Generalizing LAYERS and supporting OpenGL ES 3.1

mode-lambda/backend/gl.rkt

@@ -3,7 +3,8 @@
          ffi/unsafe/cvector
          (only-in ffi/vector
                   u32vector
-                  list->s32vector)
+                  list->s32vector
+                  s32vector-ref)
          mode-lambda/backend/gl/util
          mode-lambda/backend/lib
          mode-lambda/core
@@ -25,9 +26,9 @@
 (define QUAD_VERTS 4)
 
 (define LAYER-VALUES 12)
-(define (layer-config->bytes layer-config)
+(define (layer-config->bytes how-many-layers layer-config)
   (define lc-bytes-per-value (ctype-sizeof _float))
-  (define lc-bs (make-bytes (* LAYER-VALUES LAYERS lc-bytes-per-value)))
+  (define lc-bs (make-bytes (* LAYER-VALUES how-many-layers lc-bytes-per-value)))
   (for ([i (in-naturals)]
         [lc (in-vector layer-config)])
     (match-define
@@ -55,13 +56,18 @@
 (define VERTEX_SPEC
   (add-between VERTEX_SPEC_L ","))
 
-(define (make-draw csd width.fx height.fx screen-mode)
+(define (make-draw csd width.fx height.fx how-many-layers screen-mode)
   (define width (fx->fl width.fx))
   (define height (fx->fl height.fx))
   (eprintf "You are using OpenGL ~v with gl-backend-version of ~v\n"
            (gl-version)
            (gl-backend-version))
 
+  (define max-draw-buffers (s32vector-ref (glGetIntegerv GL_MAX_DRAW_BUFFERS) 0))
+  (unless (<= how-many-layers max-draw-buffers)
+    (error 'mode-lambda "Too many layers for device: ~v vs ~v."
+           how-many-layers max-draw-buffers))
+
   (define shot! (gl-screenshot!))
 
   (match-define
@@ -77,8 +83,9 @@
         (unless (equal? layer-config last-layer-config)
           (set! last-layer-config layer-config)
           (with-texture (GL_TEXTURE3 LayerConfigId)
-            (load-texture/float-bytes LAYER-VALUES LAYERS
-                                      (layer-config->bytes layer-config)))))))
+            (load-texture/float-bytes LAYER-VALUES how-many-layers
+                                      (layer-config->bytes how-many-layers
+                                                           layer-config)))))))
 
   (define render-layers!
     (let ()
@@ -108,7 +115,7 @@
         [(gl-es?)
          (eprintf "GL: Skipping glBindFragDataLocation on OpenGL ES\n")]
         [else
-         (for ([i (in-range LAYERS)])
+         (for ([i (in-range how-many-layers)])
            (glBindFragDataLocation layer-program i (format "out_Color~a" i)))])
 
       (define tmp-vao (glGen glGenVertexArrays))
@@ -127,7 +134,7 @@
 
       (define layer-dfbos
         (for/list ([i (in-range 2)])
-          (make-delayed-fbo LAYERS)))
+          (make-delayed-fbo how-many-layers)))
 
       (define (make-sprite-draw!)
         (define layer-vao (glGen glGenVertexArrays))
@@ -187,9 +194,9 @@
           [with-feature (GL_BLEND)]
           [with-program (layer-program)])
          (set-uniform-scale-info! layer-program the-scale-info)
-         (glDrawBuffers LAYERS
+         (glDrawBuffers how-many-layers
                         (list->s32vector
-                         (for/list ([i (in-range LAYERS)])
+                         (for/list ([i (in-range how-many-layers)])
                            (GL_COLOR_ATTACHMENTi i))))
          (glClearColor 0.0 0.0 0.0 0.0)
          (glBlendFunc GL_SRC_ALPHA GL_ONE_MINUS_SRC_ALPHA)
@@ -216,9 +223,9 @@
           (glUniform1i (glGetUniformLocation combine-program "LayerConfigTex")
                        (gl-texture-index GL_TEXTURE0))
           (glUniform1iv (glGetUniformLocation combine-program "LayerTargets")
-                        LAYERS
+                        how-many-layers
                         (list->s32vector
-                         (for/list ([i (in-range LAYERS)])
+                         (for/list ([i (in-range how-many-layers)])
                            (fx+ 1 i))))))
 
