Merge pull request regl-project#76 from mikolalysenko/framebuffer-bit…

…-planes-validation Added Framebuffer bit planes validation
jwittenbach · Jul 17, 2016 · 84b20f5 · 84b20f5
2 parents 99500f9 + 5a70c91
commit 84b20f5
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diff --git a/lib/framebuffer.js b/lib/framebuffer.js
@@ -20,6 +20,10 @@ var GL_FRAMEBUFFER_INCOMPLETE_MISSING_ATTACHMENT = 0x8CD7
 var GL_FRAMEBUFFER_INCOMPLETE_DIMENSIONS = 0x8CD9
 var GL_FRAMEBUFFER_UNSUPPORTED = 0x8CDD
 
+var GL_HALF_FLOAT_OES = 0x8D61
+var GL_UNSIGNED_BYTE = 0x1401
+var GL_FLOAT = 0x1406
+
 var GL_RGBA = 0x1908
 var GL_ALPHA = 0x1906
 var GL_RGB = 0x1907
@@ -36,6 +40,22 @@ var colorTextureFormatEnums = [
   GL_RGBA
 ]
 
+// for every texture format, store
+// the number of channels
+var textureFormatChannels = []
+textureFormatChannels[GL_ALPHA] = 1
+textureFormatChannels[GL_LUMINANCE] = 1
+textureFormatChannels[GL_LUMINANCE_ALPHA] = 2
+textureFormatChannels[GL_RGB] = 3
+textureFormatChannels[GL_RGBA] = 4
+
+// for every texture type, store
+// the size in bytes.
+var textureTypeSizes = []
+textureTypeSizes[GL_UNSIGNED_BYTE] = 1
+textureTypeSizes[GL_FLOAT] = 4
+textureTypeSizes[GL_HALF_FLOAT_OES] = 2
+
 var GL_RGBA4 = 0x8056
 var GL_RGB5_A1 = 0x8057
 var GL_RGB565 = 0x8D62
@@ -530,6 +550,8 @@ module.exports = function wrapFBOState (
         (!!depthBuffer) + (!!stencilBuffer) + (!!depthStencilBuffer) <= 1,
         'invalid framebuffer configuration, can specify exactly one depth/stencil attachment')
 
+      var commonColorAttachmentSize = null
+
       for (i = 0; i < colorAttachments.length; ++i) {
         incRefAndCheckShape(colorAttachments[i], width, height)
         check(!colorAttachments[i] ||
@@ -538,6 +560,22 @@ module.exports = function wrapFBOState (
           (colorAttachments[i].renderbuffer &&
             colorRenderbufferFormatEnums.indexOf(colorAttachments[i].renderbuffer._renderbuffer.format) >= 0),
           'framebuffer color attachment ' + i + ' is invalid')
+
+        if (colorAttachments[i] && colorAttachments[i].texture) {
+          var colorAttachmentSize =
+              textureFormatChannels[colorAttachments[i].texture._texture.format] *
+              textureTypeSizes[colorAttachments[i].texture._texture.type]
+
+          if (commonColorAttachmentSize === null) {
+            commonColorAttachmentSize = colorAttachmentSize
+          } else {
+            // We need to make sure that all color attachments have the same number of bitplanes
+            // (that is, the same numer of bits per pixel)
+            // This is required by the GLES2.0 standard. See the beginning of Chapter 4 in that document.
+            check(commonColorAttachmentSize === colorAttachmentSize,
+                  'all color attachments much have the same number of bits per pixel.')
+          }
+        }
       }
       incRefAndCheckShape(depthAttachment, width, height)
       check(!depthAttachment ||

diff --git a/test/framebuffer-parse.js b/test/framebuffer-parse.js
@@ -194,7 +194,49 @@ tape('framebuffer parsing', function (t) {
     'color renderbuffer')
 
   // TODO: float, half float types
-  // TODO: multiple render targets
+
+  if (regl.hasExtension('WEBGL_draw_buffers')) {
+    t.throws(function () {
+      regl.framebuffer({
+        color: [
+          regl.texture({type: 'float'}),
+          regl.texture({type: 'uint8'})
+        ]}) },
+             /\(regl\)/,
+             '#1 check color attachments with different bit planes throws')
+
+    t.throws(function () {
+      regl.framebuffer({
+        color: [
+          regl.texture({type: 'uint8', format: 'rgb'}),
+          regl.texture({type: 'float', format: 'rgba'})
+        ]}) },
+             /\(regl\)/,
+             '#2 check color attachments with different bit planes throws')
+
+    t.throws(function () {
+      regl.framebuffer({
+        color: [
+          regl.texture({type: 'half float', format: 'rgb'}),
+          regl.texture({type: 'uint8', format: 'rgba'})
+        ]}) },
+             /\(regl\)/,
+             '#3 check color attachments with different bit planes throws')
+
+    var thrown = false
+    try {
+      regl.framebuffer({
+        color: [
+          regl.texture({type: 'float'}),
+          regl.texture({type: 'float'})
+        ]})
+    } catch (e) {
+      thrown = true
+    }
+
+    // TODO: multiple render targets
+    t.equals(thrown, false, 'check color attachments with same bit planes do not throw')
+  }
 
   regl.destroy()
   createContext.destroy(gl)