Comp Form: Week 1 Assignment
Drawing a portrait, landscape, and grid in C and openGL. . .
| Problem 1. Write a comment for every line in the main.cpp file. | |
| /* * main.cpp * CompFormApp * */#include <OpenGL/gl.h> //openGL lib #include <GLUT/glut.h> //glut lib#include <stdio.h> //input output lib #include <stdlib.h> //standard lib #include <math.h> //math libfloat mouseX = 0; //new variable, mouseX float mouseY = 0; //mouseY int windowW = 800; //window Width int windowH = 600; //window Height#define PI 3.14159265358979 //variable for pivoid displayFunc ( void ) { glClear( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT ); //clears screen, color and depth, | binary OR// place your drawing code here glColor3f( 1,0,0 ); //pen color (r,g,b) //glColor4f(1,0,0,.5);//pen color + alpha glRectf( mouseX-5, mouseY-5, mouseX+5, mouseY+5 ); //draw rectangle (only built-in function), corner to cornerglutPostRedisplay(); //repeat, redraw glutSwapBuffers(); //swaps offscreen buffer, offscreen to onscreen }void reshapeFunc ( int w, int h ) { windowW = w; //window width windowH = h; //window height//camera setup glViewport( 0, 0, w, h ); //camera view, drawing region (x,y,x,y) glMatrixMode( GL_PROJECTION );//camera operations matrix glLoadIdentity();//load projection gluOrtho2D( 0,w,0,h ); //set camera to ortho, 2dglMatrixMode( GL_MODELVIEW );//drawing space matrix glLoadIdentity();//load model space }//mouse functions void mouseDownFunc ( int button, int state, int x, int y ) { mouseX = x; mouseY = windowH - y;//y=0 at bottom of screen printf(”%d %dn”,x,y);//print mouse x,y loc}void mouseMoveFunc ( int x, int y )//if mouse is moved { mouseX = x; mouseY = windowH - y; }void mouseDragFunc ( int x, int y )//if mouse is dragged { mouseX = x; mouseY = windowH - y; }//keyboard functions void keyboardFunc ( unsigned char key, int x, int y ) { }void arrowKeyFunc ( int a_keys, int x, int y ) { }void init ( GLvoid ) { glShadeModel( GL_SMOOTH ); // flat or smooth shading glClearColor( 1.0, 1.0, 1.0, 1.0 ); //specify clear values for the color buffers glEnable ( GL_COLOR_MATERIAL );//enable server side color material tracking glEnable( GL_BLEND );//enable server side blend of rgb values glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);//specify pixel rgb math } //main function at bottom glutInitDisplayMode( GLUT_RGBA | GLUT_DOUBLE ); //display mode //callback functions init();//call void init func glutMainLoop( );//main event loop, calls custom functions when even occurs return 0; //returns main=0 |
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Problem 2. A Portrait. a. Make a function called drawPortrait that is called from displayFunc. Draw the shape of your head in profile. Use GL_TRIANGLE_FAN. The portrait should be as accurate as possible and involve at least 30 points. Carefully place the first point to ensure a proper fill. |
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void drawPortrait(void){glBegin(GL_TRIANGLE_FAN);//draw triangles from a single starting point glColor3f( 1,0,0 ); glVertex2f(400,windowH-300); glVertex2f(371,windowH-518); glVertex2f(361,windowH-500); glVertex2f(356,windowH-489); glVertex2f(350,windowH-480); glVertex2f(340,windowH-466); glVertex2f(338,windowH-452); glVertex2f(337,windowH-442); glVertex2f(329,windowH-432); glVertex2f(319,windowH-426); glVertex2f(300,windowH-428); glVertex2f(259,windowH-422); glVertex2f(249,windowH-416); glVertex2f(244,windowH-410); glVertex2f(238,windowH-398); glVertex2f(236,windowH-385); glVertex2f(241,windowH-371); glVertex2f(236,windowH-366); glVertex2f(231,windowH-356); glVertex2f(233,windowH-347); glVertex2f(230,windowH-342); glVertex2f(229,windowH-332); glVertex2f(230,windowH-321); glVertex2f(235,windowH-314); glVertex2f(238,windowH-305); glVertex2f(232,windowH-300); glVertex2f(221,windowH-292); glVertex2f(216,windowH-285); glVertex2f(220,windowH-272); glVertex2f(230,windowH-264); glVertex2f(238,windowH-256); glVertex2f(250,windowH-248); glVertex2f(256,windowH-238); glVertex2f(257,windowH-224); glVertex2f(255,windowH-207); glVertex2f(253,windowH-191); glVertex2f(252,windowH-182); glVertex2f(259,windowH-174); glVertex2f(265,windowH-157); glVertex2f(269,windowH-148); glVertex2f(278,windowH-134); glVertex2f(291,windowH-113); glVertex2f(302,windowH-89); glVertex2f(320,windowH-77); glVertex2f(346,windowH-64); glVertex2f(380,windowH-56); glVertex2f(440,windowH-53); glVertex2f(490,windowH-63); glVertex2f(543,windowH-96); glVertex2f(577,windowH-147); glVertex2f(593,windowH-205); glVertex2f(593,windowH-238); glVertex2f(589,windowH-270); glVertex2f(578,windowH-301); glVertex2f(554,windowH-341); glVertex2f(546,windowH-358); glVertex2f(537,windowH-379); glVertex2f(525,windowH-393); glVertex2f(525,windowH-404); glVertex2f(527,windowH-419); glVertex2f(527,windowH-428); glVertex2f(530,windowH-443); glVertex2f(534,windowH-471); glVertex2f(370,windowH-519);glEnd();//end line strip} |
