1 files changed, 192 insertions, 0 deletions
diff --git a/progs/tests/zdrawpix.c b/progs/tests/zdrawpix.c
new file mode 100644
index 0000000000..dd222e7dd0
--- /dev/null
+++ b/progs/tests/zdrawpix.c
@@ -0,0 +1,192 @@
+/**
+ * Test glDrawPixels(GL_DEPTH_COMPONENT)
+ *
+ * We load a window-sized buffer of Z values so that Z=1 at the top and
+ * Z=0 at the bottom (and interpolate between).
+ * We draw that image into the Z buffer, then draw an ordinary cube.
+ * The bottom part of the cube should be "clipped" where the cube fails
+ * the Z test.
+ *
+ * Press 'd' to view the Z buffer as a grayscale image.
+ */
+
+#define GL_GLEXT_PROTOTYPES
+#include <stdio.h>
+#include <stdlib.h>
+#include <math.h>
+#include <GL/glut.h>
+#include "../util/showbuffer.c"
+
+
+static int Win;
+static GLfloat Xrot = 50, Yrot = 40, Zpos = 6;
+static GLboolean Anim = GL_FALSE;
+
+static int Width = 200, Height = 200;
+static GLfloat *z;
+static GLboolean showZ = 0;
+
+
+static void
+Idle(void)
+{
+   Xrot += 3.0;
+   Yrot += 4.0;
+   glutPostRedisplay();
+}
+
+
+static void
+Draw(void)
+{
+   glClearColor(0, 0, 0.5, 0);
+   glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
+
+#if 1
+   glColor3f(1, 0, 0);
+   glWindowPos2i(0,0);
+   glColorMask(0,0,0,0);
+   glDrawPixels(Width, Height, GL_DEPTH_COMPONENT, GL_FLOAT, z);
+#elif 0
+   glPushMatrix();
+   glTranslatef(-0.75, 0, Zpos);
+   glutSolidSphere(1.0, 20, 10);
+   glPopMatrix();
+#endif
+   glColorMask(1,1,1,1);
+
+   /* draw cube */
+   glPushMatrix();
+   glTranslatef(0, 0, Zpos);
+   glRotatef(Xrot, 1, 0, 0);
+   glRotatef(Yrot, 0, 1, 0);
+   glutSolidCube(2.0);
+   glPopMatrix();
+
+#if 0
+   /* drawpixels after cube */
+   glColor3f(1, 0, 0);
+   glWindowPos2i(0,0);
+   //glColorMask(0,0,0,0);
+   glDrawPixels(Width, Height, GL_DEPTH_COMPONENT, GL_FLOAT, z);
+#endif
+
+   if (showZ) {
+      ShowDepthBuffer(Width, Height, 0.0, 1.0);
+   }
+
+   glutSwapBuffers();
+}
+
+
+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, 30.0);
+   glMatrixMode(GL_MODELVIEW);
+   glLoadIdentity();
+   glTranslatef(0.0, 0.0, -15.0);
+
+   Width = width;
+   Height = height;
+
+   z = (float *) malloc(width * height * 4);
+   {
+      int i, j, k = 0;
+      for (i = 0; i < height; i++) {
+         float zval = (float) i / (height - 1);
+         for (j = 0; j < width; j++) {
+            z[k++] = zval;
+         }
+      }
+   }
+}
+
+
+static void
+Key(unsigned char key, int x, int y)
+{
+   const GLfloat step = 1.0;
+   (void) x;
+   (void) y;
+   switch (key) {
+      case 'a':
+         Anim = !Anim;
+         if (Anim)
+            glutIdleFunc(Idle);
+         else
+            glutIdleFunc(NULL);
+         break;
+      case 'd':
+         showZ = !showZ;
+         break;
+      case 'z':
+         Zpos -= step;
+         break;
+      case 'Z':
+         Zpos += 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
+Init(void)
+{
+   /* setup lighting, etc */
+   glEnable(GL_DEPTH_TEST);
+   glEnable(GL_LIGHTING);
+   glEnable(GL_LIGHT0);
+}
+
+
+int
+main(int argc, char *argv[])
+{
+   glutInit(&argc, argv);
+   glutInitWindowPosition(0, 0);
+   glutInitWindowSize(400, 400);
+   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;
+}