I report the bug about Color handling of glRasterPos.
As you know, glRasterPos memories RasterColor through shade.c:gl_shade_rastpos
function. When lighting is enabled, rgba value is calcurated and stored as
float [0, 1].
Sometimes, calcurated color values become over 1.0.
glBitmap function does not check if RasterColor is in range [0, 1],
so image is drawn with strange color.
This problem seems in MesaCVS.tar.gz and cvs -r mesa_3_2.
I created test program and patch. patch is for src/shade.c
Regards,
Takashi Matsuda
[EMAIL PROTECTED]
TEST PROGRAM:
--------------8<----------------------8<---------------------8<------------
#include <stdio.h>
#include <GL/gl.h>
#include <GL/glut.h>
static GLenum __gl_error;
#define GL_CHECK(expr) \
{ \
expr; \
if ((__gl_error = glGetError ()) != GL_NO_ERROR) { \
fprintf (stderr, "%s:%d (%s): OpenGL error: %s", \
__FILE__, \
__LINE__, \
__PRETTY_FUNCTION__, \
gluErrorString (__gl_error)); \
} \
}
#define FADE_IN_INTERVAL 100
static int time = 0;
static int fade_in_time = 2000;
static GLfloat diffuse [4] = {1, 1, 1, 1};
static GLubyte rasters [24] = {
0xc0, 0x00, 0xc0, 0x00, 0xc0, 0x00, 0xc0, 0x00, 0xc0, 0x00,
0xff, 0x00, 0xff, 0x00, 0xc0, 0x00, 0xc0, 0x00, 0xc0, 0x00,
0xff, 0xc0, 0xff, 0xc0
};
static void display (void)
{
GL_CHECK (glEnable (GL_COLOR_MATERIAL));
GL_CHECK (glEnable (GL_LIGHTING));
GL_CHECK (glEnable (GL_LIGHT0));
GL_CHECK(glClearColor (0, 0, 0, 1));
GL_CHECK(glClear (GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT));
GL_CHECK(glMatrixMode (GL_PROJECTION));
GL_CHECK(glLoadIdentity ());
GL_CHECK(glOrtho (-1, 1, -1, 1, -1, 1));
GL_CHECK(glMatrixMode (GL_MODELVIEW));
GL_CHECK(glLoadIdentity ());
GL_CHECK(glPixelStorei (GL_UNPACK_ALIGNMENT, 1));
GL_CHECK(glColor3f (1, 1, 1));
GL_CHECK(glRasterPos2i (0, 0));
GL_CHECK(glBitmap (10, 12, 0, 0, 11, 0, rasters));
GL_CHECK(glFlush ());
GL_CHECK(glutSwapBuffers ());
}
static void reshape (int width, int height)
{
GL_CHECK(glViewport (0, 0, width, height));
glutPostRedisplay ();
}
static void keyboard (unsigned char key, int x, int y)
{
if (key == 27) {
exit (0);
}
}
static void timer (int value)
{
GLfloat f[4];
float scale;
scale = (double)(time) / fade_in_time;
f[0] = scale * diffuse[0];
f[1] = scale * diffuse[1];
f[2] = scale * diffuse[2];
f[3] = diffuse[3];
glLightfv (GL_LIGHT0, GL_DIFFUSE, f);
time += FADE_IN_INTERVAL;
if (time <= fade_in_time) {
glutTimerFunc (FADE_IN_INTERVAL, timer, value);
}
glutPostRedisplay ();
}
int main (int argc, char **argv)
{
glutInit (&argc, argv);
glutInitDisplayMode (GLUT_RGBA | GLUT_DOUBLE | GLUT_DEPTH);
glutCreateWindow ("testgl");
glutDisplayFunc (display);
glutReshapeFunc (reshape);
glutKeyboardFunc (keyboard);
timer (0);
glutMainLoop ();
return 0;
}
PATCH:
--------------8<----------------------8<---------------------8<------------
*** shade.c.old Tue Nov 9 00:29:57 1999
--- shade.c Sun Nov 28 02:42:22 1999
***************
*** 354,360 ****
--- 354,367 ----
}
if (ctx->Visual->RGBAflag) {
+ #if 1
+ Rcolor[0] = CLAMP( color[0], 0.0F, 1.0F );
+ Rcolor[1] = CLAMP( color[1], 0.0F, 1.0F );
+ Rcolor[2] = CLAMP( color[2], 0.0F, 1.0F );
+ Rcolor[3] = CLAMP( color[3], 0.0F, 1.0F );
+ #else
COPY_4FV(Rcolor, color);
+ #endif
} else {
GLfloat ind;
struct gl_material *mat = &ctx->Light.Material[0];
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_______________________________________________
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