#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include <string.h>
#include <GL/glut.h>
#include "readtex.h"
#define IMAGE_FILE "../images/girl.rgb"
static int ImgWidth, ImgHeight;
static GLenum ImgFormat;
static GLubyte *Image = NULL;
static int Xpos, Ypos;
static int SkipPixels, SkipRows;
static int DrawWidth, DrawHeight;
static int Scissor = 0;
static int Fog = 0;
static GLfloat Zpos = -1.0;
static float Xzoom, Yzoom;
static GLboolean DrawFront = GL_FALSE;
static GLboolean Dither = GL_TRUE;
static void Reset( void )
{
Xpos = Ypos = 20;
DrawWidth = ImgWidth;
DrawHeight = ImgHeight;
SkipPixels = SkipRows = 0;
Scissor = 0;
Fog = 0;
Zpos = -1.0;
Xzoom = Yzoom = 1.0;
}
static void Display( void )
{
glClear( GL_COLOR_BUFFER_BIT );
#if 0
glRasterPos2i(Xpos, Ypos);
#else
glRasterPos3f(0, 0, Zpos);
glBitmap(0, 0, 0, 0, Xpos, Ypos, NULL);
#endif
glPixelStorei(GL_UNPACK_SKIP_PIXELS, SkipPixels);
glPixelStorei(GL_UNPACK_SKIP_ROWS, SkipRows);
glPixelZoom( Xzoom, Yzoom );
if (Scissor)
glEnable(GL_SCISSOR_TEST);
if (Fog)
glEnable(GL_FOG);
glDrawPixels(DrawWidth, DrawHeight, ImgFormat, GL_UNSIGNED_BYTE, Image);
glDisable(GL_SCISSOR_TEST);
glDisable(GL_FOG);
if (DrawFront)
glFinish();
else
glutSwapBuffers();
}
static void Benchmark( void )
{
int startTime, endTime;
int draws = 500;
double seconds, pixelsPerSecond;
printf("Benchmarking...\n");
glPixelStorei(GL_UNPACK_SKIP_PIXELS, SkipPixels);
glPixelStorei(GL_UNPACK_SKIP_ROWS, SkipRows);
glPixelZoom( Xzoom, Yzoom );
if (Scissor)
glEnable(GL_SCISSOR_TEST);
if (Fog)
glEnable(GL_FOG);
if (DrawFront)
glDrawBuffer(GL_FRONT);
else
glDrawBuffer(GL_BACK);
draws = 0;
startTime = glutGet(GLUT_ELAPSED_TIME);
do {
glDrawPixels(DrawWidth, DrawHeight, ImgFormat, GL_UNSIGNED_BYTE, Image);
draws++;
endTime = glutGet(GLUT_ELAPSED_TIME);
} while (endTime - startTime < 4000);
glDisable(GL_SCISSOR_TEST);
glDisable(GL_FOG);
seconds = (double) (endTime - startTime) / 1000.0;
pixelsPerSecond = draws * DrawWidth * DrawHeight / seconds;
printf("Result: %d draws in %f seconds = %f pixels/sec\n",
draws, seconds, pixelsPerSecond);
}
static void Reshape( int width, int height )
{
glViewport( 0, 0, width, height );
glMatrixMode( GL_PROJECTION );
glLoadIdentity();
glOrtho( 0.0, width, 0.0, height, 0.0, 2.0 );
glMatrixMode( GL_MODELVIEW );
glLoadIdentity();
glScissor(width/4, height/4, width/2, height/2);
}
static void Key( unsigned char key, int x, int y )
{
(void) x;
(void) y;
switch (key) {
case ' ':
Reset();
break;
case 'd':
Dither = !Dither;
if (Dither)
glEnable(GL_DITHER);
else
glDisable(GL_DITHER);
break;
case 'w':
if (DrawWidth > 0)
DrawWidth--;
break;
case 'W':
DrawWidth++;
break;
case 'h':
if (DrawHeight > 0)
DrawHeight--;
break;
case 'H':
DrawHeight++;
break;
case 'p':
if (SkipPixels > 0)
SkipPixels--;
break;
case 'P':
SkipPixels++;
break;
case 'r':
if (SkipRows > 0)
SkipRows--;
break;
case 'R':
SkipRows++;
break;
case 's':
Scissor = !Scissor;
break;
case 'x':
Xzoom -= 0.1;
break;
case 'X':
Xzoom += 0.1;
break;
case 'y':
Yzoom -= 0.1;
break;
case 'Y':
Yzoom += 0.1;
break;
case 'z':
Zpos -= 0.1;
printf("RasterPos Z = %g\n", Zpos);
break;
case 'Z':
Zpos += 0.1;
printf("RasterPos Z = %g\n", Zpos);
break;
case 'b':
Benchmark();
break;
case 'F':
Fog = !Fog;