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b. Draw the shape of an eye from the front. Use GL_TRIANGLE_STRIP. |
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| void drawEye(){ float scale=120; int posX=windowW/2-scale*1.5; int posY=windowH/2;//eyeball glColor3f( 1,.9,.9 ); glBegin(GL_TRIANGLE_STRIP);//draw triangles from a single starting point for (float i=0;i<PI;i=i+.1){ glVertex2f(posX+i*scale,posY+sin(i)*scale);//line strip coordinates glVertex2f(posX+i*scale,posY-sin(i)*scale);//line strip coordinates } glEnd();//end line strip//Iris glColor3f( 0,.4,.35 ); scale=scale*.8; glBegin(GL_TRIANGLE_FAN);//draw triangles from a single starting point glVertex2f(windowW/2,windowH/2);//line strip coordinates for (float i=0;i<=PI*2;i=i+.1){ glVertex2f(windowW/2+scale*sin(i),windowH/2+scale*cos(i)); } glVertex2f(windowW/2+scale*sin(0),windowH/2+scale*cos(0)); glEnd();//end line strip//pupil glColor3f( 0,.05,0 ); scale=scale*.5; glBegin(GL_TRIANGLE_FAN);//draw triangles from a single starting point glVertex2f(windowW/2,windowH/2);//line strip coordinates for (float i=0;i<=PI*2;i=i+.1){ glVertex2f(windowW/2+scale*sin(i),windowH/2+scale*cos(i)); } glVertex2f(windowW/2+scale*sin(0),windowH/2+scale*cos(0)); glEnd();//end line strip} |
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c. Draw your initials as stroked lines with a thicknes of 3 pixels. Use GL_LINE_STRIP. |
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| void drawInitials(){ glLineWidth(3); glBegin(GL_LINE_STRIP); glVertex2f(325,windowW/2-170); glVertex2f(321,windowW/2-182); glVertex2f(318,windowW/2-198); glVertex2f(319,windowW/2-217); glVertex2f(320,windowW/2-223); glVertex2f(309,windowW/2-225); glVertex2f(304,windowW/2-211); glVertex2f(295,windowW/2-190); glVertex2f(273,windowW/2-181); glVertex2f(256,windowW/2-177); glVertex2f(236,windowW/2-175); glVertex2f(208,windowW/2-182); glVertex2f(182,windowW/2-201); glVertex2f(171,windowW/2-212); glVertex2f(162,windowW/2-228); glVertex2f(155,windowW/2-244); glVertex2f(155,windowW/2-250); glVertex2f(151,windowW/2-270); glVertex2f(151,windowW/2-280); glVertex2f(150,windowW/2-292); glVertex2f(150,windowW/2-304); glVertex2f(153,windowW/2-315); glVertex2f(160,windowW/2-330); glVertex2f(170,windowW/2-352); glVertex2f(177,windowW/2-360); glVertex2f(186,windowW/2-368); glVertex2f(198,windowW/2-378); glVertex2f(210,windowW/2-382); glVertex2f(221,windowW/2-386); glVertex2f(240,windowW/2-390); glVertex2f(254,windowW/2-389); glVertex2f(267,windowW/2-388); glVertex2f(277,windowW/2-385); glVertex2f(286,windowW/2-381); glVertex2f(299,windowW/2-374); glVertex2f(309,windowW/2-365); glVertex2f(313,windowW/2-356); glVertex2f(318,windowW/2-349); glVertex2f(320,windowW/2-343); glVertex2f(324,windowW/2-346); glVertex2f(327,windowW/2-350); glVertex2f(323,windowW/2-360); glVertex2f(317,windowW/2-374); glVertex2f(314,windowW/2-385); glVertex2f(309,windowW/2-393); glVertex2f(295,windowW/2-399); glVertex2f(278,windowW/2-402); glVertex2f(260,windowW/2-404); glVertex2f(238,windowW/2-404); glVertex2f(205,windowW/2-401); glVertex2f(177,windowW/2-391); glVertex2f(166,windowW/2-386); glVertex2f(157,windowW/2-380); glVertex2f(151,windowW/2-373); glVertex2f(142,windowW/2-365); glVertex2f(128,windowW/2-346); glVertex2f(119,windowW/2-327); glVertex2f(118,windowW/2-315); glVertex2f(114,windowW/2-288); glVertex2f(115,windowW/2-271); glVertex2f(119,windowW/2-245); glVertex2f(125,windowW/2-228); glVertex2f(142,windowW/2-203); glVertex2f(158,windowW/2-191); glVertex2f(195,windowW/2-173); glVertex2f(218,windowW/2-168); glVertex2f(242,windowW/2-161); glVertex2f(259,windowW/2-162); glVertex2f(274,windowW/2-162); glVertex2f(285,windowW/2-165); glVertex2f(292,windowW/2-167); glVertex2f(301,windowW/2-170); glVertex2f(308,windowW/2-172); glVertex2f(313,windowW/2-169); glVertex2f(318,windowW/2-167); glVertex2f(322,windowW/2-167); glVertex2f(325,windowW/2-169);glEnd(); glBegin(GL_LINE_STRIP); glVertex2f(424,windowW/2-172); } |
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Problem 3. A Landscape. a. Make a function called drawLanscape that is called from displayFunc. Draw two gradients, one for the sky and one for the ground. The sky and ground together should fill the window. Use GL_QUADS.
