Hi.
Usually, I use render-to-texture technique to process the image.
However, recently, I need to read the contents to the system memory.
So, I tried to use glReadPixels as follows:
GLubyte pixels[256] = { 0, 0, 0, 0 };
GL_CHECK( glReadPixels(100, 100, 2, 2, GL_RGBA, GL_UNSIGNED_BYTE, pixels) );
LOGI("%d %d %d %d\n", pixels[0], pixels[1], pixels[2], pixels[3]);
This code works well on my desktop PC with NVIDIA card.
But, it fails with ARM Mali-T628.
Debug: test0clear.cpp:36: glGetError() = OUT_OF_MEMORY at test0clear.cpp:36
Here is the details of my system:
EGL vendor = ARM
EGL version = 1.4 Midgard-"r4p0-02rel0"
EGL client apis = OpenGL_ES
GL ES vendor = ARM
GL ES version = OpenGL ES 3.0
GL ES renderer = Mali-T628
GL ES SL version = OpenGL ES GLSL ES 3.00
Do you have any idea to overcome this abnormal situation?
Thanks in advance.
--
oceancru
What device are you running on?
To help us give you a quick answer, can you also share a complete test case (source or Android APK is fine), so we're not trying to reproduce what you have done from the tiny snippet above?
A couple of starting points:
Cheers, Pete
Hi, Mr. Harris.
My system is: Odroid-XU3, running Ubuntu 14.04 LTS.
It is equipped with ARM armv7l and Mali-T628.
With its original OpenGL ES SDK, the "libmali.so" file works well for most applications.
But, it generates 0x505 OUT_OF_MEMORY error for any glReadPixels function call.
Sigh.
I made the very simple drawing function as follows:
void mydraw(void) {
static GLubyte buf[1024*1024] = { 0, 0, 0, 0 };
GL_CHECK( glClearColor(0.5f, 0.5f, 0.5f, 1.0f) );
GL_CHECK( glClear(GL_COLOR_BUFFER_BIT) );
GL_CHECK( glFinish() );
GL_CHECK( glReadPixels(0, 0, 1, 1, GL_RGBA, GL_UNSIGNED_BYTE, (void*)(&buf[0])) );
}
It also generates OUT_OF_MEMORY.
I cannot understand why ReadPixels function call requires memory...
Nakhoon Baek
Hi Oceancru,
Thank you for the code snippet you provided. Before I investigate the issue I was wondering if you could tell me more about the Ubuntu distribution you are currently running. As the Odroid XU3 only started shipping 2 days ago, I am guessing that you have access to pre release hardware? If this is the case where did you get the binary from? If it is directly from hard kernel, can you tell me which version you are using?
Cheers,
Stephen
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