• Diffuse and ambient reflection
Viewpoint position independent. Can be set simultaneously with:

glMaterialfv( GL_FRONT_AND_BACK, GL_AMBIENT_AND_DIFFUSE, mat_amb_diff );

• Specular reflection
Viewpoint position dependent.

GL_SPECULAR(reflect effect) and GL_SHININESS(the size and brightness of the higlight).

Value ranges from 0.0 to 128.0, the higher the value, the smaller and brighter the highlight.

• Emission
As if the object/polygon is glowing. But,

emission light will not be treated as a light source.

To simulate a lamp, place a light source in the position of a sphere(for example).

glMaterial*()

void glMaterial{if} (GLenum face, GLenum pname, TYPE param); void glMaterial{if}v (GLenum face, GLenum pname, TYPE *param); face -> { GL_FRONT, GL_BACK, GL_FRONT_AND_BACK } Non-vector version only works for GL_SHINNESS. Like colors, material properties are 'state' oriented.

Table 6-3. Default Values for pname Parameter of glMaterial*()

Example:Different Material Properties

//material.cpp GLfloat no_mat[] = { 0.0, 0.0, 0.0, 1.0 }; GLfloat mat_ambient[] = { 0.7, 0.7, 0.7, 1.0 }; GLfloat mat_ambient_color[] = { 0.8, 0.8, 0.2, 1.0 }; GLfloat mat_diffuse[] = { 0.1, 0.5, 0.8, 1.0 }; GLfloat mat_specular[] = { 1.0, 1.0, 1.0, 1.0 }; GLfloat no_shininess[] = { 0.0 }; GLfloat low_shininess[] = { 5.0 }; GLfloat high_shininess[] = { 100.0 }; GLfloat mat_emission[] = {0.3, 0.2, 0.2, 0.0}; glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); /* draw sphere in first row, first column * diffuse reflection only; no ambient or specular */ glPushMatrix(); glTranslatef (-3.75, 3.0, 0.0); glMaterialfv(GL_FRONT, GL_AMBIENT, no_mat); glMaterialfv(GL_FRONT, GL_DIFFUSE, mat_diffuse); glMaterialfv(GL_FRONT, GL_SPECULAR, no_mat); glMaterialfv(GL_FRONT, GL_SHININESS, no_shininess); glMaterialfv(GL_FRONT, GL_EMISSION, no_mat); glutSolidSphere(1.0, 16, 16); glPopMatrix(); /* draw sphere in first row, second column * diffuse and specular reflection; low shininess; no ambient */ glPushMatrix(); glTranslatef (-1.25, 3.0, 0.0); glMaterialfv(GL_FRONT, GL_AMBIENT, no_mat); glMaterialfv(GL_FRONT, GL_DIFFUSE, mat_diffuse); glMaterialfv(GL_FRONT, GL_SPECULAR, mat_specular); glMaterialfv(GL_FRONT, GL_SHININESS, low_shininess); glMaterialfv(GL_FRONT, GL_EMISSION, no_mat); glutSolidSphere(1.0, 16, 16); glPopMatrix(); /* draw sphere in first row, third column * diffuse and specular reflection; high shininess; no ambient */ glPushMatrix(); glTranslatef (1.25, 3.0, 0.0); glMaterialfv(GL_FRONT, GL_AMBIENT, no_mat); glMaterialfv(GL_FRONT, GL_DIFFUSE, mat_diffuse); glMaterialfv(GL_FRONT, GL_SPECULAR, mat_specular); glMaterialfv(GL_FRONT, GL_SHININESS, high_shininess); glMaterialfv(GL_FRONT, GL_EMISSION, no_mat); glutSolidSphere(1.0, 16, 16); glPopMatrix(); /* draw sphere in first row, fourth column * diffuse reflection; emission; no ambient or specular refl. */ glPushMatrix(); glTranslatef (3.75, 3.0, 0.0); glMaterialfv(GL_FRONT, GL_AMBIENT, no_mat); glMaterialfv(GL_FRONT, GL_DIFFUSE, mat_diffuse); glMaterialfv(GL_FRONT, GL_SPECULAR, no_mat); glMaterialfv(GL_FRONT, GL_SHININESS, no_shininess); glMaterialfv(GL_FRONT, GL_EMISSION, mat_emission); glutSolidSphere(1.0, 16, 16); glPopMatrix();

