| |
| /* Draw test patterns to help determine correct gamma value for a display. |
| When the intensities of the inner squares nearly match the intensities |
| of their frames (from some distance the borders should disappear) then |
| you've found the right gamma value. |
| |
| You can set Mesa's gamma values (for red, green and blue) with the |
| MESA_GAMMA environment variable. But only on X windows! |
| For example: |
| setenv MESA_GAMMA 1.5 1.6 1.4 |
| Sets the red gamma value to 1.5, green to 1.6 and blue to 1.4. |
| See the main README file for more information. |
| |
| For more info about gamma correction see: |
| http://www.inforamp.net/~poynton/notes/colour_and_gamma/GammaFAQ.html |
| |
| This program is in the public domain |
| |
| Brian Paul 19 Oct 1995 |
| Kai Schuetz 05 Jun 1999 */ |
| |
| /* Conversion to GLUT by Mark J. Kilgard */ |
| |
| |
| #include <stdio.h> |
| #include <string.h> |
| #include <stdlib.h> |
| #include <GL/glut.h> |
| |
| static void |
| Reshape(int width, int height) |
| { |
| glViewport(0, 0, (GLint) width, (GLint) height); |
| |
| glMatrixMode(GL_PROJECTION); |
| glLoadIdentity(); |
| glOrtho(-1.0, 1.0, -1.0, 1.0, -1.0, 1.0); |
| glMatrixMode(GL_MODELVIEW); |
| glShadeModel(GL_FLAT); |
| } |
| |
| /* ARGSUSED1 */ |
| static void |
| key_esc(unsigned char key, int x, int y) |
| { |
| if(key == 27) exit(0); /* Exit on Escape */ |
| } |
| |
| static GLubyte p25[] = { |
| 0xaa, 0xaa, 0xaa, 0xaa, 0x00, 0x00, 0x00, 0x00, |
| 0xaa, 0xaa, 0xaa, 0xaa, 0x00, 0x00, 0x00, 0x00, |
| 0xaa, 0xaa, 0xaa, 0xaa, 0x00, 0x00, 0x00, 0x00, |
| 0xaa, 0xaa, 0xaa, 0xaa, 0x00, 0x00, 0x00, 0x00, |
| 0xaa, 0xaa, 0xaa, 0xaa, 0x00, 0x00, 0x00, 0x00, |
| 0xaa, 0xaa, 0xaa, 0xaa, 0x00, 0x00, 0x00, 0x00, |
| 0xaa, 0xaa, 0xaa, 0xaa, 0x00, 0x00, 0x00, 0x00, |
| 0xaa, 0xaa, 0xaa, 0xaa, 0x00, 0x00, 0x00, 0x00, |
| 0xaa, 0xaa, 0xaa, 0xaa, 0x00, 0x00, 0x00, 0x00, |
| 0xaa, 0xaa, 0xaa, 0xaa, 0x00, 0x00, 0x00, 0x00, |
| 0xaa, 0xaa, 0xaa, 0xaa, 0x00, 0x00, 0x00, 0x00, |
| 0xaa, 0xaa, 0xaa, 0xaa, 0x00, 0x00, 0x00, 0x00, |
| 0xaa, 0xaa, 0xaa, 0xaa, 0x00, 0x00, 0x00, 0x00, |
| 0xaa, 0xaa, 0xaa, 0xaa, 0x00, 0x00, 0x00, 0x00, |
| 0xaa, 0xaa, 0xaa, 0xaa, 0x00, 0x00, 0x00, 0x00, |
| 0xaa, 0xaa, 0xaa, 0xaa, 0x00, 0x00, 0x00, 0x00, |
| }; |
| |
| static GLubyte p50[] = { |
| 0xaa, 0xaa, 0xaa, 0xaa, 0x55, 0x55, 0x55, 0x55, |
| 0xaa, 0xaa, 0xaa, 0xaa, 0x55, 0x55, 0x55, 0x55, |
| 0xaa, 0xaa, 0xaa, 0xaa, 0x55, 0x55, 0x55, 0x55, |
| 0xaa, 0xaa, 0xaa, 0xaa, 0x55, 0x55, 0x55, 0x55, |
| 0xaa, 0xaa, 0xaa, 0xaa, 0x55, 0x55, 0x55, 0x55, |
| 0xaa, 0xaa, 0xaa, 0xaa, 0x55, 0x55, 0x55, 0x55, |
| 0xaa, 0xaa, 0xaa, 0xaa, 0x55, 0x55, 0x55, 0x55, |
| 0xaa, 0xaa, 0xaa, 0xaa, 0x55, 0x55, 0x55, 0x55, |
| 0xaa, 0xaa, 0xaa, 0xaa, 0x55, 0x55, 0x55, 0x55, |
| 0xaa, 0xaa, 0xaa, 0xaa, 0x55, 0x55, 0x55, 0x55, |
| 0xaa, 0xaa, 0xaa, 0xaa, 0x55, 0x55, 0x55, 0x55, |
