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