1 files changed, 60 insertions, 8 deletions
diff --git a/engine/src/ui/imgui.rs b/engine/src/ui/imgui.rs
index 75ce9c0..bb13d8d 100644
--- a/engine/src/ui/imgui.rs
+++ b/engine/src/ui/imgui.rs
@@ -63,9 +63,11 @@ use crate::rendering::{
     Command as RenderingCommand,
     DrawMeshOptions,
     DrawProperties,
+    DrawPropertiesUpdateFlags,
     MeshUsage,
     RenderPass,
     RenderPasses,
+    ScissorBox,
     SurfaceId,
     SurfaceSpec,
     PRE_RENDER_PHASE,
@@ -561,6 +563,7 @@ fn add_drawing_render_pass(
             },
             depth_test_enabled: false,
             face_culling_enabled: false,
+            scissor_test_enabled: true,
             ..Default::default()
         },
     });
@@ -644,14 +647,26 @@ fn add_drawing_render_pass(
         for command in draw_list.commands() {
             match command {
                 ImguiDrawCmd::Elements { count, cmd_params, raw_cmd: _ } => {
-                    render_pass.commands.push(RenderingCommand::DrawMesh(
-                        mesh_obj_id,
-                        DrawMeshOptions::builder()
-                            .element_offset(cmd_params.idx_offset.try_into().unwrap())
-                            .vertex_offset(cmd_params.vtx_offset.try_into().unwrap())
-                            .element_cnt(count.try_into().unwrap())
-                            .build(),
-                    ));
+                    let Some(scissor_box) =
+                        calc_draw_cmd_scissor_box(draw_data, &cmd_params)
+                    else {
+                        continue;
+                    };
+
+                    render_pass.commands.extend([
+                        RenderingCommand::UpdateDrawProperties(
+                            DrawProperties { scissor_box, ..Default::default() },
+                            DrawPropertiesUpdateFlags::SCISSOR_BOX,
+                        ),
+                        RenderingCommand::DrawMesh(
+                            mesh_obj_id,
+                            DrawMeshOptions::builder()
+                                .element_offset(cmd_params.idx_offset.try_into().unwrap())
+                                .vertex_offset(cmd_params.vtx_offset.try_into().unwrap())
+                                .element_cnt(count.try_into().unwrap())
+                                .build(),
+                        ),
+                    ]);
                 }
                 _ => {}
             }
@@ -659,6 +674,43 @@ fn add_drawing_render_pass(
     }
 }
 
+fn calc_draw_cmd_scissor_box(
+    draw_data: &dear_imgui_rs::DrawData,
+    cmd_params: &dear_imgui_rs::DrawCmdParams,
+) -> Option<ScissorBox>
+{
+    let clip_rect = cmd_params.clip_rect;
+
+    let clip_min_x =
+        (clip_rect[0] - draw_data.display_pos[0]) * draw_data.framebuffer_scale[0];
+
+    let clip_min_y =
+        (clip_rect[1] - draw_data.display_pos[1]) * draw_data.framebuffer_scale[1];
+
+    let clip_max_x =
+        (clip_rect[2] - draw_data.display_pos[0]) * draw_data.framebuffer_scale[0];
+
+    let clip_max_y =
+        (clip_rect[3] - draw_data.display_pos[1]) * draw_data.framebuffer_scale[1];
+
+    if clip_max_x <= clip_min_x || clip_max_y <= clip_min_y {
+        return None;
+    }
+
+    let fb_height = draw_data.display_size[1] * draw_data.framebuffer_scale[1];
+
+    Some(ScissorBox {
+        size: Some(Dimens {
+            width: (clip_max_x - clip_min_x) as u16,
+            height: (clip_max_y - clip_min_y) as u16,
+        }),
+        lower_left_corner_pos: Vec2 {
+            x: clip_min_x as u16,
+            y: (fb_height - clip_max_y) as u16,
+        },
+    })
+}
+
 fn create_font_texture(
     font_texture_data: &dear_imgui_rs::texture::TextureData,
 ) -> Result<Texture, ImageFromBytesError>