make arbitrary triangles work with a command queue

src/arbtri.jai

@@ -1,20 +1,51 @@
 Arb_Tri :: struct {
-    pos: [3]Vector3;
-    col: [3]Vector4;
-    uv: [3]Vector2;
+    pos : [3]Vector3;
+    col : [3]Vector4;
+    uv  : [3]Vector2;
+}
+
+Arb_Draw_Command_Type :: enum {
+    INVALID;
+    FLUSH_TRI;
+    SET_TEXTURE;
+    REMOVE_TEXTURE;
+}
+
+Arb_Draw_Command :: struct {
+    type       : Arb_Draw_Command_Type = .INVALID;
+    tri_offset : int = 0;
+    tri_count  : int = 0;
+    texture    : *Ui_Texture;
 }
 
 Arb_Tri_State :: struct {
     active       : bool = false;
     trilist      : [..]Arb_Tri;
+    command_list : [..]Arb_Draw_Command;
+    latest_flush : int = 0;
 }
 
 arbTriState : Arb_Tri_State;
 
+init_arb_state :: () {
+    gPipelines.arbtri.bind.images[0] = default_texture.tex;
+    array_reset_keeping_memory(*arbTriState.trilist);
+    array_reset_keeping_memory(*arbTriState.command_list);
+    arbTriState.active = true;
+    arbTriState.latest_flush = 0;
+} 
+
+arb_tri_command_add :: (command: Arb_Draw_Command) {
+    if !arbTriState.active {
+        init_arb_state();
+    }
+
+    array_add(*arbTriState.command_list, command);
+}
+
 arb_tri_add :: (tri: Arb_Tri) {
     if !arbTriState.active {
-        array_reset_keeping_memory(*arbTriState.trilist);
-        arbTriState.active = true;
+        init_arb_state();
     }
 
     array_add(*arbTriState.trilist, tri);
@@ -55,7 +86,21 @@ arb_tri_flush :: () {
 
     sg_update_buffer(gPipelines.arbtri.bind.vertex_buffers[0], *(sg_range.{ ptr = gArbtriMem.data, size = size_of(type_of(gArbtriMem)) }));
 
+    flush_arb_commands();
+}
+
+flush_arb_commands :: () {
+    for arbTriState.command_list {
+        if it.type == {
+            case .SET_TEXTURE;
+                gPipelines.arbtri.bind.images[0] = it.texture.tex;
+                gCurrentTexture = it.texture;
+            case .REMOVE_TEXTURE;
+                gCurrentTexture = null;
+            case .FLUSH_TRI;
                 sg_apply_pipeline(gPipelines.arbtri.pipeline);
                 sg_apply_bindings(*gPipelines.arbtri.bind);
-    sg_draw(0, xx (arbTriState.trilist.count * 3), 1);
+                sg_draw(xx (it.tri_offset * 3), xx (it.tri_count * 3), 1);
+        }
+    }
 }

src/ui/ui.jai

@@ -1,6 +1,7 @@
 GR :: #import "GetRect_LeftHanded"()(Type_Indicator = Ui_Type_Indicator);
 Input :: #import "Input";
 
+default_texture : *Ui_Texture = null;
 
 Ui_Font_Glyph :: struct {
     advance : u32 = 1;
@@ -76,6 +77,7 @@ texture_load_from_memory :: (texture: *Ui_Texture, memory: []u8, srgb: bool, bui
 
     stbi.stbi_image_free(data);
     texture.tex = img;
+    if !default_texture then default_texture = texture;
     return true;
 }
 
@@ -96,15 +98,22 @@ clear_scissor :: () {
 }
 
 gCurrentTexture : *Ui_Texture = null;
+add_uvs         : bool        = false;
 
 set_shader_for_color :: (enable_blend := false) {
-    gCurrentTexture = null;
+    arb_tri_command_add(.{
+        type = .REMOVE_TEXTURE
+    });
+    add_uvs = false;
 }
 
 
 set_shader_for_images :: (texture: *Ui_Texture) {
-    gPipelines.arbtri.bind.images[0] = texture.tex;
-    gCurrentTexture = texture;
+    arb_tri_command_add(.{
+        type = .SET_TEXTURE,
+        texture = texture
+    });
+    add_uvs = true;
 }
 
 gPreppedText: string;
@@ -163,7 +172,7 @@ immediate_triangle :: (p0: Vector3, p1: Vector3, p2: Vector3, c0 := Vector4.{1,1
     // This UV symbolizes that the sampler should not be used.
     nullUV : Vector2 = .{-4, -2};
 
-    if gCurrentTexture == null {
+    if !add_uvs {
         tri.uv[0] = nullUV;
         tri.uv[1] = nullUV;
         tri.uv[2] = nullUV;
@@ -185,7 +194,12 @@ immediate_quad :: (p0: Vector2, p1: Vector2, p2: Vector2, p3: Vector2, color :=
 }
 
 immediate_flush :: () {
-    // arb_tri_flush();
+    arb_tri_command_add(.{
+        type = .FLUSH_TRI,
+        tri_offset = arbTriState.latest_flush,
+        tri_count = arbTriState.trilist.count - arbTriState.latest_flush
+    });
+    arbTriState.latest_flush = arbTriState.trilist.count;
 }
 
 init_ui :: () {