glfw/examples/gears.c
Camilla Löwy d7e30b1c74 Replace glad and the Vulkan SDK with glad2
This removes all dependencies from the GLFW test programs on the Vulkan
SDK.

It also removes support for linking the GLFW shared library (dynamic
library, DLL) against the Vulkan loader static library.
2019-04-15 02:45:48 +02:00

360 lines
9.7 KiB
C

/*
* 3-D gear wheels. This program is in the public domain.
*
* Command line options:
* -info print GL implementation information
* -exit automatically exit after 30 seconds
*
*
* Brian Paul
*
*
* Marcus Geelnard:
* - Conversion to GLFW
* - Time based rendering (frame rate independent)
* - Slightly modified camera that should work better for stereo viewing
*
*
* Camilla Löwy:
* - Removed FPS counter (this is not a benchmark)
* - Added a few comments
* - Enabled vsync
*/
#if defined(_MSC_VER)
// Make MS math.h define M_PI
#define _USE_MATH_DEFINES
#endif
#include <math.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <glad/gl.h>
#include <GLFW/glfw3.h>
/**
Draw a gear wheel. You'll probably want to call this function when
building a display list since we do a lot of trig here.
Input: inner_radius - radius of hole at center
outer_radius - radius at center of teeth
width - width of gear teeth - number of teeth
tooth_depth - depth of tooth
**/
static void
gear(GLfloat inner_radius, GLfloat outer_radius, GLfloat width,
GLint teeth, GLfloat tooth_depth)
{
GLint i;
GLfloat r0, r1, r2;
GLfloat angle, da;
GLfloat u, v, len;
r0 = inner_radius;
r1 = outer_radius - tooth_depth / 2.f;
r2 = outer_radius + tooth_depth / 2.f;
da = 2.f * (float) M_PI / teeth / 4.f;
glShadeModel(GL_FLAT);
glNormal3f(0.f, 0.f, 1.f);
/* draw front face */
glBegin(GL_QUAD_STRIP);
for (i = 0; i <= teeth; i++) {
angle = i * 2.f * (float) M_PI / teeth;
glVertex3f(r0 * (float) cos(angle), r0 * (float) sin(angle), width * 0.5f);
glVertex3f(r1 * (float) cos(angle), r1 * (float) sin(angle), width * 0.5f);
if (i < teeth) {
glVertex3f(r0 * (float) cos(angle), r0 * (float) sin(angle), width * 0.5f);
glVertex3f(r1 * (float) cos(angle + 3 * da), r1 * (float) sin(angle + 3 * da), width * 0.5f);
}
}
glEnd();
/* draw front sides of teeth */
glBegin(GL_QUADS);
da = 2.f * (float) M_PI / teeth / 4.f;
for (i = 0; i < teeth; i++) {
angle = i * 2.f * (float) M_PI / teeth;
glVertex3f(r1 * (float) cos(angle), r1 * (float) sin(angle), width * 0.5f);
glVertex3f(r2 * (float) cos(angle + da), r2 * (float) sin(angle + da), width * 0.5f);
glVertex3f(r2 * (float) cos(angle + 2 * da), r2 * (float) sin(angle + 2 * da), width * 0.5f);
glVertex3f(r1 * (float) cos(angle + 3 * da), r1 * (float) sin(angle + 3 * da), width * 0.5f);
}
glEnd();
glNormal3f(0.0, 0.0, -1.0);
/* draw back face */
glBegin(GL_QUAD_STRIP);
for (i = 0; i <= teeth; i++) {
angle = i * 2.f * (float) M_PI / teeth;
glVertex3f(r1 * (float) cos(angle), r1 * (float) sin(angle), -width * 0.5f);
glVertex3f(r0 * (float) cos(angle), r0 * (float) sin(angle), -width * 0.5f);
if (i < teeth) {
glVertex3f(r1 * (float) cos(angle + 3 * da), r1 * (float) sin(angle + 3 * da), -width * 0.5f);