       (define combine-dfbos
@@ -357,7 +364,7 @@
 (define-make-delayed-render
   stage-draw/dc
   make-draw
-  (csd width height)
+  (csd width height how-many-layers)
   ((gl-filter-mode))
   (layer-config static-st dynamic-st))
 

mode-lambda/backend/gl/combine.fragment.glsl

@@ -1,6 +1,6 @@
 @glsl-include["lib.glsl"]
 
-uniform sampler2D LayerTargets[@LAYERS];
+uniform sampler2D LayerTargets[@how-many-layers];
 uniform sampler2D LayerConfigTex;
 uniform float XScale;
 uniform float YScale;
@@ -41,7 +41,7 @@ void main() {
   float ay = height - iTexCoord.y * height;
 
   vec4 fin_Color = vec4(0.0, 0.0, 0.0, 1.0);
-@in[compiletimelayer (in-range LAYERS)]{
+@in[compiletimelayer (in-range @how-many-layers)]{
   {
     int layer = @compiletimelayer;
     @glsl-include["layer.glsl"]

mode-lambda/backend/gl/combine.vertex.glsl

@@ -1,7 +1,7 @@
 @glsl-include["lib.glsl"]
 @glsl-include["quad.glsl"]
 
-uniform sampler2D LayerTargets[@LAYERS];
+uniform sampler2D LayerTargets[@how-many-layers];
 uniform sampler2D LayerConfigTex;
 uniform vec2 LogicalSize;
 

mode-lambda/backend/gl/ngl.fragment.glsl

@@ -11,15 +11,20 @@ in vec2 TexCoord;
 in float Palette;
 in float Layer;
 
-@in[i (in-range LAYERS)]{
+@in[i (in-range how-many-layers)]{
   layout (location = @i) out vec4 out_Color@i;
 }
 
 void main(void)
 {
-  vec4 PixelColor;
   vec4 SpriteColor = texture(SpriteAtlasTex, TexCoord);
 
+  SpriteColor = texelFetch(SpriteAtlasTex,
+                           ivec2( round(TexCoord.x), round(TexCoord.y) ),
+                           0);
+
+  vec4 PixelColor;
+
   if ( Palette == 0.0 ) {
     PixelColor = SpriteColor;
   } else {
@@ -29,14 +34,14 @@ void main(void)
   }
 
   vec4 fin_Color;
-  
+
   fin_Color.a = PixelColor.a * Color.a;
   fin_Color.rgb = PixelColor.rgb + Color.rgb;
 
   vec4 blank_Color = vec4(0.0,0.0,0.0,0.0);
 
   int iLayer = int(floor(Layer));
-  @in[i (in-range LAYERS)]{
+  @in[i (in-range how-many-layers)]{
     out_Color@i = (iLayer == @i) ? fin_Color : blank_Color;
   }
 }

mode-lambda/backend/gl/ngl.vertex.glsl

@@ -84,7 +84,7 @@ void main(void)
   TexCoord =
     vec2(tx + ((horiz + 1.0)/+2.0) * w,
          ty + (( vert + 1.0)/+2.0) * h)
-    / float(atlasSize.x);
+    ; // / float(atlasSize.x); // for use with texture (rather than texelFetch)
   Palette = float(pal);
   Layer = float(layer);
 }

mode-lambda/backend/gl/util.rkt

@@ -11,9 +11,9 @@
 
 ;; XXX maybe 410
 (define gl-backend-version (make-parameter '3.3))
-(define valid-gl-backends '(3.3 es3.2))
+(define valid-gl-backends '(3.3 es3.1))
 (define (gl-es?)
-  (eq? 'es3.2 (gl-backend-version)))
+  (eq? 'es3.1 (gl-backend-version)))
 
 (define-syntax-rule (glsl-include p) (include-template p))
 
