(const LightDesc* desc) {
+  assert(desc);
+
+  Light* light = mem_alloc_light();
+
+  switch (desc->type) {
+  case EnvironmentLightType:
+    make_environment_light(light, &desc->light.environment);
+    break;
+  default:
+    log_error("Unhandled light type");
+    gfx_destroy_light(&light);
+    return 0;
+  }
+
+  return light;
+}
+
+void gfx_destroy_light(Light** light) {
+  assert(light);
+  if (*light) {
+    if ((*light)->parent.val) {
+      gfx_del_node((*light)->parent);
+    }
+    mem_free_light(light);
+  }
+}
+
+static void material_make(Material* material, const MaterialDesc* desc) {
+  assert(material);
+  assert(desc);
+  assert(desc->num_uniforms < GFX_MAX_UNIFORMS_PER_MATERIAL);
+  material->num_uniforms = desc->num_uniforms;
+  for (int i = 0; i < desc->num_uniforms; ++i) {
+    material->uniforms[i] = desc->uniforms[i];
+  }
+}
+
+Material* gfx_make_material(const MaterialDesc* desc) {
+  assert(desc);
+  Material* material = mem_alloc_material();
+  material_make(material, desc);
+  return material;
+}
+
+void gfx_destroy_material(Material** material) { mem_free_material(material); }
+
+static void set_uniform(ShaderProgram* prog, const ShaderUniform* uniform) {
+  switch (uniform->type) {
+  case UniformTexture:
+    gfx_set_texture_uniform(prog, uniform->name.str, uniform->value.texture);
+    break;
+  case UniformMat4:
+    gfx_set_mat4_uniform(prog, uniform->name.str, &uniform->value.mat4);
+    break;
+  case UniformVec3:
+    gfx_set_vec3_uniform(prog, uniform->name.str, uniform->value.vec3);
+    break;
+  case UniformVec4:
+    gfx_set_vec4_uniform(prog, uniform->name.str, uniform->value.vec4);
+    break;
+  case UniformFloat:
+    gfx_set_float_uniform(prog, uniform->name.str, uniform->value.scalar);
+    break;
+  case UniformMat4Array:
+    gfx_set_mat4_array_uniform(
+        prog, uniform->name.str, uniform->value.array.values,
+        uniform->value.array.count);
+    break;
+  }
+}
+
+/// Activate the material.
+///
+/// This configures the shader uniforms that are specific to the material.
+static void gfx_material_activate(
+    ShaderProgram* shader, const Material* material) {
+  assert(material);
+  for (int i = 0; i < material->num_uniforms; ++i) {
+    const ShaderUniform* uniform = &material->uniforms[i];
+    set_uniform(shader, uniform);
+  }
+}
+
+static void mesh_make(Mesh* mesh, const MeshDesc* desc) {
+  assert(mesh);
+  assert(desc);
+  assert(desc->geometry);
+  assert(desc->material);
+  assert(desc->shader);
+  mesh->geometry = desc->geometry;
+  mesh->material = desc->material;
+  mesh->shader   = desc->shader;
+}
+
+Mesh* gfx_make_mesh(const MeshDesc* desc) {
+  Mesh* mesh = mem_alloc_mesh();
+  mesh_make(mesh, desc);
+  return mesh;
+}
+
+void gfx_destroy_mesh(Mesh** mesh) { mem_free_mesh(mesh); }
+
 /// Initialize renderer state for IBL.
 static bool init_ibl(LLR* renderer) {
   assert(renderer);
diff --git a/src/llr/llr_impl.h b/src/llr/llr_impl.h
index 3f6a68f..6318ee0 100644
--- a/src/llr/llr_impl.h
+++ b/src/llr/llr_impl.h
@@ -3,6 +3,8 @@
 #include <gfx/llr/llr.h>
 #include <gfx/sizes.h>
 
+#include "scene/types.h"
+
 #include <math/mat4.h>
 #include <math/vec3.h>
 
@@ -17,6 +19,35 @@ typedef struct Material      Material;
 typedef struct ShaderProgram ShaderProgram;
 typedef struct Texture       Texture;
 
