framebuffer

How to get RGB pixel values from Linux framebuffer?

由 谁说胖子不能爱 提交于 2019-12-10 18:57:57
问题 I want to get RGB values of screen pixels in the most efficient way, using Linux. So I decided to use the framebuffer library in C ( fb.h ) to access the framebuffer device ( /dev/fb0 ) and read from it directly. This is the code: #include <stdint.h> #include <linux/fb.h> #include <fcntl.h> #include <unistd.h> #include <stdio.h> #include <stdlib.h> #include <sys/ioctl.h> #include <sys/mman.h> int main() { int fb_fd; struct fb_fix_screeninfo finfo; struct fb_var_screeninfo vinfo; uint8_t *fb_p

Android source code not working, reading frame buffer through glReadPixels

由 夙愿已清 提交于 2019-12-10 13:48:02
问题 I am new to Android development and have an assignment to read frame buffer data after a specified interval of time. I have come up with the following code: public class mainActivity extends Activity { Bitmap mSavedBM; private EGL10 egl; private EGLDisplay display; private EGLConfig config; private EGLSurface surface; private EGLContext eglContext; private GL11 gl; protected int width, height; //Called when the activity is first created. @Override public void onCreate(Bundle

LibGDX - Drawing to a FrameBuffer does not work

由 橙三吉。 提交于 2019-12-10 11:33:24
问题 So I'm trying to make custom buttons, for which I need to combine different parts of the button background. To do this I figured using a FrameBuffer would work, however it did not give viable results. Therefore I attempted to test my FrameBuffer drawing method, by writing a simple test method, which returns a texture that is drawn to the display at every render() call. This method is here (note that it is a test method, so it may be a little poorly optimized): private Texture test() {

Writing to then reading from an offscreen FBO on iPhone; works on simulator but not on device?

由 时间秒杀一切 提交于 2019-12-10 02:06:34
问题 I'm trying to do some image manipulation on the iPhone, basing things on the GLImageProcessing example from Apple. Ultimately what I'd like to do is to load an image into a texture, perform one or more of the operations in the example code (hue, saturation, brightness, etc.), then read the resulting image back out for later processing/saving. For the most part, this would never need to touch the screen, so I thought that FBOs might be the way to go. To start with, I've cobbled together a

Does glBlitFramebuffer copy all color attachments if GL_COLOR_BUFFER_BIT mask is specified?

由 浪尽此生 提交于 2019-12-10 01:31:33
问题 If I am copying pixels from one FBO to another and each of them have multiple (not necessary the same number) of color attachments, and if my mask is GL_COLOR_BUFFER_BIT , which color attachments ( GL_COLOR_ATTACHMENT0 , GL_COLOR_ATTACHMENT1 , ...., GL_COLOR_ATTACHMENTi ) does it copy? All of them? If yes, what if these FBOs have different number of color buffers attached to them? Assume that there are 2 FBOs that are bound in this way: glBindFramebuffer(GL_READ_FRAMEBUFFER, fbo1);

OpenGL: Rendering to texture by using FBO and viewport offset problems

由 三世轮回 提交于 2019-12-10 00:44:11
问题 I have noticed unexpected behavior of frame-buffer objects (FBO) when rendering to a texture. If we set viewport in following way: glViewport(0, 0, w, h); glMatrixMode(GL_PROJECTION); glLoadIdentity(); gluOrtho2D(0.0, 1.0, 1.0, 0.0); glMatrixMode(GL_MODELVIEW); glLoadIdentity() ; (w and h doesn't need to match window size) everything is rendered fine: So lets say we need to draw bounding rectangle of viewport: glBegin(GL_LINE_STRIP); glVertex2f(0.0, 0.0); glVertex2f(0.0, 1.0); glVertex2f(1.0,

-[EAGLContext renderbufferStorage:fromDrawable:] Failing the second time on?

由 混江龙づ霸主 提交于 2019-12-09 16:39:43
问题 I'm developing an iOS openGL ES application. I'm doing the usual EAGLView / ES2Render stuff. On startup, frambuffer creation succeeds, using the following code: - (BOOL) createFramebuffers { [EAGLContext setCurrentContext:_mainContext]; // [ A ] On-screen // 1. Framebuffer glGenFramebuffers(1, &_mainFramebuffer); bindFramebuffer(_mainFramebuffer); // 2. Color buffer glGenRenderbuffers(1, &_mainColorbuffer); bindRenderbuffer(_mainColorbuffer); // Adjust size to view's layer: CAEAGLLayer* layer

How to use depth testing when rendering to an offscreen buffer then onto texture

由 柔情痞子 提交于 2019-12-09 16:26:21
问题 I'm rendering my scene to a texture. This works fine except that depth testing does not work. How do I enable depth testing if rendering to an offscreen texture? I'm using the FrameBuffer class http://www.opengl.org/news/comments/framebuffer_object_fbo_c_class_available_with_example_application/ glGetIntegerv(GL_DRAW_BUFFER, &drawBuffer); frameBuffer->Bind(); glDrawBuffer(GL_COLOR_ATTACHMENT0_EXT); rAngle += 0.3f; glUseProgram(0); drawSpinningTeapot(); FramebufferObject::Disable();

Writing to framebuffer directly on Android

由 情到浓时终转凉″ 提交于 2019-12-09 07:14:19
问题 I've a rooted phone with Android 4.2.2. I'd like to use minui API used (source here) in bootloader code to draw stuff on the screen. minui is much simpler than native OpenGL and I don't need any complex functionality exposed by OpenGL. The problem is that I can't write stuff directly to fb0 device. FBIOPUT_VSCREENINFO fails for unknown reason. How can I draw directly to fb0 on Android, or how can I use minui outside the bootloader mode? 回答1: device node:/dev/graphics/fb0 you can build in

Is there a fast way to the average colors from several framebuffers in WebGL / Javascript?

由 独自空忆成欢 提交于 2019-12-08 18:17:29
I am very new to the WebGL subject. What I want to do is to calculate the average color of 6 different framebuffers like the ones below in the picture. Now I am wondering what the best way to go about it would be? I tried to do gl.readPixels(0, 0, 256, 256, gl.RGBA, gl.UNSIGNED_BYTE, pixelValues); but that seems to be very slow... Is there a way that this can happen on the graphics card? this is how the FBO is set up - I have this from a tutorial: ... You have two options Write a fragment shader that runs once per row (per texture) by rendering a quad (1 x textureheight) and runs through all
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