Example doesn't work correctly on Windows

[organic-nailer]

Hello.
Thank you for creating such an amazing package!

I tried to run example app (flutter_gl/example), but when I run it on Windows, the triangle doesn't show up. When I run it on the Web under the same condition, it displays correctly.
Could you see what's wrong?

• Windows
  

• Web
  

[beelabcloud]

The example should work on Intel integratied graphic rather AMD or Nvidia adapter. The vertex shader should be like:
"""#version 300 es
precision mediump float;
in vec4 a_position;
in vec2 a_texCoord;
out highp vec2 vTexCoord;
void main() {
gl_Position = a_position;
vTexCoord = a_texCoord;
}
""";

[beelabcloud]

for AMD case, "vec4 a_position" is the key, vec2/vec3 just not working, I don't know why.

[organic-nailer]

I found a weak solution in my environment (Windows/AMD).

https://github.com/organic-nailer/flutter_gl_sample_windows/blob/master/lib/main.dart

for AMD case, "vec4 a_position" is the key, vec2/vec3 just not working, I don't know why.

The above solution was not effective in my environment. I found that calling glVertexAttribPointer twice results in the correct display instead. I don't know why this code works correctly.

gl.bindVertexArray(_vao);
{
  gl.bindBuffer(gl.ARRAY_BUFFER, vertexBuffer);
  gl.enableVertexAttribArray(positionLocation);
  // call twice
  gl.vertexAttribPointer(positionLocation, 4, gl.FLOAT, false, 4 * Float32List.bytesPerElement, 0);
  gl.vertexAttribPointer(positionLocation, 4, gl.FLOAT, false, 4 * Float32List.bytesPerElement, 0);
}
gl.bindVertexArray(0);

[forthtemple]

gl.bindVertexArray(_vao);
{
gl.bindBuffer(gl.ARRAY_BUFFER, vertexBuffer);
gl.enableVertexAttribArray(positionLocation);
// call twice
gl.vertexAttribPointer(positionLocation, 4, gl.FLOAT, false, 4 * Float32List.bytesPerElement, 0);
gl.vertexAttribPointer(positionLocation, 4, gl.FLOAT, false, 4 * Float32List.bytesPerElement, 0);
}
gl.bindVertexArray(0);

@organic-nailer I also have the issue where I can only get the demo to work if I call vertexAttribPointer twice. Did you ever work out another fix for this?

[organic-nailer]

@forthtemple
Thanks for reaching out. I haven't found a different solution for this yet, so I'm still using the same method.

[forthtemple]

@organic-nailer Ok. I've ended up using three_js https://github.com/Knightro63/three_js which seems to be more compatible though is a little slower than three_dart because it uses Angle and also Knightro hasn't tried to keep it compatible with the original three.js