nv path sample

nvpath.c

// gcc nvpath.c -o nvpath -lGL -lglfw && primusrun ./nvpath

#include <stdio.h>
#include <stdlib.h>

#include <GLFW/glfw3.h>

#ifndef __APPLE__
PFNGLPATHCOMMANDSNVPROC glPathCommandsNV = NULL;
PFNGLCOVERSTROKEPATHNVPROC glCoverStrokePathNV = NULL;
#endif

#if defined(linux) || defined(sun)
#include <GL/glx.h>
# define GET_PROC_ADDRESS(name)  glXGetProcAddressARB((const GLubyte *) #name)
#elif defined(vxworks)
# define GET_PROC_ADDRESS(name)  rglGetProcAddress(#name)
#elif defined(__APPLE__)
# define GET_PROC_ADDRESS(name)  /*nothing*/
#elif defined(_WIN32)
# define GET_PROC_ADDRESS(name)  wglGetProcAddress(#name)
#else
# error unimplemented code!
#endif

#ifdef __APPLE__
#define LOAD_PROC(type, name) /*nothing*/
#else
#define LOAD_PROC(type, name) name = (type) GET_PROC_ADDRESS(name); if (!name) exit(1);
#endif

int
main(int argc, char **argv)
{
    if (!glfwInit()) return -1;

    GLFWwindow *window = glfwCreateWindow(640, 480, "Hello World", NULL, NULL);
    if (!window) {
        glfwTerminate();
        return -1;
    }
    glfwMakeContextCurrent(window);

    // Load extensions
    LOAD_PROC(PFNGLPATHCOMMANDSNVPROC, glPathCommandsNV);
    LOAD_PROC(PFNGLCOVERSTROKEPATHNVPROC, glCoverStrokePathNV);

    // Init a path
    GLubyte pathCommands[5] =
      { GL_MOVE_TO_NV, GL_LINE_TO_NV, GL_LINE_TO_NV, GL_LINE_TO_NV, GL_CLOSE_PATH_NV };
    GLfloat pathCoords[4][2] = { {.1, .1}, {.3, .1}, {.3, .3}, {.1, .3} };

    GLuint pathObj = 42;
    glPathCommandsNV(pathObj, 5, pathCommands, 8, GL_FLOAT, pathCoords);
    
    while (!glfwWindowShouldClose(window)) {
        glClear(GL_COLOR_BUFFER_BIT | GL_STENCIL_BUFFER_BIT);
        glClearColor(0, 0, 0, 0);
        glStencilMask(~0);

        glCoverStrokePathNV(pathObj, GL_CONVEX_HULL_NV);

        glfwSwapBuffers(window);
        glfwPollEvents();
    }

    glfwTerminate();
    return 0;
}