Hello everyone,
I've been working on a project using the beagle board C4. I'm trying
to figure out how to enable extension GL_OES_standard_derivatives. But
i encountered some weird issues.
Basically, i want to call built-in functions from the extension
( dFdx(), dFdy() , fwidth()) in my fragment shader(See below).
precision mediump float;
#extension GL_OES_standard_derivatives : enable
varying vec3 myVec;
uniform vec4 vColor;
void main() {
vec3 px = dFdx(myVec);
vec3 py = dFdy(myVec); // this line can not compile on
beagle.
gl_FragColor = vColor;
}
Once i add dFdy() or fwidth() to the fragment shader, it fails to
compile with error message "Compile Failed". There is no other verbose
message from which i can figure out what's wrong with the shader. And
the most weird is that dFdx() can be compiled and linked successfully.
So i guess the extension has been enabled, but some built-in functions
(dFdy() , fwidth()) are missing.
I work on beagleboard C4(OMAP3530 ARM Cortex A8 + PowerVR SGX530 GPU)
with Angstrom linux distro, using OMAP35x_Graphics_SDK_3_01_00_06.
BTW, the fragment shader can compile on OpenGL ES 2.0 PC Emulation SDK
from Imagination Technologies.
Could anyone give me a pointer on how to resolve this issue.
Thanks for any help or advice!