@@ -139,7 +139,7 @@
                    (string-append (format "#version ~a\n"
                                           (match (gl-backend-version)
                                             ['3.3 "330 core"]
-                                            ['es3.2 "320 es"]))
+                                            ['es3.1 "310 es"]))
                                   VertexShader))
                   (s32vector))
   (glCompileShader VertexShaderId)

mode-lambda/backend/software.rkt

@@ -125,7 +125,7 @@
       (when (fl<=3 0.0 λ3 1.0)
         (draw-triangle! t x y λ1 λ2 λ3)))))
 
-(define (stage-render csd width height)
+(define (stage-render csd width height layers)
   (define width.0 (fx->fl width))
   (define hwidth.0 (fl* 0.5 width.0))
   (define height.0 (fx->fl height))
@@ -135,7 +135,7 @@
                        pal-size pal-bs pal->idx)
    csd)
   (define root-bs-v
-    (build-vector LAYERS (λ (i) (make-bytes (* 4 width height)))))
+    (build-vector layers (λ (i) (make-bytes (* 4 width height)))))
   (define combined-bs
     (make-bytes (* 4 width height)))
   (define tri-hash (make-2d-hash width height))
@@ -441,8 +441,8 @@
   (make-parameter #f))
 
 (define gui-mode 'draw)
-(define (stage-draw/dc csd width height)
-  (define render (stage-render csd width height))
+(define (stage-draw/dc csd width height how-many-layers)
+  (define render (stage-render csd width height how-many-layers))
   (λ (layer-config static-st dynamic-st)
     (define sprite-tree (cons static-st dynamic-st))
     (define bs (render layer-config sprite-tree))

mode-lambda/core.rkt

@@ -14,9 +14,7 @@
 (struct compiled-sprite-db
   (atlas-size atlas-bs spr->idx idx->w*h*tx*ty pal-size pal-bs pal->idx))
 
-(define LAYERS 8)
-(define layer/c
-  (and/c byte? (between/c 0 (sub1 LAYERS))))
+(define layer/c byte?)
 
 (define-cstruct _layer-data
   ([cx _float]
@@ -36,8 +34,6 @@
 
 (define default-layer
   (make-layer-data 0.0 0.0 0.0 0.0 1.0 1.0 0.0 0.0 0.0 1.0 #f #f))
-(define default-layer-config
-  (make-vector LAYERS #f))
 
 ;; Mode7 Docs:
 ;; - http://www.coranac.com/tonc/text/mode7.htm
@@ -85,7 +81,7 @@
   (printf "sprite-data size: ~v bytes\n" (ctype-sizeof _sprite-data)))
 
 (define layer-vector/c
-  (apply vector/c (make-list LAYERS (or/c false/c layer-data?))))
+  (vectorof (or/c false/c layer-data?)))
 
 (define-syntax-rule (backend/c (addl-input ...) output)
   (-> layer-vector/c tree/c tree/c addl-input ... output))
@@ -97,6 +93,7 @@
 
 (define (stage-backend/c output/c)
   (-> compiled-sprite-db?
+      exact-nonnegative-integer?
       exact-nonnegative-integer?
       exact-nonnegative-integer?
       output/c))

mode-lambda/examples/one.rkt

@@ -115,7 +115,7 @@
   (define csd-p (build-path here "csd"))
   (save-csd! original-csd csd-p #:debug? #t)
   (define csd (load-csd csd-p))
-  (define render (stage-draw/dc csd W H))
+  (define render (stage-draw/dc csd W H 8))
   (vector ns csd render (make-text-renderer the-font csd)))
 
 (define (go renderi mode spin?)

mode-lambda/main.rkt

@@ -68,12 +68,8 @@
 
 (provide
  (contract-out
-  [LAYERS
-   exact-nonnegative-integer?]
   [PALETTE-DEPTH
    exact-nonnegative-integer?]
-  [default-layer-config
-    layer-vector/c]
   [compiled-sprite-db?
    (-> any/c
        boolean?)]

