int R3Mesh::
ReadImage(const char *filename)
{
// Create a mesh by reading an image file,
// constructing vertices at (x,y,luminance),
// and connecting adjacent pixels into faces.
// That is, the image is interpretted as a height field,
// where the luminance of each pixel provides its z-coordinate.
// Read image
R2Image *image = new R2Image();
if (!image->Read(filename)) return 0;
// Create vertices and store in arrays
R3MeshVertex ***vertices = new R3MeshVertex **[image->Width() ];
for (int i = 0; i < image->Width(); i++) {
vertices[i] = new R3MeshVertex *[image->Height() ];
for (int j = 0; j < image->Height(); j++) {
double luminance = image->Pixel(i, j).Luminance();
double z = luminance * image->Width();
R3Point position((double) i, (double) j, z);
R2Point texcoords((double) i, (double) j);
vertices[i][j] = CreateVertex(position, R3zero_vector, texcoords);
}
}
// Create faces
vector<R3MeshVertex *> face_vertices;
for (int i = 1; i < image->Width(); i++) {
for (int j = 1; j < image->Height(); j++) {
face_vertices.clear();
face_vertices.push_back(vertices[i-1][j-1]);
face_vertices.push_back(vertices[i][j-1]);
face_vertices.push_back(vertices[i][j]);
CreateFace(face_vertices);
face_vertices.clear();
face_vertices.push_back(vertices[i-1][j-1]);
face_vertices.push_back(vertices[i][j]);
face_vertices.push_back(vertices[i-1][j]);
CreateFace(face_vertices);
}
}
// Delete vertex arrays
for (int i = 0; i < image->Width(); i++) delete [] vertices[i];
delete [] vertices;
// Delete image
delete image;
// Return success
return 1;
}
static R2Image *
ReadImage(const char *filename)
{
// Allocate a image
R2Image *image = new R2Image();
if (!image) {
fprintf(stderr, "Unable to allocate image");
return NULL;
}
// Read image
if (!image->Read(filename)) {
fprintf(stderr, "Unable to read image file %s", filename);
return NULL;
}
// Print message
if (print_verbose) {
printf("Read image from %s\n", filename);
printf(" Resolution = %d %d\n", image->Width(), image->Height());
printf(" L1Norm = %g\n", image->L1Norm());
printf(" L2Norm = %g\n", image->L2Norm());
fflush(stdout);
}
// Return image
return image;
}
void R2Image::
Multiply(const R2Image& image)
{
// Multiply by image pixel-by-pixel
assert(image.Width() == Width());
assert(image.Height() == Height());
assert(image.NChannels() == NChannels());
int nvalues = NValues();
for (int i = 0; i < nvalues; i++) {
pixels[i] *= image.pixels[i];
}
}
void R2Image::
Subtract(const R2Image& image)
{
// Subtract image pixel-by-pixel
assert(image.Width() == Width());
assert(image.Height() == Height());
assert(image.NChannels() == NChannels());
int nvalues = NValues();
for (int i = 0; i < nvalues; i++) {
pixels[i] -= image.pixels[i];
}
}
void R2Image::
Filter(const R2Image& filter)
{
// Get useful variables
int xr = filter.Width()/2;
int yr = filter.Height()/2;
R2Image copy(*this);
// This is the straight-forward implementation (slow for large filters)
for (int j = 0; j < Height(); j++) {
for (int i = 0; i < Width(); i++) {
for (int c = 0; c < NChannels(); c++) {
int fc = (NChannels() == filter.NChannels()) ? c : 0;
// Compute new value
double sum = 0;
for (int s = 0; s < filter.Width(); s++) {
int x = i - xr + s;
if (x < 0) x = 0;
else if (x >= Width()) x = Width()-1;
for (int t = 0; t < filter.Height(); t++) {
int y = j - yr + t;
if (y < 0) y = 0;
else if (y >= Height()) y = Height()-1;
double filter_value = filter.Value(s, t, fc);
double image_value = copy.Value(x, y, c);
sum += filter_value * image_value;
}
}
// Assign new value for channel
SetValue(i, j, c, sum);
}
}
}
}
void R2Image::
Divide(const R2Image& image)
{
// Add image pixel-by-pixel
assert(image.Width() == Width());
assert(image.Height() == Height());
assert(image.NChannels() == NChannels());
int nvalues = NValues();
for (int i = 0; i < nvalues; i++) {
if (image.pixels[i] == 0) {
if (pixels[i] == 0.0) continue;
else pixels[i] = FLT_MAX;
}
else {
pixels[i] /= image.pixels[i];
}
}
}
void LoadMaterial(R3Material *material)
{
GLfloat c[4];
// Check if same as current
static R3Material *current_material = NULL;
if (material == current_material) return;
current_material = material;
// Compute "opacity"
double opacity = 1 - material->kt.Luminance();
// Load ambient
c[0] = material->ka[0];
c[1] = material->ka[1];
c[2] = material->ka[2];
c[3] = opacity;
glMaterialfv(GL_FRONT_AND_BACK, GL_AMBIENT, c);
// Load diffuse
c[0] = material->kd[0];
c[1] = material->kd[1];
c[2] = material->kd[2];
c[3] = opacity;
glMaterialfv(GL_FRONT_AND_BACK, GL_DIFFUSE, c);
// Load specular
c[0] = material->ks[0];
c[1] = material->ks[1];
c[2] = material->ks[2];
c[3] = opacity;
glMaterialfv(GL_FRONT_AND_BACK, GL_SPECULAR, c);
// Load emission
c[0] = material->emission.Red();
c[1] = material->emission.Green();
c[2] = material->emission.Blue();
c[3] = opacity;
glMaterialfv(GL_FRONT_AND_BACK, GL_EMISSION, c);
// Load shininess
c[0] = material->shininess;
glMaterialf(GL_FRONT_AND_BACK, GL_SHININESS, c[0]);
// Load texture
if (material->texture) {
if (material->texture_index <= 0) {
// Create texture in OpenGL
GLuint texture_index;
glGenTextures(1, &texture_index);
material->texture_index = (int) texture_index;
glBindTexture(GL_TEXTURE_2D, material->texture_index);
R2Image *image = material->texture;
int npixels = image->NPixels();
R2Pixel *pixels = image->Pixels();
GLfloat *buffer = new GLfloat [ 4 * npixels ];
R2Pixel *pixelsp = pixels;
GLfloat *bufferp = buffer;
for (int j = 0; j < npixels; j++) {
*(bufferp++) = pixelsp->Red();
*(bufferp++) = pixelsp->Green();
*(bufferp++) = pixelsp->Blue();
*(bufferp++) = pixelsp->Alpha();
pixelsp++;
}
glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MIN_FILTER,GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MAG_FILTER,GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_WRAP_S,GL_REPEAT);
glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_WRAP_T,GL_REPEAT);
glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE);
glTexImage2D(GL_TEXTURE_2D, 0, 4, image->Width(), image->Height(), 0, GL_RGBA, GL_FLOAT, buffer);
delete [] buffer;
}
// Select texture
glBindTexture(GL_TEXTURE_2D, material->texture_index);
glEnable(GL_TEXTURE_2D);
}
else {
glDisable(GL_TEXTURE_2D);
}
// Enable blending for transparent surfaces
if (opacity < 1) {
glDepthMask(false);
glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
glEnable(GL_BLEND);
}
else {
glDisable(GL_BLEND);
glBlendFunc(GL_ONE, GL_ZERO);
glDepthMask(true);
}
}