render: scene: Stop allocating matrices when rendering.

* chickadee/render/scene.scm (<primitive>): Add matrix field.
(make-primitive): Call %make-primitive with additional matrix arg.
(<scene-node>): Add world-matrix field.
(make-scene-node): Call %make-scene-node with additional matrix arg.
(modelview): Delete.
(draw-primitive): Perform matrix multiplication without allocating.
(draw-scene-node): Likewise.
(draw-scene): Pass pre-built matrix rather than allocating.

1 files changed, 17 insertions, 22 deletions

diff --git a/chickadee/render/scene.scm b/chickadee/render/scene.scm
index 8aa6f1f..434f301 100644
--- a/chickadee/render/scene.scm
+++ b/chickadee/render/scene.scm
@@ -143,11 +143,12 @@
       (force shader))))
 
 (define-record-type <primitive>
-  (%make-primitive vertex-array material targets)
+  (%make-primitive vertex-array material targets matrix)
   primitive?
   (vertex-array primitive-vertex-array)
   (material primitive-material)
-  (targets primitive-targets))
+  (targets primitive-targets)
+  (matrix primitive-matrix))
 
 (define (display-primitive primitive port)
   (format port "#<primitive material: ~s targets: ~s>"
@@ -160,7 +161,7 @@
                          vertex-array
                          (material default-material)
                          targets)
-  (%make-primitive vertex-array material targets))
+  (%make-primitive vertex-array material targets (make-identity-matrix4)))
 
 (define-record-type <mesh>
   (%make-mesh name primitives weights)
@@ -181,14 +182,15 @@
   (%make-mesh name primitives weights))
 
 (define-record-type <scene-node>
-  (%make-scene-node name children camera skin matrix mesh
-                    rotation scale translation weights)
+  (%make-scene-node name children camera skin matrix world-matrix
+                    mesh rotation scale translation weights)
   node?
   (name scene-node-name)
   (children scene-node-children)
   (camera scene-node-camera)
   (skin scene-node-skin)
   (matrix scene-node-matrix)
+  (world-matrix scene-node-world-matrix)
   (mesh scene-node-mesh)
   (rotation scene-node-rotation)
   (scale scene-node-scale)
@@ -211,8 +213,8 @@
                           (scale (vec3 1.0 1.0 1.0))
                           (translation (vec3 0.0 0.0 0.0))
                           weights)
-  (%make-scene-node name children camera skin matrix mesh
-                    rotation scale translation weights))
+  (%make-scene-node name children camera skin matrix (make-identity-matrix4)
+                    mesh rotation scale translation weights))
 
 (define-record-type <scene>
   (%make-scene name nodes)
@@ -223,21 +225,14 @@
 (define* (make-scene #:key (name "anonymous") (nodes '()))
   (%make-scene name nodes))
 
-(define modelview
-  (make-matrix4 1.0 0.0 0.0 0.0
-                0.0 1.0 0.0 0.0
-                0.0 0.0 1.0 0.0
-                0.0 0.0 1.0 1.0)
-  ;;(make-identity-matrix4)
-  )
-
 (define (draw-primitive primitive matrix)
   ;; TODO: Use material.
   ;; TODO: Actually use physically based rendering.
-  (gpu-apply (pbr-shader)
-             (primitive-vertex-array primitive)
-             #:mvp (matrix4* modelview (current-projection))
-             ))
+  (let ((mvp (primitive-matrix primitive)))
+    (matrix4-mult! mvp matrix (current-projection))
+    (gpu-apply (pbr-shader)
+               (primitive-vertex-array primitive)
+               #:mvp mvp)))
 
 (define (draw-mesh mesh matrix)
   (for-each (lambda (primitive)
@@ -245,8 +240,8 @@
             (mesh-primitives mesh)))
 
 (define (draw-scene-node node matrix)
-  ;; TODO: Apply transformation matrix.
-  (let ((world-matrix (matrix4* matrix (scene-node-matrix node))))
+  (let ((world-matrix (scene-node-world-matrix node)))
+    (matrix4-mult! world-matrix matrix (scene-node-matrix node))
     (when (scene-node-mesh node)
       (draw-mesh (scene-node-mesh node) world-matrix))
     (for-each (lambda (node)
@@ -255,5 +250,5 @@
 
 (define (draw-scene scene)
   (for-each (lambda (scene)
-              (draw-scene-node scene (make-identity-matrix4)))
+              (draw-scene-node scene (scene-node-world-matrix scene)))
             (scene-nodes scene)))