364 lines
7.8 KiB
C
364 lines
7.8 KiB
C
|
|
#include <assert.h>
|
|
#include <string.h>
|
|
#include <stdio.h>
|
|
#include <stdlib.h>
|
|
#include <math.h>
|
|
|
|
#include <GL/glew.h>
|
|
#include <GL/glut.h>
|
|
|
|
static const char *filename = NULL;
|
|
static GLuint nr_steps = 4;
|
|
static GLuint prim = GL_TRIANGLES;
|
|
static GLfloat psz = 1.0;
|
|
static GLboolean pointsmooth = 0;
|
|
static GLboolean program_point_size = 0;
|
|
|
|
static GLuint fragShader;
|
|
static GLuint vertShader;
|
|
static GLuint program;
|
|
|
|
static void usage( char *name )
|
|
{
|
|
fprintf( stderr, "usage: %s [ options ] shader_filename\n", name );
|
|
fprintf( stderr, "\n" );
|
|
fprintf( stderr, "options:\n" );
|
|
fprintf( stderr, " -f flat shaded\n" );
|
|
fprintf( stderr, " -nNr subdivision steps\n" );
|
|
}
|
|
|
|
|
|
static void load_and_compile_shader(GLuint shader, const char *text)
|
|
{
|
|
GLint stat;
|
|
|
|
glShaderSource(shader, 1, (const GLchar **) &text, NULL);
|
|
|
|
glCompileShader(shader);
|
|
|
|
glGetShaderiv(shader, GL_COMPILE_STATUS, &stat);
|
|
if (!stat) {
|
|
GLchar log[1000];
|
|
GLsizei len;
|
|
glGetShaderInfoLog(shader, 1000, &len, log);
|
|
fprintf(stderr, "vp-tris: problem compiling shader:\n%s\n", log);
|
|
exit(1);
|
|
}
|
|
}
|
|
|
|
static void read_shader(GLuint shader, const char *filename)
|
|
{
|
|
const int max = 100*1000;
|
|
int n;
|
|
char *buffer = (char*) malloc(max);
|
|
FILE *f = fopen(filename, "r");
|
|
if (!f) {
|
|
fprintf(stderr, "vp-tris: Unable to open shader file %s\n", filename);
|
|
exit(1);
|
|
}
|
|
|
|
n = fread(buffer, 1, max, f);
|
|
printf("vp-tris: read %d bytes from shader file %s\n", n, filename);
|
|
if (n > 0) {
|
|
buffer[n] = 0;
|
|
load_and_compile_shader(shader, buffer);
|
|
}
|
|
|
|
fclose(f);
|
|
free(buffer);
|
|
}
|
|
|
|
static void check_link(GLuint prog)
|
|
{
|
|
GLint stat;
|
|
glGetProgramiv(prog, GL_LINK_STATUS, &stat);
|
|
if (!stat) {
|
|
GLchar log[1000];
|
|
GLsizei len;
|
|
glGetProgramInfoLog(prog, 1000, &len, log);
|
|
fprintf(stderr, "Linker error:\n%s\n", log);
|
|
}
|
|
}
|
|
|
|
static void setup_uniforms()
|
|
{
|
|
{
|
|
GLint loc1f = glGetUniformLocationARB(program, "Offset1f");
|
|
GLint loc2f = glGetUniformLocationARB(program, "Offset2f");
|
|
GLint loc4f = glGetUniformLocationARB(program, "Offset4f");
|
|
GLfloat vecKer[] =
|
|
{ 1.0, 0.0, 0.0, 1.0,
|
|
0.0, 1.0, 0.0, 1.0,
|
|
1.0, 0.0, 0.0, 1.0,
|
|
0.0, 0.0, 0.0, 1.0
|
|
};
|
|
if (loc1f >= 0)
|
|
glUniform1fv(loc1f, 16, vecKer);
|
|
|
|
if (loc2f >= 0)
|
|
glUniform2fv(loc2f, 8, vecKer);
|
|
|
|
if (loc4f >= 0)
|
|
glUniform4fv(loc4f, 4, vecKer);
|
|
|
|
}
|
|
|
|
{
|
|
GLint loc1f = glGetUniformLocationARB(program, "KernelValue1f");
