1371627 - GL_EXT_draw_buffers extension not supported

Status: UNCONFIRMED

(Core :: Graphics: CanvasWebGL, enhancement, P3)

Description

[ml.matrix]

User Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:53.0) Gecko/20100101 Firefox/53.0
Build ID: 20170518000419

Steps to reproduce:

Open https://www.khronos.org/registry/webgl/sdk/tests/conformance/extensions/webgl-draw-buffers.html?webglVersion=1&quiet=0 and go to 'test that gl_FragColor does not broadcast unless extension is enabled in fragment shader'. There are FAILs for attachments 1-7. This apparently causes a shader compilation error when using the directive 
#extension GL_EXT_draw_buffers : require
in the fragment shader. My webgl debugging lib returns: "Failed to compile shader: ERROR: 0:3: 'GL_EXT_draw_buffers' : extension is not supported".
This happens on several systems with different graphics cards (integrated, dedicated, whatever).
Works well in Chrome.


Actual results:

test that gl_FragColor does not broadcast unless extension is enabled in fragment shader
PASS attachment 0 should be 255,0,0,255
FAIL attachment 1 [details] [diff] [review] should be 0,255,0,255
at (0, 0) expected: 0,255,0,255 was 255,0,0,255
FAIL attachment 2 [details] [diff] [review] should be 0,255,0,255
at (0, 0) expected: 0,255,0,255 was 255,0,0,255
FAIL attachment 3 [details] [diff] [review] should be 0,255,0,255
at (0, 0) expected: 0,255,0,255 was 255,0,0,255
FAIL attachment 4 [details] [diff] [review] should be 0,255,0,255
at (0, 0) expected: 0,255,0,255 was 255,0,0,255
FAIL attachment 5 [details] should be 0,255,0,255
at (0, 0) expected: 0,255,0,255 was 255,0,0,255
FAIL attachment 6 [details] should be 0,255,0,255
at (0, 0) expected: 0,255,0,255 was 255,0,0,255
FAIL attachment 7 [details] should be 0,255,0,255
at (0, 0) expected: 0,255,0,255 was 255,0,0,255


Expected results:

test that gl_FragColor does not broadcast unless extension is enabled in fragment shader
PASS attachment 0 should be 255,0,0,255
PASS attachment 1 [details] [diff] [review] should be 0,255,0,255
PASS attachment 2 [details] [diff] [review] should be 0,255,0,255
PASS attachment 3 [details] [diff] [review] should be 0,255,0,255
PASS attachment 4 [details] [diff] [review] should be 0,255,0,255
PASS attachment 5 [details] should be 0,255,0,255
PASS attachment 6 [details] should be 0,255,0,255
PASS attachment 7 [details] should be 0,255,0,255