| 0xaa, 0xaa, 0xaa, 0xaa, 0x55, 0x55, 0x55, 0x55, |
| 0xaa, 0xaa, 0xaa, 0xaa, 0x55, 0x55, 0x55, 0x55, |
| 0xaa, 0xaa, 0xaa, 0xaa, 0x55, 0x55, 0x55, 0x55, |
| 0xaa, 0xaa, 0xaa, 0xaa, 0x55, 0x55, 0x55, 0x55, |
| 0xaa, 0xaa, 0xaa, 0xaa, 0x55, 0x55, 0x55, 0x55, |
| }; |
| |
| static GLubyte p75[] = { |
| 0xaa, 0xaa, 0xaa, 0xaa, 0xff, 0xff, 0xff, 0xff, |
| 0xaa, 0xaa, 0xaa, 0xaa, 0xff, 0xff, 0xff, 0xff, |
| 0xaa, 0xaa, 0xaa, 0xaa, 0xff, 0xff, 0xff, 0xff, |
| 0xaa, 0xaa, 0xaa, 0xaa, 0xff, 0xff, 0xff, 0xff, |
| 0xaa, 0xaa, 0xaa, 0xaa, 0xff, 0xff, 0xff, 0xff, |
| 0xaa, 0xaa, 0xaa, 0xaa, 0xff, 0xff, 0xff, 0xff, |
| 0xaa, 0xaa, 0xaa, 0xaa, 0xff, 0xff, 0xff, 0xff, |
| 0xaa, 0xaa, 0xaa, 0xaa, 0xff, 0xff, 0xff, 0xff, |
| 0xaa, 0xaa, 0xaa, 0xaa, 0xff, 0xff, 0xff, 0xff, |
| 0xaa, 0xaa, 0xaa, 0xaa, 0xff, 0xff, 0xff, 0xff, |
| 0xaa, 0xaa, 0xaa, 0xaa, 0xff, 0xff, 0xff, 0xff, |
| 0xaa, 0xaa, 0xaa, 0xaa, 0xff, 0xff, 0xff, 0xff, |
| 0xaa, 0xaa, 0xaa, 0xaa, 0xff, 0xff, 0xff, 0xff, |
| 0xaa, 0xaa, 0xaa, 0xaa, 0xff, 0xff, 0xff, 0xff, |
| 0xaa, 0xaa, 0xaa, 0xaa, 0xff, 0xff, 0xff, 0xff, |
| 0xaa, 0xaa, 0xaa, 0xaa, 0xff, 0xff, 0xff, 0xff, |
| }; |
| |
| static GLubyte *stippletab[4] = {NULL, p25, p50, p75}; |
| |
| static void |
| gamma_ramp(GLfloat yoffs, GLfloat r, GLfloat g, GLfloat b) |
| { |
| GLint d; |
| |
| glColor3f(0.0, 0.0, 0.0); /* solid black, no stipple */ |
| glRectf(-1.0, yoffs, -0.6, yoffs + 0.5); |
| |
| for(d = 1; d < 4; d++) { /* increasing density from 25% to 75% */ |
| GLfloat xcoord = (-1.0 + d*0.4); |
| GLfloat t = d * 0.25; |
| |
| glColor3f(r*t, g*t, b*t); /* draw outer rect */ |
| glRectf(xcoord, yoffs, xcoord+0.4, yoffs + 0.5); |
| |
| glColor3f(0.0, 0.0, 0.0); /* "clear" inner rect */ |
| glRectf(xcoord + 0.1, yoffs + 0.125, xcoord + 0.3, yoffs + 0.375); |
| |
| glColor3f(r, g, b); /* draw stippled inner rect */ |
| glEnable(GL_POLYGON_STIPPLE); |
| glPolygonStipple(stippletab[d]); |
| glRectf(xcoord + 0.1, yoffs + 0.125, xcoord + 0.3, yoffs + 0.375); |
| glDisable(GL_POLYGON_STIPPLE); |
| } |
| glColor3f(r, g, b); /* solid color, no stipple */ |
| glRectf(0.6, yoffs, 1.0, yoffs + 0.5); |
| } |
| |
| static void |
| display(void) |
| { |
| gamma_ramp( 0.5, 1.0, 1.0, 1.0); /* white ramp */ |
| gamma_ramp( 0.0, 1.0, 0.0, 0.0); /* red ramp */ |
| gamma_ramp(-0.5, 0.0, 1.0, 0.0); /* green ramp */ |
| gamma_ramp(-1.0, 0.0, 0.0, 1.0); /* blue ramp */ |
| glFlush(); |
| } |
| |
| int |
| main(int argc, char **argv) |
| { |
| glutInit(&argc, argv); |
| glutInitDisplayMode(GLUT_RGB | GLUT_SINGLE); |
| |
| glutInitWindowPosition(50, 50); |
| glutInitWindowSize(500, 400); |
| |
| glutCreateWindow("gamma test patterns"); |
| glutReshapeFunc(Reshape); |
| glutDisplayFunc(display); |
| glutKeyboardFunc(key_esc); |
| |
| glutMainLoop(); |
| return 0; /* ANSI C requires main to return int. */ |
| } |