Refactor pixel rendering method

Author: wedesoft

src/volumetric_clouds/main.clj

@@ -482,9 +482,9 @@
 
 (defn octaves
   [n decay]
-  (let [series (take n (iterate #(* ^double % decay) 1.0))
+  (let [series (take n (iterate #(* % decay) 1.0))
         sum    (apply + series)]
-    (mapv #(/ ^double % ^double sum) series)))
+    (mapv #(/ % sum) series)))
 
 
 (defn noise-octaves
@@ -595,43 +595,64 @@ void main()
   "Convert float buffer to flaot array"
   {:malli/schema [:=> [:cat :some] seqable?]}
   [buffer]
-  (let [result (float-array (.limit ^java.nio.DirectFloatBufferU buffer))]
-    (.get ^java.nio.DirectFloatBufferU buffer result)
-    (.flip ^java.nio.DirectFloatBufferU buffer)
+  (let [result (float-array (.limit buffer))]
+    (.get buffer result)
+    (.flip buffer)
     result))
 
 
+(defn make-texture
+  [width height]
+  (let [texture (GL11/glGenTextures)]
+    (GL11/glBindTexture GL11/GL_TEXTURE_2D texture)
+    (GL42/glTexStorage2D GL11/GL_TEXTURE_2D 1 GL30/GL_RGBA32F width height)
+    texture))
+
+
+(defn read-texture
+  [texture width height]
+  (let [buffer (BufferUtils/createFloatBuffer (* height width 4))]
+    (GL11/glBindTexture GL11/GL_TEXTURE_2D texture)
+    (GL11/glGetTexImage GL11/GL_TEXTURE_2D 0 GL12/GL_RGBA GL11/GL_FLOAT buffer)
+    (seq (float-buffer->array buffer))))
+
+
+(defmacro framebuffer-render
+  [texture width height & body]
+  `(let [fbo# (GL30/glGenFramebuffers)]
+     (GL30/glBindFramebuffer GL30/GL_FRAMEBUFFER fbo#)
+     (GL11/glBindTexture GL11/GL_TEXTURE_2D ~texture)
+     (GL32/glFramebufferTexture GL30/GL_FRAMEBUFFER GL30/GL_COLOR_ATTACHMENT0 ~texture 0)
+     (GL20/glDrawBuffers (volumetric-clouds.main/make-int-buffer (int-array [GL30/GL_COLOR_ATTACHMENT0])))
+     (GL11/glViewport 0 0 ~width ~height)
+     (let [result# (do ~@body)]
+       (GL30/glBindFramebuffer GL30/GL_FRAMEBUFFER 0)
+       (GL30/glDeleteFramebuffers fbo#)
+       result#)))
+
+
 (defn render-pixel
   [vertex-source fragment-source]
-  (let [vertices        (float-array [ 1.0  1.0 0.0, -1.0  1.0 0.0, -1.0 -1.0 0.0, 1.0 -1.0 0.0])
+  (let [vertices        (float-array [1.0 1.0 0.0, -1.0 1.0 0.0, -1.0 -1.0 0.0, 1.0 -1.0 0.0])
         indices         (int-array [0 1 2 3])
         vertex-shader   (make-shader vertex-source GL20/GL_VERTEX_SHADER)
         fragment-shader (make-shader fragment-source GL20/GL_FRAGMENT_SHADER)
         program         (make-program vertex-shader fragment-shader)
-        location        (GL20/glGetAttribLocation program "point")
+        point-attribute (GL20/glGetAttribLocation program "point")
         vao             (setup-vao vertices indices)
-        texture         (GL11/glGenTextures)
-        fbo             (GL30/glGenFramebuffers)
-        buf             (BufferUtils/createFloatBuffer (* 1 1 3))]
-    (GL20/glVertexAttribPointer location 3 GL11/GL_FLOAT false (* 3 Float/BYTES) (* 0 Float/BYTES))
-    (GL20/glEnableVertexAttribArray location)
-    (GL11/glBindTexture GL11/GL_TEXTURE_2D texture)
-    (GL42/glTexStorage2D GL11/GL_TEXTURE_2D 1 GL30/GL_RGBA32F 1 1)
-    (GL30/glBindFramebuffer GL30/GL_FRAMEBUFFER fbo)
-    (GL32/glFramebufferTexture GL30/GL_FRAMEBUFFER GL30/GL_COLOR_ATTACHMENT0 texture 0)
-    (GL20/glDrawBuffers (make-int-buffer (int-array [GL30/GL_COLOR_ATTACHMENT0])))
-    (GL11/glViewport 0 0 1 1)
-    (GL20/glUseProgram program)
-    (GL11/glClearColor 1.0 0.5 0.25 1.0)
-    (GL11/glClear GL11/GL_COLOR_BUFFER_BIT)
-    (GL11/glDrawElements GL11/GL_QUADS (count indices) GL11/GL_UNSIGNED_INT 0)
-    (GL30/glBindFramebuffer GL30/GL_FRAMEBUFFER 0)
-    (GL30/glDeleteFramebuffers fbo)
-    (GL11/glGetTexImage GL11/GL_TEXTURE_2D 0 GL12/GL_RGBA GL11/GL_FLOAT buf)
-    (GL11/glDeleteTextures texture)
-    (teardown-vao vao)
-    (GL20/glDeleteProgram program)
-    (seq (float-buffer->array buf))))
+        texture         (make-texture 1 1)]
+    (GL20/glVertexAttribPointer point-attribute 3 GL11/GL_FLOAT false (* 3 Float/BYTES) (* 0 Float/BYTES))
+    (GL20/glEnableVertexAttribArray point-attribute)
+    (framebuffer-render texture 1 1
+                        (GL20/glUseProgram program)
+                        (GL11/glClearColor 1.0 0.5 0.25 1.0)
+                        (GL11/glClear GL11/GL_COLOR_BUFFER_BIT)
+                        (GL11/glDrawElements GL11/GL_QUADS (count indices) GL11/GL_UNSIGNED_INT 0))
+    (let [result (read-texture texture 1 1)]
+      (GL11/glDeleteTextures texture)
+      (teardown-vao vao)
+      (GL20/glDeleteProgram program)
+      result)))
 
 
 (render-pixel vertex-test fragment-test)