CODEWITHSUNDEEP
androidopengl-es-2.0framebufferrender-to-texture
DrGerm
DrGerm

Reputation: 275

Android GLES 2.0: framebuffer rendering to half-float texture works on some devices, not others

Using GLES 2.0 on Android, I am trying to render to a framebuffer backed by a texture. The texture and framebuffer are created like this:

final int GL_RGB16F_EXT = 0x881B;
GLES20.glTexImage2D(GLES20.GL_TEXTURE_2D, 0, GLES20.GL_RGB, width, height, 0,
        GL_RGB16F_EXT, type, null);
GLES20.glFramebufferTexture2D(GLES20.GL_FRAMEBUFFER, GLES20.GL_COLOR_ATTACHMENT0,
    GLES20.GL_TEXTURE_2D, textureHandle, 0);

For type=GL_HALF_FLOAT_OES, this works on some devices, but gives a GL_FRAMEBUFFER_INCOMPLETE_ATTACHMENT status on others.

The texture was created with GL_NEAREST minify and magnify mode.

Note that on some devices (Nexus 5), the above works only when I use "GL_RGB" instead of "GL_RGB16F_EXT" as the internal format, on some (Nexus 6/7) it works only with GL_RGB16F_EXT, on some it works with both (Nexus 9) and on some it doesn't work with either (Nexus 4).

The weird thing is that all my devices, including the failing ones, report GL_OES_texture_half_float and GL_EXT_color_buffer_half_float.

What else could I be missing here?

Upvotes: 1

Views: 1460

Answers (1)

Reto Koradi
Reto Koradi

Reputation: 54642

I believe the correct combination of arguments for ES 2.0 is:

final int GL_HALF_FLOAT_OES = 0x8D61;
GLES20.glTexImage2D(GLES20.GL_TEXTURE_2D, 0, GLES20.GL_RGB, width, height, 0,
        GLES20.GL_RGB, GL_HALF_FLOAT_OES, null);

ES 2.0 unfortunately does not support sized internal formats for glTexImage2D(). It derives the internal format from the format/type parameters. Sized internal formats were added in ES 3.0.

Based on the EGL_color_buffer_half_float spec, GL_RGB16F_EXT is only supported as the internalformat for glRenderbufferStorage().

Upvotes: 1

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