Fix projection transform that was leading to ~100 max draws. (#92)

Author: tychedelia

crates/processing_render/src/graphics.rs

@@ -29,7 +29,7 @@ use crate::{
     Flush,
     image::{Image, create_readback_buffer, pixel_size, pixels_to_bytes},
     render::{
-        RenderState,
+        BATCH_INDEX_STEP, RenderState,
         command::{CommandBuffer, DrawCommand},
     },
     surface::Surface,
@@ -112,19 +112,18 @@ pub struct SurfaceSize(pub u32, pub u32);
 /// Custom orthographic projection for Processing's coordinate system.
 /// Origin at top-left, Y-axis down, in pixel units (aka screen space).
 #[derive(Debug, Clone, Reflect)]
-#[reflect(Default)]
 pub struct ProcessingProjection {
     pub width: f32,
     pub height: f32,
     pub near: f32,
     pub far: f32,
 }
 
-impl Default for ProcessingProjection {
-    fn default() -> Self {
+impl ProcessingProjection {
+    pub fn new(width: f32, height: f32) -> Self {
         Self {
-            width: 1.0,
-            height: 1.0,
+            width,
+            height,
             near: 0.0,
             far: 1000.0,
         }
@@ -234,14 +233,9 @@ pub fn create(
         Tonemapping::None,
         // we need to be able to write to the texture
         CameraMainTextureUsages::default().with(TextureUsages::COPY_DST),
-        Projection::custom(ProcessingProjection {
-            width: width as f32,
-            height: height as f32,
-            near: 0.0,
-            far: 1000.0,
-        }),
+        Projection::custom(ProcessingProjection::new(width as f32, height as f32)),
         Msaa::Off,
-        Transform::from_xyz(0.0, 0.0, 999.9),
+        Transform::from_xyz(0.0, 0.0, BATCH_INDEX_STEP),
         render_layer,
         CommandBuffer::new(),
         RenderState::default(),
@@ -340,18 +334,13 @@ pub fn mode_2d(
         .get_mut(entity)
         .map_err(|_| ProcessingError::GraphicsNotFound)?;
 
-    *projection = Projection::custom(ProcessingProjection {
-        width: *width as f32,
-        height: *height as f32,
-        near: 0.0,
-        far: 1000.0,
-    });
+    *projection = Projection::custom(ProcessingProjection::new(*width as f32, *height as f32));
 
     let mut transform = transforms
         .get_mut(entity)
         .map_err(|_| ProcessingError::GraphicsNotFound)?;
 
-    *transform = Transform::from_xyz(0.0, 0.0, 999.9);
+    *transform = Transform::from_xyz(0.0, 0.0, BATCH_INDEX_STEP);
 
     Ok(())
 }

crates/processing_render/src/render/mod.rs

@@ -23,6 +23,8 @@ use crate::{
     render::{material::UntypedMaterial, primitive::rect},
 };
 
+pub(crate) const BATCH_INDEX_STEP: f32 = 0.001;
+
 #[derive(Component)]
 #[relationship(relationship_target = TransientMeshes)]
 pub struct BelongsToGraphics(pub Entity);
@@ -350,7 +352,7 @@ pub fn flush_draw_commands(
 
                     flush_batch(&mut res, &mut batch, &p_material_handles);
 
-                    let z_offset = -(batch.draw_index as f32 * 0.001);
+                    let z_offset = -(batch.draw_index as f32 * BATCH_INDEX_STEP);
                     let mut transform = state.transform.to_bevy_transform();
 
                     // if the "source" geometry was parented in a gltf scene, we need to make sure that
@@ -565,7 +567,7 @@ fn flush_batch(
     material_handles: &Query<&UntypedMaterial>,
 ) {
     if let Some(mesh) = batch.current_mesh.take() {
-        let z_offset = -(batch.draw_index as f32 * 0.001);
+        let z_offset = -(batch.draw_index as f32 * BATCH_INDEX_STEP);
         spawn_mesh(res, batch, mesh, z_offset, material_handles);
         batch.draw_index += 1;
     }
@@ -616,7 +618,7 @@ fn add_shape3d(
         }
     };
 
-    let z_offset = -(batch.draw_index as f32 * 0.001);
+    let z_offset = -(batch.draw_index as f32 * BATCH_INDEX_STEP);
     let mut transform = state.transform.to_bevy_transform();
     transform.translation.z += z_offset;