glVertex3f(r0 * (float) cos(angle), r0 * (float) sin(angle), -width * 0.5f);
}
}
glEnd();
/* draw back sides of teeth */
glBegin(GL_QUADS);
da = 2.f * (float) M_PI / teeth / 4.f;
for (i = 0; i < teeth; i++) {
angle = i * 2.f * (float) M_PI / teeth;
glVertex3f(r1 * (float) cos(angle + 3 * da), r1 * (float) sin(angle + 3 * da), -width * 0.5f);
glVertex3f(r2 * (float) cos(angle + 2 * da), r2 * (float) sin(angle + 2 * da), -width * 0.5f);
glVertex3f(r2 * (float) cos(angle + da), r2 * (float) sin(angle + da), -width * 0.5f);
glVertex3f(r1 * (float) cos(angle), r1 * (float) sin(angle), -width * 0.5f);
}
glEnd();
/* draw outward faces of teeth */
glBegin(GL_QUAD_STRIP);
for (i = 0; i < teeth; i++) {
angle = i * 2.f * (float) M_PI / teeth;
glVertex3f(r1 * (float) cos(angle), r1 * (float) sin(angle), width * 0.5f);
glVertex3f(r1 * (float) cos(angle), r1 * (float) sin(angle), -width * 0.5f);
u = r2 * (float) cos(angle + da) - r1 * (float) cos(angle);
v = r2 * (float) sin(angle + da) - r1 * (float) sin(angle);
len = (float) sqrt(u * u + v * v);
u /= len;
v /= len;
glNormal3f(v, -u, 0.0);
glVertex3f(r2 * (float) cos(angle + da), r2 * (float) sin(angle + da), width * 0.5f);
glVertex3f(r2 * (float) cos(angle + da), r2 * (float) sin(angle + da), -width * 0.5f);
glNormal3f((float) cos(angle), (float) sin(angle), 0.f);
glVertex3f(r2 * (float) cos(angle + 2 * da), r2 * (float) sin(angle + 2 * da), width * 0.5f);
glVertex3f(r2 * (float) cos(angle + 2 * da), r2 * (float) sin(angle + 2 * da), -width * 0.5f);
u = r1 * (float) cos(angle + 3 * da) - r2 * (float) cos(angle + 2 * da);
v = r1 * (float) sin(angle + 3 * da) - r2 * (float) sin(angle + 2 * da);
glNormal3f(v, -u, 0.f);
glVertex3f(r1 * (float) cos(angle + 3 * da), r1 * (float) sin(angle + 3 * da), width * 0.5f);
glVertex3f(r1 * (float) cos(angle + 3 * da), r1 * (float) sin(angle + 3 * da), -width * 0.5f);
glNormal3f((float) cos(angle), (float) sin(angle), 0.f);
}
glVertex3f(r1 * (float) cos(0), r1 * (float) sin(0), width * 0.5f);
glVertex3f(r1 * (float) cos(0), r1 * (float) sin(0), -width * 0.5f);
glEnd();
glShadeModel(GL_SMOOTH);
/* draw inside radius cylinder */
glBegin(GL_QUAD_STRIP);
for (i = 0; i <= teeth; i++) {
angle = i * 2.f * (float) M_PI / teeth;
glNormal3f(-(float) cos(angle), -(float) sin(angle), 0.f);
glVertex3f(r0 * (float) cos(angle), r0 * (float) sin(angle), -width * 0.5f);
glVertex3f(r0 * (float) cos(angle), r0 * (float) sin(angle), width * 0.5f);
}
glEnd();
}
static GLfloat view_rotx = 20.f, view_roty = 30.f, view_rotz = 0.f;
static GLint gear1, gear2, gear3;
static GLfloat angle = 0.f;
/* OpenGL draw function & timing */
static void draw(void)
{
glClearColor(0.0, 0.0, 0.0, 0.0);
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glPushMatrix();
glRotatef(view_rotx, 1.0, 0.0, 0.0);
glRotatef(view_roty, 0.0, 1.0, 0.0);
glRotatef(view_rotz, 0.0, 0.0, 1.0);
glPushMatrix();
glTranslatef(-3.0, -2.0, 0.0);
glRotatef(angle, 0.0, 0.0, 1.0);
glCallList(gear1);
glPopMatrix();
glPushMatrix();
glTranslatef(3.1f, -2.f, 0.f);
glRotatef(-2.f * angle - 9.f, 0.f, 0.f, 1.f);
glCallList(gear2);
glPopMatrix();
glPushMatrix();
