FAKULTI TEKNOLOGI MAKLUMAT DAN KOMUNIKASI BITM INTERACTIVE COMPUTER GRAPHICS LAB SESSION 4. C++ - OpenGL

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1 FAKULTI TEKNOLOGI MAKLUMAT DAN KOMUNIKASI BITM INTERACTIVE COMPUTER GRAPHICS LAB SESSION 4 C++ - OpenGL

2 Part 1- C++ - Texture Mapping 1. Download texture file and put it into your current folder where main.cpp stay 2. Code the following program #include <GL\glew.h> #include <GL\freeglut.h> #include <math.h> #include <windows.h> #include <stdio.h> #include <stdlib.h> GLuint texture; //the array for our texture GLfloat angle = 0.0; //function to load the RAW file GLuint LoadTexture(const char * filename, int width, int height) { GLuint texture; unsigned char * data; FILE * file; //The following code will read in our RAW file file = fopen(filename, "rb"); if (file == NULL) return 0; data = (unsigned char *)malloc(width * height * 3); fread(data, width * height * 3, 1, file); fclose(file); glgentextures(1, &texture); //generate the texture with the loaded data glbindtexture(gl_texture_2d, texture); //bind the textureto it s array gltexenvf(gl_texture_env, GL_TEXTURE_ENV_MODE, GL_MODULATE); //set texture environment parameters gltexparameterf(gl_texture_2d, GL_TEXTURE_MIN_FILTER, GL_LINEAR); gltexparameterf(gl_texture_2d, GL_TEXTURE_MAG_FILTER, GL_LINEAR); gltexparameterf(gl_texture_2d, GL_TEXTURE_WRAP_S, GL_REPEAT); gltexparameterf(gl_texture_2d, GL_TEXTURE_WRAP_T, GL_REPEAT); //Generate the texture glteximage2d(gl_texture_2d, 0, GL_RGB, width, height, 0, GL_RGB, GL_UNSIGNED_BYTE, data); free(data); //free the texture return texture; //return whether it was successfull void FreeTexture(GLuint texture)

3 { gldeletetextures(1, &texture); void square(void) { glbindtexture(gl_texture_2d, texture); glrotatef(angle, 1.0f, 1.0f, 1.0f); glbegin(gl_quads); gltexcoord2d(0.0, 0.0); glvertex2d(-1.0, -1.0); gltexcoord2d(1.0, 0.0); glvertex2d(+1.0, -1.0); gltexcoord2d(1.0, 1.0); glvertex2d(+1.0, +1.0); gltexcoord2d(0.0, 1.0); glvertex2d(-1.0, +1.0); void display(void) { glclearcolor(0.0, 0.0, 0.0, 1.0); glclear(gl_color_buffer_bit); glloadidentity(); glenable(gl_texture_2d); glulookat(0.0, 0.0, 5.0, 0.0, 0.0, 0.0, 0.0, 1.0, 0.0); square(); glutswapbuffers(); angle=angle+0.05; void reshape(int w, int h) { glviewport(0, 0, (GLsizei)w, (GLsizei)h); glmatrixmode(gl_projection); glloadidentity(); gluperspective(60, (GLfloat)w / (GLfloat)h, 1.0, 100.0) ; glmatrixmode(gl_modelview); int main(int argc, char **argv) { glutinit(&argc, argv); glutinitdisplaymode(glut_double); glutinitwindowsize(500, 500); glutinitwindowposition(100, 100); glutcreatewindow("a basic OpenGL Window"); glutdisplayfunc(display); glutidlefunc(display); glutreshapefunc(reshape); //Load our texture texture = LoadTexture("Data/texture.bmp", 256, 256); glutmainloop(); //Free our texture FreeTexture(texture); EXERCISE: 1. Try to understand the code

4 Part 2- C++ - OpenGL Add few modifications Modifications And this codes into void display(void) // Rotate when user changes rotate_x and rotate_y glrotatef(rotate_x, 1.0, 0.0, 0.0); glrotatef(rotate_y, 0.0, 1.0, 0.0); And Dont forget to put this to declare variable void specialkeys(); // Global Variables double rotate_y = 0; double rotate_x = 0; Now add void specialkeys void specialkeys(int key, int x, int y) { // Right arrow - increase rotation by 5 degree if (key == GLUT_KEY_RIGHT) rotate_y += 5; // Left arrow - decrease rotation by 5 degree else if (key == GLUT_KEY_LEFT) rotate_y -= 5; else if (key == GLUT_KEY_UP) rotate_x += 5; else if (key == GLUT_KEY_DOWN) rotate_x -= 5; // Request display update glutpostredisplay(); Put below in int main(int argc, char **argv) glenable(gl_depth_test); glutspecialfunc(specialkeys); change glutinitdisplaymode(glut_double); into glutinitdisplaymode(glut_double GLUT_RGB GLUT_DEPTH); Change glclear(gl_color_buffer_bit); Into glclear(gl_color_buffer_bit GL_DEPTH_BUFFER_BIT);

5 Disabled these And //glbegin(gl_quads); //gltexcoord3d(0.0, 0.0, 0.0); glvertex2d(-1.0, -1.0); //gltexcoord3d(1.0, 0.0, 0.0); glvertex2d(+1.0, -1.0); //gltexcoord3d(1.0, 1.0, 0.0); glvertex2d(+1.0, +1.0); //gltexcoord3d(0.0, 1.0, 0.0); glvertex2d(-1.0, +1.0); // //angle=angle+0.05; Change the textured cube into below //Multi-colored side - FRONT glcolor3f(1.0, 0.0, 0.0); glvertex3f(0.5, -0.5, -0.5); // P1 is red glcolor3f(0.0, 1.0, 0.0); glvertex3f(0.5, 0.5, -0.5); // P2 is green glcolor3f(0.0, 0.0, 1.0); glvertex3f(-0.5, 0.5, -0.5); // P3 is blue glcolor3f(1.0, 0.0, 1.0); glvertex3f(-0.5, -0.5, -0.5); // P4 is purple // White side - BACK glcolor3f(1.0, 1.0, 1.0); glvertex3f(0.5, -0.5, 0.5); glvertex3f(0.5, 0.5, 0.5); glvertex3f(-0.5, 0.5, 0.5); glvertex3f(-0.5, -0.5, 0.5); // Purple side - RIGHT glcolor3f(1.0, 0.0, 1.0); glvertex3f(0.5, -0.5, -0.5); glvertex3f(0.5, 0.5, -0.5); glvertex3f(0.5, 0.5, 0.5); glvertex3f(0.5, -0.5, 0.5); // Green side - LEFT glcolor3f(0.0, 1.0, 0.0); glvertex3f(-0.5, -0.5, 0.5); glvertex3f(-0.5, 0.5, 0.5); glvertex3f(-0.5, 0.5, -0.5); glvertex3f(-0.5, -0.5, -0.5); // Blue side - TOP glcolor3f(0.0, 0.0, 1.0); glvertex3f(0.5, 0.5, 0.5); glvertex3f(0.5, 0.5, -0.5); glvertex3f(-0.5, 0.5, -0.5); glvertex3f(-0.5, 0.5, 0.5); // Red side - BOTTOM

6 glcolor3f(1.0, 0.0, 0.0); glvertex3f(0.5, -0.5, -0.5); glvertex3f(0.5, -0.5, 0.5); glvertex3f(-0.5, -0.5, 0.5); glvertex3f(-0.5, -0.5, -0.5); EXERCISE: 1. Run the code 2. Test the code 3. Understand the code

7 Part 3: Make a Textured Cube just like below SUBMIT VIA ULEARN BY 6 am 7 April 2016.

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