Question

I made a simple app that takes an input image and outputs a processed one using a fragment shader. When using a 2^n image it’s OK. But if I use a rectangular not-power-of-2 image I get a black stitch running from top to bottom.

This is the original:

This is after being processed:

Here’s my fragment shader:

precision mediump float;
uniform vec2 uSize;
uniform sampler2D sTexture;
void main()
{
    gl_FragColor = texture2D(sTexture, vec2(gl_FragCoord) / uSize)
}

Where, uSize is a vec2 having the size of the image

Generally I can work with a power-of-2 textures, but as OGLES2 supports rectangular textures I was thinking of sparing myself some work.

Thanks!

UPDATE

Here go my vertices:

static GLfloat vVertices[] =
    {
     -1.0f,  1.0f, 0.0f,
     -1.0f, -1.0f, 0.0f,
      1.0f, -1.0f, 0.0f,

      1.0f, -1.0f, 0.0f,
      1.0f,  1.0f, 0.0f,
     -1.0f,  1.0f, 0.0f,
    };

And here is the vertex shader:

attribute vec4 vPosition;
void main()
{
   gl_Position = vPosition;
}

UPDATE

Now, that’s strange. Here are the two triangles rendered separately (first using the first 3 vertices, and then using the next (last) three).

Here go for the square image (as expected):

And here are how the same triangles look for the rectangle image/texture. They look bizarre:

They don’t look like triangles at all. Does anyone know what’s happening?

Answer 1

Seems the drivers were bad. Updating them fixed the problem.