feat(engine): add scissor testing to renderer draw propsHEADmaster

5 files changed, 98 insertions, 2 deletions

diff --git a/engine/src/data_types/dimens.rs b/engine/src/data_types/dimens.rs
index 8bf239f..12f912e 100644
--- a/engine/src/data_types/dimens.rs
+++ b/engine/src/data_types/dimens.rs
@@ -1,7 +1,7 @@
 use std::num::NonZeroU32;
 
 /// 2D dimensions.
-#[derive(Debug, Clone, Copy)]
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
 pub struct Dimens<Value>
 {
     pub width: Value,
diff --git a/engine/src/data_types/vector.rs b/engine/src/data_types/vector.rs
index e745387..933ca51 100644
--- a/engine/src/data_types/vector.rs
+++ b/engine/src/data_types/vector.rs
@@ -2,7 +2,7 @@ use std::ops::{Add, AddAssign, Div, Mul, Neg, Sub, SubAssign};
 
 use crate::color::Color;
 
-#[derive(Debug, Default, Clone, Copy, PartialEq)]
+#[derive(Debug, Default, Clone, Copy, PartialEq, Eq)]
 pub struct Vec2<Value>
 {
     pub x: Value,
diff --git a/engine/src/renderer.rs b/engine/src/renderer.rs
index 3b6bdf0..52764db 100644
--- a/engine/src/renderer.rs
+++ b/engine/src/renderer.rs
@@ -14,6 +14,7 @@ use ecs::{Component, Query, Sole, declare_entity};
 
 use crate::asset::{Assets, Handle as AssetHandle};
 use crate::builder;
+use crate::data_types::dimens::Dimens;
 use crate::draw_flags::{DrawFlags, NoDraw, PolygonModeConfig};
 use crate::mesh::Mesh;
 use crate::model::{MaterialSearchResult, Model};
@@ -32,6 +33,7 @@ use crate::shader::{
     Shader,
 };
 use crate::texture::{Texture, WHITE_1X1_ASSET_LABEL as TEXTURE_WHITE_1X1_ASSET_LABEL};
+use crate::vector::Vec2;
 use crate::windowing::window::Window;
 
 pub mod blending;
@@ -216,6 +218,28 @@ pub enum MeshUsage
 }
 
 #[derive(Debug, Clone, PartialEq, Eq)]
+pub struct ScissorBox
+{
+    /// Size of the scissor box in window coordinates. When `None`, the dimensions of the
+    /// window is used
+    pub size: Option<Dimens<u16>>,
+
+    /// Position (in window coordinates) of the lower left corner of the scissor box.
+    pub lower_left_corner_pos: Vec2<u16>,
+}
+
+impl Default for ScissorBox
+{
+    fn default() -> Self
+    {
+        Self {
+            size: None,
+            lower_left_corner_pos: Vec2 { x: 0, y: 0 },
+        }
+    }
+}
+
+#[derive(Debug, Clone, PartialEq, Eq)]
 #[non_exhaustive]
 pub struct DrawProperties
 {
@@ -223,6 +247,8 @@ pub struct DrawProperties
     pub blending_enabled: bool,
     pub blending_config: BlendingConfig,
     pub depth_test_enabled: bool,
+    pub scissor_test_enabled: bool,
+    pub scissor_box: ScissorBox,
 }
 
 impl Default for DrawProperties
@@ -234,6 +260,8 @@ impl Default for DrawProperties
             blending_enabled: false,
             blending_config: BlendingConfig::default(),
             depth_test_enabled: true,
+            scissor_test_enabled: false,
+            scissor_box: ScissorBox::default(),
         }
     }
 }
@@ -246,6 +274,8 @@ bitflags! {
         const BLENDING_CONFIG = 1 << 1;
         const BLENDING_ENABLED = 1 << 2;
         const DEPTH_TEST_ENABLED = 1 << 3;
+        const SCISSOR_TEST_ENABLED = 1 << 4;
+        const SCISSOR_BOX = 1 << 5;
     }
 }
 
diff --git a/engine/src/renderer/opengl.rs b/engine/src/renderer/opengl.rs
index df57b84..b434cd8 100644
--- a/engine/src/renderer/opengl.rs
+++ b/engine/src/renderer/opengl.rs
@@ -40,7 +40,9 @@ use opengl_bindings::misc::{
     Capability,
     SetViewportError as GlSetViewportError,
     clear_buffers,
+    define_scissor_box as gl_define_scissor_box,
     enable,
+    get_viewport as gl_get_viewport,
     set_enabled,
 };
 use opengl_bindings::shader::{
@@ -1203,6 +1205,43 @@ fn handle_commands(
                             draw_props.depth_test_enabled,
                         );
                     }
+
+                    if draw_props_update_flags
+                        .contains(DrawPropertiesUpdateFlags::SCISSOR_TEST_ENABLED)
+                    {
+                        set_enabled(
+                            curr_gl_ctx,
+                            Capability::ScissorTest,
+                            draw_props.scissor_test_enabled,
+                        );
+                    }
+
+                    if draw_props_update_flags
+                        .contains(DrawPropertiesUpdateFlags::SCISSOR_BOX)
+                    {
+                        gl_define_scissor_box(
+                            curr_gl_ctx,
+                            draw_props.scissor_box.lower_left_corner_pos.into(),
+                            draw_props
+                                .scissor_box
+                                .size
+                                .unwrap_or_else(|| {
+                                    let (_, viewport_size) = gl_get_viewport(curr_gl_ctx);
+
+                                    Dimens::<u16> {
+                                        width: viewport_size
+                                            .width
+                                            .try_into()
+                                            .expect("Viewport width too large"),
+                                        height: viewport_size
+                                            .height
+                                            .try_into()
+                                            .expect("Viewport height too large"),
+                                    }
+                                })
+                                .into(),
+                        );
+                    }
                 }
             }
         }
diff --git a/opengl-bindings/src/misc.rs b/opengl-bindings/src/misc.rs
index 6206b79..3a3335d 100644
--- a/opengl-bindings/src/misc.rs
+++ b/opengl-bindings/src/misc.rs
@@ -54,6 +54,33 @@ pub fn set_viewport(
     Ok(())
 }
 
+pub fn get_viewport(
+    current_context: &CurrentContextWithFns<'_>,
+) -> (Vec2<u32>, Dimens<u32>)
+{
+    let mut values = [0i32; 4];
+
+    unsafe {
+        current_context
+            .fns()
+            .GetIntegerv(crate::sys::VIEWPORT, values.as_mut_ptr());
+    }
+
+    let [x, y, width, height] = values;
+
+    let pos = Vec2::<u32> {
+        x: x.try_into().expect("Negative viewport x coordinate"),
+        y: y.try_into().expect("Negative viewport y coordinate"),
+    };
+
+    let size = Dimens::<u32> {
+        width: width.try_into().expect("Negative viewport width"),
+        height: height.try_into().expect("Negative viewport height"),
+    };
+
+    (pos, size)
+}
+
 pub fn clear_buffers(current_context: &CurrentContextWithFns<'_>, mask: BufferClearMask)
 {
     unsafe {