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-rw-r--r--xc/extras/Mesa/demos/tessdemo.c422
1 files changed, 422 insertions, 0 deletions
diff --git a/xc/extras/Mesa/demos/tessdemo.c b/xc/extras/Mesa/demos/tessdemo.c
new file mode 100644
index 000000000..d11616e01
--- /dev/null
+++ b/xc/extras/Mesa/demos/tessdemo.c
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+/* $Id: tessdemo.c,v 1.1.1.1 2000/12/05 16:38:38 dawes Exp $ */
+
+/*
+ * A demo of the GLU polygon tesselation functions written by Bogdan Sikorski.
+ */
+
+
+#include <GL/glut.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#define MAX_POINTS 200
+#define MAX_CONTOURS 50
+
+static int menu;
+typedef enum
+{ QUIT, TESSELATE, CLEAR }
+menu_entries;
+
+typedef enum
+{ DEFINE, TESSELATED }
+mode_type;
+
+struct
+{
+ GLint p[MAX_POINTS][2];
+ GLuint point_cnt;
+}
+contours[MAX_CONTOURS];
+
+static GLuint contour_cnt;
+static GLsizei width, height;
+static mode_type mode;
+
+struct
+{
+ GLsizei no;
+ GLfloat color[3];
+ GLint p[3][2];
+ GLclampf p_color[3][3];
+}
+triangle;
+
+
+static void GLCALLBACK
+my_error(GLenum err)
+{
+ int len, i;
+ char const *str;
+
+ glColor3f(0.9, 0.9, 0.9);
+ glRasterPos2i(5, 5);
+ str = (const char *) gluErrorString(err);
+ len = strlen(str);
+ for (i = 0; i < len; i++)
+ glutBitmapCharacter(GLUT_BITMAP_9_BY_15, str[i]);
+}
+
+
+static void GLCALLBACK
+begin_callback(GLenum mode)
+{
+ triangle.no = 0;
+}
+
+
+static void GLCALLBACK
+edge_callback(GLenum flag)
+{
+ if (flag == GL_TRUE) {
+ triangle.color[0] = 1.0;
+ triangle.color[1] = 1.0;
+ triangle.color[2] = 0.5;
+ }
+ else {
+ triangle.color[0] = 1.0;
+ triangle.color[1] = 0.0;
+ triangle.color[2] = 0.0;
+ }
+}
+
+
+static void GLCALLBACK
+end_callback()
+{
+ glBegin(GL_LINES);
+ glColor3f(triangle.p_color[0][0], triangle.p_color[0][1],
+ triangle.p_color[0][2]);
+ glVertex2i(triangle.p[0][0], triangle.p[0][1]);
+ glVertex2i(triangle.p[1][0], triangle.p[1][1]);
+ glColor3f(triangle.p_color[1][0], triangle.p_color[1][1],
+ triangle.p_color[1][2]);
+ glVertex2i(triangle.p[1][0], triangle.p[1][1]);
+ glVertex2i(triangle.p[2][0], triangle.p[2][1]);
+ glColor3f(triangle.p_color[2][0], triangle.p_color[2][1],
+ triangle.p_color[2][2]);
+ glVertex2i(triangle.p[2][0], triangle.p[2][1]);
+ glVertex2i(triangle.p[0][0], triangle.p[0][1]);
+ glEnd();
+}
+
+
+static void GLCALLBACK
+vertex_callback(void *data)
+{
+ GLsizei no;
+ GLint *p;
+
+ p = (GLint *) data;
+ no = triangle.no;
+ triangle.p[no][0] = p[0];
+ triangle.p[no][1] = p[1];
+ triangle.p_color[no][0] = triangle.color[0];
+ triangle.p_color[no][1] = triangle.color[1];
+ triangle.p_color[no][2] = triangle.color[2];
+ ++(triangle.no);
+}
+
+
+static void
+set_screen_wh(GLsizei w, GLsizei h)
+{
+ width = w;
+ height = h;
+}
+
+
+static void
+tesse(void)
+{
+ GLUtriangulatorObj *tobj;
+ GLdouble data[3];
