Attachment 7698 Details for Bug 7444 – Little GLUT app showing the problem

Little GLUT app showing the problem

mesa_bug.c (text/x-csrc), 2.06 KB, created by Cihan on 2006-11-07 10:48:56 UTC

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Creator: Cihan

Created: 2006-11-07 10:48:56 UTC

Size: 2.06 KB

patch

obsolete

>// demonstrates bug in Mesa where a black border appears on the right hand
>// side of the window.
>// Compile with:
>//
>// gcc -lglut mesa_bug.c -o mesa_bug
>//
>
>#include <stdlib.h> // for malloc
>#include <GL/glut.h>
>
>#define WIDTH 150
>#define HEIGHT 150
>
>unsigned char *pixels;
>
>void reshapeFunc(int w, int h)
>{
>	glViewport(0, 0, w, h);
>	glMatrixMode(GL_PROJECTION);
>	glLoadIdentity();
>	glOrtho(0.0f, w, h, 0.0f, 0.0f, 1.0f);
>	glMatrixMode(GL_MODELVIEW);
>}
>
>static void dispOpts(int align, int format, float zoomY)
>{
>	glClear(GL_COLOR_BUFFER_BIT);
>	glPixelZoom(1.0f, zoomY);
>	glPixelStorei(GL_UNPACK_ALIGNMENT, align);
>	glRasterPos2i(0, 0);
>	glDrawPixels(WIDTH, HEIGHT, format, GL_UNSIGNED_BYTE, pixels);
>	glutSwapBuffers();
>}
>
>// This combination exposes the bug
>// (Unpack alignment 1, format Luminance, vertical pixel zoom -1.0f)
>void dispFunc1(void)
>{
>	dispOpts(1, GL_LUMINANCE, -1.0f);
>}
>
>// Other format: works
>void dispFunc2(void)
>{
>	dispOpts(1, GL_RED, -1.0f);
>}
>
>// Other pixel zoom value: works
>void dispFunc3(void)
>{
>	dispOpts(1, GL_LUMINANCE, -1.0001f);
>}
>
>// Other alignment value: works
>void dispFunc4(void)
>{
>	dispOpts(2, GL_LUMINANCE, -1.0f);
>}
>
>
>int main(int argc, char** argv)
>{
>	int i, j;
>	unsigned char *ptr;
>
>	glutInit(&argc, argv);
>
>	pixels = (unsigned char *)malloc(WIDTH*HEIGHT);
>	ptr = pixels;
>
>	// create a simple gradient
>	for (i=0; i < HEIGHT; i++)
>		for (j=0; j < WIDTH; j++)
>			*(ptr++) = j;
>
>	glutInitDisplayMode(GLUT_RGB | GLUT_DOUBLE);
>	glutInitWindowSize(WIDTH, HEIGHT);
>
>	// Window 1
>	glutInitWindowPosition(100, 100);
>	glutCreateWindow("BUG");
>	glutDisplayFunc(dispFunc1);
>	glutReshapeFunc(reshapeFunc);
>
>	// Window 2
>	glutInitWindowPosition(200+WIDTH, 100);
>	glutCreateWindow("WORKS");
>	glutDisplayFunc(dispFunc2);
>	glutReshapeFunc(reshapeFunc);
>
>	// Window 3
>	glutInitWindowPosition(100, 200+HEIGHT);
>	glutCreateWindow("WORKS");
>	glutDisplayFunc(dispFunc3);
>	glutReshapeFunc(reshapeFunc);
>
>	// Window 4
>	glutInitWindowPosition(200+WIDTH, 200+HEIGHT);
>	glutCreateWindow("WORKS");
>	glutDisplayFunc(dispFunc4);
>	glutReshapeFunc(reshapeFunc);
>
>	glutMainLoop();
>
>	return 0;
>}
>

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