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authorBrian <brian.paul@tungstengraphics.com>2007-07-11 13:11:47 -0600
committerBrian <brian.paul@tungstengraphics.com>2007-07-11 16:20:32 -0600
commit34f6243beff6a66a76814638db68897eb719dd30 (patch)
tree86d661e3b51c15c91f00b16de6e732b14fae1350 /progs/xdemos
parentee7fece05462e3cc00b4f24069748c1401fcacef (diff)
Improve this demo in a few ways.
1. Use more reasonable hither/yon clip planes to make better use of shallow (16-bit) z buffers. 2. Use different colors on cube faces to help detect Z fighting if it occurs. 3. Report GL_DEPTH_BITS on start-up.
Diffstat (limited to 'progs/xdemos')
-rw-r--r--progs/xdemos/offset.c34
1 files changed, 22 insertions, 12 deletions
diff --git a/progs/xdemos/offset.c b/progs/xdemos/offset.c
index 3e92e68daa..0ad9147aea 100644
--- a/progs/xdemos/offset.c
+++ b/progs/xdemos/offset.c
@@ -71,12 +71,12 @@ typedef Vertex Quad[4];
/* data to define the six faces of a unit cube */
Quad quads[MAXQUAD] = {
- { {0,0,0}, {1,0,0}, {1,1,0}, {0,1,0} },
- { {0,0,1}, {1,0,1}, {1,1,1}, {0,1,1} },
- { {0,0,0}, {1,0,0}, {1,0,1}, {0,0,1} },
- { {0,1,0}, {1,1,0}, {1,1,1}, {0,1,1} },
- { {0,0,0}, {0,0,1}, {0,1,1}, {0,1,0} },
- { {1,0,0}, {1,0,1}, {1,1,1}, {1,1,0} }
+ { {0,0,0}, {0,0,1}, {0,1,1}, {0,1,0} }, /* x = 0 */
+ { {0,0,0}, {1,0,0}, {1,0,1}, {0,0,1} }, /* y = 0 */
+ { {0,0,0}, {1,0,0}, {1,1,0}, {0,1,0} }, /* z = 0 */
+ { {1,0,0}, {1,0,1}, {1,1,1}, {1,1,0} }, /* x = 1 */
+ { {0,1,0}, {1,1,0}, {1,1,1}, {0,1,1} }, /* y = 1 */
+ { {0,0,1}, {1,0,1}, {1,1,1}, {0,1,1} } /* z = 1 */
};
#define WIREFRAME 0
@@ -86,7 +86,7 @@ static void error(const char* prog, const char* msg);
static void cubes(int mx, int my, int mode);
static void fill(Quad quad);
static void outline(Quad quad);
-static void draw_hidden(Quad quad, int mode);
+static void draw_hidden(Quad quad, int mode, int face);
static void process_input(Display *dpy, Window win);
static int query_extension(char* extName);
@@ -101,6 +101,7 @@ int main(int argc, char** argv) {
XSetWindowAttributes swa;
Window win;
GLXContext cx;
+ GLint z;
dpy = XOpenDisplay(0);
if (!dpy) error(argv[0], "can't open display");
@@ -134,13 +135,16 @@ int main(int argc, char** argv) {
/* set up viewing parameters */
glMatrixMode(GL_PROJECTION);
- gluPerspective(20, 1, 0.1, 20);
+ gluPerspective(20, 1, 10, 20);
glMatrixMode(GL_MODELVIEW);
glTranslatef(0, 0, -15);
/* set other relevant state information */
glEnable(GL_DEPTH_TEST);
+ glGetIntegerv(GL_DEPTH_BITS, &z);
+ printf("GL_DEPTH_BITS = %d\n", z);
+
#ifdef GL_EXT_polygon_offset
printf("using 1.0 offset extension\n");
glPolygonOffsetEXT( 1.0, 0.00001 );
@@ -160,6 +164,7 @@ int main(int argc, char** argv) {
static void
draw_scene(int mx, int my) {
+ glClearColor(0.25, 0.25, 0.25, 0);
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glPushMatrix();
@@ -206,7 +211,7 @@ cubes(int mx, int my, int mode) {
glTranslatef(x, y, z);
glScalef(0.8, 0.8, 0.8);
for (i = 0; i < MAXQUAD; i++)
- draw_hidden(quads[i], mode);
+ draw_hidden(quads[i], mode, i);
glPopMatrix();
}
}
@@ -236,13 +241,18 @@ outline(Quad quad) {
}
static void
-draw_hidden(Quad quad, int mode) {
+draw_hidden(Quad quad, int mode, int face) {
+ static const GLfloat colors[3][3] = {
+ {0.5, 0.5, 0.0},
+ {0.8, 0.5, 0.0},
+ {0.0, 0.5, 0.8}
+ };
if (mode == HIDDEN_LINE) {
- glColor3f(0, 0, 0);
+ glColor3fv(colors[face % 3]);
fill(quad);
}
- /* draw the outline using white, optionally fill the interior with black */
+ /* draw the outline using white */
glColor3f(1, 1, 1);
outline(quad);
}