We’ve put together a CMake starter project for anyone who wants to use GLFW and needs help getting started / creating a project:
Thanks to everyone who supports us on Patreon / GitHub and made this possible!
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Hi,
This is a great kit. I can get the default repo easily to work and cmake is daunting for beginners.
I am however having trouble re-writing the main.cpp so that it runs the quick tutorial example:
https://www.glfw.org/docs/latest/quick.html
basically, these 2 includes from the quick example are not working:
#include <glad/gl.h>
#include “linmath.h”
I’ve toyed around with the toplevel CMakeLists.txt, but to no avail. The "./glfw folder in the kit appears to however contain the necessary sources. I suppose its just a target_link and include definition thats missing.
Can anyone provide the correct CMakeLists.txt so that GLFW-CMake-starter will run this simple example program?
(copy of the source from above link)
#include <glad/gl.h>
#define GLFW_INCLUDE_NONE
#include <GLFW/glfw3.h>
#include "linmath.h"
#include <stdlib.h>
#include <stdio.h>
static const struct
{
float x, y;
float r, g, b;
} vertices[3] =
{
{ -0.6f, -0.4f, 1.f, 0.f, 0.f },
{ 0.6f, -0.4f, 0.f, 1.f, 0.f },
{ 0.f, 0.6f, 0.f, 0.f, 1.f }
};
static const char* vertex_shader_text =
"#version 110\n"
"uniform mat4 MVP;\n"
"attribute vec3 vCol;\n"
"attribute vec2 vPos;\n"
"varying vec3 color;\n"
"void main()\n"
"{\n"
" gl_Position = MVP * vec4(vPos, 0.0, 1.0);\n"
" color = vCol;\n"
"}\n";
static const char* fragment_shader_text =
"#version 110\n"
"varying vec3 color;\n"
"void main()\n"
"{\n"
" gl_FragColor = vec4(color, 1.0);\n"
"}\n";
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 (key == GLFW_KEY_ESCAPE && action == GLFW_PRESS)
glfwSetWindowShouldClose(window, GLFW_TRUE);
}
int main(void)
{
GLFWwindow* window;
GLuint vertex_buffer, vertex_shader, fragment_shader, program;
GLint mvp_location, vpos_location, vcol_location;
glfwSetErrorCallback(error_callback);
if (!glfwInit())
exit(EXIT_FAILURE);
glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 2);
glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 0);
window = glfwCreateWindow(640, 480, "Simple example", NULL, NULL);
if (!window)
{
glfwTerminate();
exit(EXIT_FAILURE);
}
glfwSetKeyCallback(window, key_callback);
glfwMakeContextCurrent(window);
gladLoadGL(glfwGetProcAddress);
glfwSwapInterval(1);
// NOTE: OpenGL error checks have been omitted for brevity
glGenBuffers(1, &vertex_buffer);
glBindBuffer(GL_ARRAY_BUFFER, vertex_buffer);
glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);
vertex_shader = glCreateShader(GL_VERTEX_SHADER);
glShaderSource(vertex_shader, 1, &vertex_shader_text, NULL);
glCompileShader(vertex_shader);
fragment_shader = glCreateShader(GL_FRAGMENT_SHADER);
glShaderSource(fragment_shader, 1, &fragment_shader_text, NULL);
glCompileShader(fragment_shader);
program = glCreateProgram();
glAttachShader(program, vertex_shader);
glAttachShader(program, fragment_shader);
glLinkProgram(program);
mvp_location = glGetUniformLocation(program, "MVP");
vpos_location = glGetAttribLocation(program, "vPos");
vcol_location = glGetAttribLocation(program, "vCol");
glEnableVertexAttribArray(vpos_location);
glVertexAttribPointer(vpos_location, 2, GL_FLOAT, GL_FALSE,
sizeof(vertices[0]), (void*) 0);
glEnableVertexAttribArray(vcol_location);
glVertexAttribPointer(vcol_location, 3, GL_FLOAT, GL_FALSE,
sizeof(vertices[0]), (void*) (sizeof(float) * 2));
while (!glfwWindowShouldClose(window))
{
float ratio;
int width, height;
mat4x4 m, p, mvp;
glfwGetFramebufferSize(window, &width, &height);
ratio = width / (float) height;
glViewport(0, 0, width, height);
glClear(GL_COLOR_BUFFER_BIT);
mat4x4_identity(m);
mat4x4_rotate_Z(m, m, (float) glfwGetTime());
mat4x4_ortho(p, -ratio, ratio, -1.f, 1.f, 1.f, -1.f);
mat4x4_mul(mvp, p, m);
glUseProgram(program);
glUniformMatrix4fv(mvp_location, 1, GL_FALSE, (const GLfloat*) mvp);
glDrawArrays(GL_TRIANGLES, 0, 3);
glfwSwapBuffers(window);
glfwPollEvents();
}
glfwDestroyWindow(window);
glfwTerminate();
exit(EXIT_SUCCESS);
}
Hi @elSomewhere,
Welcome to the GLFW forum, glad you liked our starter example. The problem with adding includes is that the build needs to know where to find them. You can use the older cmake command include_directories or the more recent target_include_directories to do this.
Using GLAD also requires the source code glad_gl.c to compile.
If you look at the file CMakeLists.txt in the GLFW example folder you can see how this is done.
I’ve modified the starter to add this and got your code working. The CMakeLists.txt I used is below:
cmake_minimum_required( VERSION 3.1 )
project( GLFW-CMake-starter )
find_package( OpenGL REQUIRED )
include_directories( ${OPENGL_INCLUDE_DIRS} )
set( GLFW_BUILD_DOCS OFF CACHE BOOL "GLFW lib only" )
set( GLFW_INSTALL OFF CACHE BOOL "GLFW lib only" )
add_subdirectory( glfw )
if( MSVC )
SET( CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} /ENTRY:mainCRTStartup" )
endif()
set(GLAD_GL "${GLFW_SOURCE_DIR}/deps/glad/gl.h"
"${GLFW_SOURCE_DIR}/deps/glad_gl.c")
set( GLFW-CMAKE-STARTER-SRC
main.cpp
${GLAD_GL}
)
add_executable( GLFW-CMake-starter WIN32 ${GLFW-CMAKE-STARTER-SRC} )
target_link_libraries( GLFW-CMake-starter ${OPENGL_LIBRARIES} glfw )
target_include_directories(GLFW-CMake-starter PRIVATE ${GLFW_SOURCE_DIR}/deps)
if( MSVC )
if(${CMAKE_VERSION} VERSION_LESS "3.6.0")
message( "\n\t[ WARNING ]\n\n\tCMake version lower than 3.6.\n\n\t - Please update CMake and rerun; OR\n\t - Manually set 'GLFW-CMake-starter' as StartUp Project in Visual Studio.\n" )
else()
set_property( DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR} PROPERTY VS_STARTUP_PROJECT GLFW-CMake-starter )
endif()
endif()