printf("Fog %d\n", Fog);
break;
case 'f':
DrawFront = !DrawFront;
if (DrawFront)
glDrawBuffer(GL_FRONT);
else
glDrawBuffer(GL_BACK);
printf("glDrawBuffer(%s)\n", DrawFront ? "GL_FRONT" : "GL_BACK");
break;
case 27:
exit(0);
break;
}
glutPostRedisplay();
}
static void SpecialKey( int key, int x, int y )
{
(void) x;
(void) y;
switch (key) {
case GLUT_KEY_UP:
Ypos += 1;
break;
case GLUT_KEY_DOWN:
Ypos -= 1;
break;
case GLUT_KEY_LEFT:
Xpos -= 1;
break;
case GLUT_KEY_RIGHT:
Xpos += 1;
break;
}
glutPostRedisplay();
}
static void Init( GLboolean ciMode, const char *filename )
{
static const GLfloat fogColor[4] = {0, 1, 0, 0};
printf("GL_VERSION = %s\n", (char *) glGetString(GL_VERSION));
printf("GL_RENDERER = %s\n", (char *) glGetString(GL_RENDERER));
Image = LoadRGBImage( filename, &ImgWidth, &ImgHeight, &ImgFormat );
if (!Image) {
printf("Couldn't read %s\n", filename);
exit(0);
}
if (ciMode) {
GLubyte *indexImage = (GLubyte *) malloc( ImgWidth * ImgHeight );
GLint i;
for (i=0; i<ImgWidth*ImgHeight; i++) {
int gray = Image[i*3] + Image[i*3+1] + Image[i*3+2];
indexImage[i] = gray / 3;
}
free(Image);
Image = indexImage;
ImgFormat = GL_COLOR_INDEX;
for (i=0;i<255;i++) {
float g = i / 255.0;
glutSetColor(i, g, g, g);
}
}
printf("Loaded %d by %d image\n", ImgWidth, ImgHeight );
glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
glPixelStorei(GL_UNPACK_ROW_LENGTH, ImgWidth);
glFogi(GL_FOG_MODE, GL_LINEAR);
glFogf(GL_FOG_START, 0);
glFogf(GL_FOG_END, 2);
glFogfv(GL_FOG_COLOR, fogColor);
Reset();
}
static void Usage(void)
{
printf("Keys:\n");
printf(" SPACE Reset Parameters\n");
printf(" Up/Down Move image up/down\n");
printf(" Left/Right Move image left/right\n");
printf(" x Decrease X-axis PixelZoom\n");
printf(" X Increase X-axis PixelZoom\n");
printf(" y Decrease Y-axis PixelZoom\n");
printf(" Y Increase Y-axis PixelZoom\n");
printf(" w Decrease glDrawPixels width*\n");
printf(" W Increase glDrawPixels width*\n");
printf(" h Decrease glDrawPixels height*\n");
printf(" H Increase glDrawPixels height*\n");
printf(" p Decrease GL_UNPACK_SKIP_PIXELS*\n");
printf(" P Increase GL_UNPACK_SKIP_PIXELS*\n");
printf(" r Decrease GL_UNPACK_SKIP_ROWS*\n");
printf(" R Increase GL_UNPACK_SKIP_ROWS*\n");
printf(" s Toggle GL_SCISSOR_TEST\n");
printf(" F Toggle GL_FOG\n");
printf(" z Decrease RasterPos Z\n");
printf(" Z Increase RasterPos Z\n");
printf(" f Toggle front/back buffer drawing\n");
printf(" b Benchmark test\n");
printf(" ESC Exit\n");
printf("* Warning: no limits are imposed on these parameters so it's\n");
printf(" possible to cause a segfault if you go too far.\n");
}
int main( int argc, char *argv[] )
{
GLboolean ciMode = GL_FALSE;
const char *filename = IMAGE_FILE;
int i = 1;
if (argc > i && strcmp(argv[i], "-ci")==0) {
ciMode = GL_TRUE;
i++;
}
if (argc > i) {
filename = argv[i];
}
glutInit( &argc, argv );
glutInitWindowPosition( 0, 0 );
glutInitWindowSize( 500, 400 );
if (ciMode)
glutInitDisplayMode( GLUT_INDEX | GLUT_DOUBLE );
else
glutInitDisplayMode( GLUT_RGB | GLUT_DOUBLE);
glutCreateWindow(argv[0]);
Init(ciMode, filename);
Usage();
glutReshapeFunc( Reshape );
glutKeyboardFunc( Key );
glutSpecialFunc( SpecialKey );
glutDisplayFunc( Display );
glutMainLoop();
return 0;
}