EGLImage & Direct Texture

Posted on 2020-11-12 Edited on 2025-03-26 In graphics Views: Disqus:

Overview

EGLImage的存在是为了更方便地在EGL client API之间共享2D Image Data. 那什么是EGL client API呢？OpenGL, OpenGL ES, OpenVG都是EGL client API. EGLImage与下面3个EGL Extensions有关:

EGL_KHR_image
EGL_KHR_image_base
EGL_KHR_image_pixmap

DRM format modifier

Posted on 2020-11-11 Edited on 2025-03-26 In linux Views: Disqus:

FourCC

FourCC format code是Linux内核DRM子系统用来描述framebuffer像素格式。它们被定义在内核源码include/uapi/drm/drm_fourcc.h. 基本上FourCC format code足以描述framebuffer中像素的内容了，但是随着GPU的更新，原来线性排列的buffers，为了获取更好的性能，可能会采取vendor specific的布局方式。另外，这些buffer也可能保存的是各种不同的压缩数据，这样一来，原来的FourCC format code就无法携带新的buffer
layout或compression format的信息，DRM format modifier就是用来解决这些问题的。

glamor

Posted on 2020-11-10 Edited on 2025-03-26 In graphics Views: Disqus:

Introduction

glamor是一个开源的2D加速驱动，它作为Xorg的一个模块被实现。相比传统的DDX 2D加速驱动，glamor主要有以下2个好处:

使用非常通用的EGL/OpenGL API去操作GPU硬件，省去了手动为每个不同的GPU编写2D加速驱动的麻烦
有了glamor，不再需要传统的2D DDX驱动

Build X Server (Xorg) from Source

Posted on 2020-10-19 Edited on 2025-03-26 In graphics Views: Disqus:

Motivation

Given that a difficulty to add a custom X11 device driver or module or extension for Xserver, I try to find out how an Xserver is built and its dependent drivers and modules and extensions are orgnized together by building it from source.

Pixmap in X

Posted on 2020-09-27 Edited on 2025-03-26 In graphics Views: Disqus:

XYPixmap

The data for a XYPixmap is organized as a set of bitmaps representing individual bit planes, with the planes appearing from MSB to LSB in bit order just as demonstrated below. Every pixel value is 0x55 (b’01010101) in this example.