|
|
GLint loc2f = glGetUniformLocationARB(program, "KernelValue2f");
|
|
GLint loc4f = glGetUniformLocationARB(program, "KernelValue4f");
|
|
GLfloat vecKer[] =
|
|
{ 1.0, 0.0, 0.0, 0.25,
|
|
0.0, 1.0, 0.0, 0.25,
|
|
0.0, 0.0, 1.0, 0.25,
|
|
0.0, 0.0, 0.0, 0.25,
|
|
0.5, 0.0, 0.0, 0.35,
|
|
0.0, 0.5, 0.0, 0.35,
|
|
0.0, 0.0, 0.5, 0.35,
|
|
0.0, 0.0, 0.0, 0.35
|
|
};
|
|
if (loc1f >= 0)
|
|
glUniform1fv(loc1f, 16, vecKer);
|
|
|
|
if (loc2f >= 0)
|
|
glUniform2fv(loc2f, 8, vecKer);
|
|
|
|
if (loc4f >= 0)
|
|
glUniform4fv(loc4f, 4, vecKer);
|
|
}
|
|
}
|
|
|
|
static void prepare_shaders()
|
|
{
|
|
static const char *fragShaderText =
|
|
"void main() {\n"
|
|
" gl_FragColor = gl_Color;\n"
|
|
"}\n";
|
|
static const char *vertShaderText =
|
|
"void main() {\n"
|
|
" gl_FrontColor = gl_Color;\n"
|
|
" gl_Position = gl_ModelViewProjectionMatrix * gl_Vertex;\n"
|
|
"}\n";
|
|
fragShader = glCreateShader(GL_FRAGMENT_SHADER);
|
|
load_and_compile_shader(fragShader, fragShaderText);
|
|
|
|
|
|
vertShader = glCreateShader(GL_VERTEX_SHADER);
|
|
if (filename)
|
|
read_shader(vertShader, filename);
|
|
else
|
|
load_and_compile_shader(vertShader, vertShaderText);
|
|
|
|
program = glCreateProgram();
|
|
glAttachShader(program, fragShader);
|
|
glAttachShader(program, vertShader);
|
|
glLinkProgram(program);
|
|
check_link(program);
|
|
glUseProgram(program);
|
|
|
|
setup_uniforms();
|
|
}
|
|
|
|
static void args(int argc, char *argv[])
|
|
{
|
|
GLint i;
|
|
|
|
for (i = 1; i < argc; i++) {
|
|
if (strncmp(argv[i], "-n", 2) == 0) {
|
|
nr_steps = atoi((argv[i]) + 2);
|
|
}
|
|
else if (strcmp(argv[i], "-f") == 0) {
|
|
glShadeModel(GL_FLAT);
|
|
}
|
|
else if (i == argc - 1) {
|
|
filename = argv[i];
|
|
}
|
|
else {
|
|
usage(argv[0]);
|
|
exit(1);
|
|
}
|
|
}
|
|
|
|
if (!filename) {
|
|
usage(argv[0]);
|
|
exit(1);
|
|
}
|
|
}
|
|
|
|
|
|
|
|
|
|
union vert {
|
|
struct {
|
|
GLfloat color[3];
|
|
GLfloat pos[3];
|
|
} v;
|
|
GLfloat f[6];
|
|
};
|
|
|
|
static void make_midpoint( union vert *out,
|
|
const union vert *v0,
|
|
const union vert *v1)
|
|
{
|
|
int i;
|
|
for (i = 0; i < 6; i++)
|
|
out->f[i] = v0->f[i] + .5 * (v1->f[i] - v0->f[i]);
|
|
}
|
|
|
|
static void subdiv( union vert *v0,
|
|
union vert *v1,
|
|
union vert *v2,
|
|
GLuint depth )
|
|
{
|
|
if (depth == 0) {
|
|
glColor3fv(v0->v.color);
|
|
glVertex3fv(v0->v.pos);
|
|
glColor3fv(v1->v.color);
|
|
glVertex3fv(v1->v.pos);
|
|
glColor3fv(v2->v.color);
|
|
glVertex3fv(v2->v.pos);
|
|
}
|
|
else {
|
|
union vert m[3];
|
|
|
|
make_midpoint(&m[0], v0, v1);
|
|
make_midpoint(&m[1], v1, v2);
|
|
make_midpoint(&m[2], v2, v0);
|
|
|
|
subdiv(&m[0], &m[2], v0, depth-1);
|
|
