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//========================================================================
// Context sharing test program
// Copyright (c) Camilla Berglund <elmindreda@glfw.org>
//
// This software is provided 'as-is', without any express or implied
// warranty. In no event will the authors be held liable for any damages
// arising from the use of this software.
//
// Permission is granted to anyone to use this software for any purpose,
// including commercial applications, and to alter it and redistribute it
// freely, subject to the following restrictions:
//
// 1. The origin of this software must not be misrepresented; you must not
// claim that you wrote the original software. If you use this software
// in a product, an acknowledgment in the product documentation would
// be appreciated but is not required.
//
// 2. Altered source versions must be plainly marked as such, and must not
// be misrepresented as being the original software.
//
// 3. This notice may not be removed or altered from any source
// distribution.
//
//========================================================================
//
// This program is used to test sharing of objects between contexts
//
//========================================================================
#include <glad/glad.h>
#include <GLFW/glfw3.h>
#include <stdio.h>
#include <stdlib.h>
#define WIDTH 400
#define HEIGHT 400
#define OFFSET 50
static GLFWwindow* windows[2];
static void error_callback(int error, const char* description)
{
fprintf(stderr, "Error: %s\n", description);
}
static void key_callback(GLFWwindow* window, int key, int scancode, int action, int mods)
{
if (action == GLFW_PRESS && key == GLFW_KEY_ESCAPE)
glfwSetWindowShouldClose(window, GLFW_TRUE);
}
static GLFWwindow* open_window(const char* title, GLFWwindow* share, int posX, int posY)
{
GLFWwindow* window;
glfwWindowHint(GLFW_VISIBLE, GLFW_FALSE);
window = glfwCreateWindow(WIDTH, HEIGHT, title, NULL, share);
if (!window)
return NULL;
glfwMakeContextCurrent(window);
gladLoadGLLoader((GLADloadproc) glfwGetProcAddress);
glfwSwapInterval(1);
glfwSetWindowPos(window, posX, posY);
glfwShowWindow(window);
glfwSetKeyCallback(window, key_callback);
return window;
}
static GLuint create_texture(void)
{
int x, y;
char pixels[256 * 256];
GLuint texture;
glGenTextures(1, &texture);
glBindTexture(GL_TEXTURE_2D, texture);
for (y = 0; y < 256; y++)
{
for (x = 0; x < 256; x++)
pixels[y * 256 + x] = rand() % 256;
}
glTexImage2D(GL_TEXTURE_2D, 0, GL_LUMINANCE, 256, 256, 0, GL_LUMINANCE, GL_UNSIGNED_BYTE, pixels);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
return texture;
}
static void draw_quad(GLuint texture)
{
int width, height;
glfwGetFramebufferSize(glfwGetCurrentContext(), &width, &height);
glViewport(0, 0, width, height);
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
glOrtho(0.f, 1.f, 0.f, 1.f, 0.f, 1.f);
glEnable(GL_TEXTURE_2D);
glBindTexture(GL_TEXTURE_2D, texture);
glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE);
glBegin(GL_QUADS);
glTexCoord2f(0.f, 0.f);
glVertex2f(0.f, 0.f);
glTexCoord2f(1.f, 0.f);
glVertex2f(1.f, 0.f);
glTexCoord2f(1.f, 1.f);
glVertex2f(1.f, 1.f);
glTexCoord2f(0.f, 1.f);
glVertex2f(0.f, 1.f);
glEnd();
}
int main(int argc, char** argv)
{
int x, y, width;
GLuint texture;
glfwSetErrorCallback(error_callback);
if (!glfwInit())
exit(EXIT_FAILURE);
windows[0] = open_window("First", NULL, OFFSET, OFFSET);
if (!windows[0])
{
glfwTerminate();
exit(EXIT_FAILURE);
}
// This is the one and only time we create a texture
// It is created inside the first context, created above
// It will then be shared with the second context, created below
texture = create_texture();
glfwGetWindowPos(windows[0], &x, &y);
glfwGetWindowSize(windows[0], &width, NULL);
// Put the second window to the right of the first one
windows[1] = open_window("Second", windows[0], x + width + OFFSET, y);
if (!windows[1])
{
glfwTerminate();
exit(EXIT_FAILURE);
}
// Set drawing color for both contexts
glfwMakeContextCurrent(windows[0]);
glColor3f(0.6f, 0.f, 0.6f);
glfwMakeContextCurrent(windows[1]);
glColor3f(0.6f, 0.6f, 0.f);
glfwMakeContextCurrent(windows[0]);
while (!glfwWindowShouldClose(windows[0]) &&
!glfwWindowShouldClose(windows[1]))
{
glfwMakeContextCurrent(windows[0]);
draw_quad(texture);
glfwMakeContextCurrent(windows[1]);
draw_quad(texture);
glfwSwapBuffers(windows[0]);
glfwSwapBuffers(windows[1]);
glfwWaitEvents();
}
glfwTerminate();
exit(EXIT_SUCCESS);
}
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