Spec and test w,h constraints for BPTC, RGTC, and S3TC. (KhronosGroup…

…#3304) `w << level` and `h << level` must be multiples of 4. This way, we forbid image allocations that are never valid, such as 1x1 for level 1. (would only be valid with a 2x2 base level, which is forbidden) Resolves KhronosGroup#3117.
chcunningham · Aug 3, 2021 · 6e9256f · 6e9256f
1 parent ad14195
commit 6e9256f
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Showing 6 changed files with 44 additions and 19 deletions.
diff --git a/extensions/EXT_texture_compression_bptc/extension.xml b/extensions/EXT_texture_compression_bptc/extension.xml
@@ -64,7 +64,7 @@
           <dt>COMPRESSED_RGB_BPTC_SIGNED_FLOAT_EXT</dt>
           <dt>COMPRESSED_RGB_BPTC_UNSIGNED_FLOAT_EXT</dt>
           <dd>
-          <p>When <code>level</code> equals zero <code>width</code> and <code>height</code>
+          <p><code>width &lt;&lt; level</code> and <code>height &lt;&lt; level</code>
           must be a multiple of 4.</p>
           <p>
           If they are not an <code>INVALID_OPERATION</code> error is generated.
@@ -117,8 +117,8 @@ interface EXT_texture_compression_bptc {
     </error>
     <error enum="INVALID_OPERATION">
       The error <code>INVALID_OPERATION</code> is generated by <code>compressedTexImage2D</code> and
-      <code>compressedTexSubImage2D</code> if the <code>level</code> parameter is
-      <code>0</code> and the <code>width</code> or <code>height</code> is not a multiple of 4.
+      <code>compressedTexSubImage2D</code> if <code>width &lt;&lt; level</code> and
+      <code>height &lt;&lt; level</code> are not multiples of 4.
     </error>
   </errors>
 

diff --git a/extensions/EXT_texture_compression_rgtc/extension.xml b/extensions/EXT_texture_compression_rgtc/extension.xml
@@ -54,7 +54,7 @@
             ceil(width / 4) * ceil(height / 4) * 8
           </code></blockquote>
           <p>If it is not, an <code>INVALID_VALUE</code> error is generated.</p>
-          <p>When <code>level</code> equals zero <code>width</code> and <code>height</code>
+          <p><code>width &lt;&lt; level</code> and <code>height &lt;&lt; level</code>
           must be a multiple of 4.</p>
           <p>
           If they are not an <code>INVALID_OPERATION</code> error is generated.
@@ -68,7 +68,7 @@
             ceil(width / 4) * ceil(height / 4) * 16
           </code></blockquote>
           <p>If it is not, an <code>INVALID_VALUE</code> error is generated.</p>
-          <p>When <code>level</code> equals zero <code>width</code> and <code>height</code>
+          <p><code>width &lt;&lt; level</code> and <code>height &lt;&lt; level</code>
           must be a multiple of 4.</p>
           <p>
           If they are not an <code>INVALID_OPERATION</code> error is generated.

diff --git a/extensions/WEBGL_compressed_texture_s3tc/extension.xml b/extensions/WEBGL_compressed_texture_s3tc/extension.xml
@@ -14,7 +14,7 @@
   </depends>
   <overview>
     <p>
-      This extension exposes the compressed texture formats defined in the 
+      This extension exposes the compressed texture formats defined in the
       <a href="http://www.opengl.org/registry/specs/EXT/texture_compression_s3tc.txt">
       EXT_texture_compression_s3tc</a> OpenGL extension to WebGL.
     </p>
@@ -53,9 +53,8 @@
           <p>
           If it is not an <code>INVALID_VALUE</code> error is generated.
           </p>
-          <p>When <code>level</code> equals zero <code>width</code> and <code>height</code>
-          must be a multiple of 4. When <code>level</code> is greater than 0 <code>width</code>
-          and <code>height</code> must be 0, 1, 2 or a multiple of 4.</p>
+          <p><code>width &lt;&lt; level</code> and <code>height &lt;&lt; level</code>
+          must be a multiple of 4.</p>
           <p>
           If they are not an <code>INVALID_OPERATION</code> error is generated.
           </p>
@@ -80,9 +79,8 @@
           <p>
           If it is not an <code>INVALID_VALUE</code> error is generated.
           </p>
-          <p>When <code>level</code> equals zero <code>width</code> and <code>height</code>
-          must be a multiple of 4. When <code>level</code> is greater than 0 <code>width</code>
-          and <code>height</code> must be 0, 1, 2 or a multiple of 4.</p>
+          <p><code>width &lt;&lt; level</code> and <code>height &lt;&lt; level</code>
+          must be a multiple of 4.</p>
           <p>
           If they are not an <code>INVALID_OPERATION</code> error is generated.
           </p>
@@ -126,7 +124,7 @@ interface WEBGL_compressed_texture_s3tc {
       <change>Added NoInterfaceObject extended attribute.</change>
     </revision>
     <revision date="2019/10/24">
-      <change>Added a note about <code>COMPRESSED_RGB_S3TC_DXT1_EXT</code> support.</change> 
+      <change>Added a note about <code>COMPRESSED_RGB_S3TC_DXT1_EXT</code> support.</change>
     </revision>
   </history>
 </ratified>
diff --git a/sdk/tests/conformance/extensions/ext-texture-compression-bptc.html b/sdk/tests/conformance/extensions/ext-texture-compression-bptc.html
@@ -87,10 +87,16 @@
         expectation: gl.INVALID_OPERATION, message: "level is 0, width is not a multiple of 4" },
       { level: 0, width: 4, height: 4,
         expectation: gl.NO_ERROR, message: "is valid" },
+      { level: 1, width: 1, height: 1,
+        expectation: gl.INVALID_OPERATION, message: "implied base mip 2x2 is invalid" },
+      { level: 1, width: 1, height: 2,
+        expectation: gl.INVALID_OPERATION, message: "implied base mip 2x4 is invalid" },
+      { level: 1, width: 2, height: 1,
+        expectation: gl.INVALID_OPERATION, message: "implied base mip 4x2 is invalid" },
       { level: 1, width: 2, height: 2,
-        expectation: gl.NO_ERROR, message: "level > 0, is valid" },
-      { level: 2, width: 1, height: 1,
-        expectation: gl.NO_ERROR, message: "level > 0, is valid" },
+        expectation: gl.NO_ERROR, message: "implied base mip 4x4 is valid" },
+      { level: 2, width: 1, height: 3,
+        expectation: gl.NO_ERROR, message: "implied base mip 4x12 is valid" },
   ]);
 
