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