render/opengl: flushed instance buffers

src/render/opengl/render_opengl.c

@@ -65,6 +65,29 @@ r_ogl_format_info_from_tex2dformat(R_Tex2DFormat fmt)
   return result;
 }
 
+internal GLuint
+r_ogl_instance_buffer_from_size(U64 size)
+{
+  GLuint buffer = r_ogl_state->scratch_buffer_64kb;
+  if(size > KB(64))
+  {
+    // rjf: build buffer
+    U64 flushed_buffer_size = size;
+    flushed_buffer_size += MB(1)-1;
+    flushed_buffer_size -= flushed_buffer_size%MB(1);
+    glGenBuffers(1, &buffer);
+    glBindBuffer(GL_ARRAY_BUFFER, buffer);
+    glBufferData(GL_ARRAY_BUFFER, flushed_buffer_size, 0, GL_DYNAMIC_DRAW);
+    glBindBuffer(GL_ARRAY_BUFFER, 0);
+    
+    // rjf: push buffer to flush list
+    R_OGL_FlushBuffer *n = push_array(r_ogl_state->buffer_flush_arena, R_OGL_FlushBuffer, 1);
+    n->id = buffer;
+    SLLQueuePush(r_ogl_state->first_buffer_to_flush, r_ogl_state->last_buffer_to_flush, n);
+  }
+  return buffer;
+}
+
 internal void
 r_ogl_debug_message_callback(GLenum source, GLenum type, GLuint id, GLenum severity, GLsizei length, const GLchar *message, const void *userParam)
 {
@@ -150,9 +173,9 @@ r_init(CmdLine *cmdln)
   
   //- rjf: set up built-in resources
   glGenVertexArrays(1, &r_ogl_state->all_purpose_vao);
-  glGenBuffers(1, &r_ogl_state->scratch_buffer_2mb);
-  glBindBuffer(GL_ARRAY_BUFFER, r_ogl_state->scratch_buffer_2mb);
-  glBufferData(GL_ARRAY_BUFFER, MB(2), 0, GL_DYNAMIC_DRAW);
+  glGenBuffers(1, &r_ogl_state->scratch_buffer_64kb);
+  glBindBuffer(GL_ARRAY_BUFFER, r_ogl_state->scratch_buffer_64kb);
+  glBufferData(GL_ARRAY_BUFFER, KB(64), 0, GL_DYNAMIC_DRAW);
   glBindBuffer(GL_ARRAY_BUFFER, 0);
   glGenTextures(1, &r_ogl_state->white_texture);
   glBindTexture(GL_TEXTURE_2D, r_ogl_state->white_texture);
@@ -160,6 +183,9 @@ r_init(CmdLine *cmdln)
   glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, 1, 1, 0, GL_RGBA, GL_UNSIGNED_BYTE, &white_pixel);
   glEnable(GL_FRAMEBUFFER_SRGB);
   
+  //- rjf: set up buffer flush state
+  r_ogl_state->buffer_flush_arena = arena_alloc();
+  
   //- rjf: set up debug callback
   B32 debug_mode = cmd_line_has_flag(cmdln, str8_lit("opengl_debug"));
 #if BUILD_DEBUG
@@ -334,6 +360,12 @@ r_window_begin_frame(OS_Handle os, R_Handle r)
 r_hook void
 r_window_end_frame(OS_Handle os, R_Handle r)
 {
+  for(R_OGL_FlushBuffer *flush_buffer = r_ogl_state->first_buffer_to_flush; flush_buffer != 0; flush_buffer = flush_buffer->next)
+  {
+    glDeleteBuffers(1, &flush_buffer->id);
+  }
+  arena_clear(r_ogl_state->buffer_flush_arena);
+  r_ogl_state->first_buffer_to_flush = r_ogl_state->last_buffer_to_flush = 0;
   r_ogl_os_window_swap(os, r);
 }
 
@@ -382,7 +414,7 @@ r_window_submit(OS_Handle window, R_Handle window_equip, R_PassList *passes)
             }
             
             //- rjf: get & fill buffer
-            GLuint buffer = r_ogl_state->scratch_buffer_2mb; // TODO(rjf): r_ogl_instance_buffer_from_size(batches->byte_count);
+            GLuint buffer = r_ogl_instance_buffer_from_size(batches->byte_count);
             {
               glBindBuffer(GL_ARRAY_BUFFER, buffer);
               U64 off = 0;

src/render/opengl/render_opengl.h

@@ -113,6 +113,7 @@ struct R_OGL_AttributeArray
 #define R_OGL_ProcedureXList \
 X(glGenBuffers, void, (GLsizei n, GLuint *buffers))\
 X(glBindBuffer, void, (GLenum target, GLuint buffer))\
+X(glDeleteBuffers, void, (GLsizei n, GLuint *buffers))\
 X(glGenVertexArrays, void, (GLsizei n, GLuint *arrays))\
 X(glBindVertexArray, void, (GLuint array))\
 X(glCreateProgram, GLuint, (void))\
@@ -179,6 +180,13 @@ struct R_OGL_Tex2D
   Vec2S32 size;
 };
 
+typedef struct R_OGL_FlushBuffer R_OGL_FlushBuffer;
+struct R_OGL_FlushBuffer
+{
+  R_OGL_FlushBuffer *next;
+  GLuint id;
+};
+
 typedef struct R_OGL_State R_OGL_State;
 struct R_OGL_State
 {
@@ -186,8 +194,11 @@ struct R_OGL_State
   R_OGL_Tex2D *free_tex2d;
   GLuint shaders[R_OGL_ShaderKind_COUNT];
   GLuint all_purpose_vao;
-  GLuint scratch_buffer_2mb;
+  GLuint scratch_buffer_64kb;
   GLuint white_texture;
+  Arena *buffer_flush_arena;
+  R_OGL_FlushBuffer *first_buffer_to_flush;
+  R_OGL_FlushBuffer *last_buffer_to_flush;
 };
 
 ////////////////////////////////
@@ -201,6 +212,7 @@ global R_OGL_State *r_ogl_state = 0;
 internal R_Handle r_ogl_handle_from_tex2d(R_OGL_Tex2D *t);
 internal R_OGL_Tex2D *r_ogl_tex2d_from_handle(R_Handle h);
 internal R_OGL_FormatInfo r_ogl_format_info_from_tex2dformat(R_Tex2DFormat fmt);
+internal GLuint r_ogl_instance_buffer_from_size(U64 size);
 internal void r_ogl_debug_message_callback(GLenum source, GLenum type, GLuint id, GLenum severity, GLsizei length, const GLchar *message, const void *userParam);
 
 #define glUseProgramScope(...) DeferLoop(glUseProgram(__VA_ARGS__), glUseProgram(0))