Add some GLSL version handling.

1 files changed, 47 insertions, 14 deletions

diff --git a/chickadee/graphics/seagull.scm b/chickadee/graphics/seagull.scm
index 44965c2..8c1fcd6 100644
--- a/chickadee/graphics/seagull.scm
+++ b/chickadee/graphics/seagull.scm
@@ -47,6 +47,7 @@
 ;;
 ;;; Code:
 (define-module (chickadee graphics seagull)
+  #:use-module (chickadee graphics engine)
   #:use-module (chickadee graphics shader)
   #:use-module (ice-9 exceptions)
   #:use-module (ice-9 format)
@@ -2600,10 +2601,18 @@
   (list output-temp))
 
 (define (emit:top-level bindings body stage version port level)
+  (define (glsl-qualifier qualifier)
+    (case qualifier
+      ((in)
+       (if (string>= version "1.3") 'in 'attribute))
+      ((out)
+       (if (string>= version "1.3") 'out 'varying))
+      ((uniform)
+       'uniform)))
   (for-each (match-lambda
               (((? top-level-qualifier? qualifier) type-desc name)
                (format port "~a ~a ~a;\n"
-                       qualifier
+                       (glsl-qualifier qualifier)
                        (type-descriptor->glsl type-desc)
                        name))
               (('function name ('t (type) ('lambda params body)))
@@ -2921,8 +2930,36 @@
             (cons (assq-ref global-map name) name)))
          (seagull-module-uniforms module))))
 
-(define* (link-seagull-modules vertex fragment #:key
-                               (version '330))
+(define (emit-version-preprocessor version port)
+  (cond
+   ((string>= version "3.3")
+    (format port "#version 330\n"))
+   ((string>= version "1.3")
+    (format port "#version 130\n"))
+   ((string>= version "1.2")
+    (format port "#version 120\n"))
+   (else
+    (error "incompatible GLSL version" version))))
+
+(define (emit-shims version port)
+  (when (string<= version "3.3")
+    (format port "
+vec4 texture(sampler2D tex, vec2 coord) {
+  return texture2D(tex, coord);
+}
+vec4 texture(samplerCube tex, vec3 coord) {
+  return textureCube(tex, coord);
+}
+")))
+
+(define (emit-stage exp stage version)
+  (call-with-output-string
+    (lambda (port)
+      (emit-version-preprocessor version port)
+      (emit-shims version port)
+      (emit-glsl exp 'fragment version port))))
+
+(define* (link-seagull-modules vertex fragment version)
   (unless (seagull-module-vertex? vertex)
     (error "not a vertex shader" vertex))
   (unless (seagull-module-fragment? fragment)
@@ -2936,26 +2973,22 @@
       (error "vertex uniforms clash with fragment uniforms"))
     (define-values (vertex* fragment* uniform-map)
       (link-vertex-outputs-with-fragment-inputs vertex fragment))
-    (define vertex-glsl
-      (call-with-output-string
-        (lambda (port)
-          (emit-glsl vertex* 'fragment version port))))
-    (define fragment-glsl
-      (call-with-output-string
-        (lambda (port)
-          (emit-glsl fragment* 'fragment version port))))
+    (define vertex-glsl (emit-stage vertex* 'vertex version))
+    (define fragment-glsl (emit-stage fragment* 'fragment version))
     (display vertex-glsl)
     (newline)
     (display fragment-glsl)
     (newline)
     (values vertex-glsl fragment-glsl uniform-map)))
 
-(define (compile-shader vertex fragment)
+(define* (compile-shader vertex fragment #:key
+                         (version (graphics-engine-glsl-version)))
   (let-values (((glsl:vertex glsl:fragment uniform-map)
-                (link-seagull-modules vertex fragment)))
+                (link-seagull-modules vertex fragment version)))
     (call-with-input-string glsl:vertex
       (lambda (vertex-port)
         (call-with-input-string glsl:fragment
           (lambda (fragment-port)
             (make-shader vertex-port fragment-port
-                         #:uniform-map uniform-map)))))))
+                         #:uniform-map uniform-map
+                         #:pre-process? #f)))))))