famous gears demo

git-svn-id: http://svn2.nishi.boats/svn/milsko/trunk@157 b9cfdab3-6d41-4d17-bbe4-086880011989

GNUmakefile

@@ -90,7 +90,7 @@ EXAMPLES = examples/example$(EXEC) examples/rotate$(EXEC) examples/image$(EXEC)
 
 ifeq ($(OPENGL),1)
 L_OBJS += src/widget/opengl.o
-EXAMPLES += examples/opengl$(EXEC)
+EXAMPLES += examples/opengl$(EXEC) examples/gears$(EXEC)
 endif
 
 ifeq ($(VULKAN),1)
@@ -114,6 +114,9 @@ src/libMw$(SO): $(L_OBJS)
 examples/opengl$(EXEC): examples/opengl.o src/libMw$(SO)
 	$(CC) $(E_LDFLAGS) -o $@ $< $(E_LIBS) $(GL)
 
+examples/gears$(EXEC): examples/gears.o src/libMw$(SO)
+	$(CC) $(E_LDFLAGS) -o $@ $< $(E_LIBS) $(GL)
+
 examples/%$(EXEC): examples/%.o src/libMw$(SO)
 	$(CC) $(E_LDFLAGS) -o $@ $< $(E_LIBS)
 

examples/gears.c

@@ -0,0 +1,278 @@
+/* $Id$ */
+#include <Mw/Milsko.h>
+#include <Mw/OpenGL.h>
+
+#include <GL/gl.h>
+
+MwWidget opengl;
+
+/*
+ * 3-D gear wheels.  This program is in the public domain.
+ *
+ * Brian Paul
+ */
+
+/* Conversion to GLUT by Mark J. Kilgard */
+
+#include <math.h>
+#include <stdlib.h>
+
+#ifndef M_PI
+#define M_PI 3.14159265
+#endif
+
+/**
+
+  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 / 2.0;
+	r2 = outer_radius + tooth_depth / 2.0;
+
+	da = 2.0 * M_PI / teeth / 4.0;
+
+	glShadeModel(GL_FLAT);
+
+	glNormal3f(0.0, 0.0, 1.0);
+
+	/* draw front face */
+	glBegin(GL_QUAD_STRIP);
+	for(i = 0; i <= teeth; i++) {
+		angle = i * 2.0 * M_PI / teeth;
+		glVertex3f(r0 * cos(angle), r0 * sin(angle), width * 0.5);
+		glVertex3f(r1 * cos(angle), r1 * sin(angle), width * 0.5);
+		glVertex3f(r0 * cos(angle), r0 * sin(angle), width * 0.5);
+		glVertex3f(r1 * cos(angle + 3 * da), r1 * sin(angle + 3 * da), width * 0.5);
+	}
+	glEnd();
+
+	/* draw front sides of teeth */
+	glBegin(GL_QUADS);
+	da = 2.0 * M_PI / teeth / 4.0;
+	for(i = 0; i < teeth; i++) {
+		angle = i * 2.0 * M_PI / teeth;
+
+		glVertex3f(r1 * cos(angle), r1 * sin(angle), width * 0.5);
+		glVertex3f(r2 * cos(angle + da), r2 * sin(angle + da), width * 0.5);
+		glVertex3f(r2 * cos(angle + 2 * da), r2 * sin(angle + 2 * da), width * 0.5);
+		glVertex3f(r1 * cos(angle + 3 * da), r1 * sin(angle + 3 * da), width * 0.5);
+	}
+	glEnd();
+
+	glNormal3f(0.0, 0.0, -1.0);
+
+	/* draw back face */
+	glBegin(GL_QUAD_STRIP);
+	for(i = 0; i <= teeth; i++) {
+		angle = i * 2.0 * M_PI / teeth;
+		glVertex3f(r1 * cos(angle), r1 * sin(angle), -width * 0.5);
+		glVertex3f(r0 * cos(angle), r0 * sin(angle), -width * 0.5);