+/// An environment light.
+typedef struct EnvironmentLight {
+  const Texture* environment_map;
+  const Texture* irradiance_map;              // Renderer implementation.
+  const Texture* prefiltered_environment_map; // Renderer implementation.
+  int max_reflection_lod; // Mandatory when prefiltered_environment_map is
+  // given.
+} EnvironmentLight;
+
+/// A scene light.
+typedef struct Light {
+  LightType type;
+  union {
+    EnvironmentLight environment;
+  };
+  node_idx parent; // Parent SceneNode.
+} Light;
+
+typedef struct Material {
+  ShaderUniform uniforms[GFX_MAX_UNIFORMS_PER_MATERIAL];
+  int           num_uniforms;
+} Material;
+
+typedef struct Mesh {
+  const Geometry* geometry;
+  const Material* material;
+  ShaderProgram*  shader; // TODO: Move this back to Material?
+} Mesh;
+
 /// Immediate mode renderer.
 ///
 /// The renderer caches state changes in memory and only programs the underlying
diff --git a/src/llr/material.c b/src/llr/material.c
deleted file mode 100644
index f09dd3f..0000000
--- a/src/llr/material.c
+++ /dev/null
@@ -1,57 +0,0 @@
-#include "material_impl.h"
-
-#include "memory.h"
-
-#include <gfx/core.h>
-
-static void material_make(Material* material, const MaterialDesc* desc) {
-  assert(material);
-  assert(desc);
-  assert(desc->num_uniforms < GFX_MAX_UNIFORMS_PER_MATERIAL);
-  material->num_uniforms = desc->num_uniforms;
-  for (int i = 0; i < desc->num_uniforms; ++i) {
-    material->uniforms[i] = desc->uniforms[i];
-  }
-}
-
-Material* gfx_make_material(const MaterialDesc* desc) {
-  assert(desc);
-  Material* material = mem_alloc_material();
-  material_make(material, desc);
-  return material;
-}
-
-void gfx_destroy_material(Material** material) { mem_free_material(material); }
-
-static void set_uniform(ShaderProgram* prog, const ShaderUniform* uniform) {
-  switch (uniform->type) {
-  case UniformTexture:
-    gfx_set_texture_uniform(prog, uniform->name.str, uniform->value.texture);
-    break;
-  case UniformMat4:
-    gfx_set_mat4_uniform(prog, uniform->name.str, &uniform->value.mat4);
-    break;
-  case UniformVec3:
-    gfx_set_vec3_uniform(prog, uniform->name.str, uniform->value.vec3);
-    break;
-  case UniformVec4:
-    gfx_set_vec4_uniform(prog, uniform->name.str, uniform->value.vec4);
-    break;
-  case UniformFloat:
-    gfx_set_float_uniform(prog, uniform->name.str, uniform->value.scalar);
-    break;
-  case UniformMat4Array:
-    gfx_set_mat4_array_uniform(
-        prog, uniform->name.str, uniform->value.array.values,
-        uniform->value.array.count);
-    break;
-  }
-}
-
-void gfx_material_activate(ShaderProgram* shader, const Material* material) {
-  assert(material);
-  for (int i = 0; i < material->num_uniforms; ++i) {
-    const ShaderUniform* uniform = &material->uniforms[i];
-    set_uniform(shader, uniform);
-  }
-}
diff --git a/src/llr/material_impl.h b/src/llr/material_impl.h
deleted file mode 100644
index 2b7cd89..0000000
--- a/src/llr/material_impl.h
+++ /dev/null
@@ -1,15 +0,0 @@
-#pragma once
-
-#include <gfx/llr/material.h>
-
-typedef struct ShaderProgram ShaderProgram;
-
-typedef struct Material {
-  ShaderUniform uniforms[GFX_MAX_UNIFORMS_PER_MATERIAL];
-  int           num_uniforms;
-} Material;
-
-/// Activate the material.
-///
-/// This configures the shader uniforms that are specific to the material.
-void gfx_material_activate(ShaderProgram* shader, const Material* material);
diff --git a/src/llr/mesh.c b/src/llr/mesh.c
deleted file mode 100644
index 5f9e5d0..0000000
--- a/src/llr/mesh.c
+++ /dev/null
@@ -1,24 +0,0 @@
-#include "mesh_impl.h"
-
-#include "memory.h"
-
-#include <assert.h>
-
-static void mesh_make(Mesh* mesh, const MeshDesc* desc) {
-  assert(mesh);
-  assert(desc);
-  assert(desc->geometry);
-  assert(desc->material);
-  assert(desc->shader);
-  mesh->geometry = desc->geometry;
-  mesh->material = desc->material;
-  mesh->shader   = desc->shader;
-}
-
-Mesh* gfx_make_mesh(const MeshDesc* desc) {
-  Mesh* mesh = mem_alloc_mesh();
-  mesh_make(mesh, desc);
-  return mesh;
-}
-
-void gfx_destroy_mesh(Mesh** mesh) { mem_free_mesh(mesh); }
diff --git a/src/llr/mesh_impl.h b/src/llr/mesh_impl.h
deleted file mode 100644
index a997d5b..0000000
--- a/src/llr/mesh_impl.h
+++ /dev/null
@@ -1,9 +0,0 @@
-#pragma once
-
-#include <gfx/llr/mesh.h>
-
-typedef struct Mesh {
-  const Geometry* geometry;
-  const Material* material;
-  ShaderProgram*  shader; // TODO: Move this back to Material?
-} Mesh;
diff --git a/src/memory.c b/src/memory.c
index 59bf8ca..39ae6ea 100644
--- a/src/memory.c
+++ b/src/memory.c
@@ -2,9 +2,7 @@
 