subdiv(&m[1], &m[0], v1, depth-1);
|
|
subdiv(&m[2], &m[1], v2, depth-1);
|
|
subdiv(&m[0], &m[1], &m[2], depth-1);
|
|
}
|
|
}
|
|
|
|
static void enable( GLenum value, GLboolean flag )
|
|
{
|
|
if (flag)
|
|
glEnable(value);
|
|
else
|
|
glDisable(value);
|
|
}
|
|
|
|
/** Assignment */
|
|
#define ASSIGN_3V( V, V0, V1, V2 ) \
|
|
do { \
|
|
V[0] = V0; \
|
|
V[1] = V1; \
|
|
V[2] = V2; \
|
|
} while(0)
|
|
|
|
static void Display( void )
|
|
{
|
|
glClearColor(0.3, 0.3, 0.3, 1);
|
|
glClear( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT );
|
|
glPointSize(psz);
|
|
|
|
glUseProgram(program);
|
|
enable( GL_POINT_SMOOTH, pointsmooth );
|
|
enable( GL_VERTEX_PROGRAM_POINT_SIZE_ARB, program_point_size );
|
|
|
|
glBegin(prim);
|
|
|
|
|
|
{
|
|
union vert v[3];
|
|
|
|
ASSIGN_3V(v[0].v.color, 0,0,1);
|
|
ASSIGN_3V(v[0].v.pos, 0.9, -0.9, 0.0);
|
|
ASSIGN_3V(v[1].v.color, 1,0,0);
|
|
ASSIGN_3V(v[1].v.pos, 0.9, 0.9, 0.0);
|
|
ASSIGN_3V(v[2].v.color, 0,1,0);
|
|
ASSIGN_3V(v[2].v.pos, -0.9, 0, 0.0);
|
|
|
|
subdiv(&v[0], &v[1], &v[2], nr_steps);
|
|
}
|
|
|
|
glEnd();
|
|
|
|
|
|
glFlush();
|
|
}
|
|
|
|
|
|
static void Reshape( int width, int height )
|
|
{
|
|
glViewport( 0, 0, width, height );
|
|
glMatrixMode( GL_PROJECTION );
|
|
glLoadIdentity();
|
|
glOrtho(-1.0, 1.0, -1.0, 1.0, -0.5, 1000.0);
|
|
glMatrixMode( GL_MODELVIEW );
|
|
glLoadIdentity();
|
|
/*glTranslatef( 0.0, 0.0, -15.0 );*/
|
|
}
|
|
|
|
|
|
static void CleanUp(void)
|
|
{
|
|
glDeleteShader(fragShader);
|
|
glDeleteShader(vertShader);
|
|
glDeleteProgram(program);
|
|
}
|
|
|
|
static void Key( unsigned char key, int x, int y )
|
|
{
|
|
(void) x;
|
|
(void) y;
|
|
switch (key) {
|
|
case 'p':
|
|
prim = GL_POINTS;
|
|
break;
|
|
case 't':
|
|
prim = GL_TRIANGLES;
|
|
break;
|
|
case 's':
|
|
psz += .5;
|
|
break;
|
|
case 'S':
|
|
if (psz > .5)
|
|
psz -= .5;
|
|
break;
|
|
case 'm':
|
|
pointsmooth = !pointsmooth;
|
|
break;
|
|
case 'z':
|
|
program_point_size = !program_point_size;
|
|
break;
|
|
case '+':
|
|
nr_steps++;
|
|
break;
|
|
case '-':
|
|
if (nr_steps)
|
|
nr_steps--;
|
|
break;
|
|
case ' ':
|
|
psz = 1.0;
|
|
prim = GL_TRIANGLES;
|
|
nr_steps = 4;
|
|
break;
|
|
case 27:
|
|
CleanUp();
|
|
exit(0);
|
|
break;
|
|
}
|
|
glutPostRedisplay();
|
|
}
|
|
|
|
int main( int argc, char *argv[] )
|
|
{
|
|
glutInit( &argc, argv );
|
|
glutInitWindowPosition( 0, 0 );
|
|
glutInitWindowSize( 250, 250 );
|
|
glutInitDisplayMode( GLUT_RGB | GLUT_SINGLE | GLUT_DEPTH );
|
|
glutCreateWindow(argv[argc-1]);
|
|
glewInit();
|
|
glutReshapeFunc( Reshape );
|
|
glutKeyboardFunc( Key );
|
|
glutDisplayFunc( Display );
|
|
args( argc, argv );
|
|
prepare_shaders();
|
|
glutMainLoop();
|
|
return 0;
|
|
}
|