+		glVertex3f(r1 * cos(angle + 3 * da), r1 * sin(angle + 3 * da), -width * 0.5);
+		glVertex3f(r0 * cos(angle), r0 * sin(angle), -width * 0.5);
+	}
+	glEnd();
+
+	/* draw back sides of teeth */
+	glBegin(GL_QUADS);
+	da = 2.0 * M_PI / teeth / 4.0;
+	for(i = 0; i < teeth; i++) {
+		angle = i * 2.0 * M_PI / teeth;
+
+		glVertex3f(r1 * cos(angle + 3 * da), r1 * sin(angle + 3 * da), -width * 0.5);
+		glVertex3f(r2 * cos(angle + 2 * da), r2 * sin(angle + 2 * da), -width * 0.5);
+		glVertex3f(r2 * cos(angle + da), r2 * sin(angle + da), -width * 0.5);
+		glVertex3f(r1 * cos(angle), r1 * sin(angle), -width * 0.5);
+	}
+	glEnd();
+
+	/* draw outward faces of teeth */
+	glBegin(GL_QUAD_STRIP);
+	for(i = 0; i < teeth; i++) {
+		angle = i * 2.0 * M_PI / teeth;
+
+		glVertex3f(r1 * cos(angle), r1 * sin(angle), width * 0.5);
+		glVertex3f(r1 * cos(angle), r1 * sin(angle), -width * 0.5);
+		u   = r2 * cos(angle + da) - r1 * cos(angle);
+		v   = r2 * sin(angle + da) - r1 * sin(angle);
+		len = sqrt(u * u + v * v);
+		u /= len;
+		v /= len;
+		glNormal3f(v, -u, 0.0);
+		glVertex3f(r2 * cos(angle + da), r2 * sin(angle + da), width * 0.5);
+		glVertex3f(r2 * cos(angle + da), r2 * sin(angle + da), -width * 0.5);
+		glNormal3f(cos(angle), sin(angle), 0.0);
+		glVertex3f(r2 * cos(angle + 2 * da), r2 * sin(angle + 2 * da), width * 0.5);
+		glVertex3f(r2 * cos(angle + 2 * da), r2 * sin(angle + 2 * da), -width * 0.5);
+		u = r1 * cos(angle + 3 * da) - r2 * cos(angle + 2 * da);
+		v = r1 * sin(angle + 3 * da) - r2 * sin(angle + 2 * da);
+		glNormal3f(v, -u, 0.0);
+		glVertex3f(r1 * cos(angle + 3 * da), r1 * sin(angle + 3 * da), width * 0.5);
+		glVertex3f(r1 * cos(angle + 3 * da), r1 * sin(angle + 3 * da), -width * 0.5);
+		glNormal3f(cos(angle), sin(angle), 0.0);
+	}
+
+	glVertex3f(r1 * cos(0), r1 * sin(0), width * 0.5);
+	glVertex3f(r1 * cos(0), r1 * sin(0), -width * 0.5);
+
+	glEnd();
+
+	glShadeModel(GL_SMOOTH);
+
+	/* draw inside radius cylinder */
+	glBegin(GL_QUAD_STRIP);
+	for(i = 0; i <= teeth; i++) {
+		angle = i * 2.0 * M_PI / teeth;
+
+		glNormal3f(-cos(angle), -sin(angle), 0.0);
+		glVertex3f(r0 * cos(angle), r0 * sin(angle), -width * 0.5);
+		glVertex3f(r0 * cos(angle), r0 * sin(angle), width * 0.5);
+	}
+	glEnd();
+}
+
+static GLfloat view_rotx = 20.0, view_roty = 30.0, view_rotz = 0.0;
+static GLint   gear1, gear2, gear3;
+static GLfloat angle = 0.0;
+
+static void draw(void) {
+	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(3.1, -2.0, 0.0);
+	glRotatef(-2.0 * angle - 9.0, 0.0, 0.0, 1.0);
