mirror of
https://github.com/TomHarte/CLK.git
synced 2024-11-25 16:31:42 +00:00
55 lines
1.7 KiB
C++
55 lines
1.7 KiB
C++
//
|
|
// Screenshot.hpp
|
|
// Clock Signal
|
|
//
|
|
// Created by Thomas Harte on 27/02/2019.
|
|
// Copyright © 2019 Thomas Harte. All rights reserved.
|
|
//
|
|
|
|
#pragma once
|
|
|
|
#include "OpenGL.hpp"
|
|
|
|
namespace Outputs::Display::OpenGL {
|
|
|
|
/*!
|
|
Upon construction, Screenshot will capture the centre portion of the currently-bound framebuffer,
|
|
cropping to an image that matches the requested aspect ratio.
|
|
|
|
The image will then be available as RGBA data, in raster order via the struct members.
|
|
*/
|
|
struct Screenshot {
|
|
Screenshot(int aspect_width, int aspect_height) {
|
|
// Get the current viewport to establish framebuffer size. Then determine how wide the
|
|
// centre portion of that would be, allowing for the requested aspect ratio.
|
|
GLint dimensions[4];
|
|
glGetIntegerv(GL_VIEWPORT, dimensions);
|
|
|
|
height = int(dimensions[3]);
|
|
width = (height * aspect_width) / aspect_height;
|
|
pixel_data.resize(size_t(width * height * 4));
|
|
|
|
// Grab the framebuffer contents, temporarily setting single-byte alignment.
|
|
int prior_alignment;
|
|
glGetIntegerv(GL_PACK_ALIGNMENT, &prior_alignment);
|
|
glReadPixels((dimensions[2] - GLint(width)) >> 1, 0, GLint(width), GLint(height), GL_RGBA, GL_UNSIGNED_BYTE, pixel_data.data());
|
|
glPixelStorei(GL_PACK_ALIGNMENT, prior_alignment);
|
|
|
|
// Flip the contents into raster order.
|
|
const size_t line_size = size_t(width * 4);
|
|
for(size_t y = 0; y < size_t(height) / 2; ++y) {
|
|
const size_t flipped_y = size_t(height - 1) - y;
|
|
|
|
uint8_t temp[line_size];
|
|
memcpy(temp, &pixel_data[flipped_y * line_size], line_size);
|
|
memcpy(&pixel_data[flipped_y * line_size], &pixel_data[y * line_size], line_size);
|
|
memcpy(&pixel_data[y * line_size], temp, line_size);
|
|
}
|
|
}
|
|
|
|
std::vector<uint8_t> pixel_data;
|
|
int width, height;
|
|
};
|
|
|
|
}
|