+ GLuint i, j, point_cnt;
+
+ tobj = gluNewTess();
+ if (tobj != NULL) {
+ glClear(GL_COLOR_BUFFER_BIT);
+ glColor3f(0.7, 0.7, 0.0);
+ gluTessCallback(tobj, GLU_BEGIN, glBegin);
+ gluTessCallback(tobj, GLU_END, glEnd);
+ gluTessCallback(tobj, GLU_ERROR, my_error);
+ gluTessCallback(tobj, GLU_VERTEX, glVertex2iv);
+ gluBeginPolygon(tobj);
+ for (j = 0; j <= contour_cnt; j++) {
+ point_cnt = contours[j].point_cnt;
+ gluNextContour(tobj, GLU_UNKNOWN);
+ for (i = 0; i < point_cnt; i++) {
+ data[0] = (GLdouble) (contours[j].p[i][0]);
+ data[1] = (GLdouble) (contours[j].p[i][1]);
+ data[2] = 0.0;
+ gluTessVertex(tobj, data, contours[j].p[i]);
+ }
+ }
+ gluEndPolygon(tobj);
+ glLineWidth(2.0);
+ gluTessCallback(tobj, GLU_BEGIN, begin_callback);
+ gluTessCallback(tobj, GLU_END, end_callback);
+ gluTessCallback(tobj, GLU_VERTEX, vertex_callback);
+ gluTessCallback(tobj, GLU_EDGE_FLAG, edge_callback);
+ gluBeginPolygon(tobj);
+ for (j = 0; j <= contour_cnt; j++) {
+ point_cnt = contours[j].point_cnt;
+ gluNextContour(tobj, GLU_UNKNOWN);
+ for (i = 0; i < point_cnt; i++) {
+ data[0] = (GLdouble) (contours[j].p[i][0]);
+ data[1] = (GLdouble) (contours[j].p[i][1]);
+ data[2] = 0.0;
+ gluTessVertex(tobj, data, contours[j].p[i]);
+ }
+ }
+ gluEndPolygon(tobj);
+ gluDeleteTess(tobj);
+ glutMouseFunc(NULL);
+ glColor3f(1.0, 1.0, 0.0);
+ glLineWidth(1.0);
+ mode = TESSELATED;
+ }
+}
+
+
+static void
+left_down(int x1, int y1)
+{
+ GLint P[2];
+ GLuint point_cnt;
+
+ /* translate GLUT into GL coordinates */
+ P[0] = x1;
+ P[1] = height - y1;
+ point_cnt = contours[contour_cnt].point_cnt;
+ contours[contour_cnt].p[point_cnt][0] = P[0];
+ contours[contour_cnt].p[point_cnt][1] = P[1];
+ glBegin(GL_LINES);
+ if (point_cnt) {
+ glVertex2iv(contours[contour_cnt].p[point_cnt - 1]);
+ glVertex2iv(P);
+ }
+ else {
+ glVertex2iv(P);
+ glVertex2iv(P);
+ }
+ glEnd();
+ glFinish();
+ ++(contours[contour_cnt].point_cnt);
+}
+
+
+static void
+middle_down(int x1, int y1)
+{
+ GLuint point_cnt;
+
+ point_cnt = contours[contour_cnt].point_cnt;
+ if (point_cnt > 2) {
+ glBegin(GL_LINES);
+ glVertex2iv(contours[contour_cnt].p[0]);
+ glVertex2iv(contours[contour_cnt].p[point_cnt - 1]);
+ contours[contour_cnt].p[point_cnt][0] = -1;
+ glEnd();
+ glFinish();
+ contour_cnt++;
+ contours[contour_cnt].point_cnt = 0;
+ }
+}
+
+
+static void
+mouse_clicked(int button, int state, int x, int y)
+{
+ x -= x % 10;
+ y -= y % 10;
+ switch (button) {
+ case GLUT_LEFT_BUTTON:
+ if (state == GLUT_DOWN)
+ left_down(x, y);
+ break;
+ case GLUT_MIDDLE_BUTTON:
+ if (state == GLUT_DOWN)
+ middle_down(x, y);
+ break;
+ }
+}
+
+
+static void
+display(void)
+{
+ GLuint i, j;
+ GLuint point_cnt;
+
+ glClear(GL_COLOR_BUFFER_BIT);
+ switch (mode) {
+ case DEFINE:
+ /* draw grid */
+ glColor3f(0.6, 0.5, 0.5);
+ glBegin(GL_LINES);
+ for (i = 0; i < width; i += 10)