 #include <gfx/sizes.h>
 
-#include "llr/light_impl.h"
-#include "llr/material_impl.h"
-#include "llr/mesh_impl.h"
+#include "llr/llr_impl.h"
 #include "scene/animation_impl.h"
 #include "scene/camera_impl.h"
 #include "scene/model_impl.h"
diff --git a/src/renderer/renderer.c b/src/renderer/renderer.c
index 6bcf5cc..7797c83 100644
--- a/src/renderer/renderer.c
+++ b/src/renderer/renderer.c
@@ -1,7 +1,6 @@
 #include "renderer_impl.h"
 
-#include "llr/light_impl.h"
-#include "llr/mesh_impl.h"
+#include "llr/llr_impl.h"
 #include "memory.h"
 #include "scene/animation_impl.h"
 #include "scene/camera_impl.h"
diff --git a/src/scene/node.c b/src/scene/node.c
index 9d45aa7..b7cf467 100644
--- a/src/scene/node.c
+++ b/src/scene/node.c
@@ -2,7 +2,7 @@
 
 #include "animation_impl.h"
 #include "camera_impl.h"
-#include "llr/light_impl.h"
+#include "llr/llr_impl.h"
 #include "memory.h"
 #include "model_impl.h"
 #include "object_impl.h"
diff --git a/src/scene/node_impl.h b/src/scene/node_impl.h
index c79f252..d43ae1e 100644
--- a/src/scene/node_impl.h
+++ b/src/scene/node_impl.h
@@ -13,6 +13,9 @@
 /// together form a strict tree hierarchy and not a more general DAG.
 typedef struct SceneNode {
   NodeType type;
+  // TODO: Inline the actual object here and get rid of the indirection and the
+  //  extra pools? The "scene camera" is kind of a useless data structure, for
+  //  example.
   union {
     anima_idx  anima;
     camera_idx camera;
diff --git a/src/scene/object.c b/src/scene/object.c
index e985fd5..3b2d498 100644
--- a/src/scene/object.c
+++ b/src/scene/object.c
@@ -2,7 +2,7 @@
 
 #include <gfx/core.h>
 
-#include "llr/mesh_impl.h"
+#include "llr/llr_impl.h"
 #include "memory.h"
 #include "node_impl.h"
 
diff --git a/src/util/skyquad.c b/src/util/skyquad.c
index 094de67..847bc91 100644
--- a/src/util/skyquad.c
+++ b/src/util/skyquad.c
@@ -1,9 +1,7 @@
 #include <gfx/util/skyquad.h>
 
 #include <gfx/core.h>
-#include <gfx/llr/light.h>
-#include <gfx/llr/material.h>
-#include <gfx/llr/mesh.h>
+#include <gfx/llr/llr.h>
 #include <gfx/scene/node.h>
 #include <gfx/scene/object.h>
 #include <gfx/util/geometry.h>