mode-lambda/scribblings/backend-gl.scrbl

@@ -15,8 +15,9 @@ pretty fast, but kind of complicated.
 @defthing[stage-draw/dc
           (->i ([cdb compiled-sprite-db?]
                 [render-width exact-nonnegative-integer?]
-                [render-height exact-nonnegative-integer?])
-               (->i ([layer-config layer-vector/c]
+                [render-height exact-nonnegative-integer?]
+                [layers exact-nonnegative-integer?])
+               (->i ([layer-config (vectorof layer-data?)]
                      [static-st any/c]
                      [dynamic-st any/c])
                     (->i ([draw-width exact-nonnegative-integer?]
@@ -25,13 +26,17 @@ pretty fast, but kind of complicated.
                          any)))]{
 
 Prepares a function that accepts rendering states and returns a
-function that draws that rendering state.}
+function that draws that rendering state. @racket[layers] must be less
+than or equal to @litchar{GL_MAX_DRAW_BUFFERS}, which tends to be
+either 4 on embedded devices, 8 on older devices, and 16 on new
+devices. (A future version of this backend will use a different
+implementation technique and limit it to be a @racket[byte?].)}
 
 @defthing[gui-mode symbol?]{
 
 A symbol to be sent to @racket[make-gui] of @racketmodname[lux/chaos/gui].}
 
-@defthing[gl-backend-version (parameter/c (one-of '3.3 'es3.2))]{
+@defthing[gl-backend-version (parameter/c (one-of '3.3 'es3.1))]{
 
 Sets the desired version of OpenGL to use.}
 

mode-lambda/scribblings/backend-software.scrbl

@@ -15,8 +15,9 @@ very slow, and a little complicated, but easier to test than
 @defthing[stage-draw/dc
           (->i ([cdb compiled-sprite-db?]
                 [render-width exact-nonnegative-integer?]
-                [render-height exact-nonnegative-integer?])
-               (->i ([layer-config layer-vector/c]
+                [render-height exact-nonnegative-integer?]
+                [layers exact-nonnegative-integer?])
+               (->i ([layer-config (vectorof layer-data?)]
                      [static-st any/c]
                      [dynamic-st any/c])
                     (->i ([draw-width exact-nonnegative-integer?]

mode-lambda/scribblings/mode-lambda.scrbl

@@ -1,6 +1,6 @@
 #lang scribble/manual
 @require[(only-in mode-lambda/core
-                  LAYERS PALETTE-DEPTH)
+                  PALETTE-DEPTH)
          @for-label[racket/base
                     racket/contract/base]]
 
@@ -26,9 +26,9 @@ drawing surface. @ML follows an ahead-of-time, staged rendering regime
 whereby all color data must be "compiled", using
 @racket[compile-sprite-db], before any drawing can occur.
 
-@ML draws sprites on to one of @racket[#,LAYERS] layers. The larger
-layers are on-top, with transparent pixels seeping through. @ML makes
-no guarantees about the layering and transparency behavior of sprites
+@ML draws sprites on to one of the layers. The larger layers are
+on-top, with transparent pixels seeping through. @ML makes no
+guarantees about the layering and transparency behavior of sprites
 within a single layer. Each layer may have an independent center
 point, width, scaling coefficients, rotation, wrapping behavior, and
 Mode-7 coefficients.
@@ -213,21 +213,11 @@ Compiles the database @racket[db].}
 Use this module to construct scenes for one of the backends. Connect
 it to @racketmodname[mode-lambda/static] with @racket[load-csd].
 
-@defthing[LAYERS exact-nonnegative-integer?]{
-
-The number of layers supported by
-@racketmodname[mode-lambda]. Currently @racket[#,LAYERS].}
-
 @defthing[PALETTE-DEPTH exact-nonnegative-integer?]{
 
 The number of colors in one palette supported by
     @racketmodname[mode-lambda]. Currently @racket[#,PALETTE-DEPTH].}
 
-@defthing[default-layer-config layer-vector/c]{
-
-The default configuration of layers. You almost certainly don't want
-to use it.}
-
 @defproc[(compiled-sprite-db? [x any/c])
          boolean?]{