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| void drawLandscape(){ glBegin(GL_QUADS); for (int i=0;i<windowW;i++){ for (int j=0;j<windowH;j++){ if (j>windowH/2){ glColor3f( 1-float(j)/windowH*.7,.4-float(j)/windowH*2,.3+float(j)/windowH/6 ); //pen color (r,g,b) } if(j<windowH/2){ glColor3f( .5-float(j)/windowH,.5-float(j)/windowH,.5-float(j)/windowH); //pen color (r,g,b) } glVertex2f(i,j); glVertex2f(i,j+1); glVertex2f(i+1,j+1); glVertex2f(i+1,j);} } glEnd();} |
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b. Draws a small mountain range. The mountain range should grow vertically with the Y position of the mouse. Use GL_TRIANGLES.
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| void drawMountain(){ //mountain range glColor3f(0,0,0); glBegin(GL_TRIANGLES); //+peak for (int k=0;k<15;k++){ float peakW=90*k; float peakH=.05; int peakX=50*k; for(float i=0;i<peakW/2;i++){ glVertex2f(peakX+i,windowH/2+i*i*mouseY/windowH*peakH); glVertex2f(peakX+i,windowH/2); glVertex2f(peakX+i+1,windowH/2); } //-peak for(float i=peakW;i>=peakW/2;i–){ glVertex2f(peakX+i,windowH/2+(peakW-i)*(peakW-i)*mouseY/windowH*peakH); glVertex2f(peakX+i,windowH/2); glVertex2f(peakX+i+1,windowH/2); } } glEnd();} |
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c. Draw a cloud. The cloud’s transparency should depend on the mouse X position. Use GL_TRIANGLE_FAN. |
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| void drawClouds(){ //clouds glColor4f(.8,.5,.3,.03*mouseX/windowW);glBegin(GL_TRIANGLE_FAN); int posX=300; int posY=500; glVertex2f(posX,posY); for (float i=0;i<=windowH/2;i++){ glVertex2f(posX+sin(i)*150,posY+cos(i)*20); } glEnd();glBegin(GL_TRIANGLE_FAN); posX=100; posY=450; glVertex2f(posX,posY); for (float i=0;i<=windowH/2;i++){ glVertex2f(posX+sin(i)*100,posY+cos(i)*10); } glEnd();glBegin(GL_TRIANGLE_FAN); posX=120; posY=470; glVertex2f(posX,posY); for (float i=0;i<=windowH/2;i++){ glVertex2f(posX+sin(i)*500,posY+cos(i)*20); } glEnd();} |
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d. Draw a winding river. The river’s width should expand as the mouse moves left and right. Use GL_TRIANGLE_STRIP. |
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| void drawRiver(){ glBegin(GL_TRIANGLE_STRIP);for (float i=0;i<=windowH/2;i++){ glColor3f(.6-.6*i/windowH/2,.6-.8*i/windowH,.7-i/windowH); glVertex2f(100+50*i/windowH+mouseX/i-sin(i*.1)*mouseX/i*10+i,i); glVertex2f(150-50*i/windowH+mouseX/i+cos(i*.1)*mouseX/i*10+i,i-13); } glEnd(); } |
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| Problem 4. A Grid.
a. Make a function called drawGrid that draws a grid across the entire window with lines that are spaced 10 pixels apart both horizontally and vertically. Make the color of the grid a very light gray. Use GL_LINES. |
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| void drawGrid(){ glColor3f(.8,.8,.8); glBegin(GL_LINES); for (int i=0;i<windowW;i=i+10){ glVertex2f(i,0); glVertex2f(i,windowH);glVertex2f(0,i); glVertex2f(windowW,i);}glEnd(); } |
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b. Draw a dark gray 3 pixel point at ever grid intersection. Use GL_POINTS. |
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| void drawPoints(){ glColor3f(.5,.5,.5); glPointSize(3.0f); glBegin(GL_POINTS); for (int i=0;i<windowW;i=i+10){ for (int j=0;j<windowH;j=j+10){glVertex2f(i,j);} } glEnd(); } |
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- Published:
- 09.08.07 / 3pm
- Category:
- C, Comp Form, ITP, Work in Progress
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