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Main file to create a transparency window + transparency framebuffer using GLFW. This sample only draws a rotating rectangle.
#include <windows.h>
#include <GLFW/glfw3.h>
#include <iostream>
// change this to int main() to allow the console
int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, char*, int nShowCmd)
{
GLFWwindow* window;
int windowSizeW = 640, windowSizeH = 480;
// initialize the library
if (!glfwInit())
return -1;
glfwWindowHint(GLFW_TRANSPARENT_FRAMEBUFFER, GLFW_TRUE);
int count, windowWidth, windowHeight, monitorX, monitorY;
// I am assuming that main monitor is in the 0 position
GLFWmonitor** monitors = glfwGetMonitors(&count);
const GLFWvidmode* videoMode = glfwGetVideoMode(monitors[0]);
// width: 75% of the screen
windowWidth = static_cast<int>(videoMode->width / 1.5);
// aspect ratio 16 to 9
windowHeight = static_cast<int>(videoMode->height / 16 * 9);
glfwGetMonitorPos(monitors[0], &monitorX, &monitorY);
// set the visibility window hint to false for subsequent window creation
glfwWindowHint(GLFW_VISIBLE, GLFW_FALSE);
// create a windowed mode window and its OpenGL context
window = glfwCreateWindow(windowSizeW, windowSizeH, "Hello World", NULL, NULL);
if (!window)
{
glfwTerminate();
return -1;
}
// make the window's context current
glfwMakeContextCurrent(window);
// reset the window hints to default
glfwDefaultWindowHints();
glfwSetWindowPos(window,
monitorX + (videoMode->width - windowWidth) / 2,
monitorY + (videoMode->height - windowHeight) / 2);
// show the window
glfwShowWindow(window);
// uncomment following line to see the border of window
glfwSetWindowAttrib(window, GLFW_DECORATED, GLFW_FALSE);
float fAngle = 0.0f;
// Loop until the user closes the window
while (!glfwWindowShouldClose(window))
{
// render
glClearColor(0.0f, 0.0f, 0.0f, 0.0f);
glClear(GL_COLOR_BUFFER_BIT);
glLoadIdentity();
glRotatef(fAngle, 0, 0, 1);
glBegin(GL_QUADS);
glColor3f(0, 0, 1);
glVertex3f(-0.5, -0.5, -1);
glColor3f(0, 1, 0);
glVertex3f(0.5, -0.5, -1);
glColor3f(1, 0, 1);
glVertex3f(0.5, 0.5, -1);
glColor3f(1, 1, 0);
glVertex3f(-0.5, 0.5, -1);
glEnd();
fAngle += 0.01; // at some point this will explote! overflow: put the corresponding of
// swap front and back buffers
glfwSwapBuffers(window);
// poll for and process events
glfwPollEvents();
}
glfwTerminate();
return 0;
}
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