From b37b5398a6afa940acd1138bde922a70838f33af Mon Sep 17 00:00:00 2001
From: 3gg <3gg@shellblade.net>
Date: Fri, 4 Jul 2025 10:37:01 -0700
Subject: Add the new low-level renderer, shared between the imm and scene
 graph renderer. LLR integration with the scene graph renderer not yet done.

---
 src/llr/llr_impl.h | 67 +++++++++++++++++++-----------------------------------
 1 file changed, 24 insertions(+), 43 deletions(-)

(limited to 'src/llr/llr_impl.h')

diff --git a/src/llr/llr_impl.h b/src/llr/llr_impl.h
index 5ccabd1..e9dc0ac 100644
--- a/src/llr/llr_impl.h
+++ b/src/llr/llr_impl.h
@@ -8,6 +8,7 @@
 
 #include <stdbool.h>
 #include <stddef.h>
+#include <stdint.h>
 
 typedef struct Geometry      Geometry;
 typedef struct GfxCore       GfxCore;
@@ -33,67 +34,47 @@ typedef struct Texture       Texture;
 /// Note that the shader program API has its own level of caching as well, so
 /// reconfiguration at the level of the renderer does not result in the
 /// worst-case set of graphics API calls.
-///
-/// Currently, the immediate mode renderer can only draw up to a maximum number
-/// of primitives per frame. It does not adjust this number dynamically. Keeps
-/// things simple while the extra complexity is not needed.
-/// TODO: Flush the buffer when it reaches its maximum size to remove this
-///  constraint.
-typedef struct ImmRenderer {
+typedef struct LLR {
   GfxCore* gfxcore;
 
-  vec3 camera_position;
-  mat4 view;           // Camera view matrix.
-  mat4 projection;     // Camera projection matrix.
-  bool camera_changed; // Whether the camera parameters have changed.
-
-  // -------------------------------------------
-  // Immediate-mode rendering of scene elements.
+  union {
+    struct {
+      bool shader_changed   : 1; // Whether the shader has changed.
+      bool camera_changed   : 1; // Whether the camera parameters have changed.
+      bool lights_changed   : 1; // Whether the lights have changed.
+      bool skeleton_changed : 1; // Whether the skeleton has changed.
+      bool matrix_changed   : 1; // Whether the matrix stack has changed.
+    };
+    uint8_t changed_flags;
+  };
 
   IBL*     ibl;
   Texture* brdf_integration_map;
 
-  ShaderProgram* shader;         // Active shader. Not owned.
-  bool           shader_changed; // Whether the shader has changed.
+  ShaderProgram* shader; // Active shader. Not owned.
+
+  vec3 camera_position;
+  mat4 view;       // Camera view matrix.
+  mat4 projection; // Camera projection matrix.
 
   // Lights are not const because environment lights store lazily-computed
   // irradiance maps.
-  Light* lights[IMM_MAX_NUM_LIGHTS]; // Lights stack.
-  int    num_lights;   // Number of lights enabled at a given point in time. It
-                       // points to one past the top of the stack.
-  bool lights_changed; // Whether the lights have changed.
+  Light* lights[GFX_LLR_MAX_NUM_LIGHTS]; // Lights stack.
+  int    num_lights; // Number of lights enabled at a given point in time. It
+                     // points to one past the top of the stack.
 
-  bool   skeleton_changed;
   size_t num_joints;
   mat4   joint_matrices[GFX_MAX_NUM_JOINTS];
 
-  // ---------------------------------------
-  // Immediate-mode rendering of primitives.
-
-  ShaderProgram* imm_shader; // Immediate-mode shader program for primitives.
-  Geometry*      triangles;
-  size_t         num_triangle_verts; // Number of triangle verts this frame.
-  // TODO: wireframe rendering.
-  struct {
-    bool wireframe : 1;
-  } flags;
-  vec3 triangle_verts[IMM_MAX_NUM_TRIANGLES * 3];
-
-  // -------------
-  // Matrix stack.
-
   // The matrix stack contains pre-multiplied matrices.
   // It is also never empty. The top of the stack is an identity matrix when the
   // stack is "empty" from the user's perspective.
-  mat4 matrix_stack[IMM_MAX_NUM_MATRICES];
+  mat4 matrix_stack[GFX_LLR_MAX_NUM_MATRICES];
   int  stack_pointer; // Points to the top of the stack.
-} ImmRenderer;
+} LLR;
 
 /// Create a new immediate mode renderer.
-bool gfx_imm_make(ImmRenderer*, GfxCore*);
+bool gfx_llr_make(LLR*, GfxCore*);
 
 /// Destroy the immediate mode renderer.
-void gfx_imm_destroy(ImmRenderer*);
-
-/// Flush draw commands.
-void gfx_imm_flush(ImmRenderer*);
+void gfx_llr_destroy(LLR*);
-- 
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