+	glCallList(gear2);
+	glPopMatrix();
+
+	glPushMatrix();
+	glTranslatef(-3.1, 4.2, 0.0);
+	glRotatef(-2.0 * angle - 25.0, 0.0, 0.0, 1.0);
+	glCallList(gear3);
+	glPopMatrix();
+
+	glPopMatrix();
+}
+
+/* new window size or exposure */
+static void reshape(int width, int height) {
+	GLfloat h = (GLfloat)height / (GLfloat)width;
+
+	glViewport(0, 0, (GLint)width, (GLint)height);
+	glMatrixMode(GL_PROJECTION);
+	glLoadIdentity();
+	glFrustum(-1.0, 1.0, -h, h, 5.0, 60.0);
+	glMatrixMode(GL_MODELVIEW);
+	glLoadIdentity();
+	glTranslatef(0.0, 0.0, -40.0);
+}
+
+static void init(void) {
+	static GLfloat pos[4] =
+	    {5.0, 5.0, 10.0, 0.0};
+	static GLfloat red[4] =
+	    {0.8, 0.1, 0.0, 1.0};
+	static GLfloat green[4] =
+	    {0.0, 0.8, 0.2, 1.0};
+	static GLfloat blue[4] =
+	    {0.2, 0.2, 1.0, 1.0};
+
+	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(1.0, 4.0, 1.0, 20, 0.7);
+	glEndList();
+
+	gear2 = glGenLists(1);
+	glNewList(gear2, GL_COMPILE);
+	glMaterialfv(GL_FRONT, GL_AMBIENT_AND_DIFFUSE, green);
+	gear(0.5, 2.0, 2.0, 10, 0.7);
+	glEndList();
+
+	gear3 = glGenLists(1);
+	glNewList(gear3, GL_COMPILE);
+	glMaterialfv(GL_FRONT, GL_AMBIENT_AND_DIFFUSE, blue);
+	gear(1.3, 2.0, 0.5, 10, 0.7);
+	glEndList();
+
+	glEnable(GL_NORMALIZE);
+}
+
+static void tick(MwWidget handle, void* user, void* client) {
+	(void)handle;
+	(void)user;
+	(void)client;
+
+	draw();
+	angle += 2.0;
+
+	MwOpenGLSwapBuffer(opengl);
+}
+
+static void resize(MwWidget handle, void* user, void* client) {
+	int ww, wh;
+
+	(void)handle;
+	(void)user;
+	(void)client;
+
+	ww = MwGetInteger(handle, MwNwidth) - 100;
+	wh = MwGetInteger(handle, MwNheight) - 100;
+
+	MwVaApply(opengl,
+		  MwNwidth, ww,
+		  MwNheight, wh,
+		  NULL);
+
+	reshape(ww, wh);
+}
+
+int main() {
+	MwWidget window;
+
+	window = MwVaCreateWidget(MwWindowClass, "main", NULL, 0, 0, 500, 500,
+				  MwNtitle, "main",
+				  NULL);
+	opengl = MwCreateWidget(MwOpenGLClass, "opengl", window, 50, 50, 400, 400);
+
+	MwOpenGLMakeCurrent(opengl);
+
+	init();
+	reshape(400, 400);
+
+	MwAddUserHandler(window, MwNresizeHandler, resize, NULL);
+	MwAddUserHandler(window, MwNtickHandler, tick, NULL);
+
+	MwLoop(window);
+}

src/core.c

@@ -96,7 +96,7 @@ MwWidget MwCreateWidget(MwClass widget_class, const char* name, MwWidget parent,
 	shdefault(h->handler, NULL);
 	shdefault(h->data, NULL);
 
-	if(MwDispatch2(h, create)) {
+	if(MwDispatch2(h, create) != 0) {
 		h->widget_class = NULL;
 		MwDestroyWidget(h);
 		return NULL;