No ambient reflection     Grey ambient reflection     Blue ambient reflection

Figure column:

1. blue diffuse material color with no specular properties
   
2. adds white specular reflection with a low shininess exponent
   
3. uses a high shininess exponent and thus a more concentrated light
   
4. uses blue diffuse color and, instead of specular reflection, adds an emissive component

More teapots:

In summary, the default OpenGL lighting math model ('redbook' page. 220 - page. 225)

vertex color = emissionmaterial +

ambientlight model * ambientmaterial +

[ambientlight *ambientmaterial +

(max { L (dot) n , 0} ) * diffuselight * diffusematerial +

(max { s (dot) n , 0} )^shininess * specularlight * specularmaterial ] _i

Multiple views with GLUT

GLUT Windows management sub-api

Ref: GLUT - Windows Managements

int glutCreateWindow(char *name)	Creates a new top-level window
int glutCreateSubWindow(int win,    int x, int y, int width, int height)	Creates a sub-window
void glutSetWindow(int winId)	Set the window with ID winId as current window
int glutGetWindow(void)	Requests the identifier for the current window
void glutDestroyWindow(int winId)	Destroys the window specified by winId
void glutPostRedisplay(void)	Tells the GLUT event processor that the current window needs to be redisplayed
void glutSwapBuffers(void)	Swaps the buffers for the current window
void glutPositionWindow(int x, int y)	Requests a change in the position of the window
void glutReshapeWindow(int width, int height)	Requests a change in the size of the window
void glutFullScreen()	Requests that the current window be made full screen
void glutPopWindow(void) void glutPushWindow(void)	Push or Pop the current window relative to others in the stack
void glutShowWindow(void) void glutHideWindow(void) void glutIconifyWindow(void)	Show, hide or iconify the current window
void glutSetWindowTitle(char *name) void glutSetIconTitle(char *name)	Set title bar in window or iconified window

Let's look at the simple code.

GLUI - GLUI User Interface Library

What is GLUI?

"GLUI is a GLUT-based C++ user interface library which provides controls such as buttons, checkboxes, radio buttons, and spinners to OpenGL applications. It is window-system independent, relying on GLUT to handle all system-dependent issues, such as window and mouse management." - GLUI website

Steps of doing texture mapping: Example: checker.c

1. Create a textue object and specify a texture for that object.
Load or create an image as texture(an 1 or multi-dimension array basically).
2. Indicate how the texture is to be applied to each pixel
3. Enable texture mapping
4. Draw the scene, supplying both texture and geometric coordinates

• Andy's shell program.
• textures are here (512x256x3 colours).
• My JPEG or BMP files?
Sorry, OpenGL or GLUT don't support that natively. :(
• All you need is a two* dimension data array
• BMP: uncompress data, easier
Parse header, get image size, and pixel info. Then parse the data in binary.
• JPEG: compressed data. :(
libjpeg comes to the rescue!

libjpeg at Wikipedia.org

• Yet another way to get textures
Use tools like Photoshop, Paint Shop Pro or so to convert your jpeg or bmp texture image files to raw image data file. Then fit into aej's shell program.

GLubyte * loadTexture (char *fileName, int width, int height, int depth) { GLubyte *raw_bitmap, *reversed_bitmap; FILE *texFile; int byteSize, textureSize; byteSize = sizeof(GLubyte); textureSize = width * height * depth * byteSize; texFile = fopen(fileName, "rb"); if (texFile == NULL) { printf ("Texture %s not found\n", fileName); exit(1); } raw_bitmap = (GLubyte *) malloc (textureSize); reversed_bitmap = (GLubyte *) malloc (textureSize); if ((raw_bitmap == NULL) || (reversed_bitmap == NULL)) { printf("Cannot allocate memory for texture %s\n", fileName); fclose(texFile); exit(1); } fread (raw_bitmap , width * height * depth, 1 , texFile ); fclose (texFile); /* need to reverse the texture horizontally here */ /************************************************/ int i, j, k; for (i=0; i < height;i++) for (j=0; j < width*depth;j+=depth) for (k=0;k < depth;k++) reversed_bitmap[i*width*depth + (j+k)] = raw_bitmap[(i+1)*width*depth-(j+depth)+k]; glTexParameteri (GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR); glTexParameteri (GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR); glTexEnvf (GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE ); free (raw_bitmap); return (reversed_bitmap); }