simple quad drawing test

1 files changed, 258 insertions, 0 deletions

diff --git a/progs/tests/quads.c b/progs/tests/quads.c
new file mode 100644
index 0000000..1bf57e6
--- /dev/null
+++ b/progs/tests/quads.c
@@ -0,0 +1,258 @@
+/**
+ * Draw colored quads.
+ */
+
+
+#define GL_GLEXT_PROTOTYPES
+#include <stdio.h>
+#include <stdlib.h>
+#include <math.h>
+#include <GL/glut.h>
+
+#define NUM_QUADS 20
+
+
+static int Win;
+static GLfloat Xrot = 40, Yrot = 0, Zrot = 0;
+static GLboolean Anim = GL_TRUE;
+static GLuint Vbuffer = 0;
+
+static GLfloat buf[NUM_QUADS * 6 * 4];
+
+static GLboolean SwapBuffers = GL_TRUE;
+
+static GLint Frames = 0, T0 = 0;
+
+
+static void
+Idle(void)
+{
+   Xrot += 3.0;
+   Yrot += 4.0;
+   Zrot += 2.0;
+   glutPostRedisplay();
+}
+
+
+static void
+Draw(void)
+{
+   glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
+
+   glPushMatrix();
+   glRotatef(Xrot, 1, 0, 0);
+   glRotatef(Yrot, 0, 1, 0);
+   glRotatef(Zrot, 0, 0, 1);
+
+   glDrawArrays(GL_QUADS, 0, NUM_QUADS*4);
+
+   glPopMatrix();
+
+   if (SwapBuffers)
+      glutSwapBuffers();
+   /*
+   else
+      glFinish();
+   */
+
+   {
+      GLint t = glutGet(GLUT_ELAPSED_TIME);
+      Frames++;
+      if (t - T0 >= 5000) {
+         GLfloat seconds = (t - T0) / 1000.0;
+         GLfloat fps = Frames / seconds;
+         printf("%d frames in %6.3f seconds = %6.3f FPS\n",
+                Frames, seconds, fps);
+         T0 = t;
+         Frames = 0;
+      }
+   }
+}
+
+
+static void
+Reshape(int width, int height)
+{
+   glViewport(0, 0, width, height);
+   glMatrixMode(GL_PROJECTION);
+   glLoadIdentity();
+   glFrustum(-1.0, 1.0, -1.0, 1.0, 5.0, 25.0);
+   glMatrixMode(GL_MODELVIEW);
+   glLoadIdentity();
+   glTranslatef(0.0, 0.0, -8.0);
+}
+
+
+static void
+Key(unsigned char key, int x, int y)
+{
+   const GLfloat step = 3.0;
+   (void) x;
+   (void) y;
+   switch (key) {
+      case 's':
+         SwapBuffers = !SwapBuffers;
+         break;
+      case 'a':
+         Anim = !Anim;
+         if (Anim)
+            glutIdleFunc(Idle);
+         else
+            glutIdleFunc(NULL);
+         break;
+      case 'z':
+         Zrot -= step;
+         break;
+      case 'Z':
+         Zrot += step;
+         break;
+      case 27:
+         glutDestroyWindow(Win);
+         exit(0);
+         break;
+   }
+   glutPostRedisplay();
+}
+
+
+static void
+SpecialKey(int key, int x, int y)
+{
+   const GLfloat step = 3.0;
+   (void) x;
+   (void) y;
+   switch (key) {
+      case GLUT_KEY_UP:
+         Xrot -= step;
+         break;
+      case GLUT_KEY_DOWN:
+         Xrot += step;
+         break;
+      case GLUT_KEY_LEFT:
+         Yrot -= step;
+         break;
+      case GLUT_KEY_RIGHT:
+         Yrot += step;
+         break;
+   }
+   glutPostRedisplay();
+}
+
+
+static void
+quad(float x, float y, float z, float *v)
+{
+   int k = 0;
+
+   /* color */
+   v[k++] = x * 0.5 + 0.5;
+   v[k++] = y * 0.5 + 0.5;
+   v[k++] = z * 0.5 + 0.5;
+   /* vert */
+   v[k++] = x;
+   v[k++] = y;
+   v[k++] = z;
+
+   /* color */
+   v[k++] = -x * 0.5 + 0.5;
+   v[k++] = -y * 0.5 + 0.5;
+   v[k++] = z * 0.5 + 0.5;
+   /* vert */
+   v[k++] = -x;
+   v[k++] = -y;
+   v[k++] = z;
+
+   /* color */
+   v[k++] = -x * 0.5 + 0.5;
+   v[k++] = -y * 0.5 + 0.5;
+   v[k++] = -z * 0.5 + 0.5;
+   /* vert */
+   v[k++] = -x;
+   v[k++] = -y;
+   v[k++] = -z;
+
+   /* color */
+   v[k++] = x * 0.5 + 0.5;
+   v[k++] = y * 0.5 + 0.5;
+   v[k++] = -z * 0.5 + 0.5;
+   /* vert */
+   v[k++] = x;
+   v[k++] = y;
+   v[k++] = -z;
+}
+
+static void
+gen_quads(GLfloat *buf)
+{
+   float *v = buf;
+   float r = 1.0;
+   int i;
+
+   for (i = 0; i < NUM_QUADS; i++) {
+      float angle = i / (float) NUM_QUADS * M_PI;
+      float x = r * cos(angle);
+      float y = r * sin(angle);
+      float z = 1.10;
+      quad(x, y, z, v);
+      v += 24;
+   }
+
+   if (0) {
+      float *p = buf;
+      for (i = 0; i < NUM_QUADS * 4 * 2; i++) {
+         printf("%d: %f %f %f\n", i, p[0], p[1], p[2]);
+         p += 3;
+      }
+   }
+}
+
+
+static void
+Init(void)
+{
+   int bytes = NUM_QUADS * 4 * 2 * 3 * sizeof(float);
+   GLfloat *f;
+
+#if 1
+   glGenBuffers(1, &Vbuffer);
+   glBindBuffer(GL_ARRAY_BUFFER, Vbuffer);
+   glBufferData(GL_ARRAY_BUFFER_ARB, bytes, NULL, GL_STATIC_DRAW_ARB);
+   f = (float *) glMapBuffer(GL_ARRAY_BUFFER_ARB, GL_WRITE_ONLY_ARB);
+   gen_quads(f);
+   glUnmapBuffer(GL_ARRAY_BUFFER_ARB);
+   glColorPointer(3, GL_FLOAT, 6*sizeof(float), (void *) 0);
+   glVertexPointer(3, GL_FLOAT, 6*sizeof(float), (void *) 12);
+#else
+   f = buf;
+   gen_quads(f);
+   glColorPointer(3, GL_FLOAT, 6*sizeof(float), buf);
+   glVertexPointer(3, GL_FLOAT, 6*sizeof(float), buf + 3);
+#endif
+
+   glEnableClientState(GL_COLOR_ARRAY);
+   glEnableClientState(GL_VERTEX_ARRAY);
+
+   glEnable(GL_DEPTH_TEST);
+
+   glClearColor(0.5, 0.5, 0.5, 0.0);
+}
+
+
+int
+main(int argc, char *argv[])
+{
+   glutInit(&argc, argv);
+   glutInitWindowPosition(0, 0);
+   glutInitWindowSize(600, 600);
+   glutInitDisplayMode(GLUT_RGB | GLUT_DOUBLE | GLUT_DEPTH);
+   Win = glutCreateWindow(argv[0]);
+   glutReshapeFunc(Reshape);
+   glutKeyboardFunc(Key);
+   glutSpecialFunc(SpecialKey);
+   glutDisplayFunc(Draw);
+   if (Anim)
+      glutIdleFunc(Idle);
+   Init();
+   glutMainLoop();
+   return 0;
+}