glTranslatef(-3.1f, 4.2f, 0.f);
glRotatef(-2.f * angle - 25.f, 0.f, 0.f, 1.f);
glCallList(gear3);
glPopMatrix();
glPopMatrix();
}
/* update animation parameters */
static void animate(void)
{
angle = 100.f * (float) glfwGetTime();
}
/* change view angle, exit upon ESC */
void key( GLFWwindow* window, int k, int s, int action, int mods )
{
if( action != GLFW_PRESS ) return;
switch (k) {
case GLFW_KEY_Z:
if( mods & GLFW_MOD_SHIFT )
view_rotz -= 5.0;
else
view_rotz += 5.0;
break;
case GLFW_KEY_ESCAPE:
glfwSetWindowShouldClose(window, GLFW_TRUE);
break;
case GLFW_KEY_UP:
view_rotx += 5.0;
break;
case GLFW_KEY_DOWN:
view_rotx -= 5.0;
break;
case GLFW_KEY_LEFT:
view_roty += 5.0;
break;
case GLFW_KEY_RIGHT:
view_roty -= 5.0;
break;
default:
return;
}
}
/* new window size */
void reshape( GLFWwindow* window, int width, int height )
{
GLfloat h = (GLfloat) height / (GLfloat) width;
GLfloat xmax, znear, zfar;
znear = 5.0f;
zfar = 30.0f;
xmax = znear * 0.5f;
glViewport( 0, 0, (GLint) width, (GLint) height );
glMatrixMode( GL_PROJECTION );
glLoadIdentity();
glFrustum( -xmax, xmax, -xmax*h, xmax*h, znear, zfar );
glMatrixMode( GL_MODELVIEW );
glLoadIdentity();
glTranslatef( 0.0, 0.0, -20.0 );
}
/* program & OpenGL initialization */
static void init(void)
{
static GLfloat pos[4] = {5.f, 5.f, 10.f, 0.f};
static GLfloat red[4] = {0.8f, 0.1f, 0.f, 1.f};
static GLfloat green[4] = {0.f, 0.8f, 0.2f, 1.f};
static GLfloat blue[4] = {0.2f, 0.2f, 1.f, 1.f};
glLightfv(GL_LIGHT0, GL_POSITION, pos);
glEnable(GL_CULL_FACE);
glEnable(GL_LIGHTING);
glEnable(GL_LIGHT0);
glEnable(GL_DEPTH_TEST);
/* make the gears */
gear1 = glGenLists(1);
glNewList(gear1, GL_COMPILE);
glMaterialfv(GL_FRONT, GL_AMBIENT_AND_DIFFUSE, red);
gear(1.f, 4.f, 1.f, 20, 0.7f);
glEndList();
gear2 = glGenLists(1);
glNewList(gear2, GL_COMPILE);
glMaterialfv(GL_FRONT, GL_AMBIENT_AND_DIFFUSE, green);
gear(0.5f, 2.f, 2.f, 10, 0.7f);
glEndList();
gear3 = glGenLists(1);
glNewList(gear3, GL_COMPILE);
glMaterialfv(GL_FRONT, GL_AMBIENT_AND_DIFFUSE, blue);
gear(1.3f, 2.f, 0.5f, 10, 0.7f);
glEndList();
glEnable(GL_NORMALIZE);
}
/* program entry */
int main(int argc, char *argv[])
{
GLFWwindow* window;
int width, height;
if( !glfwInit() )
{
fprintf( stderr, "Failed to initialize GLFW\n" );
exit( EXIT_FAILURE );
}
glfwWindowHint(GLFW_DEPTH_BITS, 16);
glfwWindowHint(GLFW_TRANSPARENT_FRAMEBUFFER, GLFW_TRUE);
window = glfwCreateWindow( 300, 300, "Gears", NULL, NULL );
if (!window)
{
fprintf( stderr, "Failed to open GLFW window\n" );
glfwTerminate();
exit( EXIT_FAILURE );
}
// Set callback functions
glfwSetFramebufferSizeCallback(window, reshape);
glfwSetKeyCallback(window, key);
glfwMakeContextCurrent(window);
gladLoadGL(glfwGetProcAddress);
glfwSwapInterval( 1 );
glfwGetFramebufferSize(window, &width, &height);
reshape(window, width, height);
// Parse command-line options
init();
// Main loop
while( !glfwWindowShouldClose(window) )
{
// Draw gears
draw();
// Update animation
animate();
// Swap buffers
glfwSwapBuffers(window);
glfwPollEvents();
}
// Terminate GLFW
glfwTerminate();
// Exit program
exit( EXIT_SUCCESS );
}