   // Test that BPTC enums are not accepted by texImage2D

diff --git a/sdk/tests/conformance/extensions/ext-texture-compression-rgtc.html b/sdk/tests/conformance/extensions/ext-texture-compression-rgtc.html
@@ -92,10 +92,16 @@
         expectation: gl.INVALID_OPERATION, message: "level is 0, width is not a multiple of 4" },
       { level: 0, width: 4, height: 4,
         expectation: gl.NO_ERROR, message: "is valid" },
+      { level: 1, width: 1, height: 1,
+        expectation: gl.INVALID_OPERATION, message: "implied base mip 2x2 is invalid" },
+      { level: 1, width: 1, height: 2,
+        expectation: gl.INVALID_OPERATION, message: "implied base mip 2x4 is invalid" },
+      { level: 1, width: 2, height: 1,
+        expectation: gl.INVALID_OPERATION, message: "implied base mip 4x2 is invalid" },
       { level: 1, width: 2, height: 2,
-        expectation: gl.NO_ERROR, message: "level > 0, is valid" },
-      { level: 2, width: 1, height: 1,
-        expectation: gl.NO_ERROR, message: "level > 0, is valid" },
+        expectation: gl.NO_ERROR, message: "implied base mip 4x4 is valid" },
+      { level: 2, width: 1, height: 3,
+        expectation: gl.NO_ERROR, message: "implied base mip 4x12 is valid" },
   ]);
 
   // Test that RGTC enums are not accepted by texImage2D

diff --git a/sdk/tests/conformance/extensions/s3tc-and-rgtc.html b/sdk/tests/conformance/extensions/s3tc-and-rgtc.html
@@ -301,9 +301,24 @@
         debug("Testing NPOT textures");
         ctu.testTexImageLevelDimensions(gl, ext, validFormats, expectedByteLength, getBlockDimensions,
           [
+            { level: 0, width: 0, height: 0, expectation: gl.NO_ERROR, message: "0: 0x0 is valid" },
+            { level: 0, width: 1, height: 1, expectation: gl.INVALID_OPERATION, message: "0: 1x1 is invalid" },
+            { level: 0, width: 2, height: 2, expectation: gl.INVALID_OPERATION, message: "0: 2x2 is invalid" },
+            { level: 0, width: 3, height: 3, expectation: gl.INVALID_OPERATION, message: "0: 3x3 is invalid" },
+            { level: 0, width: 10, height: 10, expectation: gl.INVALID_OPERATION, message: "0: 10x10 is invalid" },
+            { level: 0, width: 11, height: 11, expectation: gl.INVALID_OPERATION, message: "0: 11x11 is invalid" },
+            { level: 0, width: 11, height: 12, expectation: gl.INVALID_OPERATION, message: "0: 11x12 is invalid" },
+            { level: 0, width: 12, height: 11, expectation: gl.INVALID_OPERATION, message: "0: 12x11 is invalid" },
             { level: 0, width: 12, height: 12, expectation: gl.NO_ERROR, message: "0: 12x12 is valid" },
+            { level: 1, width:  0, height:  0, expectation: gl.NO_ERROR, message: "1: 0x0, is valid" },
+            { level: 1, width:  3, height:  3, expectation: gl.INVALID_OPERATION, message: "1: 3x3, is invalid" },
+            { level: 1, width:  5, height:  5, expectation: gl.INVALID_OPERATION, message: "1: 5x5, is invalid" },
+            { level: 1, width:  5, height:  6, expectation: gl.INVALID_OPERATION, message: "1: 5x6, is invalid" },
+            { level: 1, width:  6, height:  5, expectation: gl.INVALID_OPERATION, message: "1: 6x5, is invalid" },
             { level: 1, width:  6, height:  6, expectation: gl.NO_ERROR, message: "1: 6x6, is valid" },
+            { level: 2, width:  0, height:  0, expectation: gl.NO_ERROR, message: "2: 0x0, is valid" },
             { level: 2, width:  3, height:  3, expectation: gl.NO_ERROR, message: "2: 3x3, is valid" },
+            { level: 3, width:  1, height:  3, expectation: gl.NO_ERROR, message: "3: 1x3, is valid" },
             { level: 3, width:  1, height:  1, expectation: gl.NO_ERROR, message: "3: 1x1, is valid" },
         ]);