Demos (master): line-sample: a new test that draws a sample of wide/ stipple/smooth lines

[Brian Paul]

Module: Demos
Branch: master
Commit: c8f52a8ea41264ae1963a89bd6f0ff2fd646d862
URL:    http://cgit.freedesktop.org/mesa/demos/commit/?id=c8f52a8ea41264ae1963a89bd6f0ff2fd646d862

Author: Brian Paul <brianp at vmware.com>
Date:   Fri Feb 13 17:59:40 2015 -0700

line-sample: a new test that draws a sample of wide/stipple/smooth lines

---

 src/tests/CMakeLists.txt |    1 +
 src/tests/Makefile.am    |    1 +
 src/tests/line-sample.c  |  187 ++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 189 insertions(+)

diff --git a/src/tests/CMakeLists.txt b/src/tests/CMakeLists.txt
index fe2c24b..5b4fb23 100644
--- a/src/tests/CMakeLists.txt
+++ b/src/tests/CMakeLists.txt
@@ -73,6 +73,7 @@ set (targets
 	invert
 	lineclip
 	linehacks
+	line-sample
 	manytex
 	mapbufrange
 	minmag
diff --git a/src/tests/Makefile.am b/src/tests/Makefile.am
index 8f40799..678295a 100644
--- a/src/tests/Makefile.am
+++ b/src/tests/Makefile.am
@@ -103,6 +103,7 @@ noinst_PROGRAMS = \
 	jkrahntest \
 	lineclip \
 	linehacks \
+	line-sample \
 	manytex \
 	mapbufrange \
 	minmag \
diff --git a/src/tests/line-sample.c b/src/tests/line-sample.c
new file mode 100644
index 0000000..d577d23
--- /dev/null
+++ b/src/tests/line-sample.c
@@ -0,0 +1,187 @@
+/*
+ * Draw samples of wide lines, smooth lines and stippled lines in
+ * all combinations.
+ *
+ * Brian Paul
+ * 13 Feb 2015
+ */
+
+
+#include <math.h>
+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+#include "glut_wrap.h"
+
+
+static int w, h;
+static float g, lw = 3.0;
+
+
+static void
+draw_line_sample(GLboolean smooth, GLboolean stipple, GLfloat width)
+{
+   float r0 = 0.4;
+   float r1 = 0.8;
+   float r2 = 0.9;
+   float r3 = 0.95;
+   int i;
+
+   glLineWidth(width);
+
+   if (stipple) {
+      glEnable(GL_LINE_STIPPLE);
+   }
+   else {
+      glDisable(GL_LINE_STIPPLE);
+   }
+
+   if (smooth) {
+      glEnable(GL_LINE_SMOOTH);
+      glEnable(GL_BLEND);
+    }
+   else {
+      glDisable(GL_LINE_SMOOTH);
+      glDisable(GL_BLEND);
+   }
+
+   /* spokes */
+   glBegin(GL_LINES);
+   for (i = 0; i < 360; i += 10) {
+      float x0 = r0 * cos(i * M_PI / 180.0);
+      float y0 = r0 * sin(i * M_PI / 180.0);
+      float x1 = r1 * cos(i * M_PI / 180.0);
+      float y1 = r1 * sin(i * M_PI / 180.0);
+
+      glVertex2f(x0, y0);
+      glVertex2f(x1, y1);
+   }
+   glEnd();
+
+   /* circle */
+   glBegin(GL_LINE_LOOP);
+   for (i = 0; i < 360; i += 10) {
+      float x = r2 * cos(i * M_PI / 180.0);
+      float y = r2 * sin(i * M_PI / 180.0);
+
+      glVertex2f(x, y);
+   }
+   glEnd();
+
+   /* box */
+   glBegin(GL_LINE_LOOP);
+   glVertex2f(-r3, -r3);
+   glVertex2f( r3, -r3);
+   glVertex2f( r3,  r3);
+   glVertex2f(-r3,  r3);
+   glEnd();
+}
+
+
+static void
+Init(void)
+{
+   GLfloat range[2];
+   char title[1000];
+
+   printf("GL_RENDERER = %s\n", (const char *) glGetString(GL_RENDERER));
+   printf("GL_VERSION = %s\n", (const char *) glGetString(GL_VERSION));
+
+   glGetFloatv(GL_ALIASED_LINE_WIDTH_RANGE, range);
+   printf("Aliased line width range %.5f .. %.5f\n", range[0], range[1]);
+   glGetFloatv(GL_LINE_WIDTH_RANGE, range);
+   printf("Smooth line width range %.5f .. %.5f\n", range[0], range[1]);
+   glGetFloatv(GL_LINE_WIDTH_GRANULARITY, &g);
+   printf("line width granularity %f\n", g);
+   fflush(stdout);
+
+   glClearColor(0.0, 0.0, 0.0, 0.0);
+   glShadeModel(GL_FLAT);
+   glBlendFunc(GL_SRC_ALPHA, GL_ONE);
+   /* pattern: |- -- --- ----   | */
+   glLineStipple(2, 0x1eed);
+
+   sprintf(title, "Line Sampler (%s)", (const char *) glGetString(GL_RENDERER));
+   glutSetWindowTitle(title);
+}
+
+
+static void
+Draw(void)
+{
+   int i;
+
+   glClear(GL_COLOR_BUFFER_BIT);
+
+   for (i = 0; i < 2; i++) {
+      float width = i ? lw : 1.0;
+      glViewport(0*w, i*h, w, h);
+      draw_line_sample(GL_FALSE, GL_FALSE, width);
+      glViewport(1*w, i*h, w, h);
+      draw_line_sample(GL_TRUE, GL_FALSE, width);
+      glViewport(2*w, i*h, w, h);
+      draw_line_sample(GL_FALSE, GL_TRUE, width);
+      glViewport(3*w, i*h, w, h);
+      draw_line_sample(GL_TRUE, GL_TRUE, width);
+   }
+
+    glutSwapBuffers();
+}
+
+
+static void
+Reshape(int width, int height)
+{
+   w = width / 4;
+   h = height / 2;
+   glMatrixMode(GL_PROJECTION);
+   glLoadIdentity();
+   glMatrixMode(GL_MODELVIEW);
+   glLoadIdentity();
+}
+
+
+static void
+Key(unsigned char key, int x, int y)
+{
+   if (key == 'w') {
+      lw -= g;
+      if (lw < g)
+         lw = g;
+   }
+   else if (key == 'W') {
+      lw += g;
+   }
+   if (key == 27)
+      exit(0);
+
+   printf("line width %.5f\n", lw);
+   fflush(stdout);
+
+   glutPostRedisplay();
+}
+
+
+int
+main(int argc, char **argv)
+{
+   glutInit(&argc, argv);
+
+   glutInitWindowPosition(0, 0);
+   glutInitWindowSize(1000, 500);
+
+   glutInitDisplayMode(GLUT_RGB | GLUT_DOUBLE);
+
+   if (!glutCreateWindow("Line Sampler")) {
+      exit(1);
+   }
+
+   Init();
+
+   glutReshapeFunc(Reshape);
+   glutKeyboardFunc(Key);
+   glutDisplayFunc(Draw);
+   glutMainLoop();
+
+   return 0;
+}