+ for (j = 0; j < height; j += 10) {
+ glVertex2i(0, j);
+ glVertex2i(width, j);
+ glVertex2i(i, height);
+ glVertex2i(i, 0);
+ }
+ glEnd();
+ glColor3f(1.0, 1.0, 0.0);
+ for (i = 0; i <= contour_cnt; i++) {
+ point_cnt = contours[i].point_cnt;
+ glBegin(GL_LINES);
+ switch (point_cnt) {
+ case 0:
+ break;
+ case 1:
+ glVertex2iv(contours[i].p[0]);
+ glVertex2iv(contours[i].p[0]);
+ break;
+ case 2:
+ glVertex2iv(contours[i].p[0]);
+ glVertex2iv(contours[i].p[1]);
+ break;
+ default:
+ --point_cnt;
+ for (j = 0; j < point_cnt; j++) {
+ glVertex2iv(contours[i].p[j]);
+ glVertex2iv(contours[i].p[j + 1]);
+ }
+ if (contours[i].p[j + 1][0] == -1) {
+ glVertex2iv(contours[i].p[0]);
+ glVertex2iv(contours[i].p[j]);
+ }
+ break;
+ }
+ glEnd();
+ }
+ glFinish();
+ break;
+ case TESSELATED:
+ /* draw lines */
+ tesse();
+ break;
+ }
+
+ glColor3f(1.0, 1.0, 0.0);
+}
+
+
+static void
+clear(void)
+{
+ contour_cnt = 0;
+ contours[0].point_cnt = 0;
+ glutMouseFunc(mouse_clicked);
+ mode = DEFINE;
+ display();
+}
+
+
+static void
+quit(void)
+{
+ exit(0);
+}
+
+
+static void
+menu_selected(int entry)
+{
+ switch (entry) {
+ case CLEAR:
+ clear();
+ break;
+ case TESSELATE:
+ tesse();
+ break;
+ case QUIT:
+ quit();
+ break;
+ }
+}
+
+
+static void
+key_pressed(unsigned char key, int x, int y)
+{
+ switch (key) {
+ case 't':
+ case 'T':
+ tesse();
+ glFinish();
+ break;
+ case 'q':
+ case 'Q':
+ quit();
+ break;
+ case 'c':
+ case 'C':
+ clear();
+ break;
+ }
+}
+
+
+static void
+myinit(void)
+{
+/* clear background to gray */
+ glClearColor(0.4, 0.4, 0.4, 0.0);
+ glShadeModel(GL_FLAT);
+
+ menu = glutCreateMenu(menu_selected);
+ glutAddMenuEntry("clear", CLEAR);
+ glutAddMenuEntry("tesselate", TESSELATE);
+ glutAddMenuEntry("quit", QUIT);
+ glutAttachMenu(GLUT_RIGHT_BUTTON);
+ glutMouseFunc(mouse_clicked);
+ glutKeyboardFunc(key_pressed);
+ contour_cnt = 0;
+ glPolygonMode(GL_FRONT, GL_FILL);
+ mode = DEFINE;
+}
+
+
+static void
+reshape(GLsizei w, GLsizei h)
+{
+ glViewport(0, 0, w, h);
+ glMatrixMode(GL_PROJECTION);
+ glLoadIdentity();
+ glOrtho(0.0, (GLdouble) w, 0.0, (GLdouble) h, -1.0, 1.0);
+ glMatrixMode(GL_MODELVIEW);
+ glLoadIdentity();
+ set_screen_wh(w, h);
+}
+
+
+static void
+usage(void)
+{
+ printf("Use left mouse button to place vertices.\n");
+ printf("Press middle mouse button when done.\n");
+ printf("Select tesselate from the pop-up menu.\n");
+}
+
+
+/* Main Loop
+ * Open window with initial window size, title bar,
+ * RGBA display mode, and handle input events.
+ */
+int
+main(int argc, char **argv)
+{
+ usage();
+ glutInit(&argc, argv);
+ glutInitDisplayMode(GLUT_SINGLE | GLUT_RGB);
+ glutInitWindowSize(400, 400);
+ glutCreateWindow(argv[0]);
+ myinit();
+ glutDisplayFunc(display);
+ glutReshapeFunc(reshape);
+ glutMainLoop();
+ return 0;
+}
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