Since we now have antialiasing it is more important to set your gamma-value
right - only then line will look really smooth.
I improved gamma.c a bit, which can be used to tune your gamma values:
- stippled patterns are now drawn as a small squares inside the homogenous ones
- this makes it easier to compare them
- additional to the white ramp red green and blue ramps are drawn, so you can
easily tune all three gamma values
Here comes the diff:
========================================================================
4,6c4,7
< When the intensities in the top row nearly match the intensities in
< the bottom row you've found the right gamma value.
<
---
> 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.
>
12c13,14
< Brian Paul 19 Oct 1995 */
---
> Brian Paul 19 Oct 1995
> Kai Schuetz 05 Jun 1999 */
107,121c109
< static void
< display(void)
< {
<
< glClear(GL_COLOR_BUFFER_BIT);
<
< /** DITHERED ROW **/
<
< /* solid black */
<
< /* 25% white */
< glEnable(GL_POLYGON_STIPPLE);
< glColor3f(1.0, 1.0, 1.0);
< glPolygonStipple(p25);
< glRectf(-0.6, 1.0, -0.2, 0.01);
---
> static GLubyte *stippletab[4]={NULL, p25, p50, p75};
123,135c111,114
< /* 50% white */
< glPolygonStipple(p50);
< glRectf(-0.2, 1.0, 0.2, 0.01);
<
< /* 75% white */
< glPolygonStipple(p75);
< glRectf(0.2, 1.0, 0.6, 0.01);
<
< /* 100% white */
< glDisable(GL_POLYGON_STIPPLE);
< glRectf(0.6, 1.0, 1.0, 0.01);
<
< /*** GRAY ROW ***/
---
> static void
> gamma_ramp(GLfloat yoffs, GLfloat r, GLfloat g, GLfloat b)
> {
> GLint d;
137c116,117
< /* solid black */
---
> glColor3f(0.0, 0.0, 0.0); /* solid black, no stipple */
> glRectf(-1.0, yoffs, -0.6, yoffs + 0.5);
139,141c119,120
< /* 25% white */
< glColor3f(0.25, 0.25, 0.25);
< glRectf(-0.6, -0.01, -0.2, -1.0);
---
> for(d=1; d < 4; d++) { /* increasing density from 25% to 75% */
> GLfloat xcoord=(-1.0 + d*0.4);
143,145c122,123
< /* 50% white */
< glColor3f(0.5, 0.5, 0.5);
< glRectf(-0.2, -0.01, 0.2, -1.0);
---
> glColor3f(r*d / 5.0, g*d / 5.0, b*d / 5.0); /* draw outer rect */
> glRectf(xcoord, yoffs, xcoord+0.4, yoffs + 0.5);
147,149c125,126
< /* 75% white */
< glColor3f(0.75, 0.75, 0.75);
< glRectf(0.2, -0.01, 0.6, -1.0);
---
> glColor3f(0.0, 0.0, 0.0); /* "clear" inner rect */
> glRectf(xcoord + 0.1, yoffs + 0.125, xcoord + 0.3, yoffs + 0.375);
151,153c128,136
< /* 100% white */
< glColor3f(1.0, 1.0, 1.0);
< glRectf(0.6, -0.01, 1.0, -1.0);
---
> 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);
> }
154a138,144
> 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 */
165c155
< glutInitWindowSize(400, 200);
---
> glutInitWindowSize(500, 400);
==========================================================================
Hope you like it,
--
|/
|\ai
---------------------------------------------------------------------
Kai Schuetz
mailto:[EMAIL PROTECTED]
Hi, I'm not a signature virus. Why don't you just copy me into your
signature?
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